Re: Does session layer protocol use IP address ? [7:28378]
To answer your question. No the session layer does not handle IP addressing. IP addressing is handled at layer 3 of the OSI model. That is why routers are known as a layer 3 device, because they route protocols at this level such as IP or IPX ( Another Layer 3 transport protocol). The session layer is a few steps up on the OSI model, it is layer 5. It handles establishing communications maintaining communications alive and the like. Hope I was of some help Steven M Aiello [EMAIL PROTECTED] (John Nemeth) wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... On May 3, 4:27am, anil wrote: } } -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) } Does that count?? Since this thread seems to have concluded, I won't belabour the point. However, comp-sci is a huge field with many specialities and in many cases, subspecialities. You say that you have a PhD in comp-sci, but you didn't tell us what the topic of your thesis was or anything else about your background. For all we know, you could have studied something human interface design or something else that has nothing to do with networking. So, saying that you have a PhD in comp-sci really doesn't tell us anything. As another example, somebody on one of the other mailing lists I'm on tried to claim that you can do full-duplex with a hub. When people corrected him, he said that he was an Electronics Engineer and that he should know. Electronics Engineering is a very large field, so unless he specifically studied physical networking hardware, he wouldn't know. Anybody that knows anything about networking knows that a hub is a dumb multiport repeater (i.e. not much more then a signal amplifier) and therefore can't support full-duplex connections (for that, you need some smarts). Needless to say, he got thoroughly trounced for his haughty attitude. }-- End of excerpt from anil Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=34287t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
Doing some catching up on your email? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Nisus Sent: Sunday, February 03, 2002 9:00 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] To answer your question. No the session layer does not handle IP addressing. IP addressing is handled at layer 3 of the OSI model. That is why routers are known as a layer 3 device, because they route protocols at this level such as IP or IPX ( Another Layer 3 transport protocol). The session layer is a few steps up on the OSI model, it is layer 5. It handles establishing communications maintaining communications alive and the like. Hope I was of some help Steven M Aiello [EMAIL PROTECTED] (John Nemeth) wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... On May 3, 4:27am, anil wrote: } } -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) } Does that count?? Since this thread seems to have concluded, I won't belabour the point. However, comp-sci is a huge field with many specialities and in many cases, subspecialities. You say that you have a PhD in comp-sci, but you didn't tell us what the topic of your thesis was or anything else about your background. For all we know, you could have studied something human interface design or something else that has nothing to do with networking. So, saying that you have a PhD in comp-sci really doesn't tell us anything. As another example, somebody on one of the other mailing lists I'm on tried to claim that you can do full-duplex with a hub. When people corrected him, he said that he was an Electronics Engineer and that he should know. Electronics Engineering is a very large field, so unless he specifically studied physical networking hardware, he wouldn't know. Anybody that knows anything about networking knows that a hub is a dumb multiport repeater (i.e. not much more then a signal amplifier) and therefore can't support full-duplex connections (for that, you need some smarts). Needless to say, he got thoroughly trounced for his haughty attitude. }-- End of excerpt from anil Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=34291t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
On May 3, 4:27am, anil wrote: } } -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) } Does that count?? Since this thread seems to have concluded, I won't belabour the point. However, comp-sci is a huge field with many specialities and in many cases, subspecialities. You say that you have a PhD in comp-sci, but you didn't tell us what the topic of your thesis was or anything else about your background. For all we know, you could have studied something human interface design or something else that has nothing to do with networking. So, saying that you have a PhD in comp-sci really doesn't tell us anything. As another example, somebody on one of the other mailing lists I'm on tried to claim that you can do full-duplex with a hub. When people corrected him, he said that he was an Electronics Engineer and that he should know. Electronics Engineering is a very large field, so unless he specifically studied physical networking hardware, he wouldn't know. Anybody that knows anything about networking knows that a hub is a dumb multiport repeater (i.e. not much more then a signal amplifier) and therefore can't support full-duplex connections (for that, you need some smarts). Needless to say, he got thoroughly trounced for his haughty attitude. }-- End of excerpt from anil Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28958t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
/ In reference to Anil and regardless of the level of education he claims, his behavior towards some of the group members was unconscionable. He certainly did not learn that type of behavior in Japan. \ Original message Date: Wed, 12 Dec 2001 15:25:28 -0500 From: [EMAIL PROTECTED] (John Nemeth) Subject: RE: Does session layer protocol use IP address ? [7:28378] To: [EMAIL PROTECTED] On May 3, 4:27am, anil wrote: } } -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) } Does that count?? Since this thread seems to have concluded, I won't belabour the point. However, comp-sci is a huge field with many specialities and in many cases, subspecialities. You say that you have a PhD in comp-sci, but you didn't tell us what the topic of your thesis was or anything else about your background. For all we know, you could have studied something human interface design or something else that has nothing to do with networking. So, saying that you have a PhD in comp- sci really doesn't tell us anything. As another example, somebody on one of the other mailing lists I'm on tried to claim that you can do full-duplex with a hub. When people corrected him, he said that he was an Electronics Engineer and that he should know. Electronics Engineering is a very large field, so unless he specifically studied physical networking hardware, he wouldn't know. Anybody that knows anything about networking knows that a hub is a dumb multiport repeater (i.e. not much more then a signal amplifier) and therefore can't support full-duplex connections (for that, you need some smarts). Needless to say, he got thoroughly trounced for his haughty attitude. }-- End of excerpt from anil [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28975t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
He certainly did not learn that type of behavior in Japan. Sore de watashi wa nihon de nani wo benkyou shita ka anata ga shiterru beki desuka? Dou yatte watashi no koto wo handan dekiru no? Sore ijou, minna ni shiraseru..! Shinjirarenai. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Wednesday, December 12, 2001 9:59 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] / In reference to Anil and regardless of the level of education he claims, his behavior towards some of the group members was unconscionable. He certainly did not learn that type of behavior in Japan. \ Original message Date: Wed, 12 Dec 2001 15:25:28 -0500 From: [EMAIL PROTECTED] (John Nemeth) Subject: RE: Does session layer protocol use IP address ? [7:28378] To: [EMAIL PROTECTED] On May 3, 4:27am, anil wrote: } } -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) } Does that count?? Since this thread seems to have concluded, I won't belabour the point. However, comp-sci is a huge field with many specialities and in many cases, subspecialities. You say that you have a PhD in comp-sci, but you didn't tell us what the topic of your thesis was or anything else about your background. For all we know, you could have studied something human interface design or something else that has nothing to do with networking. So, saying that you have a PhD in comp- sci really doesn't tell us anything. As another example, somebody on one of the other mailing lists I'm on tried to claim that you can do full-duplex with a hub. When people corrected him, he said that he was an Electronics Engineer and that he should know. Electronics Engineering is a very large field, so unless he specifically studied physical networking hardware, he wouldn't know. Anybody that knows anything about networking knows that a hub is a dumb multiport repeater (i.e. not much more then a signal amplifier) and therefore can't support full-duplex connections (for that, you need some smarts). Needless to say, he got thoroughly trounced for his haughty attitude. }-- End of excerpt from anil [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=29012t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
Please stop sending messages about this topic (or any other topic) until you have done some real research. I had no idea you were the moderator of this group. My sincere apologies -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Sunday, December 09, 2001 7:05 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB
RE: Does session layer protocol use IP address ? [7:28378]
What's your point? This is total crap coming from a self proclaimed moderator. The session layer is an elusive beast that is not implemented much That is my point. - until you have done some real research -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) Does that count?? -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 2:14 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] Please stop sending messages about this topic (or any other topic) until you have done some real research. I had no idea you were the moderator of this group. My sincere apologies -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Sunday, December 09, 2001 7:05 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However
RE: Does session layer protocol use IP address ? [7:28378]
Anil, First, let me say I _am_ one of Paul's moderators. Moderation, on this list, works on an exception basis -- certain key phrases and names put things into a queue for moderator review before they post. People that don't play nicely with others have been known to join those filters. A friendly reminder. I'm not saying don't post, but use some discretion. Now, speaking for myself rather than Paul, let me respond a bit to your concern. As a PhD, you presumably know the differences between primary and secondary research sources. Primary sources were directly involved in the development or experiment in question, while secondary sources are paraphrasing and commenting on primary sources. I believe I have some reasonable credentials as a primary source on OSI, and, for that matter, current IETF work. In the OSI context, I was involved, through the US Federal Telecommunications Standards Committee, with the ANSI Distributed Systems (DISY) project, which was a significant starting point for the CCITT/ISO work (1976-1979). After that, I was the network management architect for GTE Telenet (1980-81) and still worked with standards groups. Subsequently, I was the first member of the technical staff for the Corporation for Open Systems (1986-1991), an international consortium for OSI/ISDN conformance testing and general development.My duties included staff liaison to the Architecture Committee (including all major vendors), test system development manager for FTAM (which does include the OSI session protocol and service), CMIP, and X.25, programmed protocol code on a number of other protocol test systems, and one of the primary external representatives for COS (including lecturing on OSI testing in Tokyo). I was also involved with harmonizing architecture between the ISO and IEEE 802 efforts. Without getting into irrelevant detail, I've been participating in IETF meetings since 1994, am the author or coauthor of three RFCs, and a coauthor of five active Internet Drafts. With respect to TCP/IP interoperability, and the TCP/IP interoperability workshops that became Interop, been there, got the T-shirt, although it doesn't fit all that well anymore...I prefer to think I've gained more knowledge than weight since the 2nd such conference. In other words, I think I can say legitimately that I have primary experience with the Internet protocol development process and the role of the OSI (and other) models in it. I've worked with Priscilla for eight years or so, during part of which time she was a Cisco employee and course developer, and I was a Cisco contractor with involvement in course development. I think we can also claim a fair bit of direct experience with how Cisco does things. Without trying to get into the middle of either you or Priscilla are phrasing your comments, I will make the observation that more than one person on the list has some pretty direct experience with the technologies and their primary specifications. Arguing they are wrong because a secondary source written for beginners says something different is, to put it gently, perhaps ill-advised. What's your point? This is total crap coming from a self proclaimed moderator. The session layer is an elusive beast that is not implemented much That is my point. - until you have done some real research -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) Does that count?? -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 2:14 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] Please stop sending messages about this topic (or any other topic) until you have done some real research. I had no idea you were the moderator of this group. My sincere apologies -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Sunday, December 09, 2001 7:05 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications
RE: Does session layer protocol use IP address ? [7:28378]
I don't agree that the other guy did any real research The other guy is called Anil You could not even be bothered to do the resrarch to check the name.. Getting sloppy in your old age miss (must be a girl). Suggest you kindly *drop dead* before making personal attacks on my credentials/ability to do research. Thanks -Anil PS Ever heard the saying Don't shoot the messenger. ?? Hurts when people attack you doesn't it..suggest you stop. An apology would be a small miracle. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28848t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
This group sure is a great way to make friends, aint it. Tend to get intimate real quick. Caps off, coats off and gloves off...here we go :-) Just my type... -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 4:38 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] I don't agree that the other guy did any real research The other guy is called Anil You could not even be bothered to do the resrarch to check the name.. Getting sloppy in your old age miss (must be a girl). Suggest you kindly *drop dead* before making personal attacks on my credentials/ability to do research. Thanks -Anil PS Ever heard the saying Don't shoot the messenger. ?? Hurts when people attack you doesn't it..suggest you stop. An apology would be a small miracle. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28849t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
until you have done some real research -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) Does that count?? - Priscilla Just in case you were wondering, that was a rhetorical question. Which means I do *not expect* a reply from your ego-centric highness. Suggest you look up rhetorical when you grow up. It is rather a long word. Thanks -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 2:54 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] What's your point? This is total crap coming from a self proclaimed moderator. The session layer is an elusive beast that is not implemented much That is my point. - until you have done some real research -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) Does that count?? -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 2:14 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] Please stop sending messages about this topic (or any other topic) until you have done some real research. I had no idea you were the moderator of this group. My sincere apologies -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Sunday, December 09, 2001 7:05 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer
RE: Does session layer protocol use IP address ? [7:28378]
Miss Priscilla The session layer is an elusive beast that is not implemented much Yes, well the level of research that went into your statement matches the intelligence of a newt, doesn't it? If you had a brain cell it would die of loneliness. -Anil PS fun isn't it, attacking someone's intelligence in public. Strongly suggest you apologise to protect yourself against further remiss. -- I don't agree that the other guy did any real research The other guy is called Anil You could not even be bothered to do the resrarch to check the name.. Getting sloppy in your old age miss (must be a girl). Suggest you kindly *drop dead* before making personal attacks on my credentials/ability to do research. Thanks -Anil PS Ever heard the saying Don't shoot the messenger. ?? Hurts when people attack you doesn't it..suggest you stop. An apology would be a small miracle. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28855t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
The session layer is an elusive beast The only elusive beast around here is a public apology. Looking forward to it. -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 5:12 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] until you have done some real research -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) Does that count?? - Priscilla Just in case you were wondering, that was a rhetorical question. Which means I do *not expect* a reply from your ego-centric highness. Suggest you look up rhetorical when you grow up. It is rather a long word. Thanks -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 2:54 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] What's your point? This is total crap coming from a self proclaimed moderator. The session layer is an elusive beast that is not implemented much That is my point. - until you have done some real research -Anil (PhD [Comp-Sci Tokyo Inst of Technology]- Sister School of MIT) Does that count?? -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Tuesday, December 11, 2001 2:14 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] Please stop sending messages about this topic (or any other topic) until you have done some real research. I had no idea you were the moderator of this group. My sincere apologies -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Sunday, December 09, 2001 7:05 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM
RE: Does session layer protocol use IP address ? [7:28378]
Good to see that poor behavior is visited with goodness and wholesome encouragment. My name is Joshua and I am new to this board. Looking to learn all that can be taught! -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of anil Sent: Tuesday, December 11, 2001 12:23 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] Miss Priscilla The session layer is an elusive beast that is not implemented much Yes, well the level of research that went into your statement matches the intelligence of a newt, doesn't it? If you had a brain cell it would die of loneliness. -Anil PS fun isn't it, attacking someone's intelligence in public. Strongly suggest you apologise to protect yourself against further remiss. -- I don't agree that the other guy did any real research The other guy is called Anil You could not even be bothered to do the resrarch to check the name.. Getting sloppy in your old age miss (must be a girl). Suggest you kindly *drop dead* before making personal attacks on my credentials/ability to do research. Thanks -Anil PS Ever heard the saying Don't shoot the messenger. ?? Hurts when people attack you doesn't it..suggest you stop. An apology would be a small miracle. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28871t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
Priscilla I have a lot to learn from you (and others), and I mean that in all honesty. Thank you for being so patient and understanding. It's good to see the real you again. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Tuesday, December 11, 2001 8:00 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] At 09:11 AM 12/11/01, anil wrote: Please stop sending messages about this topic (or any other topic) until you have done some real research. I'm sorry I was so hard on you. You're right that I don't have a right to tell you what to send. You irritated me because you kept sending links to wrong info and I misunderstood your motive for doing that. I gave more thought to NFS and the issue of wrong info everywhere. I stick to my guns that you have to dig deeper sometimes and investigate the messages that the protocol sends, the services it offers, the services below it that it uses, what problem the creators of the protocol were trying to solve, etc. Knowing (or investigating) some history helps. Sun developed NFS as part of their Open Network Computing platform in the late 1980s. The OSI model was already being used for what it's good for. NFS was designed to be an application-layer protocol that ran above a session-layer protocol and uses XDR at the presentation layer. This is not a good one to turn into an arguable issue. It's straight forward. Because it's a Sun protocol, I wasn't really sure if there was an RFC, but there does seem to be one, RFC 1094. I found it by searching on NFS RFC in Google. It was the first hit. Regarding the existence of session-layer protocols, there really are very few in the IP world. RPC is one. NetBIOS is one. AppleTalk has the AppleTalk Session Protocol (ASP), but when Apple Filing Protocol (AFP) runs above TCP, the session layer disappears. There is something called Data Stream Identifier (DSI) between AFP and TCP, but it doesn't do much. OSI did a good job of defining the session layer. Believe it or not, Cisco Network Academy materials describe it reasonably well and cover two-way alternating and two-way simultaneous relationships, etc. But then they categorized the wrong protocols as being session-layer protocols. OSI's definitions for the session layer are just academic these days. Even the protocols I mentioned, such as NetBIOS, etc. don't behave the way OSI said would!? ;-) Priscilla I had no idea you were the moderator of this group. My sincere apologies -Anil Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=13t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Sunday, December 09, 2001 7:05 PM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] ... This list is for people studying for advanced Cisco certifications. ^^ Could have fooled me ... by the knowledge level of some of the enquires on this list ... I have no Cisco certifications but I'll be damned if I don't know a lot more than a lot of you certified ones ... remember people, the paper means nothing if the knowledge isn't there to back it up ... Hugo Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28869t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Does session layer protocol use IP address ? [7:28378]
I was told that there are 7 layers in the OSI model (from a guy who worked on this stuff back in the early 80's) only because IBM's protocol had 7 layers at the time, and OSI had 6. They added the session-layer to make it seem like a viable model. True story. :) Steve Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28697t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
you sure? well, OK, I actually braved my garage and dug out my old text Business Telecommunications by Sanford Rowe. This is the one that hooked me into networking as opposed to PC support 15 years ago. I vaguely recalled SNA as being nine layers, but I must have confused that with the nine bits in an EBCDIC character. In any case, there it is - OSI and SNA side by side. Wow it's been a while. Interesting the way the two organizations pictured how data communications works. Wonder if Howard has any comment as to the relative merits of either perception? Another aside, and it has been a very long while since I read this, so I can't validate either its accuracy or my memory, but at one time the largest seller of OSI compliant gear in the world was IBM. Probably due to their selling into the US Govt GOSIP market. Tanks for the memories. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Monday, December 10, 2001 8:56 AM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] I was told that there are 7 layers in the OSI model (from a guy who worked on this stuff back in the early 80's) only because IBM's protocol had 7 layers at the time, and OSI had 6. They added the session-layer to make it seem like a viable model. True story. :) Steve Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28738t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
Thank-you for your intelligent comments. See, you did some research (or knew NFS already). I don't agree that the other guy did any real research. I would also disagree with you about file synchronization. It is an application-layer function. The session layer doesn't know what a file is. The materials that you see that assign NFS to the wrong layer are just copy and paste errors. It just takes common sense to see that. A lot of the course developers at Cisco were not very technical. They didn't understand layering, protocol analysis, etc., and had probably never heard of RPC. For a while the Cisco training department hired education majors instead of engineers or network administrators. That's why you see so much effort put into the Objectives slides and so many mistakes when you get into the meat. ;-) While I respect the Packet magazine, it's important to realize it's a marketing magazine. Also, the author of this particular article has a CCNA and CCDA. So, we know what sources he used. (the wrong ones) If you want to read a good (academic and engineering-focused) magazine from Cisco, try the Internet Protocol Journal. They wouldn't make such a mistake (hopefully!?) ;-) Peace, Priscilla At 04:59 PM 12/9/01, Carroll Kong wrote: Priscilla, I think you are being a bit too hard on the guy. He tried to do some real research, he is referencing other written material. I did some quick research and I am finding some information is clashing about it. I think sometimes it is hard to make the differentiate between the layers for certain constructs. I think perhaps, WHY NFS is so often put in the Session Layer is because it uses RPC. Also, NFS does do synchronization of files, which can be heavily argued as a Session Layer characteristic. I would say RPC definitely is in the Session Layer. NFS does synchronization, (remember the ancient days of keeping file consistency with UDP?) but looks like it might be at the application layer. I suppose that is where the confusion is. And since NFS definitely uses RPC, and there can only be ONE, perhaps NFS is truly just at the application layer. You could argue that it mountd that really allows remote mounting and nfsd just does synchronization. I think it is somewhat debatable and reasonable for him to think otherwise if so many other references point it to the wrong direction. I am interested in any reference, as that is how we make sure we did not mislearn something. At 02:04 PM 12/9/01 -0500, Priscilla Oppenheimer wrote: At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast
RE: Does session layer protocol use IP address ? [7:28378]
Carroll Kong wrote, That is one of the sentences I wrote. You seemed to have missed that one. Although I suppose I was not as clear. Sorry. I agree with what you said or at least speculated that yes, there can only be ONE component of the particular layer. Which would imply that NFS is indeed at the application layer since it uses RPC which RPC itself is in the Session layer. NFS itself has synchronization issues which some have considered to be a Session Layer characteristic. I never said once that the USE of RPC means that it should be in the session layer. I did mention that the fact that NFS has synchronization primitives, which is considered a characteristic of the Session layer. From a formal OSI perspective, the synchronization primitives in the Session _service_ deal first with establishing the two-way alternating/two-way simultaneous relationship of the application stream of records, the delimiting of records, and the ability to checkpoint records or, in some cases, groups of records. The session service, however, does not contain the abstraction of a file. File synchronization would be an application service, typically in a transaction processing protocol with commitment features. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28780t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Does session layer protocol use IP address ? [7:28378]
At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? According to some experts, the address is the message. See this RFC: http://www.wildpackets.com/elements/rfcs/RFC1776.TXT Priscilla Do note the date of this RFC. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28782t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
keep in mind that OSI is a reference model, and may or may not have anything to do with the way things really work. if I am using my word processor, and want to open a file located Out There, I perform a couple of actions, each of which triggers subroutines in the word processor, which in turn passes calls to the OS which in turn performs certain actions, including interfacing with network hardware. For purposes of discussion one might say that things are being passed up and down the OSI layers, but practically speaking, all that is happening is that bits are being pushed and pulled out of processor registers. In terms of OSI, layer 4 is responsible for the call setup and maintaining end to end communication. I have yet to figure out what the session layer does. I doubt that even Howard can explain it so it makes sense. In fact, IIRC, Howard once said that the session layer exists because a committee was set up to work on it, and the CCITT of course had to incorporate their work into the model. ( forgive me if I misremember your comment, Howard. It's been a while ) Chuck Reaching back into my non-silicon memory, the original proposals for OSI Transport included an advanced version that did, indeed, have the concept of some record-level integrity. There was, however, an existing CCITT standard (and committee) for, IIRC, Teletext, which had an existing standard for record delimiting, the push function, etc. It was that committee that claimed it had already developed a solution., OSI Transport Protocol, Class 4, the version standardized with the greatest functionality, does NOT have the graceful close (i.e., PUSH) that is in TCP. Graceful close is architecturally an OSI session, not transaction, feature. A reliable transport service ensures delivery of bytes but not records. TCP has _some_ functions associated with OSI Layer 5. At a slightly less serious level, from the days I actively worked with OSI protocols: The Seven Deadly Layers By Howard C. Berkowitz Among the most frequent questions I'm asked in OSI teaching is, Do I need to know what all the layers do? This is especially true of management audiences, who need to know the power centers. (They may not kno what a layer is, but they know there are seven of them and they don't want a single one to go unsupervised.) Over the years, I have found a useful analogy. Educational theory suggests we should start with something that the student knows and build from there. Therefore, I ask management audiences to reflect not on theoretical network architecture, but on sin. Specifically, I ask them to consider the Seven Deadly Sins (Note 0). These sins have definite relevance to the OSI Reference Model. The most popular deadly sins are analogies for the layers most important for non-developers to know about. Audiences think of sins in a fairly consistent way. Approximately 75 percent immediately think of Lust. Lust, clearly, relates directlyto the Physical Layer. It is essential to be aware of the function of the Lust Layer, for that defines how to plug in. (Note 1) Most of the remaining audience split between Avarice and Gluttony. These also are important in OSI. Avarice, or Greed, is often realized as the Bottom Line in business. One is closer to understanding the Tao of OSI when one realizes that it places the Bottom Line (i.e. what OSI does for real user applications programs) on Top. The top of the Avarice Layer is the Service Access Point to the Application, or Avarice, Layer. ([Note 2) Those members of the audience who thought first of Gluttony also have some understanding of OSI. Gluttony deals with establishing a relationship between a mouth entity and a food entity. Network deals with the next course while Transport deals with the end goal of dessert. Users really need to know the functions of Application, Transport/Network (as the distinction blurs here), and Physical. They often also need to know the characteristics of the data link layer. Since Data Link has to deal with collisions, master/slave relationships, etc., it may correspond to the sin of Anger. I tend to associate the sin of Pride with the Presentation Layer, on the grounds that Presentation is rather prideful to think that it justifies its own layer. There is always one in the audience, however, who thinks of Sloth. Sloth is a difficult sin. How does one confess it? Bless me, I have slothed? Forgive me for committing sloth? How can I commit not doing something? Since Sloth is a sin we really have trouble talking about,and involves not doing useful things, it is a relevant analogy to the Session Layer. Both Sloth and Session are needed for theological completeness, but their relevance to the ordinary sinner or the OSI user is fairly limited. [Note 4] If we were to redesign the OSI Reference Model today, its exact number of layers would be controversial, but it would almost certaily not be
RE: Does session layer protocol use IP address ? [7:28378]
you sure? well, OK, I actually braved my garage and dug out my old text Business Telecommunications by Sanford Rowe. This is the one that hooked me into networking as opposed to PC support 15 years ago. I vaguely recalled SNA as being nine layers, but I must have confused that with the nine bits in an EBCDIC character. In any case, there it is - OSI and SNA side by side. Wow it's been a while. Interesting the way the two organizations pictured how data communications works. Wonder if Howard has any comment as to the relative merits of either perception? In my days at the Corporation for Open Systems, I remember both John Aschenbrenner, the lead SNA architect at the time for IBM, and Rick McGee, director of the SNA architecture center, say it was pure coincidence.John also noted that no one in IBM ever came up with a coherent explanation of why there is no Physical Unit Type 3, although the best guess is that at one point it dealt with media. While the number of layers in the original (NOT evolved) models happened to be the same, the architectural principles, especially in management, were quite different. SNA was hierarchical while OSI was peer-to-peer. APPN/APPC was the evolution to an architecture much more like OSI and the Internet suite, but still had to retain legacy compatibility. Another aside, and it has been a very long while since I read this, so I can't validate either its accuracy or my memory, but at one time the largest seller of OSI compliant gear in the world was IBM. Probably due to their selling into the US Govt GOSIP market. I can't say IBM was the largest, but I do remember that IBM had an extensive OSI product line that they refused to sell in the US until GOSIP was passed. They released it in the US a few days later. They were so serious about this policy that they were judged non-responsive when they refused to quote OSI software to to the very visible Corporation for Open Systems, the North American OSI/ISDN consortium. Tanks for the memories. Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Monday, December 10, 2001 8:56 AM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] I was told that there are 7 layers in the OSI model (from a guy who worked on this stuff back in the early 80's) only because IBM's protocol had 7 layers at the time, and OSI had 6. They added the session-layer to make it seem like a viable model. True story. :) Steve Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28785t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Does session layer protocol use IP address ? [7:28378]
http://www.wildpackets.com/elements/rfcs/RFC1776.TXT Do note the date of this RFC. was it 1776, per chance? _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28807t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Does session layer protocol use IP address ? [7:28378]
I hear early april is a popular date for RFCs. It's probably easy to verify, but there's not much sport in that. EA Louie @groupstudy.com on 12/11/2001 12:19:28 AM Please respond to EA Louie Sent by: [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc:(bcc: Kevin Cullimore) Subject: Re: Does session layer protocol use IP address ? [7:28378] http://www.wildpackets.com/elements/rfcs/RFC1776.TXT Do note the date of this RFC. was it 1776, per chance? _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation. Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28810t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses
RE: Does session layer protocol use IP address ? [7:28378]
Priscilla, I think you are being a bit too hard on the guy. He tried to do some real research, he is referencing other written material. I did some quick research and I am finding some information is clashing about it. I think sometimes it is hard to make the differentiate between the layers for certain constructs. I think perhaps, WHY NFS is so often put in the Session Layer is because it uses RPC. Also, NFS does do synchronization of files, which can be heavily argued as a Session Layer characteristic. I would say RPC definitely is in the Session Layer. NFS does synchronization, (remember the ancient days of keeping file consistency with UDP?) but looks like it might be at the application layer. I suppose that is where the confusion is. And since NFS definitely uses RPC, and there can only be ONE, perhaps NFS is truly just at the application layer. You could argue that it mountd that really allows remote mounting and nfsd just does synchronization. I think it is somewhat debatable and reasonable for him to think otherwise if so many other references point it to the wrong direction. I am interested in any reference, as that is how we make sure we did not mislearn something. At 02:04 PM 12/9/01 -0500, Priscilla Oppenheimer wrote: At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's
RE: Does session layer protocol use IP address ? [7:28378]
It's possibly an exercise in bad faith to continually reintroduce written materials that have been explicitly discounted by people who can make a legitimate claim to understand the context they were churned out in. In this case, the cisco materials often don't offer any substantiative reasoning for their arbitrary taxonomical assignents of protocols as far as higher-numbered layers of the osi stack are concerned (providing somewhat of a contrast to their treatment of better-scrutinized layers). I'm a little concerned though, about the following: In sentence 7, you place RPC in the session layer. Two sentences earlier, you cite NFS' use of RPC as a justification for assuming that NFS resides in the session layer. While it might be exactly an example of the discontinuities you cite in your first paragraph, one of the few straightforward parts of the out-of-control agglomeration of ideas assertions that constitute the concept of osi communications protocol layering as it appears in (english) print seemed to be the notion that services maintained at level X+1 use services at layers X, and do not (directly) interact with other X+1 entities. Am I missing something? In either case, some instances where treatments clash are rife with potential insight revelant ambiguities, while others are not. It's not clear that the certification prep treatments of this abstraction belong in the former category (most notably for their unignorably light treatment of upper-layer protocol characteristics), rendering them a dubious justification for a reasonable opportunity to think otherwise. I dread the day when all extant statements about a given topic are accorded equal weight (not least of all because I make statements about given topics and would find it hard to live with such a weighty burden). Carroll Kong @groupstudy.com on 12/09/2001 04:59:49 PM Please respond to Carroll Kong Sent by: [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc:(bcc: Kevin Cullimore) Subject: RE: Does session layer protocol use IP address ? [7:28378] Priscilla, I think you are being a bit too hard on the guy. He tried to do some real research, he is referencing other written material. I did some quick research and I am finding some information is clashing about it. I think sometimes it is hard to make the differentiate between the layers for certain constructs. I think perhaps, WHY NFS is so often put in the Session Layer is because it uses RPC. Also, NFS does do synchronization of files, which can be heavily argued as a Session Layer characteristic. I would say RPC definitely is in the Session Layer. NFS does synchronization, (remember the ancient days of keeping file consistency with UDP?) but looks like it might be at the application layer. I suppose that is where the confusion is. And since NFS definitely uses RPC, and there can only be ONE, perhaps NFS is truly just at the application layer. You could argue that it mountd that really allows remote mounting and nfsd just does synchronization. I think it is somewhat debatable and reasonable for him to think otherwise if so many other references point it to the wrong direction. I am interested in any reference, as that is how we make sure we did not mislearn something. At 02:04 PM 12/9/01 -0500, Priscilla Oppenheimer wrote: At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What are its functions? What do its messages look like? What protocols below it does it rely on? What problems were its creators trying to solve? Please stop sending messages about this topic (or any other topic) until you have done some real research. In your last message you quoted page 9 of a CCNA book. Sorry to burst your bubble, but nobody on this list could care less what it says on page 9 of a CCNA book. This list is for people studying for advanced Cisco certifications. Priscilla -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto
RE: Does session layer protocol use IP address ? [7:28378]
And since NFS definitely uses RPC, and there can only be ONE, perhaps NFS is truly just at the application layer. That is one of the sentences I wrote. You seemed to have missed that one. Although I suppose I was not as clear. Sorry. I agree with what you said or at least speculated that yes, there can only be ONE component of the particular layer. Which would imply that NFS is indeed at the application layer since it uses RPC which RPC itself is in the Session layer. NFS itself has synchronization issues which some have considered to be a Session Layer characteristic. I never said once that the USE of RPC means that it should be in the session layer. I did mention that the fact that NFS has synchronization primitives, which is considered a characteristic of the Session layer. So that is the possible two sides. I did not take a particular side, and perhaps I should work more carefully with nfsd. I do know that the final application uses mountd, which hooks into NFSd. NFSd alone will not let you do a remote mount. Hope that clears things up a bit. This sure seems as debatable as whether or not ARP should be in Layer 3 or Layer 2. At 07:59 PM 12/9/01 -0500, [EMAIL PROTECTED] wrote: It's possibly an exercise in bad faith to continually reintroduce written materials that have been explicitly discounted by people who can make a legitimate claim to understand the context they were churned out in. In this case, the cisco materials often don't offer any substantiative reasoning for their arbitrary taxonomical assignents of protocols as far as higher-numbered layers of the osi stack are concerned (providing somewhat of a contrast to their treatment of better-scrutinized layers). I'm a little concerned though, about the following: In sentence 7, you place RPC in the session layer. Two sentences earlier, you cite NFS' use of RPC as a justification for assuming that NFS resides in the session layer. While it might be exactly an example of the discontinuities you cite in your first paragraph, one of the few straightforward parts of the out-of-control agglomeration of ideas assertions that constitute the concept of osi communications protocol layering as it appears in (english) print seemed to be the notion that services maintained at level X+1 use services at layers X, and do not (directly) interact with other X+1 entities. Am I missing something? In either case, some instances where treatments clash are rife with potential insight revelant ambiguities, while others are not. It's not clear that the certification prep treatments of this abstraction belong in the former category (most notably for their unignorably light treatment of upper-layer protocol characteristics), rendering them a dubious justification for a reasonable opportunity to think otherwise. I dread the day when all extant statements about a given topic are accorded equal weight (not least of all because I make statements about given topics and would find it hard to live with such a weighty burden). Carroll Kong @groupstudy.com on 12/09/2001 04:59:49 PM Please respond to Carroll Kong Sent by: [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc:(bcc: Kevin Cullimore) Subject: RE: Does session layer protocol use IP address ? [7:28378] Priscilla, I think you are being a bit too hard on the guy. He tried to do some real research, he is referencing other written material. I did some quick research and I am finding some information is clashing about it. I think sometimes it is hard to make the differentiate between the layers for certain constructs. I think perhaps, WHY NFS is so often put in the Session Layer is because it uses RPC. Also, NFS does do synchronization of files, which can be heavily argued as a Session Layer characteristic. I would say RPC definitely is in the Session Layer. NFS does synchronization, (remember the ancient days of keeping file consistency with UDP?) but looks like it might be at the application layer. I suppose that is where the confusion is. And since NFS definitely uses RPC, and there can only be ONE, perhaps NFS is truly just at the application layer. You could argue that it mountd that really allows remote mounting and nfsd just does synchronization. I think it is somewhat debatable and reasonable for him to think otherwise if so many other references point it to the wrong direction. I am interested in any reference, as that is how we make sure we did not mislearn something. At 02:04 PM 12/9/01 -0500, Priscilla Oppenheimer wrote: At 06:18 PM 12/8/01, anil wrote: This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) Not out of date. Just wrong. You can keep coming up with wrong material. What's your point? Have you looked at NFS with a Sniffer? Have you read a Unix man page? Have you checked some RFCs? Have you considered what NFS does? What
RE: Does session layer protocol use IP address ? [7:28378]
Thanks for the clarification. The two sets of beliefs appeared to be in conflict; I was focusing on the seemingly untenable one. Since I was parsing top down, it wasn't necessarily clear what your position was. However, you therefore appear to be reasoning through the issue of matching individual protocols to appropriate OSI communications protocol layers. In the post you were directly addressing the objection was not to incessant re-introduction of (some of these) sources into the dialog because they provided conflicting information, but because they arbitrarily associated these apparently pairs without any apparent effort at thinking through why those associations might be true. Sorry about qualifying my statements about the truth or falsehood of a given association, but i'm only at RFC 819, and it's going to take a long, long time before i get to peruse the ISO OSI documentation make even a bad guess (I'm really hoping that they're free by then). Carroll Kong @groupstudy.com on 12/09/2001 10:15:46 PM Please respond to Carroll Kong Sent by: [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc:(bcc: Kevin Cullimore) Subject: RE: Does session layer protocol use IP address ? [7:28378] And since NFS definitely uses RPC, and there can only be ONE, perhaps NFS is truly just at the application layer. That is one of the sentences I wrote. You seemed to have missed that one. Although I suppose I was not as clear. Sorry. I agree with what you said or at least speculated that yes, there can only be ONE component of the particular layer. Which would imply that NFS is indeed at the application layer since it uses RPC which RPC itself is in the Session layer. NFS itself has synchronization issues which some have considered to be a Session Layer characteristic. I never said once that the USE of RPC means that it should be in the session layer. I did mention that the fact that NFS has synchronization primitives, which is considered a characteristic of the Session layer. So that is the possible two sides. I did not take a particular side, and perhaps I should work more carefully with nfsd. I do know that the final application uses mountd, which hooks into NFSd. NFSd alone will not let you do a remote mount. Hope that clears things up a bit. This sure seems as debatable as whether or not ARP should be in Layer 3 or Layer 2. At 07:59 PM 12/9/01 -0500, [EMAIL PROTECTED] wrote: It's possibly an exercise in bad faith to continually reintroduce written materials that have been explicitly discounted by people who can make a legitimate claim to understand the context they were churned out in. In this case, the cisco materials often don't offer any substantiative reasoning for their arbitrary taxonomical assignents of protocols as far as higher-numbered layers of the osi stack are concerned (providing somewhat of a contrast to their treatment of better-scrutinized layers). I'm a little concerned though, about the following: In sentence 7, you place RPC in the session layer. Two sentences earlier, you cite NFS' use of RPC as a justification for assuming that NFS resides in the session layer. While it might be exactly an example of the discontinuities you cite in your first paragraph, one of the few straightforward parts of the out-of-control agglomeration of ideas assertions that constitute the concept of osi communications protocol layering as it appears in (english) print seemed to be the notion that services maintained at level X+1 use services at layers X, and do not (directly) interact with other X+1 entities. Am I missing something? In either case, some instances where treatments clash are rife with potential insight revelant ambiguities, while others are not. It's not clear that the certification prep treatments of this abstraction belong in the former category (most notably for their unignorably light treatment of upper-layer protocol characteristics), rendering them a dubious justification for a reasonable opportunity to think otherwise. I dread the day when all extant statements about a given topic are accorded equal weight (not least of all because I make statements about given topics and would find it hard to live with such a weighty burden). Carroll Kong @groupstudy.com on 12/09/2001 04:59:49 PM Please respond to Carroll Kong Sent by: [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc:(bcc: Kevin Cullimore) Subject: RE: Does session layer protocol use IP address ? [7:28378] Priscilla, I think you are being a bit too hard on the guy. He tried to do some real research, he is referencing other written material. I did some quick research and I am finding some information is clashing about it. I think sometimes it is hard to make the differentiate between the layers for certain constructs. I think perhaps, WHY NFS is so often put in the Session Layer is because it uses RPC. Also, NFS does do synchronization of files, which can be heavily argued as a Session
RE: Does session layer protocol use IP address ? [7:28378]
This is from Cisco Oct 2001 Packet.. http://www.cisco.com/warp/public/784/packet/oct01/p76-training.html It must be out of date :-) -Anil 5. Session Layer The session layer provides services in the application to manage inter-host communication. Think of this function as the old-time telephone switchboard operator: first, watching for a light on the switchboard indicating a connection was needed, next connecting and monitoring the call, and then finally disconnecting it by pulling the plug. For example, Network File System (NFS) is like an extended feature Telnet program for UNIX that keeps a connection (session) alive and available until the terminate command is given. Other examples include Structured Query Language (SQL), Remote Procedure Call (RPC), and X-Windows. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Saturday, December 08, 2001 3:13 AM To: [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses at the transport layer. Anyway, back to the question. The statement is at best over-simplified. I recommend you get yourself a sniffer and watch what really happens between layers. (Ethereal is free by the way.) Priscilla Thank you for your time. mlh Priscilla Oppenheimer http://www.priscilla.com Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28543t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
Ports and sockets. The session layer only needs to know about a session, no matter where that session is located on the network. The upper layers use ports, for individual application requests, eg FTP port 23, and each FTP session opened up has a unique socket number. So if you have 2 FTP sessions each will have a seperate socket number. The IP and MAC address do not enter the equation here. That is my understanding. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of mlh Sent: Friday, December 07, 2001 8:00 AM To: [EMAIL PROTECTED] Subject: Does session layer protocol use IP address ? [7:28378] Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? Thank you for your time. mlh Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28391t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
keep in mind that OSI is a reference model, and may or may not have anything to do with the way things really work. if I am using my word processor, and want to open a file located Out There, I perform a couple of actions, each of which triggers subroutines in the word processor, which in turn passes calls to the OS which in turn performs certain actions, including interfacing with network hardware. For purposes of discussion one might say that things are being passed up and down the OSI layers, but practically speaking, all that is happening is that bits are being pushed and pulled out of processor registers. In terms of OSI, layer 4 is responsible for the call setup and maintaining end to end communication. I have yet to figure out what the session layer does. I doubt that even Howard can explain it so it makes sense. In fact, IIRC, Howard once said that the session layer exists because a committee was set up to work on it, and the CCITT of course had to incorporate their work into the model. ( forgive me if I misremember your comment, Howard. It's been a while ) Chuck -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of mlh Sent: Friday, December 07, 2001 12:00 AM To: [EMAIL PROTECTED] Subject: Does session layer protocol use IP address ? [7:28378] Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? Thank you for your time. mlh Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28416t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Does session layer protocol use IP address ? [7:28378]
At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses at the transport layer. Anyway, back to the question. The statement is at best over-simplified. I recommend you get yourself a sniffer and watch what really happens between layers. (Ethereal is free by the way.) Priscilla Thank you for your time. mlh Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28465t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Does session layer protocol use IP address ? [7:28378]
At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? According to some experts, the address is the message. See this RFC: http://www.wildpackets.com/elements/rfcs/RFC1776.TXT Priscilla Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28473t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses at the transport layer. Anyway, back to the question. The statement is at best over-simplified. I recommend you get yourself a sniffer and watch what really happens between layers. (Ethereal is free by the way.) Priscilla Thank you for your time. mlh Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28487t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses at the transport layer. Anyway, back to the question. The statement is at best over-simplified. I recommend you get yourself a sniffer and watch what really happens between layers. (Ethereal is free by the way.) Priscilla Thank you for your time. mlh Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28490t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
NFS is not a session-layer protocol. Cisco said it was in some early courseware and the mistake has lived on. The mistake is still in some CCNA and Cisco Networking Academy materials, I think, but it's wrong. NFS is clearly an application-layer protocol. It uses XDR at the presentation layer. It runs above RPC which is a session-layer protocol. RPC runs above UDP, which runs above IP. Here was a perfect chance to show an actual 7-layer protocol stack and Cisco blew it! ;-) NetBIOS is a session-layer protocol, as I said in the message. Did you read it? SQL does application-layer stuff, like reading from databases. In an Oracle environment, it uses the Transparent Network Substrate (TNS) which has session-layer-like behavior. TNS can run above a variety of protocol stacks, including TCP/IP, IPX, etc. Cisco texts ignore TNS. I think they call SQL a session-layer protocol. Priscilla At 06:15 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses at the transport layer. Anyway, back to the question. The statement is at best over-simplified. I recommend you get yourself a sniffer and watch what really happens between layers. (Ethereal is free by the way.) Priscilla Thank you for your time. mlh Priscilla Oppenheimer http://www.priscilla.com Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28501t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Does session layer protocol use IP address ? [7:28378]
That's 40% right. SQL, NFS, and XWindows are application-layer protocols. RPC and NetBIOS are session-layer protocols. We often have discussions about which books are best. Todd Lammle books can teach you basic router configuration. They are often wrong where protocol behavior is concerned. A better reference for learning about OSI is the OSI paper by Howard Berkowitz at http://www.certificationzone.com. Priscilla At 11:32 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Yes, I checked it out.. Session layer protocols include: SQL, NFS, RPC, NetBios, Xwindows are examples of session layer protocols. Page 9 of CCNA 2nd Edition study guide Todd Lammle -Anil -Original Message- From: anil [mailto:[EMAIL PROTECTED]] Sent: Friday, December 07, 2001 11:17 PM To: Priscilla Oppenheimer; [EMAIL PROTECTED] Subject: RE: Does session layer protocol use IP address ? [7:28378] The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses at the transport layer. Anyway, back to the question. The statement is at best over-simplified. I recommend you get yourself a sniffer and watch what really happens between layers. (Ethereal is free by the way.) Priscilla Thank you for your time. mlh Priscilla Oppenheimer http://www.priscilla.com Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28503t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Does session layer protocol use IP address ? [7:28378]
The Netacad course material now lists NFS as an Application Layer protocol. Prof. Tom Lisa, CCAI Community College of Southern Nevada Cisco Regional Networking Academy Priscilla Oppenheimer wrote: NFS is not a session-layer protocol. Cisco said it was in some early courseware and the mistake has lived on. The mistake is still in some CCNA and Cisco Networking Academy materials, I think, but it's wrong. NFS is clearly an application-layer protocol. It uses XDR at the presentation layer. It runs above RPC which is a session-layer protocol. RPC runs above UDP, which runs above IP. Here was a perfect chance to show an actual 7-layer protocol stack and Cisco blew it! ;-) NetBIOS is a session-layer protocol, as I said in the message. Did you read it? SQL does application-layer stuff, like reading from databases. In an Oracle environment, it uses the Transparent Network Substrate (TNS) which has session-layer-like behavior. TNS can run above a variety of protocol stacks, including TCP/IP, IPX, etc. Cisco texts ignore TNS. I think they call SQL a session-layer protocol. Priscilla At 06:15 PM 12/7/01, anil wrote: The session layer is an elusive beast that is not implemented much Wait a sec, I thought SQL, NFS and netbios were session layer protocols? Someone please correct me. -Anil -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Priscilla Oppenheimer Sent: Friday, December 07, 2001 9:55 PM To: [EMAIL PROTECTED] Subject: Re: Does session layer protocol use IP address ? [7:28378] At 02:59 AM 12/7/01, mlh wrote: Hi, there, I read Todd Lammle's CCNA2.0 study guide and found this sentence: Remember that none of the upper layers know anything about networking or network addresses. I am wondering if the session layer doesn't use network address, how can it establish a dialogue with other session layer in other host? I would probably disagree with Todd's statement, although it's taken out of context and you haven't given us enough information to say that the statement is definitely wrong. However, try to picture the numerous OSI pictures you have seen. Most of them show horizontal lines between a layer on one host talking to the same layer on another host. So the session layer talks to the session layer on the other host. That's probably what Todd was getting at. However, the pictures also show vertical lines. A layer calls on a layer below to provide services. Each layer offers services to layers above it. The session layer is an elusive beast that is not implemented much. But one example might help. NetBIOS is a session layer. On a Windows client, when you access a Server Message Block (SMB) server, NetBIOS has the job of setting up a session with the server. Before it can do that, however, it must find the address of the server. If it's a modern Windows network, then SMB and NetBIOS are probably running above TCP/IP and UDP/IP. So NetBIOS sends a DNS or WINS query to find the IP address of the named server. It then sets up a NetBIOS session with the server. Actually, first, the client sets up a TCP connection. TCP has port numbers. The client sends to the well-known TCP port for NetBIOS session (139) and use an ephemeral port on its side. These port numbers could be considered addresses at the transport layer. Anyway, back to the question. The statement is at best over-simplified. I recommend you get yourself a sniffer and watch what really happens between layers. (Ethereal is free by the way.) Priscilla Thank you for your time. mlh Priscilla Oppenheimer http://www.priscilla.com Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7i=28510t=28378 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
