Re: Comcast Ethernet Feed
On Thu, Mar 29, 2012 at 10:07 PM, Nathan Anderson nath...@fsr.com wrote: On Thursday, March 29, 2012 7:03 PM, Brian R. Watters mailto:brwatt...@absfoc.com wrote: [snip] Fast Ether has always been set @ auto Just in case you missed it, I would echo Brielle's earlier advice: please try forcing both laptop and the FE it's plugged into to 100/Full, auto disabled, and try your tests again. I feel like this thread has developed an unhealthy fixation with the GE - Comcast segment when it's just as likely that it's working perfectly fine and the problem is between Laptop - FE. :-) For whatever reason, I have historically had very bad luck/experience with 7200 FE interfaces and auto-negotiation, FWIW. Ditto! Plug laptop_2 into one of the FE ports and see if you get good speeds between the laptops. On the 7200, show interface for each of the FE ports, compare to what the laptops think it has. Our 7200's have FE ports that have to be hard coded to get full duplex. (We no longer have that issue since almost all 7200's have only GigE ports, we only have one 7204 with a FE port and it's the only one that's hard coded to duplex full). ...Todd -- Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live. -- Martin Golding
Re: Comcast Ethernet Feed
What does Comcast do if you exceed 20 meg? We were told by ATT that anything over the specified limit would be dropped, so we use rate limiting...not sure if Comcast does the same. Cody - Original Message - From: Brian R. Watters brwatt...@absfoc.com To: NANOG list nanog@nanog.org Sent: Thursday, March 29, 2012 5:36:43 PM Subject: Comcast Ethernet Feed We are about to accept a 20MEG Ethernet feed via Comcast and their fiber plant as well as a BGP feed across the same link. I have a space GIGE interface on a 7206VXR and would like to know best practice for deploying for optimal performance across this interface. Any ideas and or direction would be extremely helpful as we are seeing some real issues such as. Direct connect (without BGP) to the CPE from Comcast (Fiber to Ethernet) via a laptop gives the level of performance we would expect, However as soon as we terminate to our router via the GIGE which is set to 100MB full duplex and all flow control turned off (Negotiation auto) per Comcast and connect up via a 100MB fast Ethernet interface directly connected we get a fraction of the speed when direct connected. Ideas? BRW Notice to Recipient: Information contained in this message may be privileged, confidential and protected from disclosure. If you are not an intended recipient, it is strictly prohibited to use, disseminate or copy this communication. If you have received this in error, please reply to the sender and then delete the message.Thank you.
Re: Comcast Ethernet Feed
On 3/29/12 6:36 PM, Brian R. Watters wrote: We are about to accept a 20MEG Ethernet feed via Comcast and their fiber plant as well as a BGP feed across the same link. I have a space GIGE interface on a 7206VXR and would like to know best practice for deploying for optimal performance across this interface. Any ideas and or direction would be extremely helpful as we are seeing some real issues such as. Direct connect (without BGP) to the CPE from Comcast (Fiber to Ethernet) via a laptop gives the level of performance we would expect, However as soon as we terminate to our router via the GIGE which is set to 100MB full duplex and all flow control turned off (Negotiation auto) per Comcast and connect up via a 100MB fast Ethernet interface directly connected we get a fraction of the speed when direct connected. From my own experience here with our 7200s, some of the PA based 100BaseT interfaces (ie: not on the IO module) can not negotiate 100-full, but rather only half. This leaves one end diff then the other and creates issues with performance. Try forcing both the laptop and router to 100-full and see if it helps. -- Brielle Bruns The Summit Open Source Development Group http://www.sosdg.org/ http://www.ahbl.org
Re: Comcast Ethernet Feed
On Thu, 29 Mar 2012, Brielle Bruns wrote: From my own experience here with our 7200s, some of the PA based 100BaseT interfaces (ie: not on the IO module) can not negotiate 100-full, but rather only half. This leaves one end diff then the other and creates issues with performance. Try forcing both the laptop and router to 100-full and see if it helps. Those interfaces don't to auto-negotiation at all. That's why they default to 100 half. OP said they were using a Gig interface though. Maybe a copper 10/100/1000 port on an NPE-G1|2? I haven't used those, but I'd bet they support auto-negotiation. 1000baseT requires it. It'd be helpful to know how they've tested through the router, and if there are other connections routed through that VXR that are working at the expected rates. -- Jon Lewis, MCP :) | I route Senior Network Engineer | therefore you are Atlantic Net| _ http://www.lewis.org/~jlewis/pgp for PGP public key_
Re: Comcast Ethernet Feed
On 3/29/12 7:06 PM, Brielle Bruns wrote: I'm pretty sure the PA-FE-TX boards can do auto neg, just not 100 full (just tested with a 7507 with a VIP4 w a PA-FE-TX and a cheap 10BT hub - my 7206VXR is not powered up ATM). Eh, just tried again to show someone and the link didn't even come up this time. I'll toss is up to an oddity or me misreading (likely the latter). My mistake. -- Brielle Bruns The Summit Open Source Development Group http://www.sosdg.org/ http://www.ahbl.org
Re: Comcast Ethernet Feed
Your correct with your understanding of our setup, I also note on our NPE-G1 that the onboard GIGE interface will auto-negotiation and I do see the flow control is not supported via the other side (Comcast) but as soon as I refresh and view the GIG# interface again I note that flow control is turned back on and no negotiation auto is back on the interface cfg ?, this is certainly part of the issue .. is their a way to disable flow control on the onboard GIGE ? .. as stated Comcast does not want flow control on. Yes there are other ports on this router that perform without issue and as designed both other GIGE interfaces that are VLAN'ed and Serial interfaces that are both DS3 and a PA-4T bonded to 6MEG's. the GIGE cfg is as follows interface GigabitEthernet0/1 description Comcast Inet Feed Metro E 20MB bandwidth 10 ip address 12.12.12.12 255.255.255.252 no ip unreachables no ip route-cache load-interval 30 duplex full speed 100 media-type rj45 no negotiation auto no cdp enable We have 2GB of memory on this router with a very light load on the CPU. On 3/29/12 6:53 PM, Jon Lewis wrote: On Thu, 29 Mar 2012, Brielle Bruns wrote: From my own experience here with our 7200s, some of the PA based 100BaseT interfaces (ie: not on the IO module) can not negotiate 100-full, but rather only half. This leaves one end diff then the other and creates issues with performance. Try forcing both the laptop and router to 100-full and see if it helps. Those interfaces don't to auto-negotiation at all. That's why they default to 100 half. OP said they were using a Gig interface though. Maybe a copper 10/100/1000 port on an NPE-G1|2? I haven't used those, but I'd bet they support auto-negotiation. 1000baseT requires it. I'm pretty sure the PA-FE-TX boards can do auto neg, just not 100 full (just tested with a 7507 with a VIP4 w a PA-FE-TX and a cheap 10BT hub - my 7206VXR is not powered up ATM). Believe it has something to do with the DEC ethernet chip they use (I have an older desktop that just happens to have the same DEC chipset that those do and has exactly the same problem). Based on what he said, I read his setup as having a G1 or G2 NPE, using the on-NPE gig to hook to comcast, and a PA-FE-TX in one of the PA slots. At least, that's how it sounded to me - why else use 100BaseT on a gige as most laptops and desktops in the past... 4-5 years or so have onboard gige? -- Brielle Bruns The Summit Open Source Development Group http://www.sosdg.org/ http://www.ahbl.org
Re: Comcast Ethernet Feed
On 3/29/12 7:32 PM, Brian R. Watters wrote: Your correct with your understanding of our setup, I also note on our NPE-G1 that the onboard GIGE interface will auto-negotiation and I do see the flow control is not supported via the other side (Comcast) but as soon as I refresh and view the GIG# interface again I note that flow control is turned back on and no negotiation auto is back on the interface cfg ?, this is certainly part of the issue .. is their a way to disable flow control on the onboard GIGE ? .. as stated Comcast does not want flow control on. Yes there are other ports on this router that perform without issue and as designed both other GIGE interfaces that are VLAN'ed and Serial interfaces that are both DS3 and a PA-4T bonded to 6MEG's. How do you have the PA modules installed? Layout can make a huge difference on those given the bandwidth points system. http://www.cisco.com/en/US/docs/routers/7200/configuration/7200_port_adapter_config_guidelines/3875In.html#wp1061412 -- Brielle Bruns The Summit Open Source Development Group http://www.sosdg.org/ http://www.ahbl.org
Re: Comcast Ethernet Feed
The GIGe is on-board with the NPE-G1 and from what I am told no bandwidth points to deal with .. the PA is in slot 4 with ZERO other traffic on that slot or the port, all other traffic that is of any real size is on the other two GIGE interfaces that are also on-board with the NPE-G1 blade. - Original Message - From: Brielle Bruns br...@2mbit.com To: NANOG list nanog@nanog.org Sent: Thursday, March 29, 2012 6:42:11 PM Subject: Re: Comcast Ethernet Feed On 3/29/12 7:32 PM, Brian R. Watters wrote: Your correct with your understanding of our setup, I also note on our NPE-G1 that the onboard GIGE interface will auto-negotiation and I do see the flow control is not supported via the other side (Comcast) but as soon as I refresh and view the GIG# interface again I note that flow control is turned back on and no negotiation auto is back on the interface cfg ?, this is certainly part of the issue .. is their a way to disable flow control on the onboard GIGE ? .. as stated Comcast does not want flow control on. Yes there are other ports on this router that perform without issue and as designed both other GIGE interfaces that are VLAN'ed and Serial interfaces that are both DS3 and a PA-4T bonded to 6MEG's. How do you have the PA modules installed? Layout can make a huge difference on those given the bandwidth points system. http://www.cisco.com/en/US/docs/routers/7200/configuration/7200_port_adapter_config_guidelines/3875In.html#wp1061412 -- Brielle Bruns The Summit Open Source Development Group http://www.sosdg.org/ http://www.ahbl.org -- Brian R. Watters Director 5718 East Shields Ave ■ Fresno, CA 93727 tel - (559) - 420-0205 ■ fax - (559) - 272-5266 Line website | My LinkedIn | email TwitterFacebookLinkedIn
Re: Comcast Ethernet Feed
--- On Thu, 3/29/12, Brian R. Watters brwatt...@absfoc.com wrote: From: Brian R. Watters brwatt...@absfoc.com Subject: Comcast Ethernet Feed To: NANOG list nanog@nanog.org Date: Thursday, March 29, 2012, 5:36 PM We are about to accept a 20MEG Ethernet feed via Comcast and their fiber plant as well as a BGP feed across the same link. I have a space GIGE interface on a 7206VXR and would like to know best practice for deploying for optimal performance across this interface. Any ideas and or direction would be extremely helpful as we are seeing some real issues such as. Direct connect (without BGP) to the CPE from Comcast (Fiber to Ethernet) via a laptop gives the level of performance we would expect, However as soon as we terminate to our router via the GIGE which is set to 100MB full duplex and all flow control turned off (Negotiation auto) per Comcast and connect up via a 100MB fast Ethernet interface directly connected we get a fraction of the speed when direct connected. Ideas? BRW A couple of questions - 1) What flavor of NPE are you using? 2) Is the GigE interface on the NPE-G1/G2 OR is this a PA? 3) Is the FaE ethernet interface that you appear to be connecting your laptop to, on a separate PA in chassis? 4) Have you verified you that bandwidth-points have not been exceeded for bus-1 and/or 2: slots 1,3,5 for bus1 and 2,4,6; also 0(if I/O controller is present. It is 600 points for bus1 and 600 for bus2. (A sh ver will provice the info) You can google: Cisco 7200 Series Port Adapter Hardware Configuration Guidelines for additional info. Finally, Have you *hard-coded* speed and duplex on any of you eth ints? Please don't! Let both ints auto-negotiate speedduplex. after having done so, post the output of: sh int gi x/y and sh int fa x/y (hardcoding speed/duplex is sometimes required when dealing with brain-dead CPE. I have also seen other flavors of brain-dead CPE that *only* work when speed/duplex are set to auto) ./Randy
Re: Comcast Ethernet Feed
On 30/03/2012, at 12:32 PM, Brian R. Watters wrote: interface GigabitEthernet0/1 description Comcast Inet Feed Metro E 20MB bandwidth 10 ip address 12.12.12.12 255.255.255.252 no ip unreachables no ip route-cache load-interval 30 duplex full speed 100 media-type rj45 no negotiation auto no cdp enable Remove 'no ip route-cache'. This will be forcing all traffic via the slowest path possible.
Re: Comcast Ethernet Feed
A couple of questions - 1) What flavor of NPE are you using? NPE-G1 2) Is the GigE interface on the NPE-G1/G2 OR is this a PA? 3) Is the FaE ethernet interface that you appear to be connecting your laptop to, on a separate PA in chassis? Laptop connected directly to router via slot 4 PA-FE-TX 4) Have you verified you that bandwidth-points have not been exceeded for bus-1 and/or 2: slots 1,3,5 for bus1 and 2,4,6; also 0(if I/O controller is present. It is 600 points for bus1 and 600 for bus2. PCI bus mb1 has 390 bandwidth points PCI bus mb2 has 500 bandwidth points Have you *hard-coded* speed and duplex on any of you eth ints? Please don't! GIGE has been both hard and auto .. same results .. Fast Ether has always been set @ auto Let both ints auto-negotiate speedduplex. Comcast states that we are required to have a hard code FULL DUPLEX and SPEED 100 as well as flow control OFF however I can not appear to be able to disable it :( after having done so, post the output of: sh int gi x/y and sh int fa x/y (hardcoding speed/duplex is sometimes required when dealing with brain-dead CPE. I have also seen other flavors of brain-dead CPE that *only* work when speed/duplex are set to auto) ./Randy
Re: Comcast Ethernet Feed
On Thu, Mar 29, 2012 at 8:02 PM, Brian R. Watters brwatt...@absfoc.com wrote: A couple of questions - 1) What flavor of NPE are you using? NPE-G1 2) Is the GigE interface on the NPE-G1/G2 OR is this a PA? 3) Is the FaE ethernet interface that you appear to be connecting your laptop to, on a separate PA in chassis? Laptop connected directly to router via slot 4 PA-FE-TX 4) Have you verified you that bandwidth-points have not been exceeded for bus-1 and/or 2: slots 1,3,5 for bus1 and 2,4,6; also 0(if I/O controller is present. It is 600 points for bus1 and 600 for bus2. PCI bus mb1 has 390 bandwidth points PCI bus mb2 has 500 bandwidth points Have you *hard-coded* speed and duplex on any of you eth ints? Please don't! GIGE has been both hard and auto .. same results .. Fast Ether has always been set @ auto Let both ints auto-negotiate speedduplex. Comcast states that we are required to have a hard code FULL DUPLEX and SPEED 100 as well as flow control OFF however I can not appear to be able to disable it :( If the Comcast side is hard-coded to 100/Full then you really only have one choice, set your side to 100/Full, as well. For the past decade, Cisco gear completely disables autonegotiation if you hard set the speed and duplex settings. Some equipment still participates in auto even when you hard set it. That's why you occasionally get duplex mismatches even when both sides are hard set. The side that participates in auto will expect to see an autonegotiating link partner. When it doesn't see one, it drops back to half duplex because it assumes it is connected to a hub (This is for Fast Ethernet.) So, if you connect a piece of Cisco gear and it is hard set to 100/full, you'll be fine. If you connect a laptop or some other device with a NIC that still participates in auto even when you hard set the settings, you won't get that to work well.
Re: Comcast Ethernet Feed
Never mind control and what Comcast says about hard-coding speed and duplex! The question is: What happens when you set the int facing Comcast CPE to auto? Does the link even come up? *IF* the link comes up, can you ping your next-hop? If you can, leave auto-neg on despite what what Comcast may say/require. Post a sh int gix/y and sh int fax/y If the above outputs are *clean*, I would say a TAC case is called for. --- On Thu, 3/29/12, Brian R. Watters brwatt...@absfoc.com wrote: From: Brian R. Watters brwatt...@absfoc.com Subject: Re: Comcast Ethernet Feed To: Randy randy_94...@yahoo.com Cc: NANOG list nanog@nanog.org Date: Thursday, March 29, 2012, 7:02 PM A couple of questions - 1) What flavor of NPE are you using? NPE-G1 2) Is the GigE interface on the NPE-G1/G2 OR is this a PA? 3) Is the FaE ethernet interface that you appear to be connecting your laptop to, on a separate PA in chassis? Laptop connected directly to router via slot 4 PA-FE-TX 4) Have you verified you that bandwidth-points have not been exceeded for bus-1 and/or 2: slots 1,3,5 for bus1 and 2,4,6; also 0(if I/O controller is present. It is 600 points for bus1 and 600 for bus2. PCI bus mb1 has 390 bandwidth points PCI bus mb2 has 500 bandwidth points Have you *hard-coded* speed and duplex on any of you eth ints? Please don't! GIGE has been both hard and auto .. same results .. Fast Ether has always been set @ auto Let both ints auto-negotiate speedduplex. Comcast states that we are required to have a hard code FULL DUPLEX and SPEED 100 as well as flow control OFF however I can not appear to be able to disable it :( after having done so, post the output of: sh int gi x/y and sh int fa x/y (hardcoding speed/duplex is sometimes required when dealing with brain-dead CPE. I have also seen other flavors of brain-dead CPE that *only* work when speed/duplex are set to auto) ./Randy
RE: Comcast Ethernet Feed
On Thursday, March 29, 2012 7:03 PM, Brian R. Watters mailto:brwatt...@absfoc.com wrote: [snip] Fast Ether has always been set @ auto Just in case you missed it, I would echo Brielle's earlier advice: please try forcing both laptop and the FE it's plugged into to 100/Full, auto disabled, and try your tests again. I feel like this thread has developed an unhealthy fixation with the GE - Comcast segment when it's just as likely that it's working perfectly fine and the problem is between Laptop - FE. :-) For whatever reason, I have historically had very bad luck/experience with 7200 FE interfaces and auto-negotiation, FWIW. -- Nathan Anderson First Step Internet, LLC nath...@fsr.com
