Someone should dig out that Radia Perlman quote from Interconnections. Something about not knowing anything about protocols if you only study one (i.e. TCP/IP) :)
I would but I don't have the book here. Darn it. ----- Original Message ----- From: "Priscilla Oppenheimer" To: Sent: Monday, July 15, 2002 12:54 PM Subject: RE: CID Exam 3.0 [7:48839] > Dan Penn wrote: > > > > Check out the outline on CCO. As far as I know SNA, IPX, and > > Applecrap, > > I mean I talk, are still there for CID. > > And, sir, why do you call it Applecrap? ;-) Seriously, can you provide some > technical reasons to disparage it? > > Perhaps it's still on Cisco tests because the philosophies behind AppleTalk > had a big impact on modern desktop protocol design. Also, many universities > and schools of all sorts still have large AppleTalk networks. You would be > surprised at how many still use it. It's also still used at scientific and > graphics arts companies. > > Many protocol designers admire the pioneering work that Apple did to make > networks plug and play. There's a new IETF working group called the Zero > Configuration Networking group that credits AppleTalk. See here for more info: > > http://www.zeroconf.org/ > > Note that IPv6 has serverless autonegotiation of network-layer addresses > which behaves quite a bit like AppleTalk. (It probably won't catch on in > many environments which have a DHCP server, but it may catch on in other > environments). And how about Microsoft's automatic addressing. (Of course we > normally only see that when DHCP has failed, but still Microsoft thought > enough of the AppleTalk mechanism to steal it. ;-) > > And how about service location? TCP/IP barely even has service location, > still to this day. Don't you think it's a little silly that we have to find > resources with a search engine? There is hope with new protocols like the > Service Location Protocol (SLP) and some of the new multicast protocols that > let you find multicasting servers. Note that the SLP RFC credits AppleTalk. > > Maybe some "expert" told you that AppleTalk is "chatty." For one thing, any > protocol that tries to automate service location, speed up routing protocol > convergence, and quickly workaround connection disconnects is going to be a > bit chatty. It's a tradeoff. AppleTalk is no more chatty than Windows > Networking or IPX. And you want chatty, how about all those keepalives and > hellos that Cisco routers send? > > Maybe that same "expert" told you to avoid AppleTalk because it broadcasts > too much. That's a myth. It uses multicasts, for one thing, which means a > decent NIC driver that doesn't do AppleTalk shouldn't bother the host. > > The descriptions you see about Chooser behavior are mostly nonsense. The > Chooser doesn't send broadcasts. It sends broadcast requests which are > forwarded (as unicasts) to each router in the zone. Those routers send a > multicast onto their networks in the zone. With good network design, this is > no problem. > > The Chooser doesn't send continually unless the user leaves it open with a > zone and service highlighted, which is almost never the case. Then it does > send rather often, but backs off after 45 seconds. The problem where it sent > the broadcast request packets (which are really unicasts) very often, > without backing off, was fixed in 1989. By then, it was too late. The > criticism of its behavior (even though already based on misinformation) was > entrenched in people's minds. > > Hey, I could go on and on, but I'll stop here, you'll be glad to see. ;-) > > ________________________ > > Priscilla Oppenheimer > http://www.priscilla.com > > > > > > Dan > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On > > Behalf Of > > suaveguru > > Sent: Monday, July 15, 2002 9:53 AM > > To: [EMAIL PROTECTED] > > Subject: CID Exam 3.0 [7:48839] > > > > hi anyone knows what I should emphasize for the CID > > exam ? Should I drop SNA , appletalk? What should I > > concentrate on > > > > > > thanks > > > > suaveguru > > > > __________________________________________________ > > Do You Yahoo!? > > Yahoo! Autos - Get free new car price quotes > > http://autos.yahoo.com Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.377 / Virus Database: 211 - Release Date: 7/15/2002 Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=48854&t=48839 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
