At 04:13 PM 5/13/02, Mike Mandulak wrote: >Lammle refers to EIGRP as being a Hybrid of distance-vector and link state.
That's wrong. EIGRP is not link-state in any way. EIGRP calculates a flat routing table that lists networks, distance, and next hop (distance vectors). If the list contains multiple entries for a destination (because there are multiple ways to reach the destination), the entries are sorted by metric and the one with the lowest metric is selected. This is very different than how a link-state protocol functions. A link-state routing protocol creates a mathematical graph that depicts the network. A link-state protocol implements a sophisticated process, called the Dijkstra algorithm, to determine the shortest path to all points in the graph when the nodes and links in the graph are known. Link-state has a specific meaning to computer scientists. You'll find a lot of good stuff about it if you search with Google. A lot of it is not related to routing protocols. EIGRP does have some features that make it different from other distance-vector protocols. Although EIGRP still sends vectors with distance information, the updates are non-periodic, partial, and bounded. Non-periodic means that updates are sent only when a metric changes rather than at regular intervals. Partial means that updates include only routes that have changed, not every entry in the routing table. Bounded means that updates are sent only to affected routers. These behaviors mean that EIGRP uses very little bandwidth. EIGRP also determines a feasible successor, which other distance-vector protocols don't do. Its complex metric is also a feature not found in many other distance-vector algorithms, (except IGRP of course). Please do not send messages to me directly, especially not to quote Lammle CCNA fluff. Priscilla >He only gives a brief mention of EIGRP and says to refer to the CCNP study >guide for more info. > >----- Original Message ----- >From: "Priscilla Oppenheimer" >To: >Sent: Monday, May 13, 2002 3:19 PM >Subject: Re: Is IGRP actually supported by other vendors? [7:43994] > > > > At 02:44 PM 5/13/02, Mike Mandulak wrote: > > >Lamme's CCNA study guide states that the courde and exam only covers > > >distance-vector routing protocols (RIP and IGRP). > > > > If it only covers distance-vector, then it could cover EIGRP also. EIGRP >is > > also distance-vector. I don't think the test does cover it, but it's not > > because the test only covers distance-vector. It's probably because of all > > the extra features in EIGRP, such as the diffusing update algorithm >(DUAL), > > with the feasible successors and all that other BS. Come to think of it, > > maybe I'm glad I don't have to cover it! ;-) > > > > > > >----- Original Message ----- > > >From: "Priscilla Oppenheimer" > > >To: > > >Sent: Monday, May 13, 2002 1:27 PM > > >Subject: Re: Is IGRP actually supported by other vendors? [7:43994] > > > > > > > > > > Well, it occurs to me that IGRP would be easy to implement even >without > > > > Cisco's permission. ;-) It's a simple protocol, for one thing. Also, >the > > > > Rutgers paper that describes IGRP has been out for years. Cisco never > > > > objected to it. > > > > > > > > EIGRP would not be easy to implement without Cisco's blessings, >developer > > > > support, licensed code, etc. We have probably all tried to figure out > > some > > > > detail of EIGRP or other and run into a brick wall. (For example, what > > >does > > > > an router EIGRP really do with the MTU that is passed around in >Updates? > > >;-) > > > > > > > > On a related tangent, will they remove IGRP from CCNA? I'm teaching a > > > > custom CCNA class next month, using my own materials. I find it >annoying > > > > that I have to sort of downgrade my materials to teach IGRP theory and > > > > hands-on instead of the EIGRP I would prefer to teach and is already >in > > my > > > > materials. But I think I'm right that CCNA expects IGRP and not EIGRP? > > > > > > > > Thx > > > > > > > > Priscilla > > > > > > > > At 04:02 AM 5/13/02, nrf wrote: > > > > >In-line > > > > > wrote in message > > > > >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > > > > > Nokia might support it, but I have been (fairly reliably) told >that > > >Cisco > > > > > > will *not* be supporting IGRP as of one of the newest IOS >releases. > > I > > > > > > can't find the announcement on CCO (if there is one), so take with >a > > > > grain > > > > > > of salt, but a Cisco instructor was quite adamant about this last > > >week. > > > > > > > > > >That makes sense, considering it's literally been years since I've > > >actually > > > > >seen a bonafide production network running IGRP. So it makes sense > > that > > > > >Cisco is finally ditching this dead wood. > > > > > > > > > >But I'm not asking this question because I'm champing at the bit to > > >install > > > > >a mixed Cisco/Nokia IGRP network. No, I'm asking because if it's >true > > >that > > > > >Nokia really does support IGRP, then that begs the question - what >other > > > > >supposedly Cisco-proprietary technologies are like this too? I'm not > > > > >talking about situations like what Howard stated where Cisco actually > > has > > >an > > > > >agreement to provide its technology to other vendors (somehow I doubt > > >that > > > > >Cisco and Nokia have such an agreement), but I'm talking about > > >full-blown > > > > >vendor compatibility between some other vendor and Cisco. For >example, > > >does > > > > >anybody know of another vendor that supports, say, EIGRP? Or CDP? >Now > > >you > > > > >might say that it would be impossible for another vendor to support > > these > > > > >technologies, but, hey, Nokia apparently somehow managed to support > > IGRP, > > >so > > > > >why exactly couldn't somebody else support, say, EIGRP? > > > > > > > > > > > > > > > > > JMcL > > > > > > ----- Forwarded by Jenny Mcleod/NSO/CSDA on 13/05/2002 04:44 >pm ----- > > > > > > > > > > > > > > > > > > "nrf" > > > > > > Sent by: [EMAIL PROTECTED] > > > > > > 13/05/2002 01:42 pm > > > > > > Please respond to "nrf" > > > > > > > > > > > > > > > > > > To: [EMAIL PROTECTED] > > > > > > cc: > > > > > > Subject: Is IGRP actually supported by other >vendors? > > > > > > [7:43994] > > > > > > Is this part of a business decision process?: > > > > > > > > > > > > > > > > > > Just found this while surfing around. > > > > > > > > > > > > "As a network device, the Nokia IP330 supports a comprehensive >suite > > >of > > > > > > IP-routing functions and protocols, including RIPv1/RIPv2, IGRP, >OSPF > > >and > > > > > > BGP4 for unicast traffic..." > > > > > > http://www.nokia.com/securitysolutions/platforms/330.html > > > > > > > > > > > > Every piece of literature I've ever read has stated without fail >that > > > > IGRP > > > > > > is proprietary to Cisco. Yet here's Nokia brazenly claiming that > > they > > >in > > > > > > fact support IGRP. What's up with that? Unfortunately I don't >have > > >an > > > > > > Ipso > > > > > > box lying around that I can actually experiment with. Can anyone > > >confirm > > > > > > whether this is true and whether it provides complete > > interoperability > > > > > > with > > > > > > Cisco? > > > > ________________________ > > > > > > > > Priscilla Oppenheimer > > > > http://www.priscilla.com > > ________________________ > > > > Priscilla Oppenheimer > > http://www.priscilla.com ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=44105&t=43994 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
