Couple thoughts here Rick. First off, always consider that there may be (and usually are) flaws in secondary source material and thus don't believe everything you read. Beyond that, I have a couple questions related to the matter.
Primarily, what exactly is a hybrid routing protocol? Hybrid is a pretty ambiguous term if you ask me. Additionally, what elements of link state routing are evident in the EIGRP implementation? Simply because a protocol happens to build adjacencies via hello packets does not categorize it as a link state protocol. I'd fully concur with Priscilla's description of the details and Howard B also has written similar on this topic in his Scalable Link State Routing series on www.certificationzone.com. At 06:42 PM 5/13/2002 -0400, Rick wrote: >Priscilla, >I hate to differ with you on this Hybrid or not but the source says >it is considered a Hybrid routing Protocol. check the link for yourself >http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/en_igrp.htm > >I myself am not a fan Lammle, but on this one he is right and you are wrong >and YES I said you are wrong! EIGRP is as much Link-State as it is Distance >Vector. >Rick > >""Priscilla Oppenheimer"" wrote in message >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > 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 >he > > 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=44140&t=43994 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
