Doug, The multicast IP for EIGRP is 224.0.0.10. This is within the Multicast Permanent address range which states that 224.0.0.0 - 224.0.0.255 are non routable (so local subnet only). The Multicast Permanent address range also includes 224.0.1.0- 224.0.1.255, which are routable, but this is out of scope of your question.
The TTL set to 1, is a method of multicast TTL scoping to limit packets being routed out of your administrative domain, but I dont think this is the purpose here. B On Wed, Aug 1, 2012 at 2:31 PM, Joe Sanchez <[email protected]> wrote: > Doug,, > > There have been lots of statements about EIGRP that have been misleading at > best. Take a look at the link below and see another discussion about this > topic: > > http://www.groupstudy.com/archives/ccielab/200506/msg00687.html > http://www.mail-archive.com/[email protected]/msg72839.html > https://supportforums.cisco.com/thread/211406 > https://learningnetwork.cisco.com/thread/40817 > > In times like these, I like to refer back to this RFC which sum's it all > up. > > http://tools.ietf.org/rfc/rfc1925.txt > > > Joe Sanchez > > > > On Tue, Jul 31, 2012 at 9:02 PM, <[email protected]> wrote: > > > My understanding of EIGRP multicast packets was that the TTL is set to > > one, and that this is the mechanism that prevents the packet from being > > routed off the local subnet. > > > > However, doing a packet capture reveals that the TTL on EIGRP multicast > > packets is actually 2. Some research hints that the same may be true for > > RIP and OSPF, although I haven't verified. The Wireshark expert note > > refers to RFC 3171, but that RFC doesn't mention TTL. Here is the actual > > text of the note: > > > > "Time To Live" != 1 for a packet sent to the Local Network Control Block > > (see RFC 3171) > > > > So what is the purpose of setting these TTL's to 2? Obviously, they are > > not getting routed off the subnet, so some other mechanism is being used > > to prevent this. > > > > Thanks, > > > > Doug > > _______________________________________________ > > For more information regarding industry leading CCIE Lab training, please > > visit www.ipexpert.com > > > > Are you a CCNP or CCIE and looking for a job? Check out > > www.PlatinumPlacement.com > > > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
