Hi David, What you are describing is pretty much the case, routing protocols have their own databases which are then feed into the routing information base, the same prefix could come in to the router from different protocols, so administration distance is used as the tiebreaker here as to which protocols for the prefix should be used. Multiple paths to a destination is provided to the RIB by the source protocol which is then used to determine the FIB (Forwarding information base) which has the L2 info like MAC Address/DLCI/VLAN and the egress port, however you probably want to know how things like CEF operates as well as MPLS and how the LFIB works.
This book http://www.ciscopress.com/bookstore/product.asp?isbn=1587052369(Cisco Express Forwarding) maybe of interest to you to, it describes in fair detail how routing, switching and CEF operate probably in less detail than a Cisco code monkey would need to know but in more detail than most people really need to be aware of, however if that sounds a bit more than you really need, it does also have a reasonable troubleshooting section on CEF (or things that get blamed on CEF), so if you provide deep level support in this area, perhaps its of help for you and it does cover some of the variations of "software" and centralised and distributed hardware routing platforms. Cheers, Adam On Mon, Nov 22, 2010 at 7:26 AM, David Betz <[email protected]> wrote: > I've been looking, but I cannot seem to find what I'm looking for. Can > anyone direct me to any resources on the mechanics on the routing table? > > My theory: all routing goes through the routing table and only the routing > table. It seems to me that in the running of a router, no packets ever > cares about what EIGRP, OSPF, BGP, or RIP are doing. They are > abstracted/black-boxed from the packet. If this is true, then, QED, EIGRP > does NOT provide load-balancing (as every books seems to suggest); it > provides multiple paths to the routing table and THE ROUTING TABLE provides > load balancing. This has been driving me mad for the longest time. I work > with extreme accuracies in my day job as an escalation engineer (core dump > analyzer) and I really need to have this perfectly precise in my mind or I'm > going to absolutely lose it. > > In sum: isn't it all about the routing table... and the routing protocols > (IGP/EGP) just provide information to the routing table... with all routing > actually routing the routing table and ONLY the routing table? > > If this is true, then when the routing table is solid... then, you have no > reason to look at the routing protocol databases or tables. > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > >
_______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
