My CISCO Journal

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

EIGRP = Enhance Interior Gateway Routing Protocol

Ok, what are the most common words that I hear about EIGRP?

Neighbor table, Topology table, Routing table, successor (primary route), feasible successor(secondary route), backup routes, DUAL, Diffused Update Algorithm, auto summarization, unequal cost load balancing, easy to configure.

Routing protocol based on: DV plus some features of Link State protocol

Hello sent every 5 seconds = >

Hold down timer = > set according to hello packets received

Have very speedy convergence time and easy on processor.

#router eigrp 10

#network <network to be advertised>  <eigrp wild card bits- optional>

Some commands to remember:

#show ip eigrp neighbors

#show ip eigrp topology

#show ip eigrp route

In EIGRP we can summarize anywhere. Load balance over unequal cost paths. Null0 created automatically to tackle the routing efficiently, in other words null garbage container, to through away the garbage routes.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Distance Vector Routing Protocols, Linkstate routing protocol. Hybrid protocols.

DV protocols send their entire routing table after a specific interval, while linkstate protocols make neighbor adjacencies and event triggered updates are sent.

DV protocols have looping issues

Count down to infinity loop!

Loop preventions mechanism in a CISCO router: like route poisoning, split horizon, hold down timer,

Link state routing protocol: OSPF: not more than 50 routers/area

ABR, ASBR, Backbone router

All routers in an area have the same topology table but they will have different routing table.

Localize updates within an area. Requires a hierarchical design, you must design network keeping in mind the hierarchical design!

Hello messages in ospf: sent every 10 seconds on broadcast/p-2-p links, once every 30 seconds on NBMA networks ie frame relay. Best practice is to tune the hello packet sending time, most case its set to 1 second.

And to make adjacency routers must agree on some specific parameters

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

OSPF general syntax and configurations

Modifying the router ID

#router ospf < processs ID>

#network <Network> <wildcard mask> area <area #>

#show ip ospf

#show ip protocols

#show ip ospf neighbors

To advertise a summary route:

#area <area #>  range  <sumar ip> <mask>