Eigrp

The EIgrp protocol is was cisco Pro rail tery but now is a Standard protocol.so let said that we have two router A and b, when router A  advertise their networking using the command router EIgrp and autonomous-system and their network we can using the wildcard, router A will send hello mess with multicast IP 224.0.0.10, so basically is said router A is anybody on a link.when router b averted network it will send back hello mess with the unicast packet. so based on this mess they build the neighbor table, now we can verify that table using the command show Ip EIgrp neighbor.  

After that, they will exchange router information they will send complete router information and they build another table it calls topology table, in this table is contains all the best route learn from each table.

1. neighbor table contains list of directly connected to the router 

   #show Ip Eigrp neighbor 

2 topology table 

   list of all the best routes learned from each neighbor 

  #show in EIgrp topology 

3 Routing table 

 the best route to the destination

 #show IP route 

Eigrp will only learn the best route in OFPF it need to be changed to all the routes