Monday, January 30, 2017

EIGRP Overview

EIGRP Overview



EIGRP (Relevant) Tables
  • Neighbor Table - Directly connected routers -  show ip eigrp neighbors 
  • Topology Table - Successor / Feasible Successor Routes -  show ip eigrp topology {all-links}
  • Routing Table   - The best routes from the topology table -  show ip route {eigrp}



Adjacency Terminology
  • Hello - Forms Relationships 
  • Update - Sends updates 
  • Query - Asks about Routes 
  • Reply - Responce to Query 
  • Ack - Acknowledges the update, query, and reply messages.
  • SIA (Stuck-in-Active) - This is bad... Waiting for Query to see if any router knows the network route.
    • Here is a crappy GIF I made to make things more clear.


Routing Terminology
  • Advertised Distance (AD) - The distance the neighbor has listed for a network.
  • Feasible Distance (FD) - The AD + the cost of the interface.
  • Successor - The route that has the lowest FD.
  • Feasible Successor - The routes with a lower FD than the Successor.
    • Note: To be considered a Feasible Successor, the AD must be less than the FD of the successor. This is called the Feasibility Condition.
  • Active Route - The route is down and you are actively trying to find a route for that network.
  • Passive Route - There is no activity on the route to the network.



2 comments:

  1. We are at the exact same point in our CCNP ROUTE studies, it seems! Will be following this blog closely, and hopefully making a few post of my own.

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    Replies
    1. Hey, I just passed my CCNP Route portion and I am on to TSHOOT. How is your studying?

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