Video 4: EIGRP Routing

In EIGRP on April 20, 2011 by carlosfvc Tagged: , , , , , , , ,

The Concepts

1) Backup Routes ( Fast Converge/ DUAL).
2) Simple configuration.
flexibility in Summarization.
Unequal or variance cost load-balancing.
Combines best of distance vector and link state (Only knows the neighbors).


Neighbor relationship is established with Hello protocol

A router running EIGRP Maintains three table:

Neighbor table
Topology table
Routing table

EIGRP Terminology

Feasible Distance: (FD) – Router to a network
Advertised Distance: (AD) – Distance from the neighbor to a network
Successor ( Primary route on route table)
Feasible Successor: ( Back up route as long as AD must be less than FD of successor)
Active Route: (Bad) active looking for a route. A in routing table
Passive Route: (Good) router is working smooth


Hello : Forms Relationship on multicast
Update: Sends updates
Query: Asks about routes
Reply: Response to a query
Ack: Acknowledges the update, query, and reply messages

EIGRP Metric Calculation

  1. Bandwidth (k1) – Normal
  2. Delay (K3) – Normal
  3. Reliability (K4 and K5)
  4. Loading (k2)
  5. MTU (how big the package can be sent in the network)


(k1 * BW + ((K2 *BW)/ (256 – load) ) + K3 * delay) * (K5/(reliability + k4)

BW = 10 ^7/BW
Delay – Delay in microseconds

Real (default) metric = 256* (slowest_BW + All_link_delays

BW = 10 ^7/BW
Delay – Delay in microseconds


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: