Tuesday, 10 December 2013

ROUTE: EIGRP Summary Route and Stub Networks

Topology


 

Objectives

  • Setup EIGRP
  • Configure loopbacks
  • Add summary address
  • Configure Stub

Check routing and topology tables


If we take a look at R1's routing table, it will list all of the routes being advertised by EIGRP;






Create Summary Address


The summary address for the network will be;

  • 10.1.4.0 255.255.252.0 or 10.1.0.0/22
 Enter the following on R2;



Now if we take a look at the R1's routing table, we will see that the networks are being summarised;



This provides the benefit when/if a network on R2 drops;

For example if 10.1.4.0/22 fails, query messages will be sent out for an alternative route. The query goes to the exact route that is lost 10.1.4.0/24. When R1 receives this, all they have is a route for 10.1.4.0/22, so they will not forward the query (if more routers were connected) and will send a reply back to R2

If all the networks were to fail the summary address will no longer be advertised.

Creating a Stub network


By configuring R2 as stub network, it will tell R1 that you hear a query message do not send it to me, as I only know the networks being advertised to you (there are no other networks that R2 can reach but its own LAN networks).

Under the EIGRP 1 process, enter the following command;



If you take a look at the neighbours table on R1 you can verify the stub setting;



Sources;
www.ine.com