Tuesday, 10 December 2013

ROUTE: EIGRP Summary Route and Stub Networks




  • 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;

  • or
 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 fails, query messages will be sent out for an alternative route. The query goes to the exact route that is lost When R1 receives this, all they have is a route for, 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;