ICND2 – Chapter 6 – Route Summarization

Another fairly short chapter but with quite a number of route summarization exercises that I will not cover here. Here are my notes:

Route summarization use the best metric of all the subordinate routes

The ip summary-address interface subcommand is used to create a manual summary route. Example:

Router(config-if)#ip summary-address [rip | eigrp | ospf]

Manual summaries are per interface.

Setting the next-hop of a route to Null0 is a method for discarding packets.

The summary route with the smallest range that covers ALL the subnets to be summarized is your summary route.

Auto-summarization prevents a network with discontiguous network from working properly.

Classful routing protocols must use auto-summarization. The classless protocols RIPv2 and EIGRP also use it by default. You can disable auto-summarization on classless protocols by using:

Router(router)#no auto-summary

OSPF does not support auto-summarization.


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