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] 10.11.0.0 255.255.0.0
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:
OSPF does not support auto-summarization.