CCNP® Practical Studies: Routing

EIGRP Route Summarization and Large IP Network Support

EIGRP supports the use of summarization to conserve IP routing table size. Summarization in EIGRP can be configured on any router in the same AS. By default, EIGRP automatically summarizes at the major network boundaries. To perform static summarization, you must disable this feature with the no auto-summary IOS command, under the routing process.

To manually summarize networks, you must advertise the supernet, for example, on an interface level with the ip summary address eigrp autonomous system mask command.

Re-examine Figure 5-1 and summarize the networks 131.108.8.0 to 131.108.15.255. First, you must disable automatic summarization on R2. Example 5-10 displays the disabling of automatic ...