BSCI Exam Cram™ 2 (Exam 642-801)

OSPF Support for Variable-Length Subnet Masking (VLSM) and Route Summarization in Multiple Areas

When you start to design your OSPF internetwork, it is important to realize that address assignment and route summarization are fundamentally connected. To build a scalable OSPF internetwork, you simply must implement route summarization. To review, route summarization is the process of aggregating routes to contiguous subnets into a single summary address. Route summarization is performed only on the area border routers because network routes are summarized for the purpose of injecting them into the OSPF backbone area. The result of this aggregation will be smaller routing tables on the ABRs, faster table lookups, and an overall decrease in the size ...