Design Considerations for Route Summarization

Design Considerations for Route Summarization
Keep the following information in mind when designing your network summarization points:
 Only classless routing protocols support manual route summarization. Examples of
classless routing protocols include RIPv2, EIGRP, OSPF, BGP4, and IS-IS. Therefore,
if you are working in a RIPv1 or IGRP environment, manual route summarization is
not going to work for you.
Classless and classful protocols were discussed in Chapter 1.
Extending IP Addresses 63
 Route summarization is most effective when the addresses have been organized in a hierarchy
(i.e., “hierarchical addressing”). When we speak of addresses being hierarchical,
we mean that the IP subnets at the “bottom of the tree” (in other words, the ones with
the longest subnet masks) are subsets of the subnets at the “top of the tree” (i.e., the ones
with the shortest subnet masks). Figure 2.6 will be used to illustrate hierarchical versus
non-hierarchical addressing.