Chapter 3. Message Types
Comparing the respective message types of OSPF and IS-IS seems like a good starting point for beginning a broader comparison of the two protocols. I find myself with something of a chicken-or-egg problem, however. To describe either protocol’s messages requires also describing the functions they support, but those functions themselves call for extensive description, and often entire chapters of their own. I trust that the preceding chapter gave you enough of a general understanding of the basic link state functions that I can now refer to the OSPF or IS-IS versions of those functions without yet giving you the details. I therefore lay a few eggs for you in this chapter and hatch the chickens later.