Tutorial: Is IS-IS It, or not? What are the IS-IS New
Technologies?
Howard Berkowitz, Nortel
What is IS-IS? Why do many ISPs use it, or not use it? This basic
tutorial examines current and evolving IS-IS usage, assuming knowledge of
OSPF. It contrasts the topologies that can be built with present and
extended IS-IS with those of OSPF. Scalability features of the protocols
will be compared. One spur to current interest in IS-IS is its use with
MPLS and traffic engineering, and its applicability here will be
presented. Another enhancement to be discussed is the controlled
injection of level 2 routes into level 1 areas, allowing best-exit/cold
potato as well as closest-exit routing.