CCIE Network Design FAQ: IS-IS Network Design   1: What protocol was IS-IS originally designed to provide routing information for? Answer: Connectionless Network Service (CLNS). 2: Where can summarization take place in IS-IS? Answer: On any L2 router. 3: How many levels of routing are there in an IS-IS network? Answer: Two. L1 and L2. 4: How many pseudonodes … [Read more...]