Refer to the exhibit. Router A and router B are physically connected over an Ethernet interface, and ISIS is configured as shown. Which option explains why the ISIS neighborship is not getting formed between router A and router B?
Correct Answer: D
Explanation/Reference:
Explanation:
With IS-IS, the LSP identifier is derived from the system ID (along with the pseudonode ID and LSP number). Each IS is usually configured with one NET and in one area; each system ID within an area must be unique.
The big difference between NSAP style addressing and IP style addressing is that, in general, there will be a single NSAP address for the entire router, whereas with IP there will be one IP address per interface. All ISs and ESs in a routing domain must have system IDs of the same length. All routers in an area must have the same area address. All Level 2 routers must have a unique system ID domain-wide, and all Level
1
routers must have a unique system ID area-wide.
Reference: http://www.cisco.com/en/US/products/ps6599/products_white_paper09186a00800a3e6f.shtml