QuestionQ156

Routing Policy and Manipulation

Question Image

Refer to the exhibit. A service provider runs IS-IS in the core, and every router uses the default IS-IS configuration and is in the same area. Each router maintains a distinct 6-byte system ID, but the attached bits in the NET are identical. After an engineer added router R6 to the network, R3 and R5 began experiencing CPU-processing issues. What action must the engineer take to resolve the issue?

  • A Configure all routers to operate as IS-IS Level 1 routers by altering the attached bit to ensure that a default route is injected into the routing tables.
  • B Configure routers RS and R3 to operate as Level 1 routers only so that they inject a default routing into the routing tables of the other routers.
  • C Configure R6 to operate as a Level 1 router only so that it maintains the Level 1 database for all routers.
  • D Configure all routers to operate as IS-IS Level 2 routers so that only a Level 2 database is maintained.
Explanation

IS-IS Level 1-2 is the default operating mode and maintains separate Level 1 and Level 2 link-state databases, with SPF processing for each. A single-area core does not need Level 1 routing or attached-bit-based default routing; configuring every router as Level 2-only leaves only the Level 2 database and removes the unnecessary Level 1 processing.

Learn more

Community Discussion

No comments yet. Be the first to start the discussion!