An organization is using a link state routing protocol that is not dependent on IP addressing. Which action should be taken to enable routing across area boundaries in this environment?
A. Assign Level 1 router interfaces to different areas
B. Assign Level 2 routers to different areas
C. Assign Level 1 routers to different areas
D. Assign Level 2 router interfaces to different areas
E. Assign Level 2 router interfaceto the backbone area
F. Assign Level 1 router interface to the backbone area
B and D, there is no backbone area in IS-IS
The Cisco ARCH book (Designing for Cisco Network Service Archtectures) does mention backbone areas in context with IS-IS.
I think the correct answers are B, AND D OR E.
The IS-IS Backbone is a contiguous chain of L2-capable routers (L2 or L1/L2) that hold the information for complete interarea routing.
Level 1 routing is routing within an area. A Level 1 router knows only the topology of its own area and can have Level 1 or Level 1/Level 2 neighbors only in its own area. It has a Level 1 linkstate database with all the information for intra-area routing. It uses the closest L1/L2 router in its own area to send packets out of the area
Level 2 routing is routing between different areas. A Level 2-capable router (L2 or L1/L2) may have L2 neighbors in the same or in different areas, and it has a Level 2 link-state database with all information for interarea routing. The router can also serve as an L1/L2 system, in which case it has both L1 and L2 link-state databases