Segregation Actions for IS-IS Routing in Cisco Enterprise Networks

BE.

To segregate three interconnected campus networks using IS-IS routing, a two-layer hierarchy must be used. The purpose of this hierarchy is to support large routing domains and to avoid more specific routes from each campus network being advertised to other campus network routers automatically. The engineer must take two actions to accomplish this segregation.

Option A: Designate two IS-IS routers as BDR routers at the edge of each campus, and configure one BDR for all Level 1 routers and one BDR for all Level 2 routers.

This option suggests designating two IS-IS routers as backup designated router (BDR) routers at the edge of each campus network. One BDR is designated for all Level 1 routers, and the other BDR is designated for all Level 2 routers. BDRs are responsible for taking over the responsibilities of the designated router (DR) if the DR fails. This option helps to maintain redundancy in the network.

Option B: Designate two IS-IS routers from each campus to act as Level 1/Level 2 backbone routers at the edge of each campus network.

This option suggests designating two IS-IS routers from each campus network to act as Level 1/Level 2 backbone routers at the edge of each campus network. These routers would be responsible for interconnecting the Level 1 and Level 2 areas of the network. By designating these routers as the backbone routers, the engineer can ensure that more specific routes from each campus network are not advertised to other campus network routers automatically.

Option C: Assign the same IS-IS NET value for each campus, and configure internal campus routers with Level 1/Level 2 routing.

This option suggests assigning the same IS-IS network entity title (NET) value for each campus and configuring internal campus routers with Level 1/Level 2 routing. The NET value is used to identify the router's domain within the IS-IS network. By assigning the same NET value for each campus, the engineer can ensure that each campus is part of the same IS-IS network. This option also allows the internal campus routers to route traffic between Level 1 and Level 2 areas.

Option D: Utilize different MTU values for each campus network segment. Level 2 backbone routers must utilize a larger MTU size of 9216.

This option suggests utilizing different maximum transmission unit (MTU) values for each campus network segment. The Level 2 backbone routers must utilize a larger MTU size of 9216. MTU is the largest size packet that can be transmitted over the network. By utilizing different MTU values for each campus network segment, the engineer can ensure that more specific routes from each campus network are not advertised to other campus network routers automatically.

Option E: Assign a unique IS-IS NET value for each campus, and configure internal campus routers with Level 1 routing.

This option suggests assigning a unique IS-IS NET value for each campus and configuring internal campus routers with Level 1 routing. By assigning a unique NET value for each campus, the engineer can ensure that each campus is part of a different IS-IS network. This option also allows the internal campus routers to route traffic within the Level 1 area.

In summary, the engineer can accomplish the segregation of three interconnected campus networks using IS-IS routing by taking two of the following actions:

1. Designating two IS-IS routers as BDR routers at the edge of each campus and configuring one BDR for all Level 1 routers and one BDR for all Level 2 routers.

2. Designating two IS-IS routers from each campus to act as Level 1/Level 2 backbone routers at the edge of each campus network.