300-510 SPRI: Implementing Cisco Service Provider Advanced Routing SolutionsDemo

By Cisco · Question Mode

QuestionQ245

Unicast Routing

A growing company with multiple internal networks has asked its network engineering team to improve communication between those networks, focusing on efficient data exchange. A network engineer is configuring IS-IS for route advertisement between routers R1 and R2, which reside in different autonomous systems. The engineer configured R1 with IP address 192.168.1.1 and R2 with IP address 192.168.1.2, in accordance with RFC 1195 and IEEE 10589 standards.

However, the routers failed to establish an IS-IS adjacency over their GigabitEthernet0/0 interfaces. The engineer checked the cables and interfaces for any faults that might affect physical connectivity and also verified that the routers' system IDs are unique.

Which action must the engineer take to resolve the issue?

Question Image

  • A Change the IS-IS network type to point-to-point.
  • B Increase the IS-IS hello Interval.
  • C Change the IS-IS metric style to wide.
  • D Configure the same IS-IS level on both routers
Explanation

IS-IS supports only two interface network types — Broadcast (the default on LAN/Ethernet media) and Point-to-Point — and these types exchange different Hello packet formats (LAN IIHs versus point-to-point IIHs). If one router's interface is configured as point-to-point while the peer's interface remains on the default broadcast type, the mismatched Hello packets are discarded by the receiving side and no adjacency is ever formed, regardless of correct cabling or unique System IDs. Since R1's debug output shows it is already sending point-to-point IIH packets, R2's interface must be configured to use the same point-to-point network type so both ends exchange compatible Hellos and the adjacency can come up.

Learn more

Community Discussion

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