IS-IS Concepts and Operation JN0-664 Practice Questions (Page 3)

Questions 11–15

1. 11application · medium

   A service provider is implementing IS-IS authentication across their network. They want to ensure that only authorized routers can form adjacencies and exchange routing information. They also want to minimize the risk of replay attacks. Which configuration approach best meets these requirements?

   • AEnable HMAC-MD5 authentication on all IS-IS interfaces.
   • BEnable authentication only on Level 2 adjacencies.
   • CEnable plain-text authentication on all IS-IS interfaces.
   • DEnable HMAC-SHA-256 authentication with a keychain that includes a sequence number.
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2. 12foundation · easy

   How does IS-IS ensure that all routers in an area have the same link-state database?

   • ABy periodically sending the entire database to all neighbors.
   • BBy flooding LSPs throughout the area and using sequence numbers to track the latest version.
   • CBy requiring all routers to be directly connected to each other.
   • DBy using a designated router to distribute the database to all routers.
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4. 13foundation · easy

   What is the purpose of IS-IS authentication?

   • ATo assign different metrics to authenticated routes.
   • BTo verify the identity of neighboring routers and ensure routing updates are not tampered with.
   • CTo encrypt the routing updates to prevent eavesdropping.
   • DTo compress the LSPs to reduce bandwidth usage.
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5. 14application · medium

   A network engineer is troubleshooting a routing issue in an IS-IS network. A router in the core is being used as a transit path for traffic between two other routers, but the engineer notices that the router's overload bit is set. What is the immediate effect of the overload bit being set on this router?

   • AThe router will continue to forward transit traffic but will not participate in the SPF calculation.
   • BThe router will not be used for transit traffic, but it will still be used as the destination for traffic destined to its own prefixes.
   • CThe router will stop advertising all of its routes, including its directly connected prefixes, to its neighbors.
   • DThe router will immediately drop all traffic that is not destined to its own IP addresses.
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6. 15expert · hard

   A network engineer is planning a maintenance window for a core router that is currently carrying transit traffic. The engineer wants to minimize the impact on traffic while the router is being upgraded. Which action should the engineer take before the maintenance window?

   • AIncrease the metric on all interfaces to make the router less attractive for transit traffic.
   • BShut down all interfaces on the router to force traffic to reroute.
   • CRemove the router from the IS-IS routing domain by disabling IS-IS on all interfaces.
   • DSet the overload bit on the router to prevent it from being used for transit traffic.
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