Route Summarization and Leaking JN0-664 Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   A network administrator is troubleshooting an IS-IS network where a Level 1 router is advertising multiple /24 routes into the area. The administrator wants to reduce the number of routes in the Level 1 link-state database and prevent route flapping from affecting other routers. The administrator configures a summary address on the router's Level 1 interface. What is the immediate effect on the router's advertisements?

   • AThe router advertises only the summary route into Level 1, and the individual /24 routes are no longer advertised.
   • BThe router stops advertising all routes on that interface until the summary is removed.
   • CThe router continues to advertise the individual /24 routes along with the summary route.
   • DThe router advertises the summary route only into Level 2, not Level 1.
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2. 2application · medium

   A service provider operates an IS-IS network with a large Level 2 backbone and many Level 1 areas. The network operations team notices that the Link-State PDU (LSP) database on backbone routers is growing rapidly, and route flapping in one area is causing SPF runs across the entire backbone. The team wants to reduce the routing table size on backbone routers and isolate the impact of route flaps. Which configuration approach directly addresses both concerns?

   • AConfigure route summarization on the Level 1/Level 2 border routers for prefixes originating in each Level 1 area.
   • BDisable the Level 1 routing level on all backbone routers to force all traffic to use Level 2 only.
   • CIncrease the SPF holddown timer on all Level 2 routers to reduce the frequency of SPF calculations.
   • DEnable route leaking on the Level 1/Level 2 border routers to advertise more specific routes into Level 2.
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4. 3foundation · easy

   How does route summarization affect route leaking in IS-IS?

   • ASummarization prevents leaking of the summarized routes.
   • BSummarized routes can be leaked into another level.
   • CSummarization automatically leaks the summary route into all other levels.
   • DSummarization changes the metric of leaked routes to a higher value.
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5. 4foundation · easy

   Which scenario is a typical use case for IS-IS route leaking?

   • ATo prevent routing loops between Level 1 and Level 2 routers.
   • BTo reduce the size of the routing table by aggregating routes.
   • CTo increase the speed of route convergence after a link failure.
   • DTo allow Level 1 routers to learn about routes outside their area for optimal routing.
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6. 5application · medium

   A service provider has a two-level IS-IS network. Level 1 routers in an area need to reach a specific /24 subnet that is only advertised into Level 2. The Level 1 routers currently only have a default route to the nearest Level 1/Level 2 router. The network team wants Level 1 routers to learn this specific route without advertising all Level 2 routes into Level 1. What should be configured?

   • AEnable the 'level 1 default-route' option on the Level 1/Level 2 border router to advertise the specific /24 route.
   • BConfigure route leaking on the Level 1/Level 2 border router to leak the specific /24 route from Level 2 into Level 1 using a routing policy.
   • CConfigure the Level 1 routers to use static routes pointing to the Level 2 network.
   • DConfigure route summarization on the Level 1/Level 2 border router to summarize all Level 2 routes into a single default route for Level 1.
   Reveal Solution Discussion Select an answer first