1.5 Configure and Verify Control Plan Security 350-501 Practice Questions (Page 2)

Questions 6–10

1. 6application · medium

   A service provider is experiencing BGP table growth due to the advertisement of many more-specific prefixes from a customer. The provider wants to reduce the number of prefixes in its BGP table without losing reachability to the customer's network. The provider also wants to be able to selectively filter traffic to the customer's prefixes in case of an attack. Which two features should the provider use?

   • ABGP prefix suppression on the customer-facing session and BGP Flowspec for traffic filtering.
   • BBGP TTL security to protect the session and BGP prefix suppression to reduce the table size.
   • CBGP route aggregation on the customer-facing router and CoPP to protect the control plane.
   • DBGP community filtering to remove unwanted prefixes and BGPsec to validate the remaining prefixes.
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2. 7foundation · easy

   What is the primary purpose of BGP TTL Security (GTSM)?

   • ATo prevent BGP sessions from being established with non-directly connected peers
   • BTo encrypt BGP session traffic between peers
   • CTo protect BGP sessions from spoofed packets by verifying that the TTL of incoming packets is within an expected range
   • DTo authenticate BGP peers using a shared secret
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4. 8application · hard

   A service provider operates an MPLS backbone with many PE routers that exchange full routing tables with each other over iBGP. The provider wants to reduce the number of BGP updates and the memory footprint on the route reflectors, while still ensuring that all customer prefixes are reachable. The provider also wants to maintain the ability to influence inbound traffic using AS path prepending on some customer routes. Which approach should the provider take?

   • AImplement BGP prefix suppression by configuring the PE routers to advertise only the aggregate prefixes for customer blocks, while still advertising more specific prefixes when needed for traffic engineering.
   • BUse BGP route reflectors with the 'advertise-best-external' option to reduce the number of iBGP updates.
   • CConfigure BGP prefix suppression on the iBGP sessions between PE routers and route reflectors, but only for the provider's own loopback prefixes, while still advertising customer prefixes normally.
   • DEnable BGP prefix suppression on the PE routers so that only the loopback prefixes are advertised into the iBGP mesh.
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5. 9application · medium

   A service provider is concerned about BGP route hijacking and wants to ensure that the origin AS and the path of BGP routes are validated. The provider also wants to reduce the number of prefixes advertised to a specific customer. Which solution should be implemented?

   • AApply a CoPP policy to BGP traffic.
   • BUse BGP TTL security on all eBGP sessions.
   • CConfigure BGP prefix suppression on the customer session.
   • DDeploy BGPsec on all eBGP sessions.
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6. 10expert · hard

   A service provider is planning to implement BGP prefix suppression on its route reflectors to reduce the number of iBGP updates. The provider also wants to maintain the ability to do traffic engineering using AS path prepending on customer routes. The provider is concerned that prefix suppression might hide the more-specific routes that are used for traffic engineering. Which approach should the provider take?

   • ADisable prefix suppression and rely on BGP Flowspec to filter the more-specific routes.
   • BConfigure BGP TTL security on the route reflectors to reduce the number of updates.
   • CUse BGPsec to validate the more-specific routes and then suppress them.
   • DEnable prefix suppression on the route reflectors but allow the more-specific routes to be advertised to a limited set of edge routers that need them for traffic engineering.
   Reveal Solution Discussion Select an answer first