Free Nokia Border Gateway Protocol for Internet Routing Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Nokia Border Gateway Protocol for Internet Routing practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1What information is the primary exchange between BGP-speaking systems?

   1. A.Network reachability and associated AS pathsCorrect answer: A
   2. B.Complete internal topology of every AS
   3. C.Every router's interior link-state database
   4. D.The detailed forwarding table of every peer

   Explanation: "The primary function of a BGP speaking system is to exchange network reachability information with other BGP systems." BGP exchanges reachability information rather than the other types of operational data.

   Reference: RFC 4271: A Border Gateway Protocol 4 (BGP-4) — Section 1

2. 2Several SR OS BGP peers need the same settings, while another group must remain unaffected. Which configuration level can hold the shared settings once for just the first group?

   1. A.The first BGP groupCorrect answer: A
   2. B.Each first-group neighbor separately
   3. C.The global BGP instance
   4. D.Each neighbor in the other group

   Explanation: "the common configuration commands can be configured once at the group level and need not be repeated for every neighbor." Group settings reduce repeated configuration across similar peers.

   Reference: SR OS Unicast Routing Protocols Guide: BGP — BGP groups

3. 3A BGP peer has an import policy configured at neighbor, group, and global levels. Which policy command applies in SR OS?

   1. A.The neighbor-level commandCorrect answer: A
   2. B.The global-level command
   3. C.All three commands cumulatively
   4. D.The group-level command only

   Explanation: "An import policy command applied at the neighbor level takes precedence over the same command applied at the group or global level." The most-specific neighbor-level import command wins; levels are not cumulative.

   Reference: SR OS Unicast Routing Protocols Guide: BGP — BGP import policies

4. 4Why does route reflection reduce the need for a full IBGP mesh?

   1. A.It re-advertises IBGP routes to IBGP peersCorrect answer: A
   2. B.It advertises IBGP routes only to EBGP peers
   3. C.It prevents advertising routes learned by IBGP
   4. D.It advertises only routes originated by the reflector

   Explanation: "BGP route reflection eliminates the need for a full IBGP mesh by allowing routers configured as route reflectors to re-advertise routes from one IBGP peer to another IBGP peer." Reflection changes the ordinary IBGP re-advertisement restriction.

   Reference: SR OS Unicast Routing Protocols Guide: BGP — Route reflection

5. 5What must both BGP peers advertise before one may send the other a Route Refresh message?

   1. A.The route refresh capabilityCorrect answer: A
   2. B.The graceful restart capability
   3. C.The add-path receive capability
   4. D.The four-octet AS capability

   Explanation: "A BGP router can send a Route Refresh message to its peer only if both have advertised the route refresh capability (code 2)." Both sides must advertise route refresh capability.

   Reference: SR OS Unicast Routing Protocols Guide: BGP — Route refresh message

6. 6What does the BGP AS_PATH attribute identify for a route?

   1. A.AS numbers traversed by the routing informationCorrect answer: A
   2. B.IP addresses of next hops for the destinations
   3. C.BGP identifiers of all route reflector clients
   4. D.Preference values for the route at every AS

   Explanation: "This attribute identifies the autonomous systems through which routing information carried in this UPDATE message has passed." AS_PATH identifies traversed autonomous systems, not interfaces, IGP routers, or policy configurations.

   Reference: RFC 4271: A Border Gateway Protocol 4 (BGP-4) — Section 5.1.2

7. 7Which SR OS command displays a summary of BGP neighbor status?

   1. A.show router bgp summaryCorrect answer: A
   2. B.show router bgp neighbor received-routes
   3. C.configure router bgp neighbor
   4. D.configure router bgp group local-address

   Explanation: "Use the following command to display BGP neighbor status. show router bgp summary" The summary command displays neighbor status; the other commands configure a peer or inspect received routes.

   Reference: SR OS Peering Quick Reference: Configuring routing protocols — BGP / BGP neighbor status

8. 8What does an SR OS policy's default action apply to?

   1. A.Routes that match every policy entry
   2. B.Routes that match no policy entryCorrect answer: B
   3. C.Only routes learned from an IGP
   4. D.Only routes that were already exported

   Explanation: "The default action of a policy applies to a route when the route does not match any of the entries of the policy." The default action handles unmatched routes.

   Reference: SR OS Unicast Routing Protocols Guide: Route policies — Default action behavior

9. 9In a route-reflector design, what forms a cluster?

   1. A.A reflector and its client peersCorrect answer: A
   2. B.A reflector and its non-client peers
   3. C.Only the reflector's external peers
   4. D.Only the reflector's non-client peers

   Explanation: "An RR and its client peers form a cluster." A cluster contains a reflector and its clients.

   Reference: SR OS Unicast Routing Protocols Guide: BGP — Route reflection

10. 10What does a BGP Route Refresh message ask its peer to do?

    1. A.Resend routes for the specified AFI/SAFICorrect answer: A
    2. B.Withdraw routes for the specified AFI/SAFI
    3. C.Stop advertising that address family
    4. D.Resend routes only for a different AFI/SAFI

    Explanation: "The Route Refresh message is a request for the peer to re-send all or some of its routes associated with a particular pair of AFI/SAFI values." A refresh requests routes for the specified address family.

    Reference: SR OS Unicast Routing Protocols Guide: BGP — Route refresh message