江浙沪招生考试网

　　1. Based on the physical topology of AS 50001, to reduce the IBGP full-mesh requirements, only two redundant

　　route reflectors (RR) will be used in a single cluster. In this case, which two routers should be the RRs and which

　　three routers should be the clients based on the recommended route reflector design rule?

　　Task: 1) Drag the matching text labels given on the left side of the topology to the correct targets on the right to

　　identify these routers.

　　2) Also, identify all the unnecessary IBGP sessions once the redundant RRs have been configured by clicking on

　　the IBGP session links to disable them. You can re-enable the IBGP sessions link by clicking on it again.

　　Answer:

　　2. What are two purposes of the BGP scan-time command? (Choose two.)

　　A. to tune the BGP process which walks the BGP table and confirms the reachability of next hops

　　B. to allow faster detection of downed BGP peers

　　C. to improve BGP convergence time

　　D. to tune the BGP update interval

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　　E. to decrease the effects of unstable routes by increasing the route suppression time

　　Answer: A, C

　　3. Which command is used to configure the external, confederation-wide AS number?

　　A. Router(config)#router bgp {as-number}

　　B. Router(config-router)#bgp confederation peers {as-number}

　　C. Router(config-router)#bgp confederation identifier{as-number}

　　D. Router(config-router)#bgp cluster-id{as-number}

　　E. Router(config-router)#neighbor {ip address} remote-as {as-number}

　　Answer: C

　　4. Lab

　　Answer: Sorry, see the next version!

　　5. List the BGP route selection steps in the correct order

　　Answer:

　　6. When creating iBGP multipaths which three criteria must be met by multiple paths to the same destination?

　　(Choose three.)

　　A. Router IDs must be the same on all routers.

　　B. Each destination must have a different next-hop address.

　　C. The destination AS-number must be different for each destination.

　　D. Multi-exit discriminator attributes must be the same on all paths.

　　E. Interior Gateway Protocol distance must be identical on each path.

　　Answer: B, D, E

　　7. Which two of these statements about hierarchical route reflectors are correct? (Choose two.)

　　A. A route reflector can be a client of another route reflector.

　　B. Each cluster within the hierarchy can only contain one route reflector.

　　C. The hierarchy can be as deep as needed.

　　D. A route reflector can have clients in different clusters.

　　E. Hierarchical route reflectors are set up using three levels (access, distribution, and core layers).

　　Answer: A, C

 

　　8. What can cause a single sourced iBGP route not to be selected as the best route?

　　A. The BGP MED is 0.

　　B. The BGP next-hop is unreachable.

　　C. The BGP origin is incomplete.

　　D. The BGP weight is 0.

　　E. The BGP local preference is 0.

　　F. BGP synchronization is disabled.

　　Answer: B

　　9. Drag the method used to influence BGP path selection on the left to the traffic flow it influences on the right.

　　Answer:

　　10. Which two of the following are true regarding the BGP Prefix-Based outbound route filtering feature?

　　(Choose two.)

　　A. IP multicast routes are not supported.

　　B. Outbound route filtering is configured only on a per-address family basis.

　　C. Outbound route filtering can be configured for either iBGP or eBGP sessions.

　　D. The outbound route filter can be defined in a Prefix list, Distribute list or Access lists.

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　　E. Outbound route filtering is more effective when a distance vector IGP is used.

　　Answer: A, B

　　11. Which configuration will enable the R1 router in the AS51003 sub-AS (member-AS) as a route reflector with

　　neighbors 10.1.1.1 and 10.2.2.2 as its route-reflector clients?

　　A. !

　　R1 router bgp 51003

　　bgp confederation identifier 55111

　　bgp confederation peers 51001 51002

　　neighbor 10.1.1.1 remote-as 51003

　　neighbor 10.2.2.2 remote-as 51003

　　neighbor 10.1.1.1 route-reflector-client

　　neighbor 10.2.2.2 route-reflector-client

　　B. !

　　R1 router bgp 51003

　　bgp confederation identifier 55111

　　bgp confederation peers 51001 51002

　　neighbor 10.1.1.1 remote-as 51001

　　neighbor 10.2.2.2 remote-as 51002

　　neighbor 10.1.1.1 route-reflector-client

　　neighbor 10.2.2.2 route-reflector-client

　　C. !

　　R1 router bgp 55111

　　bgp confederation identifier 51003

　　neighbor 10.1.1.1 remote-as 51003

　　neighbor 10.2.2.2 remote-as 51003

　　neighbor 10.1.1.1 route-reflector-client

　　neighbor 10.2.2.2 route-reflector-client

　　D. !

　　R1 router bgp 55111

　　bgp confederation identifier 51003

　　neighbor 10.1.1.1 remote-as 55111

　　neighbor 10.2.2.2 remote-as 55111

　　neighbor 10.1.1.1 route-reflector-client

　　neighbor 10.2.2.2 route-reflector-client

　　Answer: A

　　12. Which BGP configuration option is designed to reduce router processing load caused by unstable routes?

　　A. neighbor {ip-address} maximum-prefix {number}

　　B. bgp dampening

　　C. no sync

　　D. bgp deterministic-med

　　E. sync

　　F. bgp scan-time

　　Answer: B

　　13. In the diagram, the customer is using BGP to connect to a single ISP over two permanent links. In this

　　scenario, which input and output prefix-list filtering is typically enabled on the ISP routers? (Choose two.)

　　A. ip prefix-list test-in permit 10.1.1.0/24 le 32

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　　B. ip prefix-list test-in permit 10.0.0.0/8 le 32

　　C. ip prefix-list test-in permit 0.0.0.0/0

　　D. ip prefix-list test-out permit 10.1.1.0/24 le 32

　　E. ip prefix-list test-out permit 10.0.0.0/8 le 32

　　F. ip prefix-list test-out permit 0.0.0.0/0

　　Answer: A, F

　　14. How can you prevent multihomed customers with connections to two service providers from acting as a transit

　　AS?

　　A. Enable BGP synchronization on all the customer routers.

　　B. Use MED to influence the inbound traffic from the ISPs.

　　C. Use static routing to the ISPs.

　　D. Use an AS-path access-list to filter the BGP updates to the ISPs.

　　E. Use conditional advertisements when sending BGP updates to the ISPs.

　　Answer: D

　　15. Based on the R1 router BGP configuration shown, which three statements are correct? (Choose three.)

　　A. R1 is in AS 50101 according to the 192.168.100.1 neighbor.

　　B. R1 is in AS 50101 according to the 10.1.1.1 neighbor.

　　C. The 192.168.100.1 neighbor must be directly connected to R1.

　　D. R1 is a route-reflector client.

　　E. The 10.4.4.4 neighbor is an EBGP neighbor.

　　F. BGP updates coming in from the 192.168.100.1 neighbor must be processed by the setlp route-map.

　　Answer: A, C, F

　　16. Based on the following show ip bgp neighbors 2.2.2.2 output, which two statements are true? (Choose two.)

　　A. R1 has accepted 20 prefixes from the 2.2.2.2 IBGP neighbor.

　　B. R1 generated a warning message to the router's console after the 2.2.2.2 IBGP neighbor sent 16 prefixes to R1.

　　C. R1 generated a warning message to the router's console after the 2.2.2.2 IBGP neighbor sent 15 prefixes to R1.

　　D. R1 will drop its neighbor relationship to the 2.2.2.2 IBGP neighbor if 2.2.2.2 sends two more additional

　　prefixes to R1.

　　E. R1 will drop its neighbor relationship to the 2.2.2.2 IBGP neighbor if 2.2.2.2 sends three more additional

　　prefixes to R1.

　　Answer: B, E

　　17. Which of these situations best describe when to use the AS number translation feature?

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　　A. All single-homed customers are using public AS numbers.

　　B. All single-homed customers are using private AS numbers.

　　C. All multihomed customers are using public AS numbers.

　　D. All multihomed customers are assigned different AS numbers from different ISPs.

　　Answer: D

　　18. Which two configuration commands will complete the BGP configuration on R1 so it will conditionally

　　announce the 172.0.0.0/8 to R4 via BGP? (Choose two)

　　A. 2. network 172.16.0.0 auto-summary

　　B. 2. network 172.0.0.0 mask 255.0.0.0

　　C. 1. ip route 172.0.0.0 255.0.0.0 null0

　　D. 1. ip route 172.0.0.0 255.0.0.0 null0 255

　　E. 1. ip route 172.0.0.0 255.0.0.0 172.16.1.1

　　F. 2. aggregate-address 172.0.0.9 mask 255.0.0.0

　　Answer: B, E

　　19. The neighbor {ip-address} maximum-prefix {maximum number} command prevents which router condition?

　　A. frequent BGP session resets

　　B. routing instability

　　C. asymmetric routing

　　D. CPU and memory exhaustion

　　E. route flaps

　　Answer: D

　　20. Refer to the exhibit. What effect will the route-map PEER-FILTER have on the route 24.11.62.0/24 with a

　　community of 10:100 injected by the peer router in AS632?

　　A. weight will be set to 100

　　B. weight will be set to 150

　　C. local preference will be set to 105

　　D. weight will be set to 100, local preference will be set to 105

　　E. weight will be set to 150, local preference will be set to 105

　　Answer: A

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　　21. Which two statements about a transit AS are correct? (Choose two.)

　　A. A transit AS has eBGP connection(s) to only one external AS.

　　B. Routes between ASs are always exchanged via eBGP.

　　C. A transit AS uses an IGP like OSPF or ISIS to propagate the external networks within the transit AS.

　　D. Core routers within a transit AS normally use default routing to reach the external networks.

　　E. iBGP sessions can be established between non directly connected routers.

　　Answer: B, E

　　22. Based on the network diagram shown in the exhibit, what is the correct configuration on the customer edge

　　router used to conditionally announce the customer networks to the ISP?

　　A. router bgp 65001

　　! neighbor commands not shown

　　network 192.168.0 mask 255.255.252.0

　　!

　　ip route 192.168.8.0 255.255.252.0 192.168.8.33

　　B. router bgp 65001

　　! neighbor commands not shown

　　aggregate-address 192.168.8.0 255.255.252.0 summary-only

　　!

　　ip route 192.168.8.0 255.255.252.0 192.168.8.33

　　C. route bgp 65001

　　! neighbor commands not shown

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　　network 192.168.8.0

　　network 192.168.9.0

　　network 192.168.10.0

　　network 192.168.11.0

　　!

　　ip route 192.168.8.0 255.255.255.0 null0

　　ip route 192.168.9.0 255.255.255.0 null0

　　ip route 192.168.10.0 255.255.255.0 null0

　　ip route 192.168.11.0 255.255.255.0 null0

　　D. router bgp 65001

　　! neighbor commands not shown

　　aggregate-address 192.168.8.0 255.255.252.0 summary-only

　　!

　　router ospf 1

　　network 192.168.8.0 0.0.3.255 area 0

　　E. router bgp 65001

　　! neighbor commands not shown

　　aggregate-address 192.168.8.0 255.255.252.0

　　!

　　ip route 192.168.0 255.255.252.0 null0

　　Answer: A

　　23. Which three actions are prerequisites to configuring the BGP link bandwidth feature? (Choose three.)

　　A. enable BGP synchronization

　　B. configure BGP multipath first

　　C. configure eBGP multihop on eBGP peers

　　D. enable Cisco Express Forwarding on the router

　　E. enable BGP community propagation between link bandwidth advertising routers

　　Answer: B, D, E

　　24. Refer to the partial topology diagram shown. Service Provider 1 (SP1) assigned the customer an AS number of

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　　65275. Service Provider 2 (SP2) assigned an AS number of 65745 to the customer. The customer decides to use

　　AS 65275 internally. Which of the following is the correct partial router configuration to cause updates from CR1

　　to SP1 to report a source AS of 65275, while updates from CR2 to SP2 report the source AS of 65745 in addition

　　to AS 65275?

　　A. !

　　CR1 router bgp 65275

　　neighbor 1.1.1.1 remote-as 65274

　　neighbor 10.1.1.2 remote-as 65275

　　!

　　CR2 router bgp 65275

　　neighbor 2.2.2.2 remote-as 65732

　　neighbor 2.2.2.2 local-as 65745

　　neighbor 10.1.1.1 remote-as 65275

　　B. !

　　CR1 router bgp 65275

　　neighbor 1.1.1.1 remote-as 65274

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　　neighbor 10.1.1.2 remote-as 65275

　　!

　　CR2 router bgp 65745

　　neighbor 2.2.2.2 remote-as 65732

　　neighbor 2.2.2.2 local-as 65745

　　neighbor 10.1.1.1 remote-as 65275

　　C. !

　　CR1 router bgp 65275

　　neighbor 1.1.1.1 remote-as 65274

　　neighbor 1.1.1.1 local-as 65745

　　neighbor 10.1.1.2 remote-as 65275

　　!

　　CR2 router bgp 65275

　　neighbor 2.2.2.2 remote-as 65732

　　neighbor 2.2.2.2 local-as 65745

　　neighbor 10.1.1.1 remote-as 65275

　　D. !

　　CR1 router bgp 65275

　　neighbor 1.1.1.1 remote-as 65274

　　neighbor 10.1.1.2 remote-as 65275

　　!

　　CR2 router bgp 65745

　　neighbor 2.2.2.2 remote-as 65732

　　neighbor 2.2.2.2 local-as 65275

　　neighbor 10.1.1.1 remote-as 65275

　　Answer: A

　　25. Which three conditions can make a transit autonomous system unable to forward packets from one

　　neighboring autonomous system to another neighboring autonomous system? (Choose three.)

　　A. sync enabled

　　B. bgp next-hop not reachable

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　　C. no full-mesh IBGP and not using route reflectors or confederations

　　D. non-directly connected IBGP neighbors

　　E. non-directly connected EBGP neighbors

　　F. EBGP to IBGP route redistribution configuration errors

　　Answer: A, B, C

　　26. What are three characteristics of the local preference BGP attribute? (Choose three.)

　　A. It is stripped in outgoing EBGP updates except with confederation peers.

　　B. It is used to influence the incoming traffic.

　　C. Its default local preference is 32768.

　　D. It is used to select routes with equal weight.

　　E. It can be used to ensure an AS-wide route selection policy.

　　F. It is a Cisco-only BGP path attribute.

　　Answer: A, D, E

　　27. Why can using the ip tcp path-mtu-discovery command improve BGP convergence?

　　A. Single packet sizes in TCP sessions are limited.

　　B. Smaller MSS sizes may reduce BGP convergence times.

　　C. BGP is allowed to use a larger TCP window size.

　　D. BGP is enabled to fragment its large update packets.

　　E. The BGP memory requirements on routers are reduced.

　　Answer: B

　　28. What state will a BGP session move to immediately after the router sends a BGP Open message to its

　　neighbor?

　　A. active

　　B. OpenConfirm

　　C. OpenSent

　　D. established

　　E. idle

　　Answer: C

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　　29. Lab

　　Answer: Sorry, see the next version!

　　30. Based on the show route-map test output shown in the exhibit, which matching routes will be set to a weight

　　of 150?

　　A. Routes that match the prefix-list named test

　　AND also match either the as-path filter 1 OR 2

　　AND also match either the community-list 1 OR 2

　　B. Routes that match the prefix-list named test

　　OR match the as-path filter 1 AND 2

　　OR match the community-list 1 AND 2

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　　C. Routes that match the prefix-list named test

　　AND match the as-path filter 1 AND 2

　　AND match the community-list 1 AND 2

　　D. Routes that match the prefix-list named test

　　OR match the as-path filter 1 OR 2

　　OR match the community-list 1 OR 2

　　Answer: A

　　31. What is a key benefit of implementing the bgp dmzlink-bw command?

　　A. establishes a secure BGP link between eBGP and iBGP peers

　　B. enables the unequal cost path load balancing feature for external BGP links

　　C. allows BGP to use link bandwidth as a metric when computing best route selection

　　D. increases BGP security by dynamically allocating community strings to eBGP routes

　　Answer: B

　　32. Which configuration command ensures BGP will not advertise a route until all the routers within the AS have

　　learned about the route via an IGP?

　　A. router BGP {as-number} redistribute {IGP}

　　B. router {IGP} redistribute BGP {as-number}

　　C. synchronization

　　D. bgp deterministic-med

　　E. network {network number} mask {subnet mask}

　　F. bgp dampening

　　Answer: C

　　33. What is the correct command to set the BGP scanner interval to two minutes?

　　A. bgp scan-time 2

　　B. bgp scan-time 120

　　C. bgp scan-time 2 60

　　D. The maximum scanning interval cannot exceed one minute.

　　Answer: D