BGP Configuration and Troubleshooting FAQ
1. Which BGP routers will become peers and share routing information?
BGP routers that are configured with the neighbor command.
2. Refer to the exhibit. BGP sessions are established between all routers. RTC receives route updates for network 209.165.200.224/27 from autonomous system 300 with the weight attribute set to 3000. RTB also learns about network 209.165.200.224/27 from autonomous system 200 with a weight of 2000. Which router will be used by RTA as a next hop?
RTB because of the shortest AS_Path.
3. Refer to the exhibit. Which statement is true?
RTA is going to advertise network 150.10.0.0 to its neighbors if 150.10.0.0 or its subnets are in the IP routing table.
4. Refer to the exhibit. Router R2 is currently unable to access network 172.16.10.0/24. Based on the information in the exhibit, which configuration would fix the problem?
R1(config)# router bgp 65100
5. Which two statements are key characteristics of BGP? (Choose two.)
- It is a policy-based routing protocol.
- It provides interdomain routing between autonomous systems.
6. Refer to the exhibit. Which two configurations will allow router R1 to establish a neighbor relationship with router R2? (Choose two.)
R1(config)# router bgp 100
R1(config-router)# network 192.168.10.0
R1(config-router)# neighbor 209.165.200.226 remote-as 200
R2(config)# router bgp 200
R2(config-router)# network 192.168.20.0
R2(config-router)# neighbor 209.165.200.225 remote-as 100
7. An enterprise must interconnect multiple sites. Which technology would provide secure and manageable connections over the Layer 3 ISP network without the additional expense of leased lines?
MPLS VPN
8. An enterprise has routers with limited resources but requires the best path to selected external networks. Which multihoming option would provide the best solution?
Multihoming with default routes and partial Internet routes from all providers.
9. Refer to the exhibit. An organization has configured a multihomed solution using EBGP between two edge routers and two ISPs. The edge routers are receiving only default routes from each ISP EBGP peer. Which two statements are true of this solution? (Choose two.)
- EIGRP will choose the best route to exit the autonomous system.
- A TCP session must be established between the edge routers and the ISP routers.
10. Refer to the exhibit. Autonomous system 65500 is routing traffic between two external BGP autonomous systems, autonomous system 65200 and autonomous system 65100. Synchronization is disabled on BGP in autonomous system 65500. Which routers should have IBGP peer relationships for routing between autonomous system 65200 and autonomous system 65100 to work properly?
R1, R3, R4, and R5
11. What is the range of autonomous system numbers reserved for private use?
64512 to 65535
12. Refer to the exhibit. BGP sessions are established between all routers. Router RTC has the local preference for network 209.165.200.224/27 set to 200 and router RTB has a local preference set to 150 for the same network. Which router will by RTA as a next hop to reach network 209.165.299.224/27?
RTC because of the highest local preference.
13. Refer to the exhibit. Router R1 is receiving the prefix 10.22.0.0/16 from an IBGP peer. The prefix appears in the BGP table of R1, but not in the IP routing table. What could be preventing R1 from installing 10.22.0.0/16 in the routing table?
Synchronization
14. How can static routes be dynamically injected into BGP?
Apply the redistribute static command to the BGP configuration.
15. Which two options best describe an exterior routing protocol (EGP)? (Choose two.)
- An interdomain routing protocol.
- A routing protocol that exchanges routing information between different autonomous systems.
16. Refer to the exhibit. Based on the show ip bgp summary and debug ip bgp output, which two statements must be true? (Choose two.)
(R1 has established an EBGP peering relationship). (R1 cannot route BGP packets to 10.255.2.2.)
17. Which BGP attribute is used by BGP to ensure a loop-free topology on the Internet?
AS_Path
18. Refer to the exhibit. A network administrator in autonomous system 65100 has set up a dual-homed BGP connection with an ISP. The administrator would like to ensure that all traffic from the ISP enters the autonomous system through router R1. Which BGP attribute can the administrator configure on routers R1 and R2 to accomplish this?
MULTI_EXIT_DISCRIMINATOR
19. Which routes are available to a BGP speaker to advertise to peers once an adjacency is formed?
Only routes in the IP routing table.
20. What is a disadvantage to multihoming and accepting only a default route from each ISP?
Because routers will select the edge router based on the IGP metric, suboptimal routing may occur.