Do I Know This Already Quiz
Table 12-1 outlines the major headings in this chapter and the corresponding "Do I Know This Already?" quiz questions.
|
Foundation Topics Section |
Questions Covered in This Section |
Score |
|
Building BGP Neighbor Relationships |
1-3 |
|
|
Building the BGP Table |
4-8 |
|
|
Building the IP Routing Table |
9-12 |
|
|
Total Score |
||
In order to best use this pre-chapter assessment, remember to score yourself strictly. You can find the answers in Appendix A, "Answers to the 'Do I Know This Already?' Quizzes."
1. Into which of the following neighbor states must a neighbor stabilize before BGP Update messages may be sent?
a. Active b. Idle c. Connected d. Established
2. BGP neighbors check several parameters before the neighbor relationship can be completed. Which of the following is not checked?
a. That the neighbor's router ID is not duplicated with other routers b. That the neighbor command on one router matches the update source IP address on the other router c. If eBGP, that the neighbor command points to an IP address in a connected network d. That a router's neighbor remote-as command refers to the same autonomous system number (ASN) as in the other router's router bgp command (assuming confederations are not used)
3. A group of BGP routers, some with iBGP and some with eBGP connections, all use loopback IP addresses to refer to each other in their neighbor commands. Which of the following statements are false regarding the configuration of these peers?
a. IBGP peers require a neighbor ip-address ibgp-multihop command for the peer to become established.
b. eBGP peers require a neighbor ip-address ebgp-multihop command for the peer to become established.
c. eBGP and iBGP peers cannot be placed into the same peer group.
d. For eBGP peers, a router's BGP router ID must be equal to the IP address listed in the eBGP neighbor's neighbor command.
4. A router has routes in the IP routing table for 20.0.0.0/8, 20.1.0.0/16, and 20.1.2.0/24. BGP on this router is configured with the no auto-summary command. Which of the following is true when using the BGP network command to cause these routes to be injected into the BGP table?
a. The network 20.0.0.0 command would cause all three routes to be added to the BGP table.
b. The network 20.0.0.0 mask 255.0.0.0 command would cause all three routes to be added to the BGP table.
c. The network 20.1.0.0 mask 255.255.0.0 command would cause 20.1.0.0/16 and 20.1.2.0/24 to be added to the BGP table.
d. The network 20.0.0.0 command would cause only 20.0.0.0/8 to be added to the BGP table.
5. A router has configured redistribution of EIGRP routes into BGP using the command redistribute eigrp 1 route-map fred. This router's BGP configuration includes the no auto-summary command. Which of the following are true?
a. route-map fred can consider for redistribution routes listed in the IP routing table as EIGRP-learned routes.
b. route-map fred can consider for redistribution routes in the IP routing table listed as connected routes, but only if those interfaces are matched by EIGRP 1's network commands.
c. route-map fred can consider for redistribution routes that are listed in the EIGRP topology table as successor routes but that are not in the IP routing table because a lower administrative distance (AD) route from a competing routing protocol exists.
d. route-map fred can consider for redistribution routes listed in the IP routing table as EIGRP-learned routes, but only if those routes also have at least one feasible successor route.
6. Using BGP, R1 has learned its best route to 9.1.0.0/16 from R3. R1 has a neighbor connection to R2, over a point-to-point serial link using subnet 8.1.1.4/30. R1 has auto-summary configured. Which of the following is true regarding what R1 advertises to R2?
a. R1 advertises only 9.0.0.0/8 to R2, and not 9.1.0.0/16.
b. If the aggregate-address 9.0.0.0 255.0.0.0 BGP subcommand is configured, R1 advertises only 9.0.0.0/8 to R2, and not 9.1.0.0/16.
c. If the network 9.0.0.0 mask 255.0.0.0 BGP subcommand is configured, R1 advertises only 9.0.0.0/8 to R2, and not 9.1.0.0/16.
d. None of the other answers is correct.
7. Which of the following statements are false regarding what routes a BGP router can advertise to a neighbor? (Assume no confederations or route reflectors are in use.)
a. To advertise a route to an eBGP peer, the route cannot have been learned from an iBGP peer.
b. To advertise a route to an iBGP peer, the route must have been learned from an eBGP peer.
c. The NEXT_HOP IP address must respond to a ping command.
d. Do not advertise routes if the neighboring router's AS is in the AS_PATH.
e. The route must be listed as valid in the output of the show ip bgp command, but it does not have to be listed as best.
8. Several different routes were injected into BGP via various methods on R1. Those routes were then advertised via iBGP to R2. R2 summarized the routes using the aggregate-address summary-only command, and then advertised via eBGP to R3. Which of the following are true about the ORIGIN path attribute of these routes?
a. The routes injected using the network command on R1 have an ORIGIN value of IGP.
b. The routes injected using the redistribute ospf command on R1 have an ORIGIN value of IGP.
c. The routes injected using the redistribute command on R1 have an ORIGIN value of EGP.
d. The routes injected using the redistribute static command on R1 have an ORIGIN value of incomplete.
e. If the as-set option was not used, the summary route created on R2 has an ORIGIN code of IGP.
9. Which of the following statements is true regarding the use of BGP synchronization?
a. With BGP synchronization enabled, a router can add an iBGP-learned route to its IP routing table only if that same prefix is also learned via eBGP.
b. With BGP synchronization enabled, a router cannot consider an iBGP-learned route as a "best" route to that prefix unless the NEXT_HOP IP address matches an IGP route in the IP routing table.
c. BGP synchronization can be safely disabled when the routers inside a single AS either create a full mesh of BGP peers or create a hub-and-spoke to the router that learns the prefix via eBGP.
d. None of the other answers is correct.
10. Which of the following statements are true regarding the operation of BGP confederations?
a. Confederation eBGP connections act like normal (nonconfederation) eBGP connections with regard to the need for the neighbor ebgp-multihop command for nonadjacent neighbor IP addresses.
b. iBGP-learned routes are advertised over confederation eBGP connections.
c. A full mesh of iBGP peers inside a confederation sub-AS is not required.
d. None of the other answers are correct.
11. R1 is BGP peered to R2, R3, R4, and R5 inside ASN 1, with no other peer connections inside the AS. R1 is a route reflector, serving R2 and R3 only. Each router also has an eBGP connection, through which it learns the following routes: 1.0.0.0/8 by R1, 2.0.0.0/8 by R2, 3.0.0.0/8 by R3, 4.0.0.0 by R4, and 5.0.0.0/8 by R5. Which of the following are true regarding the propagation of these routes?
a. NLRI 1.0.0.0/8 is forwarded by R1 to each of the other routers.
b. NLRI 2.0.0.0/8 is sent by R2 to R1, with R1 forwarding only to R3.
c. NLRI 3.0.0.0/8 is sent by R3 to R1, with R1 forwarding to R2, R4, and R5.
d. NLRI 4.0.0.0/8 is sent by R4 to R1, but R1 does not forward the information to R2 or R3.
e. NLRI 5.0.0.0/8 is sent by R5 to R1; R1 reflects the route to R2 and R3, but not to R4.
12. R1 is in confederation ASN 65001; R2 and R3 are in confederation ASN 65023. R1 is peered to R2, and R2 is peered to R3. These three routers are perceived to be in AS 1 by eBGP peers. Which of the following is true regarding the configuration of these routers?
a. Each of the three routers has a router bgp 1 command.
b. Both R2 and R3 need a bgp confederation peers 65001 BGP subcommand.
c. R1 needs a bgp confederation identifier 1 BGP subcommand.
d. Both R2 and R3 need a bgp confederation identifier 65023 BGP subcommand.
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