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Exam A
QUESTION 1
Exhibit: Certkiller router#show ip route Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2 E1 – OSPF external type 1, E2 – OSPF external type 2, EEGP i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, * -candidate default U – per-user static route, o – ODR T – traffic engineered route Gateway of last resort is not set 172.16.0.0/24 is subnetted, 2 subnets B 172.16.10.0 [20/0] via 10.1.1.100, 00:00:24 B 172.16.11.0 [20/0] via 10.1.1.100, 00:00:24 172.26.0.0/28 is subnetted, 3 subnets B 172.26.1.48 [200/0] via 192.168.1.50, 00:00:31 B 172.26.1.32 [200/0] via 192.168.1.50, 00:00:31 B
172.26.1.16 [200/0] via 192.168.1.50, 00:00:31 10.0.0.0/8 is variable subnetted, 2 subnets, 2 masks B 10.0.0/8 [20/0] via 10.1.1.100, 00:00:24 C 10.1.1.0/24 is directly connected, Serial3 192.168.1.0/28 is subnetted, 3 subnets C 192.168.1.32 is directly connected, Serial1 C 192.168.1.48 is directly connected, Serial2 C 192.168.1.16 is directly connected, Serial0 192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks B 192.168.2.64/28 [20/0] via 10.1.1.100,
00:00:26
Based on the show ip route output in the exhibit, how can you tell if a BGP route is learned via IBGP or EBGP?
A.
By the Metric
B.
By the Next Hop
C.
By the Admin Distance
D.
By the code “B” or “B Ex”
Correct Answer: C Section: (none) Explanation
Explanation/Reference:
Explanation: admin distance. Distance of EBGP is 20, Distance of IBGP is 200.
QUESTION 2
What is the range of values from which an ISP can assign a private AS number?
A. 32768 to 65535
B. 64512 to 65535
C. 65101 to 65535
D. 65001 to 65535
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation: An autonomous system (AS) is a collection of networks under a single technical administration. Some other definitions refer to a collection of routers or IP prefixes, but in the end they all mean the same entity. The important principle is the technical administration, which means sharing the same routing protocol and routing policy. Legal and administrative ownership of the routers does not matter in terms of autonomous systems. Autonomous systems are identified by AS numbers, 16-bit unsigned quantities ranging from 1 to 65535. Public AS numbers are assigned by Internet registries. For customers that need AS numbers to run BGP in their private networks, a range of private AS numbers (64512 – 65535) has been reserved. Reference: Configuring BGP on Cisco Routers volume 1 p.2-4
QUESTION 3
Network topology exhibit
What can prevent the corresponding BGP session from being successfully established?
A. Certkiller 2 and Certkiller 5 cannot establish the IBGP session because Certkiller 2 and Certkiller 5 are not directly connected.
B. Certkiller 1 and Certkiller 2 establish the EBGP session if the BGP holddown timers between the two EBGP neighbors are different.
C. Certkiller 2 and Certkiller 5 cannot establish the IBGP session using the loopback0 interface if the EBGP-multihop value is set to the default value.
D. Certkiller 1 and Certkiller 2 cannot establish the EBGP session using the loopback0 interface if the EBGP-multihop value is set to the default value.
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
QUESTION 4
Exhibit:
How should the EBGP session between R1 and R2 be established to enable load balancing? (Choose three)
A. Use the maximum-paths 2 option.
B. Use the ebgp-multihop 2 option.
C. Use static routes on R1 and R2 to reach the other router’s loopback.
D. Establish a single EBGP session using the loopback0 interface IP address on R1 and R2.
E. Establish twp EBGP sessions using both the S0 and S1 interface IP address on R1 and R2.
Correct Answer: BCD Section: (none) Explanation
Explanation/Reference:
Explanation:
1.
B R1 – R2 requires a EBGP ebgp-multihop of 2.
2.
C Requires two static routes going to each other router loopback interface
3.
D A BGP session of course is required. Only a single connection is required. Use the loopback is what allows things to work even during a failure Wrong Answer
1.
A This is not required because there is only on EBGP path. Would need two if static routes were not define and were going between different routers
2.
E Not an efficient way of doing things requires double the tables and bandwidth for updates
QUESTION 5
Which two statements are true about an EBGP session or an IBGP session? (Choose two.)
A. IBGP uses AS-Path to detect routing information loops within the AS.
B. EBGP routes have a default Admin Distance of 20 and IBGP routes have a default Admin Distance of
200.
C. No BGP attributes are changed in EBGP updates except for the next-hop attribute if next-hop-self is configured.
D. Routes learned from an EBGP peer not advertised to another EBGP peer to prevent routing information loops.
E. IBGP uses split horizon to prevent routing information loops; routes learned from an IBGP peer are not advertised to another IBGP peer.
Correct Answer: BE Section: (none) Explanation
Explanation/Reference:
QUESTION 6
Network Topology Exhibit
Exhibit #2: Certkiller 2 configuration When Certkiller 2 sends the TCP SYN packet to Certkiller 3 to establish the IBGP session, what will be the source IP address of the TCP SYN packet from Certkiller 2 to Certkiller 3?
A. 2.2.2.2
B. 3.3.3.3
C. 10.1.1.1
D. 10.1.1.2
Correct Answer: C Section: (none) Explanation
Explanation/Reference:
QUESTION 7
Network topology Exhibit
How should the EBGP session between Certkiller 1 and Certkiller 2 be established to enable load balancing? (Choose three.)
A. Use the maximum-paths 2 option
B. Use the ebgp-multihop 2 option
C. Use static routes on Certkiller 1 and Certkiller 2 to reach the other router’s loopback
D. Establish a single EBGP session using the loopback0 interface IP address on Certkiller 1 and Certkiller
E. Establish two EBGP sessions using both the S0 and D1 interface IP address on Certkiller 1 and Certkiller 2
Correct Answer: BCD Section: (none) Explanation
Explanation/Reference:
QUESTION 8
Exhibit
What can prevent the corresponding BGP session from being successfully established?
A. CK2 and CK5 cannot establish the IBGP session if the BGP Hello Timer between the two IBGP neighbors is different.
B. CK1 and CK2 cannot establish the EBGP session if the BGP Hello Timer between the two EBGP neighbors are different.
C. CK1 and CK2 cannot establish the EBGP session using the loopback0 interface if the EBGP-mutlihop value is set to 2.
D. CK2 and CK5 cannot establish the IBGP session because they are not using the loopback0 interface to establish the IBGP session.
E. CK2 and CK5 cannot establish the IBGP session if CK3 and CK4 have an access list permitting only TCP port 80 and IP protocol number 89 traffic.
Correct Answer: E Section: (none) Explanation
Explanation/Reference:
QUESTION 9
The Outbound Route Filter (ORF) capability is negotiated between BGP neighbors during the BGP ____ process via the _____ message.
A. route propagation; Update
B. session establishment; Open
C. route propagation; Notification
D. route propagation; Route Refresh
E. session establishment; Route Refresh
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation: Capabilities are negotiated during session establishment in the open message. Appendix C P456 Internet routing Architectures. Wrong
1.
A needs to be decided before update
2.
C notification is an error message
3.
D not a message type
4.
E not a message type
QUESTION 10
BGP table
Address Prefix AS-Path Next hop Communities Other attr.
10.0.0.0 /8 65100 65101 1.1.1.1 65101:111 … … … … … …
IP routing table
Protocol Address Prefix Next-hop Outgoing interface BGP 10.0.0.0 /8 1.1.1.1
OSPF 1.1.1.1 /32 172.16.1.2 Ethernet 0
conn. 172.16.1.0 /24 Ethernet 0
IP routing table
Protocol Address Prefix Next-hop Outgoing
interface
BGP 10.0.0.0 /8 1.1.1.1
OSPF 1.1.1.1 /32 172.16.1.2 Ethernet 0
conn. 172.16.1.0 /24 Ethernet 0
To forward a packet to 10.0.0.0/8, the router perform the following steps:
Step 1. Search the ip routing table for a route to reach the 10.0.0.0/8 network.
Step 2. ___________________________
Step 3. Find the connected outgoing interface to reach 172.16.1.2. Step 4. Arp for the 172.16.1.2 MAC
address if it is not already in the ARP cache. Step 5. Store the 172.16.1.2 MAC address in the Fast
Switching cache for successive packets to network 10.0.0.0.
What is step 2?
A. Search the BGP table for an IGP route to reach the BGP next-hop 1.1.1.1.
B. Search the BGP table for an IBGP route to reach the BGP next-hop 1.1.1.1.
C. Search the IP routing table for an IGBP route to reach the BGP next-hop 1.1.1.1.
D. Search the IP routing table for an IGP route to reach the BGP next-hop of 1.1.1.1.
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation: Routing table specifies to get to 10.0.0.0 goto 1.1.1.1. To get to 1.1.1.1 do a lookup in the routing table on the next hop.
QUESTION 11
Exhibit What is the limitation of BGP?
A. AS 65101 cannot use BGP to connect to AS 65102.
B. AS 65102 cannot use MED to influence the return traffic from AS 65103.
C. AS 65102 cannot influence how AS 65103 will route traffic out to AS 65105.
D. AS 65102 cannot load balance the traffic to AS 65105 via AS 65103 and AS 65104.
E. Since AS 65102, 65103, and AS 65104 are Transit AS, they must enable synchronization.
Correct Answer: C Section: (none) Explanation
Explanation/Reference:
QUESTION 12
Exhibit:
What is the required configuration on Certkiller 2 to allow Certkiller 2 to announce the 192.168.0.0/16 prefix to Certkiller 3 via BGP?
A. router bgp 65101 neighbor 10.1.1.2 remote-as 65102 neighbor 192.168.1.2 remote-as 65101
network 192.168.1.0
auto-summary
B. router bgp 65101 neighbor 10.1.1.2 remote-as 65102 neighbor 192.168.1.2 remote-as 65101 network 192.168.0.0 ! ip route 192.168.0.0 255.255.0.0 192.168.1.2
C. router bgp 65101 neighbor 10.1.1.2 remote-as 65102 neighbor 192.168.1.2 remote-as 65101 network 192.168.0.0 mask 255.255.0.0 auto-summary ! ip route 192.0.0.0 255.0.0.0 192.168.1.2
D. router bgp 65101 neighbor 10.1.1.2 remote-as 65102 neighbor 192.168.1.2 remote-as 65101 network 192.168.0.0 mask 255.255.0.0 ! ip route 192.168.0.0 255.255.0.0 192.168.1.2
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation: Without knowing the IGP, we must ensure that an exact route into the routing table for the network advertised. Wrong Answer
1.
A Auto summary would only summarize 192.168.1.0/24 and not /16
2.
B Will only advertise 198.168.0.0/24 and not /16
3.
C Need an exact match on route in Routing table and network command
QUESTION 13
Exhibit:
What is the proper BGP configuration on Certkiller 3 to have Certkiller 3 announce the 172.0.0.0/8 prefix from Certkiller 4 to Certkiller 2 via BGP with a next hop of 10.1.1.1?
A. router bgp 65102 neighbor 10.2.2.1 remote-as 65103 neighbor 10.1.1.2 remote-as 65102
B. router bgp 65102 neighbor 10.2.2.1 remote-as 65103 neighbor 10.1.1.2 remote-as 65102 neighbor 10.2.2.1 next-hop-self
C. router bgp 65102 neighbor 10.2.2.1 remote-as 65103 neighbor 10.1.1.2 remote-as 65102 neighbor 10.1.1.2 next-hop-self
D. router bgp 65102 neighbor 10.2.2.1 remote-as 65103 neighbor 10.1.1.2 remote-as 65102 neighbor 10.1.1.2 update-source-self
Correct Answer: C Section: (none) Explanation
Explanation/Reference:
Explanation: Causes next-hop to be outgoing interface to neighbor 10.1.1.2 Wrong Answer
1.
A is missing Next-hop-self command
2.
B This is not done at the EBGP level
3.
D update-source-self invalid parameter update-source address is the proper neighbor parameter
QUESTION 14
Exhibit:
Which two configuration commands will complete the BGP configuration on Certkiller 1 so it will conditionally announce the 172.0.0.0/8 to Certkiller 4 via BGP? (Choose two) hostname Certkiller 1 ! !output omitted !
1.
_____________________ ! router bgp 65001 neighbor 172.16.1.1 remote-as 65001 neighbor 2.2.2.2 remote-as 65001 neighbor 4.4.4.4 remote-as 387 !
2.
____________________ !
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
Correct Answer: BE Section: (none) Explanation Explanation/Reference:
Explanation:
1.
1 E, conditional static route disappears when the link to 172.16.1.1 disappears
2.
2B, correct network command, correct mask, will not advertise when link goes down. Wrong
1.
A wrong mask need /8 this defaults to /16
2.
C This is unconditional
3.
D This is an unconditional floating static route
4.
F should be 172.0.0.0 not 172.0.0.9
QUESTION 15
Exhibit:
What is wrong with the BGP configuration in the exhibit?
A. The auto-summary configuration is missing.
B. The network 10.0.0.0 statement is missing mask 0.255.255.255.
C. The network 10.0.0.0 statement is missing mask 255.0.0.0
D. The network 192.168.0.0 statement is missing mask 255.255.0.0.
E. The network 192.168.0.0 statement is missing mask 0.0.255.255
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
QUESTION 16
Based on the following show ip bgp neighbor 10.1.1.1 output: R1#show ip bgp neighbors 10.1.1.1 BGP neighbor is 10.1.1.1, remote AS 65103, external link BGP version 4, remote under ID 0.0.0.0 BGP state = Active Last read 00:00:04, hold time is 180, keepalive interval is 60 seconds Received 44 messages, 0 notifications, 0 in queue Sent 45 messages, 6 notifications, 0 in queue Route refresh request: received 0, sent 0 Default minimum time between advertisement runs in 30 seconds For address family: IPv4 Unicast BGP table version 1, neighbor version 0 Index 2, Offset 0, Mask 0x4 0 accepted prefixes consume 0 bytes Prefix advertised 0, suppressed 0, withdraw 0 Number of NLRIs in the update sent: max 0, min 0 Connections established 7; dropped 7 Last reset 00:05:18, due to BGP Notification received, peer in wrong AS External BGP neighbor may be up to 2 hops away. No active TCP connection What is causing the BGP session to the 10.1.1.1 neighbor to toggle between the Idle and Active state?
A. There is an AS number configuration error.
B. The BGP neighbor 10.1.1.1 is not reachable.
C. The EBGP-multihop value for neighbor 10.1.1.1 is set to the default value.
D. The BGP session is using the loopback interface but the update source is not set to specify the loopback interface.
Correct Answer: A Section: (none) Explanation
Explanation/Reference:
Explanation: The key is looking at the last section of the output. We specified the neighbor in AS 65103 but received an error (Notification) that it is not in that AS.
QUESTION 17
Exhibit: R1#show ip bgp BGP table version is 1, local router ID is 10.0.0.1 Status codes: s suppressed, d damped, h history, *valid,>best,iinternal Origin codes: i – IGP, e – EGP,? – incomplete Network Next Hop Metric LocPrf Wight Path *i133.3.0.0 3.3.3.3 0 100 0 65101 i *i172.0.0.0/8 20.1.1.5 0 100 0 65102 i R1#show ip route Codes: C – connected, S – static, I – IGRP, R -RIP, M -mobile, B
–
BGP D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2 E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, * – candidate default U – per-user static route, o – ODR, P – periodic downloaded staticroute T – traffic engineered route Gateway of last resort is not set C 30.0.0.0/8 is directly connected, FastEthernet0/0 C 10.0.0.0/8 is directly connected, Loopback111 C 40.0.0.0/8 is directly connected, Serial0/0 Based on the exhibits show ip bg and show ip route output, what is the most likely problem that causes the two IBGP routes NOT to be selected as the best route in the BGP table?
A.
The Weight is 0.
B.
The origin code is “i,”.
C.
The Metric (MED) is 0.
D.
BGP synchronization is disabled.
E.
The BGP next-hop is not reachable.
Correct Answer: E Section: (none) Explanation
Explanation/Reference:
Explanation: One of the first criteria in BGP to accept a route is that the next hop must be reachable.
QUESTION 18
Based on the following show ip bgp neighbors output from Certkiller 2, which two statements are true? (Choose two) Certkiller 2#show ip bgp neighbors BGP neighbor is 10.1.1.5, remote AS 65101, internal link Index 1, Offset 0, Mask 0x2 Route-Reflector Client BGP version 4, remote router ID 5.5.5.5 BGP state = Established, table version = 4, up for
00:01:29 Last read 00:00:29, hold time is 180, keepalive interval is 60 seconds Minimum time between advertisement runs is 5 seconds Received 13556 messages, 0 notifications, 0 in queue Sent 13454 messages, 0 notifications, 0 in queue Prefix advertised 0, suppressed 0, withdraw 0 Default weight 900 Inbound path policy configured Route map for incoming advertisement is test Connections established 31; dropped 30 Last reset 00:01:40, due to User reset 3 accepted prefixes consume 96 bytes 0 history paths consume 0 bytes 0 history paths consume 0 bytes
A. Certkiller 2 is a route reflector client of the 10.1.1.5 neighbor.
B. Certkiller 2 is a route reflector and the 10.1.1.5 neighbor is a client of Certkiller 2.
C. Certkiller 2 has successfully established the IBGP session with the 10.1.1.5 neighbor.
D. All the BGP updates from Certkiller 2 to the 10.1.1.5 neighbor must go through the route-map called “test”.
Correct Answer: BC Section: (none) Explanation
Explanation/Reference:
Explanation:
1.
B The neighbor does not know that it is a route reflector client.
2.
C Certkiller 2 established the IBGP session with 10.1.1.5 . Must be IBGP because we are using route reflectors. Wrong Answer
1.
A. Certkiller 2 is a reflector and not a client
2.
D. BGP updates from 10.1.1.5 not Certkiller 2 must go through route map test. Key this route map is used for incoming advertisement.
QUESTION 19
Which Cisco IOS command is used to view the amount of CPU resources consumed (utilization) due to running BGP processes?
A. show ip bgp process
B. show memory | include BGP
C. show process cpu | include BGP
D. show ip protocols | include BGP
E. show cpu utilization | include BGP
Correct Answer: C Section: (none) Explanation
Explanation/Reference:
Explanation: show process cpu is the command used to show cpu resources of all processes. Piping to include show only BGP’s usage.
QUESTION 20
Exhibit Which two statements are true? (Choose two).
A. Certkiller 1 has accepted 20 prefixes from the 2.2.2.2 IBGP neighbor.
B. Certkiller 1 generated a warning message to the router’s console after the 2.2.2.2 IBGP neighbor sent 16 prefixes to Certkiller 1.
C. Certkiller 1 generated a warning message to the router’s console after the 2.2.2.2 IBGP neighbor sent 15 prefixes to Certkiller 1.
D. Certkiller 1 will drop its neighbor relationship to the 2.2.2.2 IBGP neighbor if 2.2.2.2 sends two more additional prefixes to Certkiller 1.
E. Certkiller 1 will drop its neighbor relationship to the 2.2.2.2 IBGP neighbor if 2.2.2.2 sends three more additional prefixes to Certkiller 1.
Correct Answer: BE Section: (none) Explanation
Explanation/Reference:
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