QUESTION 1 Exhibit: There is no direct physical connectivity between Cisco Sources 3 and Cisco Sources 5. The Transit AS 65102 is only running partial-meshed IBGP between Cisco Sources 3 and Cisco Sources 5 and is using OSPF as its IGP. Both Cisco Sources 3 and Cisco Sources 5 are using the next-hop-self options. The external BGP routes are not being redistributed into OSPF. BGP synchronization is disabled. What happens to the packet from AS 65101 to AS 65103?

A. Packets will be black-holed because it will be dropped by Cisco Sources 4.

B. Packets will be black-holed because it will be dropped by Cisco Sources 5.

C. Packets will be black-holed because it will be dropped by Cisco Sources 6.

D. Packets can be transported via the Transit AS 65102 without any problems. Answer: C Explanation: Even with synchronization off testing 6 does not know how to route the packet because OSPF does not know about the route that BGP knows about. Synchronization being off assumes that there is a full mesh of BGP routers.

QUESTION 2 Identify the most appropriate method to connect the customers to the ISPs, to interconnect the two ISPs, and to interconnect the router within each ISP. Place the methods in their correct locations in the diagram.

Answer:

Explanation:

• Box1 EBGP Cisco Sources .com 1 to ISP1. This is a multi-homed Internet connection. Most appropriate
• Box 2 IBGP Routers within ISP1
• Box 3 EBGP Between ISP1 and ISP2
• Box 4 IBGP Routers within ISP 2
• Box 5 Static Routing (Here is the catch). Because this is not a multi-homed connection the most appropriate method is static routes
• Box 6 EBGP Cisco Sources .com 2 to ISP2. This is a multi-homed Internet connection. Most appropriate

QUESTION 3 By default, NOT using the next-hop-self option, what is the next-hop for the 172.0.0.0/8 BGP updates shown in the diagram? Place the correct next-hops in their locations in the diagram.

Answer: Explanation:

• Cisco Sources 1- Cisco Sources 2 Next Hop 10.1.1.1 This is an EBGP connection. Next hop is address of EBGP peer that advertised the route.
• Cisco Sources 4- Cisco Sources 5 Next Hop 10.4.4.1 This is an EBGP connection. Next hop is address of EBGP peer that advertised the route.
• Cisco Sources 3- Cisco Sources 4 Next Hop 10.1.1.1 This is an IBGP connection. Next hop is address of EBGP peer that advertised the route.

QUESTION 4 Exhibit:What can prevent the corresponding BGP session from being successfully established?

A. R2 and R5 cannot establish the IBGP session if the BGP Hello Timer between the two IBGP neighbors is different.

B. R1 and R2 cannot establish the EBGP session if the BGP Hello Timer between the two EBGP neighbors is different.

C. R1 and R2 cannot establish the EBGP session using the loopback0 interface if the EBGP-multihop value is set to 2.

D. R2 and R5 cannot establish the IBGP session because they are not using the loopback0 interface to establish the IBGP session.

E. R2 and R5 cannot establish the IBGP session if R4 and R4 have an access list

permitting only TCP port 80 and IP protocol number 89 traffic. Answer: C, E Explanation:

• C By default EBGP has multi-hop of 1. Without a multi-hop of 2 a connection can not be established
• E TCP for 179 is use by BGP. BGP session is routed through the IGP (OSPF). This means by default traffic between R2 and R5 will route through R4, because R4 has the lowest cost path. However if only ports 80 and 89 are allowed 179 will not work. Wrong Answers
• D If between R2 and R5 will work as long as links are up. The sessions will succeed no matter how it is configured. The catch is when the link breaks then the session may or may not fail. It would be best to use a loopback.
• A Hello timers can be different. Use caution
• B Hello Timers can be different. Use caution.

QUESTION 5 Exhibit: What is the required configuration on Cisco Sources 2 to allow Cisco Sources 2 to announce the 192.168.0.0/16 prefix to Cisco Sources 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 Answer: D Explanation: Without knowing the IGP, we must ensure that an exact route into the routing table for the network advertised. Wrong Answers

• A Auto summary would only summarize 192.168.1.0/24 and not /16
• B Will only advertise 198.168.0.0/24 and not /16
• C Need an exact match on route in Routing table and network command

QUESTION 6 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. Answer: A 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 7 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. Answer: B, C, D Explanation:

• B R1 - R2 requires a EBGP eBGP-multihop of 2.
• C Requires two static routes going to each other router loopback interface
• 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 Answers
• 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
• E Not an efficient way of doing things requires double the tables and bandwidth for updates

QUESTION 8 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,i- internal 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 - EGPi - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate

default

U - per-user static route, o - ODR, P - periodic downloaded

static route

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. Answer: E Explanation: One of the first criteria in BGP to accept a route is that the next hop must be reachable.

QUESTION 9 Exhibit: The best path from Cisco Sources 18 (AS 65103) to the 172.0.0.0/8 prefix (AS 65101) is _______.

A. Via Cisco Sources 15 to AS 65104 then to AS 65101 because it has the best MED.

B. Via Cisco Sources 17 to AS 65102 then to AS 65101 because it has the best MED.

C. Load balanced between Cisco Sources 15 and Cisco Sources 17 due to the equal AS-Path length.

D. Via Cisco Sources 15 to AS 65104 then to AS 65101 because it has the best Local Preference.

E. Via Cisco Sources 17 to AS 65102 then to AS 65101 because it has the best Local Preference. Answer: D Explanation: BGP selects routes based on Higher Local Preference and then lower MED. LP is use to route to a designation. MED is used for path back. Wrong Answers

• A. MED is not used for path there
• B. MED is not used for path there
• C Not load balanced because Local Preference takes precedence. BGP only hand over best path to IP by default. multi-path would have to be specified for the chance to load balance
• E Best local preference is the one with the highest value.

QUESTION 10 Exhibit: What is the proper BGP configuration on Cisco Sources 3 to have Cisco Sources 3 announce the 172.0.0.0/8 prefix from Cisco Sources 4 to Cisco Sources 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 Answer: C Explanation: Causes next-hop to be outgoing interface to neighbor 10.1.1.2 Wrong Answers

• A is missing Next-hop-self command
• B This is not done at the EBGP level
• D update-source-self invalid parameter update-source address is the proper neighbor parameter