QUESTION 51 Given the following: The customer (AS 65100) is advertising the 172.0.0.0/8 prefix over the upper link without using AS-Path pretending. The customer (AS 65100) is advertising the 172.0.0.0/8 prefix with a pretended AS-Path of AS 65100 65100 65100 65100 over the lower link. Which two statements are true about the incoming traffic to 172.0.0.0/8? (Choose two)

A. The lower link will be preferred over the upper link.

B. The upper link will be preferred over the lower link.

C. The upper link will act as a backup for the lower link.

D. The lower link will act as a backup for the upper link.

E. The upper and lower Links will be used simultaneously for load balancing Answer: B, D Explanation:

• B. The upper link is preferred over the lower link, since, the shortest AS-PATH is preferred
• D. The lower link will act as a backup. If the upper link fails then the lower link will be the preferred path

QUESTION 52 Exhibit:

Which two configuration commands will complete the BGP configuration on Cisco Highway 1 so it will conditionally announce the 172.0.0.0/8 to Cisco Highway 4 via BGP? (Choose two) hostname Cisco Highway 1 ! !output omitted !

1. _____________________ ! router bgp 65001 neighbor 172.16.1.1 remote-as 65001 neighbor 2.2.2.2 remote-as 65001
2. neighbor 4.4.4.4 remote-as 387 !
1. ____________________ !

A. 2. network 172.16.0.0

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 Explanation:

• 1 E, conditional static route disappears when the link to 172.16.1.1 disappears
• 2B, correct network command, correct mask, will not advertise when link goes down. Wrong Answers
• A. wrong mask need /8 this defaults to /16
• C. This is unconditional
• D. This is an unconditional floating static route
• F. should be 172.0.0.0 not 172.0.0.9

QUESTION 53 Which two statements are true about multihomed customers? (Choose two)

A. The customer usually uses provider assigned (PA) address space.

B. The customer usually uses provider independent (PI) address space.

C. Static routing is always adequate between the customer and service provider.

D. BGP is only needed if physical link failures on the primary link cannot be detected.

E. The customer runs BGP with the service provider using either a private or a public AS number. Answer: B, E? Explanation:

• B use PI when possible so route aggregation of ISP is not prevented
• E Can be either and private or public AS number. However, the private number is not common practice. See ISP essentials. Wrong Answers
• A. Provider assigned is not common for multi-home, common for Single connected
• C. Static routing is not appropriate when multi-homing to multiple ISP's
• D. multi-homing can be used for load balancing.

QUESTION 54 In a multihomed environment with two ISP connections, which two statements are true? (Choose two)

A. The customer should not be configured to act as a transit AS between the two ISPs.

B. It is recommended that the multi-homed customer use a registered (public) AS number.

C. AS-Path pretending can be configured on the customer's edge router to influence the BGP path selection process for the outbound traffic (traffic from the customer to the ISPs).

D. The customer can use Local Preference on the customer's edge routers to influence the BGP path selection process for the inbound traffic (traffic from the ISPs to the customer).

E. The advertisement of customer's IP address space can be conditioned by the customer's edge routers by using a static route to the null0 interface and by using the proper network statement under router bgp. Answer: A, E Explanation:

• A Customers do not want to become a transit for ISP's
• E This a valid way to advertise routes to the ISP Wrong Answers
• B. ISP essentials says most popular, does not say recommend
• C. affects inbound traffic
• D. local preference is for outbound traffic

QUESTION 55 Exhibit: Based on the show ip bgp 11.2.3.0 output shown in the exhibit, which two statements are true? (Choose two)

A. The route will not be sent to any EBGP neighbors.

B. The route is using the default Weight and Local Preference values.

C. The route will not be propagated to any IBGP or EBGP peers because it has the "no_export" community.

D. The origin code is "incomplete" because the network command was used to advertise the route via BGP. Answer: A, B Explanation:

• A Route will not be sent to any EBGP neighbor, no-export ensures this
• B Default local preference is 100 Wrong Answers
• C no-export means do not advertise to EBGP peer. no-advertise means do not advertise to any peer.
• D incomplete is if IGP is redistributed into BGP.

QUESTION 56 Which three statements about an EBGP session or an IBGP session are true? (Choose three)

A. EBGP uses AS-Path to detect routing information loops.

B. BGP route selection rules favor IBGP routes over EBGP routes.

C. No BGP attributes are changed in IBGP updates except for the next-hop attribute if next-hop-self is configured.

D. Routes learned from an IBGP peer are not advertised to another IBGP peer to prevent routing information loops within the AS.

E. EBGP uses split horizon to prevent routing information loops; routes learned from an EBGP peer are not advertised to another EBGP peer. Answer: A, C, D Explanation:

• A EBGP uses AS-Path to ensure that it is not passing its own route back to itself
• C No BGP attributes are changed
• D Router learned via IBGP are not advertised to prevent loops Wrong Answers
• B. IBGP routes have admin distance of 200 and EBGP of 20. 20 is preferred
• E. routes learned from EBGP peers are advertised to other EBGP peers.

QUESTION 57 Which optional configuration parameter is required on a static route so a route-map can be used to match the static route?

A. Tag

B. Distance

C. Community

D. Permanent Answer: A Explanation: Command is ip route prefix mask { address | interface } [distance] [tag tag][permanent]. Where tag can be used a match value in route-maps

QUESTION 58 Exhibit: Complete the following Cisco Highway 1 BGP configuration to load balance the traffic from AS 65101 to AS 65102 if two identical EBGP routes are learned from AS 65102. hostname Cisco Highway 1 ! router bgp 65101 neighbor 10.1.1.2 remote-as 65102 neighbor 10.2.2.2 remote-as 65102

A. variance 2

B. maximum-paths 2

C. neighbor 10.1.1.2 weight 100 neighbor 10.2.2.2 weight 100

D. neighbor 10.1.1.2 eBGP-multihop 2 neighbor 10.2.2.2 eBGP-multihop 2

E. neighbor 10.1.1.2 local-preference 100 neighbor 10.2.2.2 local-preference 100 Answer: B Explanation: Maximum-paths 2 is required to load balance traffic between the two AS's. Wrong Answers

• A. Variance 2 is an EIGRP command to balance between over two BGP sessions
• C. Similar weight is required to load balance
• D. Multihop is not required
• E. Local preference needs to be similar to allow load balancing

QUESTION 59 Exhibit: Given the following configurations, Cisco Highway 2 and Cisco Highway 3 are not able to successfully establish the IBGP session using the loopback 0 interface. What could be the cause of this problem? ! ! output omitted ! hostname Cisco Highway 2 interface lo 0 ip address 2.2.2.2 ! interface e0 ip address 10.1.1.1 255.255.255.0 no shut ! interface e1 ip address 10.2.2.1 255.255.255.0

no shut ! router bgp 65101 neighbor 172.16.1.1 remote-as 65100 neighbor 3.3.3.3 remote-as 65101 neighbor 3.3.3.3 update-source loopback0 ! router eigrp 101 network 10.0.0.0 ! ! output omitted ! hostname Cisco Highway 3 ! interface lo 0 ip address 3.3.3.3 ! interface e0 ip address 10.1.1.2 255.255.255.0 no shut ! interface e1 ip address 10.2.2.2 255.255.255.0 no shut ! router bgp 65101 neighbor 192.168.1.1 remote-as 65102 neighbor 2.2.2.2 remote-as 65101 neighbor 2.2.2.2 update-source loopback0 ! router eigrp 101 network 10.0.0.0 !

A. The "No Sync" BGP configuration command is missing.

B. Cisco Highway 2 and Cisco Highway 3 are using the loopback0 IP address as the source address for the BGP messages to each other.

C. The "network 2.0.0.0" EIGRP configuration command is missing on Cisco Highway 2 and the "network 3.0.0.0" EIGRP configuration command is missing on Cisco Highway 3.

D. The "Neighbor 2.2.2.2 iBGP-multihop 2" BGP configuration command is missing on Cisco Highway 3 and the "neighbor 3.3.3.3 iBGP-multihop 2" BGP configuration command is missing on Cisco Highway 2. Answer: C Explanation: Without the network statements the IGP does not know how to find the loopback interfaces. Wrong Answers

• A. No Sync will not stop the fact that the IGP does not know to route to the loopback interfaces
• B. This statement is ok, but is not what is wrong
• D. IBGP does not require a multihop statement

QUESTION 60 Which forward mechanism pre-builds the complete IP forwarding table (FIB) based on the IP routing table?

A. CEF Switching

B. Fast Switching

C. Process Switching

D. Optimum Switching Answer: A Explanation: CEF is the most advanced form and build a separate FIB. See cef.htm#5757

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