QUESTION 90
Every time a flap occurs on a route, the route receives ________.
A. 750 per-flap penalty points which are user configurable.
B. 1500 per-flap penalty points which are user configurable.
C. 2000 per-flap penalty points which are user configurable.
D. 1000 per-flap penalty points which are not user configurable.
E. 2000 per-flap penalty points which are not user configurable.
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation: Everytime a flap occurs a penalty of 1000 is made and is not configurable. See sections on route dampening in Internet routing architectures guide.
QUESTION 91
In reference to BGP route flap dampening feature, when will the penalty and the flap history of a route clear?
A. When the penalty associated with a route reaches the reuse limit.
B. When a route is in the history state for longer than the half-time limit.
C. When the penalty associated with a route reaches the suppress limit.
D. When a route in the suppressed state for longer then the half-time limit.
E. When the penalty associated with a route drops below half the reuse limit.
Correct Answer: E Section: (none) Explanation
Explanation/Reference:
Explanation: A router stops tracking penalty points once they are below half of the reuse limit. After enabling RFD, the router never rmoves a route from the BGP table. A route that has been withdrawn by a BGP neighbor can still be seen in the BGP table marked with “h” (history state. The penalty is always applied to a path and not a prefix. If one of the paths is flapping, it does not mean that the destination is flapping. Reference: Configuring BGP on Cisco routers p. 7-120
QUESTION 92
DRAG DROP
A.
B.
C.
D.
Correct Answer: Section: (none) Explanation
Explanation/Reference:
QUESTION 93
Exhibit:
Complete the following Certkiller 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 Certkiller 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
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation: Maximum-paths 2 is required to load balance traffic between the two AS’s. Wrong
1.
A Variance 2 is an EIGRP command to balance between over two BGP sessions
2.
C Similar weight is required to load balance
3.
D Multihop is not required
4.
E Local preference needs to be similar to allow load balancing
QUESTION 94
In a Transit AS, how do the internal routers within the Transit AS forward packets destined for the external networks using a scalable solution?
A. Using the default route.
B. Using the IGP routes where the external networks are redistributed into the IGP by the edge routers.
C. Using the EBGP routes where the external networks are redistributed into the IBGP by the edge routers.
D. Using the IBGP routes, then using recursive lookup based on IGP information to resolve the BGP next-hop.
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation: The BGP route is installed in the routing table only if the IP address in the next-hop attribute is reachable according to the information already in the routing table. The BGP route is installed with a reference to that next-hop address. So the network will be reachable via an IP address, which may or may not be directly connected. Since there is no clear reference to a physical interface, the BGP route is installed in the IP routing table withut any information about outgoing interface. Reference: Configuring BGP on Cisco routers. P.4-30
QUESTION 95
Which BGP dampening configuration parameter is not configurable by the user?
A. half-time
B. reuse-limit
C. max-suppress
D. suppress-limit
E. per-flap-penalty
Correct Answer: E Section: (none) Explanation
Explanation/Reference:
QUESTION 96
Exhibit: There is no direct physical connectivity between Certkiller 3 and Certkiller 5. The Transit AS 65102 is only running partial-meshed IBGP between Certkiller 3 and Certkiller 5 and is using OSPF as its IGP. Both Certkiller 3 and Certkiller 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 Certkiller 4.
B. Packets will be black-holed because it will be dropped by Certkiller 5.
C. Packets will be black-holed because it will be dropped by Certkiller 6.
D. Packets can be transported via the Transit AS 65102 without any problems.
Correct Answer: C Section: (none) Explanation
Explanation/Reference:
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 97
SIMULATION Network Topology Exhibit
Certkiller .com is a stock broker service that is using EIGRP AS 1 as the IGP in its network. Certkiller .com has decided to establish connectivity between the New York site and the Los Angeles site. NiceNet, a
service provider, has been selected by Certkiller .com to provide the connectivity between the two sites.
For this implementation NiceNet is using a MPLS VPN solution. NiceNet has already established MPLS
connectivity between all of its PE routers. MPBGP connectivity has also been established on all PE
routers. Certkiller .com has successfully completed all necessary tasks on the CE routers, and NiceNet
has **MISSING***.
The RD is 10:10.
The route target for import is 17:10.
The route target for export is 17:10.
Configure EIGRP between CE11A and PE11 using AS number 10. Redistribute from BGP to EIGRP AS 10
using a metric string of 10000 100 255 1 1500.
Redistribute from EIGRP AS 10 to BGP using metric string of 1. VPN is operational when you see the
routes for both the local (10.1.11.0) and the remote (10.1.12.0) sites in the VRF routing table. Click on the
host computer to start the simulation.
A.
B.
C.
D.
Correct Answer: Section: (none) Explanation
Explanation/Reference:
ip cef ! ip vrf customer description customer vrf rd 10:10 route-target export 17:10 route-target import 17:10 ! interface FastEthernet0/0 description customer ip vrf forwarding customer ip address 10.1.11.1 255.255.255.0 no shutdown ! router eigrp 10 no auto-summary ! address-family ipv4 vrf customer redistribute bgp default-metric 10000 100 255 1 1500 network 10.1.11.0 network 10.1.12.0 no auto-summary exit-address-summary ! router bgp 17 neigbor 10.1.12.1 remote-as 17 no auto-summary ! address-family ipv4 no auto-summary no synchronization exit-address-family ! address-family vpnv4 neighbor 10.1.12.1 activate neighbor 10.1.12.1 send-community extended exit-address-family !
address-family ipv4 vrf customer redistribute eigrp 10 default-metric 1 no auto-summary no synchronization exit-address-family !
QUESTION 98
What is the main advantage of the BGP Route Refresh capability as compared to the “BGP soft-reconfiguration in” option?
A. Route Refresh is not Cisco proprietary.
B. Route Refresh does not require additional memory.
C. Route Refresh does not require the BGP session to be taken down.
D. Route Refresh allows BGP routers to automatically send out new BGP updates.
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation:
Route Refresh Capability:
1) Does not require the BGP session to close
2) Does not require any additional memory
3) No down-time
4) Two versions:
-Cisco proprietary (Capability Code 128; for all protocols)
-Standard (RFC 2918; Capability Code 2; per-address-family Reference: Configuring BGP on Cisco Routers p.0-29
QUESTION 99
What are the three main BGP scaling issues for service providers? (Choose three.)
A. BGP policy scaling issues
B. IBGP full mesh scaling issues
C. BGP to IGP redistribution scaling issue
D. BGP updates and BGP table size scaling issues
Correct Answer: ABD Section: (none) Explanation
Explanation/Reference:
QUESTION 100
Network topology exhibit Based on the exhibit, what is the correct BGP confederation required on Certkiller 4?
A. router bgp 65001 bgp confederation indentifier 65101 bgp confederation peers 65002 65003 neighbor 10.3.3.5 remote-as 65001 neighbor 10.1.1.2 remote-as 65002 neighbor 10.2.2.3 remote-as 65003 neighbor 192.168.1.1 remote-as 65102
B. router bgp 65001 bgp confederation indentifier 65001 bgp confederation peers 65002 65003 neighbor 10.3.3.5 remote-as 65001 neighbor 10.1.1.2 remote-as 65002 neighbor 10.2.2.3 remote-as 65003 neighbor 192.168.1.1 remote-as 65102
C. router bgp 65101 bgp confederation peers 65001 65002 65003 neighbor 10.3.3.5 remote-as 65001 neighbor 10.1.1.2 remote-as 65002 neighbor 10.2.2.3 remote-as 65003 neighbor 192.168.1.1 remote-as 65102
D. router bgp 65001 bgp confederation peers 65002 65003 neighbor 10.3.3.5 remote-as 65001 neighbor 10.1.1.2 remote-as 65002 neighbor 10.2.2.3 remote-as 65003 neighbor 192.168.1.1 remote-as 65102
Correct Answer: A Section: (none) Explanation
Explanation/Reference:
Explanation: router bgp 65001 % Confed AS number, not the real BGP AS number as seen by real EBGP neighbor bgpconfederation identifier 65101 % Actual AS number as seen by real EBGP peer. The confederation identifier refers to external AS number neighbor 10.3.3.5 remote-as 65001 For B,C and D, they all have the incorrect bgp confederation identifier
QUESTION 101
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.
Correct Answer: ACD Section: (none) Explanation
Explanation/Reference:
Explanation:
1.
A EBGP uses AS-Path to ensure that it is not passing its own route back to itself
2.
C No BGP attributes are changed
3.
D Router learned via IBGP are not advertised to prevent loops Wrong
1.
B IBGP routes have admin distance of 200 and EBGP of 20. 20 is preferred
2.
E routes learned from EBGP peers are advertised to other EBGP peers.
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