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QUESTION 40
Your OSPF router has one serial interface, and one Ethernet LAN interface. The subinterface is configured in the following manner: interface serial 0.122 point-to-point ip address 192.168.1.1 255.255.255.0 encapsulation frame-relay frame-relay interface-dlci 122 Your want to allow hosts on your LAN to send and receive data, but you don’t want routing traffic to go through that interface. Which of the following commands should you use to complete your configuration?
A. interface serial 0.122 point-to-point passive-interface ethernet 0
B. interface ethernet 0 ip address 192.168.12.1 255.255.255.0 passive-interface
C. router ospf 172 area 1 nssa network 192.168.1.0 0.0.0.255 area 0 network 192.168.12.0 0.0.0.255 area 1
D. router ospf 172 passive-interface ethernet 0 network 192.168.1.0 0.0.0.255 area 0 network
192.168.12.0 0.0.0.255 area 1
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation:
We use the passive-interface command to configure the ethernet interface to be passive. The passive-
interface router configuration command is used to disable sending routing updates on an interface.
Incorrect Answers:
A: We are not configuring the serial interface. Furthermore, the passive-interface command is a router configuration command, not an interface configuration command.
B: We cannot use the passive-interface command like this.
C: We should configure the Ethernet interface as passive, not the area as a not-so-stubby area (NSSA).
QUESTION 41
You have a named Router CertK running EIGRP that has already been configured with the following: Router CertK (config)#access-list 30 deny any Router CertK (config)#access-list 40 permit ip any Router CertK (config)#router eigrp 1 To complete your configuration you want to configure the serial 0/0 interface to prevent routing updates from going out that interface while still allowing the formation and upkeep of neighbor adjacencies on that interface. Drag the correct command phrase from the bottom and place it in
A.
B.
C.
D.
Correct Answer: Section: (none) Explanation
Explanation/Reference:
Explanation:
We use distribute list 30, which stops IP traffic, on outward traffic on the serial 0/0 interface.
RouterTK continues receiving routing updates from its neighbor, but the distribute-list prevents routes from
being advertised out of serial 0. Furthermore, neighbor adjacencies are allowed to be formed between
RouterTK and its neighbor on serial 0/0.
Incorrect Answers:
passive interface serial 0/0:
On EIGRP, passive interface causes the router to stop sending and receiving hello packets. This will
prevent the interface from maintaining neighbor adjacencies.
distribute-list 40 out serial 0/0:
We must stop outgoing traffic, not allow it.
distribute-list 30 in serial 0-0:
We must stop outgoing traffic, not incoming traffic.
Reference: How Does the Passive Interface Feature Work in EIGRP?
http://www.cisco.com/warp/public/103/16.html
QUESTION 42
he Certkiller network is displayed below:
You need to configure a static route so that users on the corporate network can reach the 172.27.6.0/24
LAN. Based on the diagram above, which of the following is the correct way to do this?
A. Certkiller 1(config)#ip route 172.27.6.0 255.255.255.0 172.17.8.2
B. Certkiller 2(config)#ip route 172.27.6.0 255.255.0.0 172.17.8.2
C. Certkiller 2(config)#ip route 172.27.6.0 255.255.255.0 172.17.8.2
D. Certkiller 1(config)#ip route 172.27.6.0 255.255.0.0 172.17.8.1
E. Certkiller 2(config)#ip route 172.27.6.0 255.255.255.0 172.17.8.1
Correct Answer: E Section: (none) Explanation
Explanation/Reference:
Explanation:
Only choice E provides the correct network subnet mask and next hop IP address.
IP route prefix mask {address|Interface} [distance] [tag tag] [permanent]
Prefix 172.27.6.0 mask 255.255.255.0 address 172.17.8.2
Address – The IP address of the next hop router that can be used to reach that network.
Reference: Building Scalable Cisco Networks (Cisco Press) page 464
QUESTION 43
The Certkiller network consists of a main office and a single remote office. You need to configure the
remote office in using the following guidelines:
The main office must learn all of its routes from the regional office.
The regional office must not learn routes from the main office.
The most scalable solution should be used.
Which of the following answer choices best describe what should be done to satisfy these
requirements?
A. Configure static routes pointing to the network behind the central office router
B. Configure a default route pointing to the networks behind the central office router
C. Make the interface that is connected to the central office a passive interface to block incoming updates
D. Enable route update filtering on the interface that is connected to the central office to block incoming updates
E. None of the above will work
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation:
The only viable solution here is to enable the main office to dynamically learn about all of the regional
office routes, while still not receiving any routes is by enabling incoming route filters.
Incorrect Answers:
A, B: Configuring static routes or default routes on the regional office will not enable the main office to
learn about any of the regional office routes.
C: A passive interface would prevent all route updates to the main office. Passive interfaces do not filter incoming routing updates, so the regional office could still learn routes from the main office. Note: Configuring the main office using a passive interface would satisfy the conditions here, but this Qasks us how to configure the regional office, not the main office.
QUESTION 44
You wish to permit all BGP prefixes between /10 and /18 for the 207.0.0.0 network. How should a BGP prefix list be configured to do this?
A. ip prefix-list 207.0.0.0/8 ge 10 le 18
B. ip prefix-list 207.0.0.0/8 ge 18 le 10
C. ip prefix-list 207.0.0.0/24 ge 10 le 18
D. ip prefix-list 207.0.0.0/24 ge 18 le 10
E. None of the above
Correct Answer: A Section: (none) Explanation
Explanation/Reference:
Explanation: With prefix lists, the “ge” means “greater than or equal to” while the le means “less than or equal to.” Here, we want to specify all prefixes greater than or equal to 10 and less than or equal to 18 as specified in choice
A. In addition, we must specify an 8 bit network mask, not a 24 bit network mask.
QUESTION 45
Routers CK1 and CK2 are configured for BGP as shown below: RTR CK1 router bgp 200 neighbor
183.215.22.1 remote-as 200 neighbor 183.215.22.1 update-source loopback 1 RTR CK2 router bgp 200 neighbor 147.229.1.1 remote-as 200 These two routers currently have an active BGP peering session between them and they are able to pass routes to each other. Based on these configuration files, which of the following are true? (Select three)
A. RTR CK1 and RTR CK2 are running IBGP inside AS 200
B. The IP address of RTR CK1 ‘s Loopback 1 interface is 147.229.1.1.
C. The IP address of RTR CK1 ‘s Loopback 1 interface is 183.215.22.1.
D. RTR CK1 and RTR CK2 are running EBGP between the autonomous systems.
E. RTR CK1 has forced BGP to use the loopback IP address as the source in the TCP neighbor connection.
Correct Answer: ABE Section: (none) Explanation Explanation/Reference:
Explanation:
A: The two statements that define a remote AS (autonomous) use the same AS number. Both routers must belong to the same AS and there IBGP is used.
B: The IP address of the CK1 loopback address is 147.229.1.1 as specified in the neighbor statement of the CK2 router: neighbor 147.229.1.1 remote-as 200
E: The “neighbor 183.215.22.1 update-source loopback 1” command issued at CK1 makes CK1 use this loopback for the BGP connection to CK2 . See Note 2 below. Note 1: Syntax of neighbor command: Router(config-router)#neighbor {ip-address | peer-group-name} remote-as as-number This command specifies a BGP neighbor. Note 2: For iBGP, you might want to allow your BGP connections to stay up regardless of which interface is used to reach a neighbor. To enable this configuration, you first configure a loopback interface and assign it an IP address (neighbor 183.215.22.1 update-source loopback 1). Next, configure the BGP update source to be the loopback interface (we have to assume this step – it is not indicated by the exhibit). Finally, configure your neighbor to use the address on the loopback interface (neighbor 147.229.1.1 remote-as 200). Incorrect Answers:
C: 183.215.22.1 is the IP address of CK2 , not CK1 .
D: There is only one AS and the routers belong to that AS. Within an AS IBGP is used, not EBGP.
QUESTION 46
The Certkiller BGP router is configured as shown below: router bgp 64000 neighbor 172.16.1.1 remote-as 64000 neighbor 10.1.1.2 remote-as 64550 network 200.52.1.192 mask 255.255.255.224 no synchronization aggregate-address 200.52.1.0 255.255.255.0 The BGP peers 172.16.1.1 and 10.1.1.2 in the above configuration are active, as well as the interface with IP address 200.52.1.192. Based on this information, which statement below is true about your configuration?
A. Router CertK has an IBGP connection with neighbor 10.1.1.2.
B. Router CertK has an EBGP connection with the neighbor 172.16.1.1.
C. Router CertK advertises only a route 200.52.1.0 255.255.255.0 in BGP.
D. Router CertK advertises only a route 200.52.1.192 255.255.255.224 in BGP.
E. Router CertK advertises both the routes to 200.52.1.0 255.255.255.0 and 200.52.1.192
255.255.255.224 in BGP.
Correct Answer: E Section: (none) Explanation
Explanation/Reference:
Explanation:
The aggregate route, 200.52.1.0 255.255.255.0, and the more specific route, 200.52.1.192
255.255.255.224, will both be advertised. To only advertise the aggregate route the summaryonly option of
the aggregate-address command must be used.
Note: The aggregate-address command is used to create an aggregate, or summary, entry in the BGP
table.
Incorrect Answers:
A: The neighbor 10.1.1.2 belongs to another autonomous system and is a EBGP neighbor, not an IBGP
neighbor.
B: Router A and neighbor 172.16.1.1 belong to the same autonomous system and is an IBGP neighbor,
not an EBGP neighbor.
C: The summary-only option of the aggregate-address command is used to only advertise the summary
and not the specific routes.
D:
The aggregate route, 200.52.1.0 255.255.255.0, will be advertised as well.
Q304 The Certkiller network consists of two separate autonomous systems as shown below:
You need to configure Router CK2 as a BGP route reflector and Router CK1 as the client. Assuming that
Router CK3 isn’t running BGP, which two of the commands below would you enter on CK2 to satisfy your
goals? (Select two)
A.
neighbor 165.50.12.1 remote-as 65100
B.
neighbor 165.50.12.2 remote-as 64000
C.
neighbor 165.50.12.1 route-reflector-client
D.
neighbor 165.50.12.2 route reflector-client
Answer: B, D
Explanation:
B: Router CK2 (config-router)# neighbor 165.50.12.2 remote-as 64000 We configure router CK1
(165.50.12.2) as a neighbor in AS 64000.
D: Router CK2 (config-router)# neighbor 165.50.12.2 route-reflector-client Configures the router CK2 as a BGP route reflector and configures the specified neighbor CK1 (165.50.12.2) as its client. Incorrect Answers:
A: We must specify router CK1 as neighbor, not CK2 itself (165.50.12.1). Furthermore, we should use the local AS (64000), not the remote AS 65100.
C: We must specify router CK1 as route reflector client, not CK2 itself (165.50.12.1).
QUESTION 47
The Certkiller network consists of a series of routers that are all configured for IBGP. Which one of the following IBGP characteristics is true?
A. The IBGP routers must always be fully meshed.
B. The IBGP routers can be in a different AS.
C. The IBGP routers must be directly connected.
D. The IBGP routers do not need to be directly connected.
E. None of the above are true.
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation: The IBGP routers do not have to be directly connected. The remote IBGP peers need only be reachable via a TCP connection. For example, if the network is also running an interior routing protocol such as EIGRP or OSPF, the remote IBGP router could be many hops away, as long as it is reachable via the IGP that is being used. Incorrect Answers:
A: Using route reflectors or confederations a full mesh topology is not necessary.
B: The IBGP routers must be placed in the same AS. Peers that are in different autonomous systems are using EBGP, not IBGP.
C: The IBGP routers do not have to be directly connected.
QUESTION 48
Which of the following statements regarding BGP peer groups are true? (Select two)
A. Peer members inherit all options of the peer group.
B. Peer groups can be used to simplify BGP configurations.
C. Peer groups are optional non-transitive attributes for BGP.
D. A peer group allows options that affect outbound updates to be overridden.
E. A common name should be used on all routers because this information is passed between neighbors.
Correct Answer: AB Section: (none) Explanation
Explanation/Reference:
Explanation:
A BGP peer group is a group of BGP neighbors with the same update policies.
A: By default members of the peer group inherit all of the configuration options of the peer group. Note: Members can also be configured to override these options
B: Peer groups are normally used to simplify router configurations when many neighbors have the same policy.
Note: BGP neighbors who share the same outbound policies can be grouped together in what is called a BGP peer group. Instead of configuring each neighbor with the same policy individually, Peer group allows to group the policies which can be applied to individual peer thus making efficient update calculation along with simplified configuration.
Incorrect Answers:
C: The only Optional non-transitive attribute in BGP is MED.
D: Does not apply.
E: Using a common router name provides no BGP benefits at all.
Reference: BGP Peer Groups, http://www.cisco.com/warp/public/459/29.html
QUESTION 49
A BGP router is configured as shown below: interface ethernet 0 ip address 10.10.10.1 255.255.0.0 ! int serial 0 ip address 172.16.1.1 255.255.255.252 ! router bgp 65001 neighbor 192.168.1.1 remote-as 65002 Based on the above configuration, which of the following BGP statements would inject the 10.10.0.0/16 prefix into the BGP routing table?
A. network 10.0.0.0
B. network 10.10.0.0 mask 255.255.0.0
C. network 10.10.10.1 mask 255.255.255.255
D. network 10.10.10.0 mask 255.255.255.0
E. network 10.0.0.0 mask 255.255.0.0
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation: The /16 mask is equal to 255.255.0.0, so answer choice B matches the address and the mask. To specify the route as classless, the mask keyword should be included or the network will be summarized at the network boundary.
QUESTION 50
Why would a systems administrator enter in the network command when configuring BGP?
A. Local routes matching the network command are filtered from the BGP routing table.
B. Local routes matching the network command can be installed into the BGP routing table.
C. Routes matching the network command will be filtered from BGP routing updates.
D. External routes matching the network command will be installed into the BGP routing table.
E. None of the above.
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation:
Use the network router configuration command to permit BGP to advertise a network if it is
present in the IP routing table.
Reference: Building Scalable Cisco Networks (Cisco Press) page 342
QUESTION 51
The Certkiller network is depicted in the following diagram: Which of the following command sets would you use if you want Certkiller 1 and Certkiller 2 to exchange BGP routing information? (Select two)
A. Certkiller 2(config)#router bgp 200 Certkiller 2(config-router)#neighbor 10.1.1.1 remote-as 100
B. Certkiller 1(config)#router bgp 100 Certkiller 1(config-router)#exit Certkiller 1(config)#interface S0
Certkiller 1(config-if)#neighbor 10.1.1.2 remote-as 200
C. Certkiller 1(config)#router bgp 100 Certkiller 1(config-router)#neighbor 10.1.1.2 remote-as 200
D. Certkiller 2(config)#router bgp 100 Certkiller 2(config-router)exit Certkiller 2(config)#interface S0
Certkiller 2(config-if)#neighbor remote-as 100
E. Certkiller 1(config)#router bgp 100 Certkiller 1(config-router)#network 10.0.0.0 Certkiller 1(config-router)#neighbor 10.1.1.2 remote-as 100
F. Certkiller 2(config)#router bgp 200 Certkiller 2(config-router)#network 10.0.0.0 Certkiller 2(config-router)#network 10.1.1.1 remote-as 200
Correct Answer: AC Section: (none) Explanation
Explanation/Reference:
Explanation:
Choices A and C give the correct syntax for configuring EBGP peering sessions.
Incorrect Answers:
B, D: The BGP peering configurations are placed under the BGP routing process, not in
interface configuration mode.
E, F: The network 10.0.0.0 command is not required here, since this is an EBGP peering session using the
directly connected interface. Since each neighbor shares the 10.0.0.0 network they each already know
how to reach this network.
QUESTION 52
Router TK-1 is configured for BGP routing as shown below: router bgp 65300 network 27.0.0.0 neighbor
192.23.1.1 remote-as 65300 From the perspective of router TK-1, what kind of router is the router with IP address 192.23.1.1?
A. A peer router running IBGP
B. A peer router running EBGP
C. A community member running IBGP
D. A peer group member running IBGP E. A peer group member running EBGP
Correct Answer: A Section: (none) Explanation
Explanation/Reference:
Explanation:
Both the local and remote router is configured with the same autonomous system number so they are peer
routers running IBGP.
QUESTION 53
When you’re configuring BGP on a Cisco router, what is true of the command “network”?
A. Local routes matching the network command are filtered from the BGP routing table.
B. Local routes matching the network command can be installed into the BGP routing table.
C. Sending and receiving BGP updates is controlled by using a number of different filtering methods.
D. The route to a neighbor autonomous system must have the correct MED applied to be installed into BGP routing table.
E. None of the above.
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation: The network command allows BGP to advertise an IGP route if it is already in the IP table. A matching route must exist in the routing table before the network is announced. The network command is used to permit BGP to advertise a network if it is present in the IP routing table.
QUESTION 54
Router CK1 needs to be configured to advertise a specific network. Which of the following commands would you use if you wanted to advertise the subnet 154.2.1.0 255.255.255.0 to the EBGP neighbors on your subnet?
A. Router (config-router)#network 154.2.1.0
B. Router (config-router)#network 164.2.1.0
C. Router (config-router)#network-advertise 154.2.1.0
D. Router (config-router)#network 154.2.1.0 mask 255.255.255.0
E. None of the above
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation:
The network command is used to specify the networks to be advertised by the Border Gateway Protocol
(BGP) and multiprotocol BGP routing processes.
Syntax: network network-number [mask network-mask] [route-map map-name]
Mask and route-map are optional. If the mask keyword is configured, then an exact match must exist in the
routing table.
Incorrect Answers:
A: If we do not specify the subnet mask then additional networks are allowed to be advertised. The classful subnet mask of 154.2.1.0 is 255.255.0.0 – a Class B network.
B: This is using the incorrect IP address, as well as a missing subnet mask.
C: The network-advertise is an invalid command.
QUESTION 55
You are the administrator of a company with BGP connections to multiple ISP’s. How could you configure BGP to make it favor one particular ISP for outbound traffic?
A. Configure weight
B. Enable route reflector
C. Create a distribute list
D. Enable the Longer Autonomous System path option.
E. All of the above.
Correct Answer: A Section: (none) Explanation
Explanation/Reference:
Explanation: If the router learns about more than one route to the same destination, the route with the highest weight will be preferred. Weight is a Cisco BGP parameter that is local to the router. When terminating multiple ISP connections into the same router, weight can be used to affect which path is chosen for outbound traffic. Incorrect Answers:
B: A route reflector cannot be used to influence outbound traffic. A route reflector modifies the BGP split horizon rule by allowing the router configured as the route reflector to propagate routes learned by IBGP to other IBGP peers. This saves on the number of BGP TCP sessions that must be maintained, and also reduces the BGP routing traffic.
C: Distribute lists restrict the routing information that the router learns or advertises. By itself a distribute list cannot make routes from one ISP be preferred to routers from another ISP.
D: This choice describes ASD path pre-pending, which would be used to influence the path that incoming traffic takes, not outgoing.
QUESTION 56
What are two solutions to overcome the full mesh requirement with iBGP? (Choose two)
A. BGP groups
B. BGP local preference
C. Route reflector
D. Confederation
E. Aggregate-address
Correct Answer: CD Section: (none) Explanation
Explanation/Reference:
Explanation: In general, all IBGP peers must be configured to be fully meshed. If they are not, then all of the IBGP routers will not have the updated information from the external BGP routers. There are two ways to overcome the scalability issues of a full IBGP mesh: route reflectors and confederations. With route reflectors, internal BGP routers peer only with the route reflector. With confederations, the AS is broken up into smaller, more manageable sub autonomous systems.
QUESTION 57
An ISP is running a large IBPG network with 25 routers. The full mesh topology that is currently in place is inefficiently using up bandwidth from all of the BGP traffic. What can the administrator configure to reduce the number of BGP neighbor relationships within the AS?
A. Route reflectors
B. Route maps
C. Route redistribution
D. Peer groups
E. Aggregate addresses
Correct Answer: A Section: (none) Explanation
Explanation/Reference:
Explanation: In general, all IBGP peers must be configured to be fully meshed. If they are not, then all of the IBGP routers will not have the updated information from the external BGP routers. There are two ways to overcome the scalability issues of a full IBGP mesh: route reflectors and confederations. With route reflectors, internal BGP routers peer only with the route reflector, and then the route reflectors connect with each other. This can considerably reduce the number of IBGP sessions. Another solution to the scalability problem of IBGP is the use of confederations. With confederations, the AS is broken up into smaller, more manageable sub autonomous systems.
QUESTION 58
Arrange the BGP attributes on the left in order or priority.
A.
B.
C.
D.
Correct Answer: Section: (none) Explanation
Explanation/Reference:
Explanation:
How the Best Path Algorithm Works:
BGP assigns the first valid path as the current best path. It then compares the best path with the next path
in list, until it reaches the end of the list of valid paths. The following is a list of rules used to determine the
best path.
1.
Prefer the path with the highest WEIGHT. Note: WEIGHT is a Cisco-specific parameter, local to the router on which it’s configured.
2.
Prefer the path with the highest LOCAL_PREF. Note the following:
Path without LOCAL_PREF is considered as having the value set with the bgp default local-preference command, or 100 by default.
3.
Prefer the path that was locally originated via a network or aggregate BGP subcommand, or through redistribution from an IGP. Local paths sourced by network or redistribute commands are preferred over local aggregates sourced by the aggregate-address command.
4.
Prefer the path with the shortest AS_PATH. Note the following:
The AS_CONFED_SEQUENCE and AS_CONFED_SET are not included in the AS_PATH length.
5.
Prefer the path with the lowest origin type: IGP is lower than EGP, and EGP is lower than INCOMPLETE.
6.
Prefer the path with the lowest multi-exit discriminator (MED). Note the following:
This comparison is only done if the first (neighboring) AS is the same in the two paths; any confederation sub-ASs are ignored. In other words, MEDs are compared only if the first AS in the AS_SEQUENCE is the same for multiple paths. Any preceding AS_CONFED_SEQUENCE is ignored. If bgp always-compare-med is enabled, MEDs are compared for all paths. This option needs to be enabled over the entire AS, otherwise routing loops can occur.
If bgp bestpath med-confed is enabled, MEDs are compared for all paths that consist only of AS_CONFED_SEQUENCE (paths originated within the local confederation).
Paths received from a neighbor with a MED of 4,294,967,295 will have the MED changed to 4,294,967,294 before insertion into the BGP table.
Paths received with no MED are assigned a MED of 0, unless bgp bestpath missing-as-worst is enabled, in which case they are assigned a MED of 4,294,967,294.
The bgp deterministic med command can also influence this step as demonstrated in the How BGP Routers Use the Multi-Exit Discriminator for Best Path Selection.
7.
Prefer external (eBGP) over internal (iBGP) paths. If bestpath is selected, go to Step 9 (multipath).
Note: Paths containing AS_CONFED_SEQUENCE and AS_CONFED_SET are local to the confederation,
and therefore treated as internal paths. There is no distinction between
Confederation External and Confederation Internal.
8.
Prefer the path with the lowest IGP metric to the BGP next hop. Continue, even if
bestpath is already selected.
9.
Check if multiple paths need to be installed in the routing table for BGP Multipath.
Continue, if bestpath is not selected yet.
10.
When both paths are external, prefer the path that was received first (the oldest one). This step
minimizes route-flap, since a newer path will not displace an older one, even if it
would be the preferred route based on the next decision criteria (Steps 11, 12, and 13).
Skip this step if any of the following is true:
o The bgp best path compare-routerid command is enabled.
Note: This command was introduced in Cisco IOS(r) Software Releases 12.0.11S, 12.0.11SC,
12.0.11S3, 12.1.3, 12.1.3AA, 12.1.3.T, and 12.1.3.E.
o The router ID is the same for multiple paths, since the routes were received from the same router.
o There is no current best path. An example of losing the current best path occurs when the neighbor offering the path goes down.
11.
Prefer the route coming from the BGP router with the lowest router ID. The router ID is the highest IP address on the router, with preference given to loopback addresses. It can also be set manually using the bgp router-id command. Note: If a path contains route-reflector (RR) attributes, the originator ID is substituted for the router ID in the path selection process.
12.
If the originator or router ID is the same for multiple paths, prefer the path with the minimum cluster list length. This will only be present in BGP route-reflector environments. It allows clients to peer with RRs or clients in other clusters. In this scenario, the client must be aware of the RR-specific BGP attribute.
13.
Prefer the path coming from the lowest neighbor address. This is the IP address used in the BGP neighbor configuration, and corresponds to the remote peer used in the TCP connection with the local router.
QUESTION 59
The Certkiller BGP routing table consists of the following network routes:
What is the correct command to summarize these prefixes into a single summary prefix of 192.168.12.0/22 while also allowing for the advertisement of the more specific prefixes?
A. network 192.168.12.0 mask 255.255.252.0
B. network 192.168.12.0 mask 0.0.3.255
C. network 192.168.12.0
D. aggregate-address 192.168.12.0 255.255.252.0
E. aggregate-address 192.168.12.0 255.255.252.0 summary-only
F. aggregate-address 192.168.12.0 255.255.252.0 as-set
Correct Answer: D Section: (none) Explanation
Explanation/Reference:
Explanation:
To summarize BGP prefixes into one aggregated route, use the “aggregate-address” command.
When used alone, this will advertise the aggregate route, along with the individual specific
routing entries. To advertise only the aggregated route, use the “summary-only” keyword, as specified in
choice E.
QUESTION 60
The Certkiller BGP network is displayed below: Certkiller 3 is the hub router and Certkiller 1 and Certkiller 2 are the spokes. There are no virtual circuits between the spoke locations. Each router is in a separate AS. What is needed to successfully route traffic to the 11.11.11.0/24 network from Certkiller 1?
A. The neighbor 10.10.10.1 next-hop-self command on Certkiller 1.
B. The neighbor 10.10.10.1 next-hop-self command on Certkiller 2.
C. The neighbor 10.10.10.1 next-hop-self command on Certkiller 3.
D. Nothing is required. This is the default behavior on this topology
Correct Answer: C Section: (none) Explanation
Explanation/Reference:
Explanation:
The following example illustrates the issue:
BGP Next Hop (NBMA)
If the common media as you see in the shaded area above is a frame relay or any NBMA cloud then the exact behavior will occur as if we were connected via Ethernet. RTC will advertise 180.20.0.0 to RTA with a next hop of 170.10.20.3. The problem is that RTA does not have a direct PVC to RTD, and cannot reach the next hop. In this case routing will fail. In order to remedy this situation a command called next-hop-self is created. The next-hop-self Command Because of certain situations with the next hop as we saw in the previous example, a command called next-hop-self is created. The syntax is: neighbor {ip-address|peer-group-name} next-hop-self The next-hop-self command allows us to force BGP to use a specified IP address as the next hop rather than letting the protocol choose the next hop. In the previous example, the following configuration solves our problem: RTC# router bgp 300 neighbor 170.10.20.1 remote-as 100 neighbor 170.10.20.1 next-hop-self RTC advertises 180.20.0.0 with a next hop = 170.10.20.2 Reference: http://www.cisco.com/warp/public/459/bgp-toc.html#bgpnexthop
QUESTION 61
Exhibit Based on the show ip bgp summary output in the exhibit, which two statements are true? Select two?
A. The BGP session to the 10.1.1.1 neighbor is established.
B. The BGP session to the 10.2.2.2 neighbor is established.
C. The BGP session to the 10.3.3.3 neighbor is established.
D. The router is attempting is attempting to establish a BGP peering to the 10.1.1.1 neighbor.
E. The BGP session to the 10.3.3.3 neighbor is established, but the router has not received any BGP routing updates from the 10.3.3.3 neighbor.
F. The router is attempting to establish BGP peering with the 10.2.2.2 neighbor.
Correct Answer: AFCEBD Section: (none) Explanation
QUESTION 62
we want to hide some of your internal IP subnets from outside networks. By what means can you conceal the details of your IP addressing scheme to the outside world?
A. Subnetting
B. Supernetting
C. Challenge Handshake Protocol
D. Usernames and passwords
Correct Answer: B Section: (none) Explanation
Explanation/Reference:
Explanation: In large internetworks, hundreds or even thousands of networks can exist. In these environments, it is often not desirable for routers to maintain all these routes in their routing table. Route summarization (also called route aggregation or supernetting) can reduce the number of routes that a router must maintain because is it a method of representing a series of network numbers in a single summary address. By advertising only one large supernet to the outise world, the details of your IP network scheme can remain hidden.
QUESTION 63
The Certkiller network will be using a new ISP for their Internet connection. The new Internet provider will be allocating a new registered class C IP address subnet to use. In order to not have to change out the entire internal IP addressing scheme on your network, you plan to use NAT to translate all of the internal IP address to the new IP addresses that are being assigned to Certkiller . You have been assigned the task of making changes so that the following requirements are met: Maintain the current IP addressing scheme Configure Certkiller ‘s router for network address translation (NAT) so all the internal computers use the same external IP address Configure a static translation so Certkiller employees can access their email from the internet. Privileged mode password: Certkiller The IP Addresses are shown below: Name: Certkiller NAT SO 192.168.15.1/24 E0 10.100.5.1/24 E-mail Server’s External Address 192.168.15.5/24 E-mail Server’s Internal Address 10.100.5.5/24 To configure the router click on a host icon that is connected to a router by a serial console cable.
A.
B.
C.
D.
Correct Answer: Section: (none) Explanation
Explanation/Reference:
Certkiller NAT(config-if)#exit Certkiller NAT(config)#exit Certkiller NAT#copy run start Q322
You have been assigned the task of configuring the routers to meet the following requirements:
In the unlikely event that a link goes down, you have to ensure a backup link exists
The proper metrics must be distributed through the IGRP portion of the network Based on this information,
which of the following should you do? (Select two)
A. Apply the distance command to Main
B. Apply the distance command to CK2
C. Apply the distribute-list command to Main
D. Apply the distribute-list command to CK2
Answer: B, C Explanation:
B: Most routing protocols, including IGRP and RIP, use the distance command to modify the administrative distance. We need to change the metric of the RIP routes learned by CK2 .
C: To control the advertising and processing of routes in routing updates the distribute-list
command is used.
Incorrect Answers:
A: We change the administrative distance of RIP routes on CK2 .
D: We should apply the distribute-list command to Main, not to CK2 .
QUESTION 64
Network topology exhibit
Certkiller .com is changing ISPs. As a result, they will need to install an Email server and utilize network address translation (NAT) for the internal network. Certkiller .com does not want to change the IP Addresses on all of the internal routers and servers. The new ISP, Foo Services, will allocate a registered class C address for Certkiller to use. The internal IP Address scheme will remain the same. Configure the router to provide NAT so that all internal Certkiller PCs will use the single external IP Address assigned to the router interface. Configure a static translation so that Certkiller .com’s Email server will be accessible from the Internet. Name: Certkiller NAT S0: 192.168.17.1/24 E0: 10.0.216.1/24 Secret Password: Certkiller
A.
B.
C.
D.
Correct Answer: Section: (none) Explanation
Explanation/Reference:
192.168.212.5/24 Web Server’s Internal Address 10.0.243.5/24
QUESTION 65
One of the virtues of a Link-State routing protocol is its hierarchical design. What advantages does this equate to in network design? (Select two)
A. It allows link-state protocols to support VLSM.
B. It allows them to support address summarization.
C. It reduces the need to flood LSAs to all devices in the internetwork.
D. Routers are no longer required to keep track of the topology of the entire autonomous system.
Correct Answer: CD Section: (none) Explanation
Explanation/Reference:
Explanation: Hierarchical design can limit the requirement to notify all devices. The use of areas restricts the flooding to the logical boundary of the area rather than to all devices in the OSPF domain. Another advantage of hierarchical network design is that the entire network is divided into multiple smaller sections, so that much of the routing information is kept within a small area. In a non-hierarchical network, each router is required to maintain routing information for all other routers within the entire network. Incorrect Answers:
A: Although link state protocols do indeed support VLSM, it is not due to a hierarchical network design. For example, RIP version 2 supports VLSM, but it is not hierarchical.
B: Although address summarization can indeed be configured on routers configured in a hierarchical design, it is an independent function and is not related to the fact that a tiered network design is being used.
QUESTION 66
In regards to the three layered hierarchical network design, which of the following are responsibilities of the distribution layer? (Choose 2)
A. Reliable transport structure
B. Route redistribution
C. Optimized transport structure
D. Address aggregation
E. Unauthorized entry access control lists
Correct Answer: BD Section: (none) Explanation
Explanation/Reference:
Explanation: The distribution layer is responsible for what enters and exits a network, including the
consolidation of traffic from multiple subnets into a core connection. Route redistribution and address
aggregation happen at this layer.
Incorrect Answers:
A, C: This is a function of the core layer.
E. This is a function of the access layer.
QUESTION 67
Which of the following are advantages of implementing a hierarchical IP addressing scheme when designing a large network? (Select two)
A. Smaller routing tables
B. Efficient address allocation
C. Translation of private addresses
D. Support for link-state routing protocols
Correct Answer: AB Section: (none) Explanation
Explanation/Reference:
Explanation: Hierarchical IP addressing uses the addresses more conservatively, by planning for the correct use of subnet masks and route summarization. A hierarchical network design facilitates the use of IP routing summarization, which will reduce the size of the routing tables.
QUESTION 68
The Certkiller frame relay network is shown in the diagram below: Based on the information given in this diagram, which of the following are true??
A. The network is using a two-layer full-mesh hierarchical design.
B. The network is using a two-layer hub-and-spoke hierarchical design.
C. To improve scalability, route summarization at Routers CK1 , CK2 , CK3 , CK4 , CK5 , and CK6 should be performed.
D. Routers A and B are the distribution layer routers.
E. Routers CK1 , CK2 , CK3 , CK4 , CK5 and CK6 are the access layer routers.
F. To improve security, packet filtering that uses ACLs at Routers A and B must be implemented.
Correct Answer: CEADB Section: (none) Explanation
Explanation/Reference:
A: The network shown here is using a 3 level tiered approach: Core, Distribution, and Access.
B: Three layers are used, not two.
D: Routers A and B are the Core routers here.
E: These routers make up the Distribution layer.
QUESTION 69
You are trying to determine the best routing protocol to use for the large Certkiller network. Which routing protocols should you avoid when deploying a large network? (Select two)
A. IGRP
B. OSPF
C. EIGRP
D. RIP v.2
E. RIP v.1
Correct Answer: DE Section: (none) Explanation
Explanation/Reference:
Explanation: Both RIP version 1 and version 2 should only be used in relatively small networks. A large network would be congested by RIP broadcasts. These frequent broadcasts contain the entire routing table, and could saturate links.
QUESTION 70
What are some of the features that are important for designing large, scalable networks? (Select three)
A. A tiered network design model.
B. Sufficient memory on the router.
C. Multiple EIGRP autonomous systems.
D. Good address space allocation scheme.
Correct Answer: ABD Section: (none) Explanation
Explanation/Reference:
Explanation:
A: A tiered network design model such as Core, Distribution, and Access is also needed for
large networks.
B: Sufficient capacity of the routers, in particular the memory, is required for large networks.
D: Good allocation of address space is required- Each region should have a unique address
space so route summarization is possible.
Incorrect Answers:
C: Configuring multiple EIGRP autonomous systems can add extra overhead and it provides no
additional benefits.
QUESTION 71
Two of the following routing protocols require a tiered, hierarchical topology. Which ones are they? (Select two)
A. IS-IS
B. IGRP
C. OSPF
D. EIGRP
E. RIP v2
Correct Answer: AC Section: (none) Explanation
Explanation/Reference:
Explanation:
IS-IS and OSPF both require a hierarchical topology. The use of multiple areas and a core
backbone area means that they are hierarchical by nature.
QUESTION 72
What has become the leading Interior Routing Protocol (IGP) in use by Internet service providers?
A. IS-IS
B. OSPF
C. EIGRP
D. RIPv2
E. BGP4
Correct Answer: A Section: (none) Explanation
Explanation/Reference:
Explanation: In recent years, the IS-IS routing protocol has become increasingly popular, with widespread use among Service Providers. It is a link state protocol, which enables very fast convergence with large scalability. It is also a very flexible protocol and has been extended to incorporate leading edge features such as MPLS Traffic Engineering. It is also chosen because it is an IETF standard based protocol, rather than a proprietary protocol such as IGRP or EIGRP. Reference: http://www.cisco.com/en/US/tech/ CK3 65/ CK3 81/technologies_white_paper09186a00800a3e6f.sht ml
QUESTION 73
Two of the following routing protocols support load balancing over unequal cost links.Which ones are they? (Select two)
A. IGRP
B. OSPF
C. EIGRP
D. RIP v2
E. RIP v1
Correct Answer: AC Section: (none) Explanation
Explanation/Reference:
Explanation:
IGRP and EIGRP support unequal cost path load balancing, which is known as variance. OSPF,
RIP v1 and RIP v2 do not support this.
Reference: http://www.cisco.com/warp/public/103/19.html
QUESTION 74
You are required to choose a routing protocol that supports variable length subnet masks (VLSM) for your network. Which of the following would meet this requirement? (Choose three)
A. IS-IS
B. IGRP
C. OSPF
D. EIGRP
E. RIP v1
Correct Answer: ACD Section: (none) Explanation
Explanation/Reference:
Explanation:
IS-IS, EIGRP, OSPF, RIP V2 and static routes all support VLSM.
Incorrect Answers:
B: IGRP is the predecessor to EIGRP and does not support VLSM.
E: RIP version 1 is a distance vector routing protocol that does not support VLSM.
QUESTION 75
Cisco routers automatically perform route summarization for various protocols. Which three of the following routing protocols are they? (Select three)
A. IS-IS
B. IGRP
C. OSPF
D. EIGRP
E. RIP v.1
Correct Answer: BDE Section: (none) Explanation
Explanation/Reference:
Explanation:
Sending route summaries – Routing information advertised out an interface is automatically summarized at
major (classful) network address boundaries by RIP, IGRP, and EIGRP. Specifically, this autonomous summarization occurs for those routes whose classful network address differs from the major network address of the interface to which the advertisement is being sent. Reference: Building Scalable Cisco Networks (Cisco Press) page 79
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