The Candid Test On CCIE-r&s-bGP Quiz

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  • 1/66 Questions

    What makes a neighbor internal BGP (iBGP)?

    • When the neighbor is in the same confederation
    • R1(config)# router bgp 3 internal
    • The command: neighbor 1.1.1.1 peer-internal
    • When the neighbor is in the same AS
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The Candid Test On CCIE-r&s-bgp Quiz - Quiz
About This Quiz

CCIE routing and switching is a certification that every expert engineer needs to undertake in order to plan, operate and troubleshoot converged network infrastructure. Take up the candid test on CCIE- r&s- bgp quiz below and get ready for the upcoming test next week. All the best and keep revising!

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  • 2. 

    In the context of CCIE Routing and Switching (R&S) and Border Gateway Protocol (BGP), what is the primary purpose of the BGP "AS_PATH" attribute?

    • To determine the router's autonomous system number. 

    • To specify the next-hop IP address for a BGP route. 

    • To track the number of autonomous systems a route has traversed.

    • To define the BGP neighbor's IP address.

    Correct Answer
    A. To track the number of autonomous systems a route has traversed.
    Explanation
    The AS_PATH attribute is used to track the path that a BGP route has taken through different autonomous systems. It helps prevent routing loops and provides information about the route's history.

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  • 3. 

    How  BGP communicates with its neighbors?

    • Using multicast address 224.0.0.2 (all routers)

    • Using unicast neighbor address to TCP port 179

    • Using unicast neighbor address to UDP port 520

    • Using reliable layer 3 protocol (IP/112)

    • Using multicast address 224.0.0.2 to UDP port 1985

    • Using multicast address 224.0.0.2 to UDP port 3222

    Correct Answer
    A. Using unicast neighbor address to TCP port 179
    Explanation
    BGP communicates with its neighbors by using the unicast neighbor address to TCP port 179. This means that BGP establishes a direct one-to-one connection with its neighbors using the TCP protocol. The use of TCP ensures reliable and ordered delivery of BGP messages between routers. The communication is not done through multicast addresses or UDP ports, but rather through a specific unicast address and TCP port number.

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  • 4. 

    An NLRI is simply an IP prefix and a prefix length?

    • True

    • False

    Correct Answer
    A. True
    Explanation
    NLRI stands for Network Layer Reachability Information. It is used in routing protocols to advertise and exchange information about IP prefixes and their associated prefix lengths. Therefore, an NLRI is indeed a combination of an IP prefix (the network address) and a prefix length (the number of bits in the network address). This information is crucial for routers to determine the best path for forwarding packets in a network. Hence, the given answer "True" is correct.

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  • 5. 

    By default, eBGP packet has a TTL = 1.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    The TTL (Time to Live) value in an eBGP (external Border Gateway Protocol) packet determines the maximum number of hops the packet can traverse before being discarded. By default, the TTL value for eBGP packets is set to 1, which means that the packet can only travel to the immediate neighbor router. This is done to prevent eBGP packets from being forwarded beyond the directly connected routers, ensuring that they reach their intended destination without being unnecessarily propagated throughout the network. Therefore, the given answer, "True," is correct.

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  • 6. 

    What authentication method is supported by BGP?

    • Plain Text

    • MD5

    • None. BGP does not support authentication

    • RADIUS

    • EAP

    Correct Answer
    A. MD5
    Explanation
    BGP supports MD5 authentication method. MD5 is a widely used cryptographic hash function that provides a secure way to authenticate BGP peers. It ensures that the BGP messages exchanged between routers are not tampered with or modified by unauthorized parties. By using MD5 authentication, BGP peers can verify each other's identities and establish a trusted connection for exchanging routing information.

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  • 7. 

    Confederation routers remove the confederation ASN from the AS_PATH in updates sent outside the confederation.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    Confederation routers remove the confederation Autonomous System Number (ASN) from the AS_PATH attribute in updates that are sent outside the confederation. This means that when a router within a confederation sends an update to a router outside the confederation, it will strip off the confederation ASN from the AS_PATH. This is done to ensure that routers outside the confederation do not see the internal structure of the confederation and treat it as a single AS. Therefore, the statement "Confederation routers remove the confederation ASN from the AS_PATH in updates sent outside the confederation" is true.

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  • 8. 

    By default, what BGP uses to choose the best route?

    • Lowest Weight

    • Lowest Local Preference

    • Shortest AS Path

    • Highest Origin

    • Highest Multi-Exit Discriminator

    • Lowest Metric

    Correct Answer
    A. Shortest AS Path
    Explanation
    BGP uses the shortest AS Path to choose the best route. The AS Path is a list of autonomous systems that a route has to traverse in order to reach its destination. BGP prefers routes with shorter AS Paths because they indicate a more direct path to the destination. This helps to reduce the likelihood of loops and improves network efficiency. Therefore, BGP selects the route with the shortest AS Path as the best route.

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  • 9. 

    What BGP message type are used when BGP errors occur; causing a reset to the neighbor relationship when sent?

    • Hello

    • Advertisement

    • Update

    • Notification

    • Reset

    • Open

    • KeepAlive

    Correct Answer
    A. Notification
    Explanation
    BGP uses the Notification message type when errors occur, causing a reset to the neighbor relationship when sent. The Notification message is used to inform the neighbor that an error has occurred and includes information about the specific error. This message is crucial in maintaining the integrity of the BGP network by allowing routers to quickly respond to errors and reestablish the neighbor relationship if necessary.

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  • 10. 

    What BGP message type are used to maintain a neighbor relationship?

    • Hello

    • Advertisement

    • Update

    • Notification

    • Reset

    • Open

    • KeepAlive

    Correct Answer
    A. KeepAlive
    Explanation
    KeepAlive messages are used to maintain a neighbor relationship in the BGP protocol. These messages are sent periodically between BGP neighbors to ensure that the connection is still active and functioning properly. By exchanging KeepAlive messages, BGP routers can confirm that their neighbors are reachable and responsive. If a router stops receiving KeepAlive messages from a neighbor, it may consider the neighbor as unreachable and take appropriate actions, such as marking the neighbor as down and removing its routes from the routing table.

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  • 11. 

    What the command "neighbor update-source" do?

    • Modify the NEXT_HOP attribute advertised to a neighbor

    • Strip Private AS from the AS_PATH attribute advertised to a neighbor

    • Determine the NLRI used to reach a neighbor

    • Determine the source IP address used to reach a neighbor

    Correct Answer
    A. Determine the source IP address used to reach a neighbor
    Explanation
    The command "neighbor update-source" is used to determine the source IP address used to reach a neighbor. This command allows the router to specify a specific interface or IP address to use when establishing a connection with its neighbor. By setting the update-source, the router ensures that the correct source IP address is used for BGP updates and communication with the neighbor. This can be useful in scenarios where the router has multiple interfaces or IP addresses and needs to control which one is used for BGP communication.

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  • 12. 

    What BGP message type are used to exchange NLRI?

    • Hello

    • Advertisement

    • Update

    • Notification

    • Reset

    • Open

    • KeepAlive

    Correct Answer
    A. Update
    Explanation
    BGP uses the "Update" message type to exchange Network Layer Reachability Information (NLRI). The Update message is used to advertise, withdraw, or modify routing information between BGP peers. It contains the NLRI, along with other attributes such as path information, to inform neighboring routers about the available network destinations and their reachability.

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  • 13. 

    Which command enables logging of BGP neighbor status changes (up or down) and resets for troubleshooting network connectivity problems and measuring network stability?

    • Debug bgp neighbor

    • Neighbor 10.1.1.1 log

    • Bgp log-neighbor-changes

    • Ip bgp logging

    Correct Answer
    A. Bgp log-neighbor-changes
    Explanation
    The command "bgp log-neighbor-changes" enables logging of BGP neighbor status changes (up or down) and resets. This command is useful for troubleshooting network connectivity problems and measuring network stability as it allows for tracking and monitoring the changes in BGP neighbor status, which can help identify any issues or instabilities in the network.

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  • 14. 

    Which statement best describe the following configuration: RTC# router bgp 100 neighbor 2.2.2.2 remote-as 100 neighbor 2.2.2.2 route-reflector-client neighbor 3.3.3.3 remote-as 100 neighbor 3.3.3.3 route-reflector-client

    • Allows RTC to have a neighbor connection with 2.2.2.2 peer that with which it does not have direct connection.

    • Implementation of BGP confederation with 2.2.2.2

    • Workaround in order to achieve load balancing between two eBGP speakers over parallel links.

    • Allows RTC router to advertise, iBGP learned routes to 2.2.2.2 and 3.3.3.3 iBGP speakers.

    Correct Answer
    A. Allows RTC router to advertise, iBGP learned routes to 2.2.2.2 and 3.3.3.3 iBGP speakers.
    Explanation
    The given configuration allows the RTC router to advertise iBGP learned routes to the iBGP speakers 2.2.2.2 and 3.3.3.3. By configuring the "neighbor" command with the "route-reflector-client" option for both neighbors, RTC is able to act as a route reflector and distribute the routes it learns from other iBGP peers to these two iBGP speakers. This helps in propagating the routes throughout the network and ensuring reachability between different BGP speakers.

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  • 15. 

    Assuming that the no auto-summary command has been configured. What the BGP network 10.1.1.0 mask 255.255.255.0 command instruct to the BGP process to do?

    • Activate BGP process on the corresponding interface (on subnet 10.1.1.0/24)

    • If 10.1.1.0/24 exactly match an entry in the current IP routing table, then put the equivalent NLRI in the local BGP topology table.

    • BGP will start advertising udpate message to its neighbors for any networks 10.0.0.0 in the current local IP routing table.

    • Send Open messages on network 10.1.1.0/24 to establish a connection with a neighbor

    Correct Answer
    A. If 10.1.1.0/24 exactly match an entry in the current IP routing table, then put the equivalent NLRI in the local BGP topology table.
    Explanation
    The command "BGP network 10.1.1.0 mask 255.255.255.0" instructs the BGP process to put the equivalent Network Layer Reachability Information (NLRI) in the local BGP topology table if there is an exact match for the subnet 10.1.1.0/24 in the current IP routing table. This means that if there is a route for 10.1.1.0/24 in the routing table, BGP will consider it as a valid network and include it in its routing updates.

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  • 16. 

    Assuming that the no auto-summary command has been configured. What the BGP network 10.1.1.0 mask 255.255.255.0 command instruct to the BGP process to do?

    • Activate BGP process on the corresponding interface (on subnet 10.1.1.0/24)

    • If 10.1.1.0/24 exactly match an entry in the current IP routing table, then put the equivalent NLRI in the local BGP topology table.

    • BGP will start advertising udpate message to its neighbors for any networks 10.0.0.0 in the current local IP routing table.

    • Send Open messages on network 10.1.1.0/24 to establish a connection with a neighbor

    Correct Answer
    A. If 10.1.1.0/24 exactly match an entry in the current IP routing table, then put the equivalent NLRI in the local BGP topology table.
    Explanation
    The BGP network 10.1.1.0 mask 255.255.255.0 command instructs the BGP process to check if the network 10.1.1.0/24 matches an entry in the current IP routing table. If it does, the equivalent Network Layer Reachability Information (NLRI) is added to the local BGP topology table. This allows BGP to advertise this network to its neighbors and include it in the BGP routing updates.

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  • 17. 

    Confederation ASN are not considered part of the length of the AS_PATH when a router chooses the best routes based on the shortes AS_PATH.

    • True

    • False

    Correct Answer
    A. True
    Explanation
    When a router chooses the best routes based on the shortest AS_PATH, it does not consider Confederation Autonomous System Numbers (ASN) as part of the length of the AS_PATH. This means that even if a route includes Confederation ASNs, they are not counted towards the length calculation. Therefore, the statement "Confederation ASN are not considered part of the length of the AS_PATH when a router chooses the best routes based on the shortest AS_PATH" is true.

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  • 18. 
    Which config should be used in order to take advantage of the redundant links between R3 and R4 (assuming the matching config is done on the other side)? - ProProfs

    Which config should be used in order to take advantage of the redundant links between R3 and R4 (assuming the matching config is done on the other side)?

    • Configure two static route to the other loopback address (on for 10.1.34.0/24 and 10.1.134.0/24). Configure neighbor 3.3.3.3 update-source looback0 and neighbor 3.3.3.3 ebgp-multihop 2(on R4).

    • EBGP neighbor command should use aggregator option

    • Nothing, eBGP will load balance automatically

    • EBGP neighbor command should use peer-group option

    Correct Answer
    A. Configure two static route to the other loopback address (on for 10.1.34.0/24 and 10.1.134.0/24). Configure neighbor 3.3.3.3 update-source looback0 and neighbor 3.3.3.3 ebgp-multihop 2(on R4).
    Explanation
    The correct answer is to configure two static routes to the other loopback addresses (10.1.34.0/24 and 10.1.134.0/24), and then configure the neighbor 3.3.3.3 update-source looback0 and neighbor 3.3.3.3 ebgp-multihop 2 commands on R4. This configuration allows R3 and R4 to establish a BGP neighbor relationship using the loopback interface as the source address and enables BGP to use multiple hops to reach the neighbor. By configuring static routes to the loopback addresses, the traffic can be load balanced between the redundant links between R3 and R4.

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  • 19. 

    What is the default action when BGP advertises routes to an eBGP neighbor?

    • Does not change the NEXT_HOP (uses the one in the routing table)

    • Change the NEXT_HOP to the update source IP address

    • Summarizes using the classful network of any subnets

    • BGP does not advertise routes to an iBGP neighbor

    Correct Answer
    A. Change the NEXT_HOP to the update source IP address
    Explanation
    When BGP advertises routes to an eBGP neighbor, the default action is to change the NEXT_HOP to the update source IP address. This means that the NEXT_HOP attribute in the BGP update message will be modified to reflect the IP address of the router that is sending the update. This is done to ensure that the eBGP neighbor will use the correct path to reach the advertised routes.

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  • 20. 

    Confederation routers add the confederation ASN to the AS_PATH in updates sent outside the confederation.

    • True

    • False

    Correct Answer
    A. False
    Explanation
    Confederation routers remove the confederation ASN from the AS_PATH in updates sent outside the confederation. So others routers does not know that a confederation was used.

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  • 21. 

    What is the first attribute BGP verifiy in its decision process to find the best route, defined by RFC 1771, for each NLRI?

    • NEXT_HOP is reachable (the router has a route in its routing table.

    • The route is synchronized by IGP

    • The NLRI is an ATOMIC AGGREGATOR

    • The router has an interface connected to the ORIGIN Path Attribute

    • The AS_PATH contains the NEXT_HOP

    Correct Answer
    A. NEXT_HOP is reachable (the router has a route in its routing table.
    Explanation
    BGP verifies the reachability of the NEXT_HOP as the first attribute in its decision process to find the best route. This means that the router checks if it has a route in its routing table to reach the NEXT_HOP specified in the route. If the NEXT_HOP is not reachable, the route is considered invalid and will not be chosen as the best route.

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  • 22. 

    Which command allows a Soft Reconfiguration of BGP? That is, allows a BGP peer to reapply its routing policies without closing its neighbor connections?

    • R1 (router-config)# neighbor 172.16.8.8 soft-reset

    • R1# reset bgp soft

    • R1# clear ip bgp * soft

    • R1 (router-config)# neighbor 172.16.8.8 shutdown soft

    • R1 (router-config)# clear connections

    • R1 (router-config)# reset connections

    • R1 (router-config)# clear neighbor * soft

    • R1 (router-config)# reset neighbor *

    Correct Answer
    A. R1# clear ip bgp * soft
    Explanation
    The correct answer is "R1# clear ip bgp * soft". This command allows a soft reconfiguration of BGP by clearing the BGP table without closing the neighbor connections. This means that the BGP peer can reapply its routing policies without disrupting the established connections with its neighbors.

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  • 23. 

    By default, keepalive are sent at which interval?

    • 5 seconds

    • 15 seconds

    • 30 seconds

    • 60 seconds

    • 120 seconds

    • 180 seconds

    • 240 seconds

    • 300 seconds

    Correct Answer
    A. 60 seconds
    Explanation
    By default, keepalive messages are sent at an interval of 60 seconds. Keepalive messages are used to ensure that a connection between two devices remains active and to detect if the connection has been lost. By sending keepalive messages at regular intervals, devices can confirm that the connection is still alive and functioning properly. In this case, the correct answer indicates that the default interval for sending these messages is 60 seconds.

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  • 24. 

    How is the destination IP address used to discover and reach a neighbor determined?

    • By the NEXT_HOP attribute advertised by a neighbor

    • Manually configured using the neighbor command

    • Send in the HELLO messages by neighbor

    • Define within the peer-group of the confederation

    Correct Answer
    A. Manually configured using the neighbor command
    Explanation
    The destination IP address is determined by manually configuring it using the neighbor command. This means that the network administrator manually specifies the IP address of the neighbor to reach.

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  • 25. 

    By default, after how many times a neighbor is considered to have failed (ie.: What is the keepalive timer default value)?

    • 5 seconds

    • 15 seconds

    • 30 seconds

    • 60 seconds

    • 120 seconds

    • 180 seconds

    • 240 seconds

    • 300 seconds

    Correct Answer
    A. 180 seconds
    Explanation
    The keepalive timer default value is 180 seconds, which means that after 180 seconds of not receiving any response from a neighbor, the neighbor is considered to have failed.

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  • 26. 

    What BGP message type are used to establish a neighbor relationship and exchange basic parameters?

    • Hello

    • Advertisement

    • Update

    • Notification

    • Reset

    • Open

    • KeepAlive

    Correct Answer
    A. Open
    Explanation
    The Open message type is used in BGP to establish a neighbor relationship and exchange basic parameters. This message is sent by a BGP speaker to initiate a TCP connection with a neighboring BGP speaker. It contains information such as the BGP version number, the BGP router ID, and the autonomous system number. The Open message is an essential step in the BGP neighbor establishment process.

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  • 27. 

    What is the BGP Routing Information Base (RIB)?

    • BGP routing policies for all the Network Layer Reachability Information (NLRI) learn by BGP

    • BGP topology table, that holds the Network Layer Reachability Information (NLRI) learn by BGP

    • BGP neighbors table

    • BGP forwarding logic base on Path Attributes learned

    Correct Answer
    A. BGP topology table, that holds the Network Layer Reachability Information (NLRI) learn by BGP
    Explanation
    The BGP Routing Information Base (RIB) refers to the BGP topology table that holds the Network Layer Reachability Information (NLRI) learned by BGP. This table contains information about the available paths to reach different network destinations. It includes details such as the next hop, path attributes, and network prefixes. The RIB is used by BGP to make routing decisions and determine the best path for forwarding traffic.

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  • 28. 

    What is the default action when BGP advertises routes to an iBGP neighbor?

    • Does not change the NEXT_HOP (uses the one in the routing table)

    • Change the NEXT_HOP to the update source IP address

    • Summarizes using the classful network of any subnets

    • BGP does not advertise routes to an iBGP neighbor

    Correct Answer
    A. Does not change the NEXT_HOP (uses the one in the routing table)
    Explanation
    When BGP advertises routes to an iBGP neighbor, the default action is that it does not change the NEXT_HOP. Instead, it uses the NEXT_HOP value that is already present in the routing table. This means that the iBGP neighbor will receive the routes with the same NEXT_HOP value that was originally determined by the routing table.

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  • 29. 

    Given that the ip route table contains only the following routes: 10.1.0.0/16 10.2.0.0/24 router bgp 234  no synchronization  bgp log-neighbor-changes  network 10.0.0.0  auto-summary Which NLRI will be found in the BGP Table?

    • 10.1.0.0/16

    • 10.2.0.0/24

    • None

    • 10.0.0.0

    Correct Answer
    A. 10.0.0.0
    Explanation
    With Auto-Summary, if any subnets of the classful network exists in the routing table, it is injected into BGP.

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  • 30. 

    What the BGP subcommand "bgp bestpath med missing-as-worst" does?

    • Promote NLRI with no MED as best path

    • Set the AS_PATH PA of a NLRI to the best path (if none are configured)

    • Reset the default value for MED to the largest/worst value possible (2^32).

    Correct Answer
    A. Reset the default value for MED to the largest/worst value possible (2^32).
    Explanation
    MED default value is 0 (best value). So if one uses MED in its network, it is better to use this command to avoid mistaken routes using the default value. BGP subcommand "bgp bestpath med missing-as-worst" reset the default value for MED to the largest/worst value possible (2^32)

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  • 31. 

    What happen when the keepalive timer within the OPEN message of each BGP neighbor mismatch?

    • They stay in "Open Sent" state

    • They use the lower keepalive timer value

    • They use the higher keepalive timer value

    • They stay in "Connect" state

    Correct Answer
    A. They use the lower keepalive timer value
    Explanation
    When the keepalive timer within the OPEN message of each BGP neighbor mismatch, they use the lower keepalive timer value. This means that both neighbors will agree to use the keepalive timer value that is lower between the two. This ensures that the BGP session remains stable and both neighbors can continue exchanging keepalive messages at the agreed upon interval.

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  • 32. 

    Given that the ip route table contains the following routes: 10.1.0.0/16 10.2.0.0/24 10.2.1.0/24 If the following line is entered, what will be the result? R1(config-router)#aggregate-address 10.2.0.0 255.255.0.0 summary-only

    • NLRI 10.2.0.0/16 will be added into the BGP table

    • NLRI 10.2.0.0/16 will be advertised to its neighbors

    • NLRI 10.2.0.0/24 will be advertised to its neighbors

    • NLRI 10.2.1.0/24 will be advertised to its neighbors

    Correct Answer
    A. NLRI 10.2.0.0/16 will be advertised to its neighbors
    Explanation
    The "aggregate-address" command is used in BGP to summarize multiple routes into a single route. In this case, the command "aggregate-address 10.2.0.0 255.255.0.0 summary-only" is entered, which means that the route 10.2.0.0/16 will be advertised to its neighbors. This is because the command specifies the network address 10.2.0.0 and the subnet mask 255.255.0.0, which covers the range of IP addresses from 10.2.0.0 to 10.2.255.255. Therefore, all the more specific routes within this range, such as 10.2.0.0/24 and 10.2.1.0/24, will be summarized into the larger route 10.2.0.0/16 and advertised to neighbors.

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  • 33. 
    What config should be used if R3 and R4 are using their loopback as source IP? - ProProfs

    What config should be used if R3 and R4 are using their loopback as source IP?

    • EBGP neighbor command should use update-source with loopback IP address

    • EBGP neighbor command should use ebgp-peer option

    • Nothing, eBGP will advertise connected loopback automatically

    • EBGP neighbor command should use ebgp-multihop option

    Correct Answer
    A. EBGP neighbor command should use ebgp-multihop option
  • 34. 

    With Cisco IOS 12.3 and later, BGP perform Auto-Summary by default?

    • True

    • False

    Correct Answer
    A. False
    Explanation
    With Cisco IOS 12.3 and later, BGP does not perform Auto-Summary by default. Auto-Summary is a feature that automatically summarizes the network prefixes at the classful network boundary. However, starting from IOS version 12.3, BGP does not perform this auto-summary feature by default. This means that BGP will not automatically summarize the network prefixes unless specifically configured to do so.

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  • 35. 

    Which statement best describe the following configuration: RTA# int loopback 0 ip address 150.10.1.1 255.255.255.0 router bgp 100 neighbor 160.10.1.1 remote-as 200 neighbor 160.10.1.1 ebgp-multihop neighbor 160.10.1.1 update-source loopback 0 network 150.10.0.0  ! ip route 160.10.0.0 255.255.0.0 1.1.1.2 ip route 160.10.0.0 255.255.0.0 2.2.2.2

    • Allows a neighbor connection between two external peers that do not have direct connection.

    • Implementation of BGP confederation over two links, using static routes in order to use loopback interface

    • Workaround in order to achieve load balancing between two eBGP speakers over parallel links.

    • Allows RTA router to advertise, or reflect, iBGP learned routes to other iBGP speakers.

    Correct Answer
    A. Workaround in order to achieve load balancing between two eBGP speakers over parallel links.
    Explanation
    The configuration includes the "neighbor 160.10.1.1 ebgp-multihop" command, which allows a neighbor connection between two external peers that do not have a direct connection. This is a workaround to achieve load balancing between two eBGP speakers over parallel links. The two static routes for the 160.10.0.0 network with different next hops also support this load balancing by distributing traffic between the two links.

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  • 36. 

    Which statement best describe this configuration: router bgp 100  neighbor 171.69.232.50 remote-as 200  neighbor 171.69.232.50 send-community  neighbor 171.69.232.50 route-map set-community out ! route-map set-community 10 permit  match address 1  set community no-export ! route-map set-community 20 permit  match address 2

    • Will remove the value (set to blank) COMMUNITY field of the routes that match access list 1

    • Will remove the ASN value from the COMMUNITY field of the routes that match access list 1.

    • The routes that match access list 1 won't be advertised by BGP speaker 171.69.232.50 in autonomous system 200.

    • None of the above.

    Correct Answer
    A. The routes that match access list 1 won't be advertised by BGP speaker 171.69.232.50 in autonomous system 200.
    Explanation
    The configuration includes a BGP neighbor statement with the "remote-as" command, indicating that the neighbor is in AS 200. The "send-community" command is used to send BGP community attributes to the neighbor. The "route-map" command is used to apply a route map named "set-community" to the neighbor, with the "out" keyword indicating that it will be applied to outbound routes. The route map includes a permit statement with a match condition using access list 1 and a set action to add the "no-export" community attribute to the routes. Therefore, the routes that match access list 1 will not be advertised by the BGP speaker 171.69.232.50 in AS 200.

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  • 37. 

    The following partial configuration uses route maps in a reverse operation to set the route tag (as defined by the BGP/OSPF interaction document, RFC 1403) when exporting routes with AS_PATH containing ASN 44 from BGP into the main IP routing table. router bgp 100  table-map set_ospf_tag ! route-map set_ospf_tag  match as-path 1  set automatic-tag ! Which command is missing to achieve the task?

    • Ip as-path access-list 1 permit .44*$

    • Ip as-path access-list 1 permit 44*

    • Ip as-path access-list 1 permit ^44_|_44_|_44$

    • Access-list 1 permit *

    • Access-list 1 permit any any

    • Access-list 1 permit as-path *44*

    Correct Answer
    A. Ip as-path access-list 1 permit ^44_|_44_|_44$
    Explanation
    The missing command to achieve the task is "ip as-path access-list 1 permit ^44_|_44_|_44$". This command allows routes with AS_PATH containing ASN 44 to match the route-map set_ospf_tag. The regular expression "^44_|_44_|_44$" matches any AS_PATH that starts with "44_", ends with "_44", or contains "_44_" in the middle. This ensures that routes with AS_PATH containing ASN 44 will be tagged when exporting into the main IP routing table.

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  • 38. 

    Which statement best describe the following configuration: RTC# router bgp 256 neighbor 1.1.1.1 remote-as 100 neighbor 128.213.11.2 remote-as 256 bgp default local-preference 150

    • RTC sets the local preference to 150 of all updates going out to neighbor 128.213.11.2

    • RTC sets the local preference to 150 of all updates going out to neighbor 1.1.1.1

    • RTC sets the local preference to 150 of all updates advertized by neighbor 128.213.11.2

    • RTC sets the local preference to 150 of all updates advertized by neighbor 1.1.1.1

    Correct Answer
    A. RTC sets the local preference to 150 of all updates going out to neighbor 128.213.11.2
    Explanation
    The bgp default local-preference command sets the local preference on the updates out of the router that go to peers in the same AS.

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  • 39. 

    The following partial configuration uses route maps in a reverse operation to set the route tag (as defined by the BGP/OSPF interaction document, RFC 1403) when exporting routes with AS_PATH containing AS_SEQ 44 from BGP into the main IP routing table. router bgp 100  table-map set_ospf_tag ! route-map set_ospf_tag  match as-path 1  set automatic-tag ! Which command is missing to achieve the task?

    • Ip as-path access-list 1 permit .44*$

    • Ip as-path access-list 1 permit 44*

    • Ip as-path access-list 1 permit ^44_|_44_|_44$

    • Access-list 1 permit *

    • Access-list 1 permit any any

    • Access-list 1 permit as-path *44*

    Correct Answer
    A. Ip as-path access-list 1 permit ^44_|_44_|_44$
    Explanation
    The missing command to achieve the task is "ip as-path access-list 1 permit ^44_|_44_|_44$". This command allows routes with AS_PATH containing AS_SEQ 44 to be matched and exported with the route tag set as defined by RFC 1403.

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  • 40. 

    Select all the properties that define a neighbor in the state "Idle"

    • Listen on port TCP 179

    • The router initiate TCP connection with that neighbor

    • The router formed TCP connection with that neighbor

    • The router sent OPEN message to that neighbor

    • The router received OPEN message from that neighbor

    • The router has Established a BGP connection with that neighbor

    • None of the above

    Correct Answer
    A. None of the above
    Explanation
    None of the above properties define a neighbor in the state "Idle." In the Idle state, the router is not actively listening on any port (TCP 179) or initiating a TCP connection with the neighbor. It has not formed a TCP connection or sent/received any OPEN messages. The router has not established a BGP connection with the neighbor either. Therefore, none of the given properties apply to a neighbor in the Idle state.

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  • 41. 

    Which statement best describe this configuration: router bgp 200  neighbor 171.69.232.90 remote-as 100  neighbor 171.69.232.90 send-community  neighbor 171.69.232.90 route-map set-community out ! route-map set-community 10 permit  match as-path 1  set community 200 200 additive ! route-map set-community 20 permit ! ip as-path access-list 1 permit _70$ ip as-path access-list 2 permit .*

    • All the routes that originate from autonomous system 70 have the community values 200 200 added to their already existing values. All other routes are advertised as normal.

    • All the routes that originate from an autonomous system which terminates by 70 (ie.: 70, 470, 6670, etc) have the community values 200 200 added to their already existing values. All other routes are advertised as normal.

    • All the routes that originate from an autonomous system which terminates by 70 (ie.: 70, 470, 6670, etc) have the community values 200 200 added to their already existing values. No other route are advertised.

    • All the route with AS_PATH which terminates by any character followed by 70 (ie.: 70, 470, 6670, etc) have the community values 200 200 added to their already existing values. No other route are advertised.

    Correct Answer
    A. All the routes that originate from autonomous system 70 have the community values 200 200 added to their already existing values. All other routes are advertised as normal.
    Explanation
    The given configuration uses BGP to add the community values 200 200 to routes originating from autonomous system 70. This is achieved by applying a route map called "set-community" to the neighbor with IP address 171.69.232.90. The route map has a permit statement with a match condition of as-path 1, which matches routes with an AS_PATH ending in 70. The set action is used to add the community values to these routes. Routes originating from other autonomous systems are advertised as normal, without any modifications.

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  • 42. 

    Which configuration removes the COMMUNITY PA from the routes advertised.

    • Router bgp 200 neighbor 171.69.232.90 remote-as 100 neighbor 171.69.232.90 community no-export

    • Router bgp 200 neighbor 171.69.232.90 remote-as 100 neighbor 171.69.232.90 route-map set-community out ! route-map set-community 10 permit set community none

    • Router bgp 200 neighbor 171.69.232.90 remote-as 100 neighbor 171.69.232.90 route-map set-community out ! route-map set-community 10 permit set community 0

    • Router bgp 200 neighbor 171.69.232.90 remote-as 100 neighbor 171.69.232.90 route-map set-community out ! route-map set-community 10 deny set community no-export

    Correct Answer
    A. Router bgp 200 neighbor 171.69.232.90 remote-as 100 neighbor 171.69.232.90 route-map set-community out ! route-map set-community 10 permit set community none
    Explanation
    The given configuration removes the COMMUNITY PA from the routes advertised because the "set community none" statement in the route-map set-community removes any community attribute from the routes.

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  • 43. 

    What command(s) allow to reset BGP neighbor connections?

    • R1 (router-config)# reset neighbor 172.16.8.8

    • R1# reset bgp all

    • R1# clear ip bgp *

    • R1 (router-config)# neighbor 172.16.8.8 shutdown

    • R1 (router-config)# clear connections

    • R1 (router-config)# reset connections

    • R1 (router-config)# clear neighbor *

    • R1 (router-config)# reset neighbor *

    Correct Answer(s)
    A. R1# clear ip bgp *
    A. R1 (router-config)# neighbor 172.16.8.8 shutdown
    Explanation
    The command "R1# clear ip bgp *" allows to reset all BGP neighbor connections by clearing the BGP routing table. The command "R1 (router-config)# neighbor 172.16.8.8 shutdown" shuts down the specific BGP neighbor connection with the IP address 172.16.8.8. Both commands are valid ways to reset BGP neighbor connections.

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  • 44. 

    Given that the ip route table contains only the following routes: 10.1.0.0/16 10.2.0.0/24 router bgp 234  no synchronization  bgp log-neighbor-changes  network 10.0.0.0  no auto-summary Which NLRI will be found in the BGP Table?

    • 10.1.0.0/16

    • 10.2.0.0/24

    • None

    • 10.0.0.0

    Correct Answer
    A. None
    Explanation
    With NO Auto-Summary, only EXACT match in the routing table, it is injected into BGP.

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  • 45. 

    Assuming that the auto-summary command has been configured. What the BGP network 10.1.1.0  command instruct to the BGP process to do?

    • Activate BGP process on the corresponding interface (on subnet 10.1.1.0/24)

    • If 10.1.1.0/24 exactly match an entry in the current IP routing table, then put the equivalent NLRI in the local BGP topology table.

    • BGP will start advertising udpate message to its neighbors for network 10.0.0.0/8 if an entry is found in the current local IP routing table.

    • Send Open messages on network 10.1.1.0/24 to establish a connection with a neighbor

    • If 10.0.0.0 match an entry in the current IP routing table, then put the equivalent NLRI in the local BGP topology table.

    Correct Answer
    A. If 10.0.0.0 match an entry in the current IP routing table, then put the equivalent NLRI in the local BGP topology table.
    Explanation
    The correct answer explains that if the network 10.0.0.0 matches an entry in the current IP routing table, then the equivalent NLRI (Network Layer Reachability Information) will be placed in the local BGP (Border Gateway Protocol) topology table. This means that BGP will consider the network 10.0.0.0 as reachable and will include it in its routing decisions and advertisements to its neighbors.

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  • 46. 

    The following partial configuration uses route maps in a reverse operation to set the route tag (as defined by the BGP/OSPF interaction document, RFC 1403) when exporting routes from BGP into the main IP routing table. router bgp 100  table-map set_ospf_tag ! route-map set_ospf_tag  match as-path 1  set automatic-tag ! Which command is missing to achieve the task?

    • Ip as-path access-list 1 permit .*

    • Ip as-path access-list 1 permit *

    • Ip as-path access-list 1 permit any

    • Access-list 1 permit *

    • Access-list 1 permit any any

    • Access-list 1 permit any

    Correct Answer
    A. Ip as-path access-list 1 permit .*
    Explanation
    The missing command to achieve the task is "ip as-path access-list 1 permit .*". This command is used to create an access list that permits any AS path. The "match as-path 1" statement in the route map is referencing this access list to match routes with any AS path. By using the regular expression ".*", it will match any AS path, allowing all routes to be tagged when exporting from BGP to the main IP routing table.

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  • 47. 

    Assuming that NO default static route (0.0.0.0/0) exist in the routing table, which router subcommand will inject the default route into BGP?

    • R1(config-router)#network 0.0.0.0

    • R1(config-router)#default-information originate

    • R1(config-router)#redistribute static

    • R1(config-router)#neighbor 1.1.1.1 default-originate

    Correct Answer
    A. R1(config-router)#neighbor 1.1.1.1 default-originate
    Explanation
    The correct answer is "R1(config-router)#neighbor 1.1.1.1 default-originate". This command will instruct the router to advertise a default route to its BGP neighbor 1.1.1.1. By using the "default-originate" keyword, the router will inject the default route (0.0.0.0/0) into BGP, even if there is no default static route present in the routing table.

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  • 48. 

    Which mecanisms RouteReflector (RR) can use to prevent loop?

    • RR add their Cluster-ID into the CLUSTER_LIST Path Attrubute before sending an update. So if the RR receives a NLRI with its ID, the prefix will be discarded.

    • Set the iBGP update messages TTL to 1.

    • ORIGINATOR_ID Path Attribute constains the RID of the first iBGP peer that advertise the route. So if a iBGP router sees its RID it will discard it.

    • RR reflect only its Best routes based on its BGP table.

    • RR must be implemented within a confederation, then using eBGP to prevent loop.

    Correct Answer(s)
    A. RR add their Cluster-ID into the CLUSTER_LIST Path Attrubute before sending an update. So if the RR receives a NLRI with its ID, the prefix will be discarded.
    A. ORIGINATOR_ID Path Attribute constains the RID of the first iBGP peer that advertise the route. So if a iBGP router sees its RID it will discard it.
    A. RR reflect only its Best routes based on its BGP table.
    Explanation
    Route Reflectors (RR) prevent loops by adding their Cluster-ID into the CLUSTER_LIST Path Attribute before sending an update. This means that if the RR receives a Network Layer Reachability Information (NLRI) with its own ID, the prefix will be discarded. Additionally, the ORIGINATOR_ID Path Attribute contains the Router ID (RID) of the first iBGP peer that advertised the route. If an iBGP router sees its own RID in this attribute, it will discard the route. Lastly, RR only reflects its best routes based on its BGP table, ensuring that only the most optimal routes are propagated.

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  • 49. 

    Select all the properties that define a neighbor in the state "Active"

    • Listen on port TCP 179

    • The router initiate TCP connection with that neighbor

    • The router formed TCP connection with that neighbor

    • The router sent OPEN message to that neighbor

    • The router received OPEN message from that neighbor

    • The router has Established a BGP connection with that neighbor

    • None of the above

    Correct Answer(s)
    A. Listen on port TCP 179
    A. The router initiate TCP connection with that neighbor
    Explanation
    A neighbor in the state "Active" is defined by two properties: listening on port TCP 179 and the router initiating a TCP connection with that neighbor. These two conditions must be met for a neighbor to be considered "Active."

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Quiz Review Timeline (Updated): Sep 13, 2023 +

Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

  • Current Version
  • Sep 13, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Feb 26, 2012
    Quiz Created by
    Fpouliot

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