NEW QUESTION 1
Which command set is used to configure BFD support for a BGP neighbor that is reachable through GigabitEthernet 0/0/0/0 on Cisco IOS XR?

• A. router bgp 300 bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200
• B. router bgp 300 bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200 bfd fast-detect
• C. bfdecho disable router bgp 300neighbor 10.20.20.2remote-as 200
• D. bfdrouter bgp 300neighbor 10.20.20.2remote-as 200
• E. interface Gi0/0/0/0ipv4 verify unicast source reachable-via rx router bgp 300bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200 bfd fast-detect
• F. interface Gi0/0/0/0ipv4 verify unicast source reachable-via rx bfdinterface Gi0/0/0/0 echo disable router bgp 300bfd multiplier 2bfd minimum-interval 20neighbor 10.20.20.2remote-as 200

Answer: B

NEW QUESTION 2
When implementing high-availability stateful switchover BGP routing, in which situation would Cisco NSR be required?

• A. On the PE routers connecting to the CE routers which are not NSF aware or are not NSF capable
• B. On the PE routers connecting to the CE routers which support graceful restart
• C. On the PE routers connecting to the CE routers which are incapable of performing stateful switchover operations because the CE routers are only NSF aware but not NSF capable
• D. On the PE routers connecting to the CE routers which are incapable of performingstateful switchover operations because the CE routers are only NSF capable but not NSF aware
• E. On the service provider core P routers which are also NSF aware
• F. On the service provider core P routers which are also NSF capable

Answer: A

NEW QUESTION 3
Which command set should be used for a 6to4 tunnel in a Cisco IOS XE router, considering the border interface with IPv4 address of 209.165.201.2?

• A. interface Tunnel2002 ipv6 enableipv6 address 2002:D1A5:C902::1/128 tunnel source Ethernet0/0tunnel mode ipv6ip 6to4
• B. interface Tunnel2002 ipv6 enableipv6 address 2002:D1A5:D902::1/128 tunnel source Ethernet0/0tunnel mode ipv6ip 6to4
• C. interface Tunnel2002 ipv6 enableipv6 address 2002:D1A5:D902::1/128 tunnel source Ethernet0/0tunnel mode ipv6ip
• D. interface Tunnel2002 ipv6 enableipv6 address 2002:D1A5:C902::1/128 tunnel source Ethernet0/0tunnel mode ipv6ip auto-tunnel
• E. interface Tunnel2002ipv6 enableipv6 address 2002:D1A5:D902::1/128 tunnel source Ethernet0/0tunnel mode ipv6ip auto-tunnel

Answer: B

NEW QUESTION 4
Refer to the exhibit.

Based on the output of two eBGP adjacent neighbors, which command can be used to set up the default BGP timers?

• A. RP/0/0/CPU0:R1(config-bgp)#timers bgp 60 30
• B. RP/0/0/CPU0:R2(config-bgp)#timers bgp 30 60
• C. RP/0/0/CPU0:R2(config-bgp-nbr)#timers bgp 180 60
• D. RP/0/0/CPU0:R2(config-bgp)#timers bgp 60 180
• E. RP/0/0/CPU0:R1(config-bgp)#timers bgp 60 180

Answer: D

NEW QUESTION 5
Refer to the exhibit for the outputs from an ASR9K router.

Why did the ping fail?

• A. The ping command is missing the ipv6 option: ping ipv6 2001:db8:10:1:10::1/128
• B. There is a problem with the IS-IS configurations
• C. The fe80::eab7:48ff:fe2c:a180 next-hop is not reachable
• D. The prefix length should be removed from the IPv6 address in the ping command: ping ipv6 2001:db8:10:1:10::1
• E. IPv6 is not enabled on the Gi0/0/0/0 interface
• F. The IPv6 neighbor discovery protocol is not enabled on the Gi0/0/0/0 interface

Answer: D

NEW QUESTION 6
In which three cases is a dual-stack IPv6/IPv4 router required? (Choose three.)

• A. tunnel endpoint routers in the case of IPv6 over GRE
• B. transit routers in case of an IPv6 over GRE implementation
• C. 6to4 implementation border routers
• D. 6to4 implementation border and neighboring routers
• E. PE routers in case of an IPv6 over IPv4 tunnel over MPLS implementation
• F. PE and P routers in case of an IPv6 over IPv4 tunnel over MPLS implementation

Answer: ACE

NEW QUESTION 7
When enabling interdomain multicast routing, which two statements are correct? (Choose two.)

• A. Multiprotocol BGP is used instead of PIM SM to build the intradomain and interdomain multicast distribution trees
• B. Use MSDP to enable the RPs from different domains to exchange information about active multicast sources
• C. MSDP SA packets are sent between the multiprotocol BGP peers
• D. Noncongruent unicast and multicast topologies can be supported using multiprotocol BGP

Answer: BD

Explanation:
http://prakashkalsaria.wordpress.com/2010/08/11/mbgp-msdp/
MSDP In the PIM-SM model, multicast sources and receivers must register with their local RP. Actually, the router closest to the sources or receivers registers with the RP, but the key point to note is that the RP knows about all the sources and receivers for any particular
group. RPs in other domains have no way of knowing about sources located in other domains. MSDP is an elegant way to solve this problem.
MSDP is a mechanism that allows RPs to share information about active sources. RPs know about the receivers in their local domain. When RPs in remote domains hear about the active sources, they can pass on that information to their local receivers and multicast data can then be forwarded between the domains. A useful feature of MSDP is that it allows each domain to maintain an independent RP that does not rely on other domains, but it does enable RPs to forward traffic between domains. PIM-SM is used to forward the traffic between the multicast domains.
The RP in each domain establishes an MSDP peering session using a TCP connection with the RPs in other domains or with border routers leading to the other domains. When the RP learns about a new multicast source within its own domain (through the normal PIM register mechanism), the RP encapsulates the first data packet in a Source-Active (SA) message and sends the SA to all MSDP peers. The SA is forwarded by each receiving peer using a modified RPF check, until the SA reaches every MSDP router in the interconnected networks—theoretically the entire multicast internet. If the receiving MSDP peer is an RP, and the RP has a (*, G) entry for the group in the SA (there is an interested receiver), the RP creates (S, G) state for the source and joins to the shortest path tree for the source. The encapsulated data is decapsulated and forwarded down the shared tree of that RP. When the packet is received by the last hop router of the receiver, the last hop router also may join the shortest path tree to the source. The MSDP speaker periodically sends SAs that include all sources within the own domain of the RP
http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.2/routing/configuration/guide/rc32bgp.html
Multiprotocol BGP
Multiprotocol BGP is an enhanced BGP that carries routing information for multiple network layer protocols and IP multicast routes. BGP carries two sets of routes, one set for unicast routing and one set for multicast routing.
The routes associated with multicast routing are used by the Protocol Independent Multicast (PIM) feature to build data distribution trees.
Multiprotocol BGP is useful when you want a link dedicated to multicast traffic, perhaps to limit which resources are used for which traffic. Multiprotocol BGP allows you to have a unicast routing topology different from a multicast routing topology providing more control over your network and resources.
In BGP, the only way to perform interdomain multicast routing was to use the BGP infrastructure that was in place for unicast routing. Perhaps you want all multicast traffic exchanged at one network access point (NAP).
If those routers were not multicast capable, or there were differing policies for which you wanted multicast traffic to flow, multicast routing could not be supported without multiprotocol BGP.
Note It is possible to configure BGP peers that exchange both unicast and multicast network layer reachability information (NLRI), but you cannot connect multiprotocol BGP clouds with a BGP cloud. That is, you cannot redistribute multiprotocol BGP routes into BGP.

NEW QUESTION 8
With IPv6 multicast, which feature can be used as a replacement method for static RP configuration?

• A. PIM Snooping
• B. MLD
• C. MLD Snooping
• D. Embedded RP
• E. DHCPv6

Answer: D

NEW QUESTION 9
What is determined by running the same hash algorithm on all PIMv2 routers?

• A. The SPT from the RP to the multicast source
• B. The SPT from the last hop router to the multicast source
• C. Auto RP election
• D. Which BSR to use for a particular multicast group
• E. Which RP to use from a set of candidate RPs in the RP set

Answer: E

NEW QUESTION 10
When implementing IP SLA icmp-echo probes on Cisco IOS-XE routers, which two options are available for IPv6? (Choose two.)

• A. flow-label
• B. hop-limit
• C. DSCP
• D. traffic-class
• E. TOS

Answer: AD

NEW QUESTION 11
Which two BGP mechanisms are used to prevent routing loops when using a design with redundant route reflectors? (Choose two.)

• A. Cluster-list
• B. AS-Path
• C. Originator ID
• D. Community
• E. Origin

Answer: AC

Explanation:
http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.7/routing/configuration/guide/rc37bgp.html
As the iBGP learned routes are reflected, routing information may loop. The route reflector model has the following mechanisms to avoid routing loops:
•Originator ID is an optional, nontransitive BGP attribute. It is a 4-byte attributed created by a route reflector.
The attribute carries the router ID of the originator of the route in the local autonomous system. Therefore, if a misconfiguration causes routing information to come back to the originator, the information is ignored.
•Cluster-list is an optional, nontransitive BGP attribute. It is a sequence of cluster IDs that the route has passed. When a route reflector reflects a route from its clients to nonclient peers, and vice versa, it appends the local cluster ID to the cluster-list. If the cluster-list is empty, a new cluster-list is created. Using this attribute, a route reflector can identify if routing information is looped back to the same cluster due to misconfiguration. If the local cluster ID is found in the cluster-list, the advertisement is ignored.

NEW QUESTION 12
The following Cisco IOS-XR configuration command will globally enable which multicast process(es) on the router?
RP/0/RP0/CPU0:router(config)# multicast-routing

• A. IGMP only
• B. PIM only
• C. IGMP and MLD only
• D. PIM and IGMP only
• E. PIM and IGMP and MLD

Answer: E

Explanation:
http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.5/multicast/configuration/guide/mc35 mcst.html
Multicast-routing Configuration Submode
When you issue the multicast-routing ipv4 or multicast-routing ipv6 command, all default multicast components (PIM, IGMP, MLD, MFWD, and MRIB) are automatically started, and the CLI prompt changes to "config-mcastipv4" or "config-mcast-ipv6", indicating that you have entered multicast-routing configuration submode

NEW QUESTION 13
What is one of the configuration errors within an AS that can stop a Cisco IOS-XR router from announcing certain prefixes to its EBGP peers?

• A. Some prefixes were mistagged with the no-export BGP community
• B. Some prefixes were set with an MED of 0
• C. The outbound BGP route policy only has set actions defined without any pass actions defined
• D. The inbound BGP route policy only has set actions defined without any pass actions defined

Answer: A

NEW QUESTION 14
Refer to the exhibit.




On the PE, which two statements are correct regarding the(192.168.156.60,224.1.1.1) entry? (Choose two,)

• A. The RPF neighbor points towards the RP
• B. The RPF neighbor is reachable overthe Gi0/0/0/1 interface
• C. The OIL contains the GiO/0/0/0 interface
• D. The IIL is Null

Answer: AC

Explanation:
#show ip mroute

NEW QUESTION 15
Given the IPv6 address of 2001:0DB8::1:800:200E:88AA, what will be its corresponding the solicited-node multicast address?

• A. FF01::1:200E:88AA
• B. FF01::1:FF0E:88AA
• C. FF01:0DB8::1:800:200E:88AA
• D. FF02::1:FF0E:88AA
• E. FF02::1:200E:88AA
• F. FF02:0DB8::1:800:200E:88AA

Answer: D

Explanation:
IPv6 nodes (hosts and routers) are required to join (receive packets destined for) the following multicast groups:
•All-nodes multicast group FF02:0:0:0:0:0:0:1 (scope is link-local)
•Solicited-node multicast group FF02:0:0:0:0:1:FF00:0000/104 for each of its assigned unicast and anycast addresses
IPv6 routers must also join the all-routers multicast group FF02:0:0:0:0:0:0:2 (scope is link- local).
The solicited-node multicast address is a multicast group that corresponds to an IPv6 unicast or anycast address. IPv6 nodes must join the associated solicited-node multicast group for every unicast and anycast address to which it is assigned. The IPv6 solicited- node multicast address has the prefix FF02:0:0:0:0:1:
FF00:0000/104 concatenated with the 24 low-order bits of a corresponding IPv6 unicast or anycast address (see Figure 2). For example, the solicited-node multicast address corresponding to the IPv6 address 2037::01:800:200E:8C6C is FF02::1:FF0E:8C6C. Solicited-node addresses are used in neighbor solicitation messages

NEW QUESTION 16
Refer to the exhibit.

Which three statements are correct regarding the Cisco IOS-XR configuration? (Choose three.)

• A. This router, acting as the RP mapping agent, will send RP announcement messages to the 224.0.1.40 group
• B. This router, acting as the RP mapping agent, will send RP discovery messages to the224.0.1.39 group
• C. This router is the RP mapping agent only for the 224.11.11.11 and 224.99.99.99 multicast groups
• D. This router is a candidate PIM-SM RP for the 224.99.99.99 multicast group
• E. This router is a candidate PIM-BIDIR RP for the 224.11.11.11 multicast group
• F. IGMPv3 is enabled on all interfaces
• G. Other routers will recognize this router as the RP for all multicast groups with this router loopback 0 IP address

Answer: DEF

NEW QUESTION 17
A network engineer for an ISP wants to reduce the number of iBGP adjacencies. A merge is taking place with another ISP network, so the network engineer needs to make both ASNs look like a single network for the Internet. Which BGP technology is most suitable?

• A. route reflector
• B. confederation
• C. clustering
• D. peer group

Answer: B

NEW QUESTION 18
A CRS router that runs Cisco IOS XR has dual routing processors installed. Which solution should be implemented to prevent OSPF adjacency flapping if the primary routing processor fails?

• A. NSR
• B. OSPF Fast Timers
• C. OSPF RE Sync
• D. router msdp
• E. NSF

Answer: A

NEW QUESTION 19
Which types of multicast distribution tree can PIM-SM use?

• A. Only shared tree rooted at the source
• B. Only shared tree rooted at the RP
• C. Only shortest path tree rooted at the RP
• D. Shared tree rooted at the source and shortest path tree switchover
• E. Shared tree rooted at the RP and shortest path tree switchover
• F. Shared tree rooted at the first-hop router and shortest path tree rooted at the RP

Answer: E

NEW QUESTION 20
Refer to the exhibit.

Router A and Router B are connected via GigabitEthernet interfaces, but they are unable to form an MSDP neighborship. Which two components must be addressed when fixing the MSDP peering issue? (Choose two.)

• A. An msdp default peer is configured on both routers.
• B. A BGP process on each router is present so that MSDP can peer and carry updates.
• C. The router interfaces are PIM-enabled to transport MSDP updates.
• D. The connect-source attribute is configured with a host route under the MSDP process.
• E. The MSDP peering on both routers specifies an origin ID so that it can peer.
• F. The router A loopback interface configures the correct subnet mask.

Answer: DF

NEW QUESTION 21
Which three methods can be used to reduce the full-mesh IBGP requirement in a service provider core network? (Choose three.)

• A. Implement route reflectors
• B. Enable multi-protocol BGP sessions between all the PE routers
• C. Implement confederations
• D. Implement MPLS (LDP) in the core network on all the PE and P routers
• E. Enable BGP synchronization
• F. Disable the IBGP split-horizon rule

Answer: ACD

NEW QUESTION 22
Refer to the exhibit.

Which statement correctly explains the bgp graceful-restart command?

• A. This command is used to enable NSR and is entered on the NSR-capable router, and also on any NSR-aware peer
• B. This command is used to enable NSF and is entered on the NSF-capable router, and also on any NSF-aware peer
• C. This command is only required on the NSF-capable routers to enable BGP graceful restart with the BGP peers
• D. This command is only required on the NSF-aware routers to enable BGP graceful restart with the BGP peers
• E. This command is only required on the NSR-capable routers to enable BGP graceful restart with the BGP peers

Answer: B

Explanation:
Graceful restart is supported in recent versions of Cisco IOS software (12.0S) and is supported in Cisco IOS XR software. Graceful restart is the mechanism by which BGP routing peers avoid changes to their forwarding paths following a switchover. If the BGP peer has received this capability, it is aware that the device sending the message is nonstop forwarding (NSF)-capable. Both the NSF-capable router and its BGP peers (NSFaware peers) need to exchange the graceful restart capability in their OPEN messages, at the time of session establishment. If both peers do not exchange the graceful restart capability, the session will not be graceful restart-capable.
If the BGP session is lost during a Route Processor (RP) switchover or BGP process restart, the NSF-aware BGP peer marks all the routes associated with the NSF-capable router as stale; however, it continues to use these routes to make forwarding decisions for a set period of time. This functionality means that no packets are lost while the newly active RP is waiting for convergence of the routing information with its BGP peers.
After a failover event occurs, the NSF-capable router reestablishes the session with the BGP peer. In establishing the new session, it sends a new graceful restart message that identifies the NSF-capable router as having restarted. At this point, the routing information is exchanged between the two BGP peers. Once this exchange is complete, the NSF- capable device uses the newly received routing information to update the RIB and the Forwarding Information Base (FIB) with the new forwarding information. The NSF-aware device uses the network information to remove stale routes from its BGP table. The BGP protocol is then fully converged.
If a BGP peer does not support the graceful restart capability, it will ignore the graceful restart capability in an OPEN message but will establish a BGP session with the NSF- capable device. This functionality will allow interoperability with non-NSF-aware BGP peers (and without NSF functionality), but the BGP session with non- NSF-aware BGP peers will not be graceful restart-capable.

NEW QUESTION 23
Which statement is correct regarding MP-BGP?

• A. MP-BGP can indicate whether an advertised prefix (NLRI) is to be used for unicast routing, multicast RPF checks or for both using different SAFIs.
• B. MP-BGP uses a single BGP table to maintain all the unicast prefixes for unicast forwarding and all the unicast prefixes for RPF checks.
• C. MP-BGP can be used to propagate multicast state information, which eliminates the need to use PIM for building the multicast distribution trees.
• D. MP-BGP enables BGP to carry IP multicast routes used by MSDP to build the multicast distribution trees.

Answer: A

Explanation:
Protocol Independent Multicast
Protocol Independent Multicast (PIM) is a routing protocol designed to send and receive multicast routing updates. Proper operation of multicast depends on knowing the unicast paths towards a source or an RP. PIM relies on unicast routing protocols to derive this reverse-path forwarding (RPF) information. As the name PIM implies, it functions independently of the unicast protocols being used. PIM relies on the Routing Information Base (RIB) for RPF information. If the multicast subsequent address family identifier (SAFI) is configured for Border Gateway Protocol (BGP), or if multicast intact is configured, a separate multicast unicast RIB is created and populated with the BGP multicast SAFI routes, the intact information, and any IGP information in the unicast RIB. Otherwise, PIM gets information directly from the unicast SAFI RIB. Both multicast unicast and unicast databases are outside of the scope of PIM.
The Cisco IOS XR implementation of PIM is based on RFC 4601 Protocol Independent Multicast - Sparse
Mode (PIM-SM): Protocol Specification. For more information, see RFC 4601 and the Protocol Independent Multicast (PIM): Motivation and Architecture Internet Engineering Task Force (IETF) Internet draft

NEW QUESTION 24
Which additional feature is provided using MLDv2 that is not available in MLDv1?

• A. Multicast Address Specific Queries
• B. Source filtering
• C. Done messages
• D. Report messages

Answer: B

Explanation:
• PIM-SSM is made possible by IGMPv3 and MLDv2. Hosts can now indicate interest in specific sources using IGMPv3 and MLDv2. SSM does not require a rendezvous point (RP) to operate.

NEW QUESTION 25
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