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Q1. Which of the following is used by an IS-IS router to detect other IS-IS neighbor routers and to form adjacencies?
A. ESH
B. ISH
C. IIH
D. PSNP
E. CSNP
Answer: C
Explanation:
ISIS actually features three different hello types An ES Hello (ESH) is send by all End Systems, and all IS devices listen for this Hello An IS Hello (ISH) announces the presence of an IS - An IS Hello is sent by all IS devices, and End Systems listen for these hellos Finally, an IS-to-IS Hello (IIH) is used by an IS to discover other ISes and to form adjacencies with them A router will send an IIH to another router on the link to form or maintain an adjacency, but it will still send an ISH as well in case there are end systems located on that segment
Q2. Which high-availability routing feature requires the neighbor router to support the graceful restart capability?
A. BFD
B. NSR
C. NSF
D. MTR
Answer: C
Explanation:
On Cisco IOS XR software, NSF minimizes the amount of time a network is unavailable to its users following a route processor (RP) failover. The main objective of NSF is to continue forwarding IP packets and perform a graceful restart following an RP failover.
When a router restarts, all routing peers of that device usually detect that the device went down and then came back up. This transition results in what is called a routing flap, which could spread across multiple routing domains. Routing flaps caused by routing restarts create routing instabilities, which are detrimental to the overall network performance. NSF helps to suppress routing flaps in NSF-aware devices, thus reducing network instability.
NSF allows for the forwarding of data packets to continue along known routes while the routing protocol information is being restored following an RP failover. When the NSF feature is configured, peer networking devices do not experience routing flaps. Data traffic is forwarded through intelligent line cards while the standby RP assumes control from the failed active RP during a failover. The ability of line cards to remain up through a failover
and to be kept current with the Forwarding Information Base (FIB) on the active RP is key
to NSF operation.
When the Cisco IOS XR router running IS-IS routing performs an RP failover, the router
must perform two tasks to resynchronize its link-state database with its IS-IS neighbors.
First, it must relearn the available IS-IS neighbors on the network without causing a reset of
the neighbor relationship. Second, it must reacquire the contents of the link-state database
for the network.
The IS-IS NSF feature offers two options when configuring NSF:
.IETF NSF
.Cisco NSF
If neighbor routers on a network segment are NSF aware, meaning that neighbor routers are running a software version that supports the IETF Internet draft for router restartability, they assist an IETF NSF router that is restarting. With IETF NSF, neighbor routers provide adjacency and link-state information to help rebuild the routing information following a failover. In Cisco IOS XR software, Cisco NSF checkpoints (stores persistently) all the state necessary to recover from a restart without requiring any special cooperation from neighboring routers. The state is recovered from the neighboring routers, but only using the standard features of the IS-IS routing protocol. This capability makes Cisco NSF suitable for use in networks in which other routers have not used the IETF standard implementation of NSF
Q3. What is defined by using the Cisco IOS XR policy-global configuration command?
A. the default BGP route policy
B. global variables that can be referenced by any route policy
C. the global default route policy
D. hierarchical route policy
E. nested route policy
Answer: B
Explanation:
Global Configuration Mode Prompt: (config) Enter global configuration mode from executive (EXEC) mode by using the configure command. Global configuration commands generally apply to the whole system rather than just one protocol or interface. You can enter all other configuration submodes listed in this section from global configuration mode. RP/0/RP0/CPU0:router# configure RP/0/RP0/CPU0:router(config)# Global Parameter Configuration Mode Prompt: (config-rpl-gl)
Enter global parameter configuration mode by using the policy-global command in global configuration mode.
In global parameter configuration mode, you can create or modify a global policy by entering successive commands and then terminating the configuration by entering the end-global command.
For example, to configure global parameters: RP/0/RP0/CPU0:router(config)# policy-global RP/0/RP0/CPU0:router(config-rp-gl)# glbpathtype ebgp RP/0/RP0/CPU0:router(config-rp-gl)# glbtag 100 RP/0/RP0/CPU0:router(config-rp-gl)# end-global
Q4. Which BGP attribute is a set of generic tags that can be used to signal various routing policies between BGP routers?
A. AS path
B. MED
C. weight
D. communities
E. route tags
Answer: D
Explanation:
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801
475b2.shtml
Q5. Which AS path access list is used by a multihomed customer to only announce their own address space to their service providers to prevent the multihomed customer from becoming a transit AS?
A. ip as-path access-list permit.*
B. ip as-path access-list permit^$
C. ip as-path access-list permit _$
D. ip as-path access-list permit _^
E. ip as-path access-list permit local-as ip as-path access-list deny *
F. ip as-path access-list deny.* ip as-path access-list permit *
Answer: B
Explanation:
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Q6. Which option is a mechanism that can be implemented between two eBGP peers to communicate the routes each peer needs from the other?
A. ORF
B. ACL
C. prefix list
D. route map
Answer: A
Q7. Under which two conditions does an enterprise require BGP peering with its upstream Internet provider? (Choose two.)
A. The enterprise has two exit points that are geographically separated and routing must be controlled so that delay variations are reduced.
B. The enterprise has one exit point and must announce the IP class it has been assigned from its ISP.
C. The enterprise has two Layer 2 links to the upstream ISP in the same location and wants to achieve redundancy.
D. The enterprise needs a simple and efficient way to ensure proper routing for its AP subnets on its single ISP link.
E. The enterprise is multihomed to two ISPs and has its own IP space AS number.
Answer: A,E
Q8. Referring to the partial Cisco IOS-XR BGP configuration exhibit, when trying to commit this configuration, the following error is displayed:
% Failed to commit one or more configuration items during a pseudo-atomic operation. All changes made have been reverted. Please issue 'show configuration failed' from this session to view the errors.
What is wrong with the configuration?
A. IPv6 unicast routing has not been enabled globally using the ipv6 unicast-routing command
B. The configuration is missing the required network command
C. The update-source loopback 0 commands must be configured under the respective neighbor address-family
D. The configuration is missing the address-family ipv4 unicast and address-family ipv6 unicast commands under router bgp 65111
Answer: D