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[Free] 2017(Jan) EnsurePass Passguide Cisco 642-883 Dumps with VCE and PDF 1-10

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2017 Jan Cisco Official New Released 642-883
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Deploying Cisco Service Provider Network Routing (SPROUTE)

Question No: 1

Which four statements are correct regarding IS-IS operations? (Choose four.)

  1. By default, Level 1 routers within an IS-IS area do not carry any routing information external to the area to which they belong. They use a default route to exit the area.

  2. Summarization should be configured on the Level 2 routers, which injects the Level 2 routes into Level 1.

  3. IS-IS supports quot;route leakingquot; in which selected Level 2 routes can be advertised by a Level 1/Level 2 router into Level 1.

  4. The IS-IS backbone is a contiguous collection of Level 1 capable routers, each of which can be in a different area.

  5. With IS-IS, an individual router is in only one area, and the border between areas is on the link that connects two routers that are in different areas.

  6. Cisco IOS XR Software supports multitopology for IPv6 IS-IS unless single topology is explicitly configured in IPv6 address-family configuration mode.

Answer: A,C,E,F Explanation:

http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.0/routing/configuration/guide/rc3isis.h tml#wp1148617

Single-Topology IPv6 Support

Single-topology IPv6 support on Cisco IOS XR software allows IS-IS for IPv6 to be configured on interfaces along with an IPv4 network protocol. All interfaces must be configured with the identical set of network protocols and all routers in the IS-IS area (for Level 1 routing) or the domain (for Level 2 routing) must support the identical set of network layer protocols on all interfaces.

When single-topology support for IPv6 is used, only narrow link metrics, also known as old- style type, length, value (TLV) arguments, may be employed. During single-topology operation, one shortest path first (SPF) computation per level is used to compute both IPv4 and IPv6 routes. Using a single SPF is possible because both IPv4 IS-IS and IPv6 IS-IS routing protocols share a common link topology.

Because multitopology is the default behavior in the software, you must explicitly configure IPv6 to use the same topology as IPv4 in order to enable single-topology IPv6. Configure the single-topology command in ipv6 address family configuration submode of the IS-IS router stanza.

Multitopology IPv6 Support

Multitopology IPv6 support on Cisco IOS XR software differs from Cisco IOS software in that IS-IS assumes that multitopology support is required as soon as it detects interfaces

configured for both IPv6 and IPv4 within the IS-IS stanza.

You must use the metric-style wide command to configure IS-IS to wide link metrics as multitopology link advertisements.

Question No: 2

When implementing LDP, what is liberal label retention mode?

  1. To reduce the convergence time, the LSR will retain all the received labels in its LIB even if all the neighbor LSRs go down temporary

  2. The LSR can assign it#39;s own label for each destination network even though it has not been assigned a next hop label from the neighbor LSR

  3. The LSR will store the label received from the downstream LSRs in its LIB even if the downstream LSRs are not the next hop for the destination

  4. The LSR will not perform PHP if it is operating in liberal label retention mode

Answer: C Explanation:

By default, LDP accepts labels (as remote bindings) for all prefixes from all peers. LDP operates in liberal label retention mode, which instructs LDP to keep remote bindings from all peers for a given prefix. For security reasons, or to conserve memory, you can override this behavior by configuring label binding acceptance for set of prefixes from a given peer.

The ability to filter remote bindings for a defined set of prefixes is also referred to as LDP inbound label filtering

Question No: 3

You are implementing OSPF as the IGP using a single OSPF area design. The router memory usage for OSPF is too high. Which two methods can lower the OSPF memory usage? (Choose two.)

  1. Enable OSPF synchronization

  2. Implement multi-area OSPF

  3. Enable OSPF sham links to reduce the number of LSAs

  4. Implement route summarization on the ABRs

  5. Enable route leaking between Level 1 and Level 2 areas

Answer: B,D

Question No: 4

Refer to the IS-IS configuration exhibit.

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This is the typical IS-IS configuration of the routers in an AS using IS-IS as the IGP. This AS is in the transition phase of integrating IPv6 into the network. During this transition phase, some of the routers within the AS might be running IPv4 only, some might be running IPv6 only, and others might be running both IPv4 and IPv6. To avoid any black holes for the IPv6 traffic, which configuration change can be made?

  1. Disable IS-IS adjacency checks.

  2. Enable IPv6 adjacency over IPv4 IS-IS peering.

  3. Enable multi-topology IS-IS.

  4. Disable the IPv4 unicast address-family.

  5. Enable IS-IS wide metric to support the single-topology mode.

Answer: C

Question No: 5

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Ensurepass 2017 PDF and VCE

Ensurepass 2017 PDF and VCE

Ensurepass 2017 PDF and VCE

Ensurepass 2017 PDF and VCE

Which router has the su [20/115] entry pointing to NullO in its routing table and why? (Choose two.)

  1. CE5

  2. PE5

  3. PE6

  4. The router is summarizing into

  5. The router is suppressing the route

  6. The L2/L1 IS-IS router is blocking the interarea route to the L1-only router

Answer: D,F Explanation:

# show clns route

Question No: 6

Refer to the Cisco IOS XE IS-IS configuration exhibit.

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What are two problems with the configuration that are causing the IPv4, or the IPv6, or the IPv4 and IPv6 IS-IS operations to fail? (Choose two.)

  1. The configuration is missing the interface gi0/0 and interface gi0/0 commands under router isis 1.

  2. The configuration is missing the address-family ipv4 unicast and address-family ipv6 unicast commands under router isis 1.

  3. IPv6 unicast routing has not been enabled globally on the Cisco IOS XE router.

  4. The gi0/0 and gi0/1 interfaces are not participating in the router isis 1 routing instance.

  5. Multitopology IS-IS must be enabled to support both IPv4 and IPv6.

  6. Another router isis instance must be enabled to support IPv6.

Answer: C,D Explanation:

http://www.cisco.com/en/US/docs/switches/metro/me3400/software/release/12.2_50_se/co nfiguration/guide/swipv6.pdf

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