Nest 0 Cart
Nest Account
Popular Exams
All Categories...
Nest
Nest 0
Contact
Log In / Sign Up
Copyright 2024 © store. All rights reserved.
Home Cisco® 642-883

Cisco® 642-883 Exam Practice Questions (P. 5)

  • Full Access (191 questions)
  • Six months of Premium Access
  • Access to one million comments
  • Seamless ChatGPT Integration
  • Ability to download PDF files
  • Anki Flashcard files for revision
  • No Captcha & No AdSense
  • Advanced Exam Configuration
Get Contributor Access
Question #21
Which three BGP configuration groupings are supported on Cisco IOS XR Software? (Choose three.)
  1. A
    peer-group
  2. B
    af-group
  3. C
    bgp-group
  4. D
    session-group
  5. E
    neighbor-group
  6. F
    as-group

Correct Answer:
BDE
Commands relating to a peer group found in Cisco IOS Release 12.2 have been removed from Cisco IOS XR software. Instead, the af-group, session-group, and neighbor-group configuration commands are added to support the neighbor in CiscoIOS XR software:
The af-group command is used to group address family-specific neighbor commands within an IPv4 or IPv6 address family. Neighbors that have the same address family configuration are able to use the address family group name for their address family-specific configuration. A neighbor inherits the configuration from an address family group by way of the use command. If a neighbor is configured to use an address family group, the neighbor will (by default) inherit the entire configuration fromthe address family group. However, a neighbor will not inherit all of the configuration from the address family group if items are explicitly configured for the neighbor.
The session-group command allows you to create a session group from which neighborscan inherit address family-independent configuration. A neighbor inherits the configuration from a session group by way of the use command. If a neighbor is configured to use a session group, the neighbor (by default) inherits the session group's entire configuration. A neighbor does not inherit all the configuration from a session group if a configuration is done directly on that neighbor.
The neighbor-group command helps you apply the same configuration to one or more neighbors. Neighbor groups can include session groups and address family groups. This additional flexibility can create a complete configuration for a neighbor. Once a neighbor group is configured, each neighbor can inherit the configuration through the use command. If a neighbor is configured to use a neighbor group, the neighbor (by default) inherits the neighbor group's entire BGP configuration.
However, a neighbor will not inherit all of the configuration from the neighbor group if items are explicitly configured for the neighbor. Inaddition, some part of the neighbor group's configuration could be hidden if a session group or address family group was also being used.

Question #22
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?
  1. A
    ip as-path access-list permit.*
  2. B
    ip as-path access-list permit^$
  3. C
    ip as-path access-list permit _$
  4. D
    ip as-path access-list permit _^
  5. E
    ip as-pathaccess-list permit local-asip as-path access-list deny *
  6. F
    ip as-path access-list deny.*ip as-path access-list permit *

Correct Answer:
B

Question #23
What is recursive lookup in BGP and how does it work?
  1. A
    The router looks up the EBGP route and the EBGP next hop to reach a destination in the remote AS. Then the router looks up the route to reach the EBGP next hop using the IBGP.
  2. B
    The router looks up the IBGP route and the IBGP next hop to reach a destination in the remote AS. Then the router looks up the route to reach the IBGP next hop using the EBGP.
  3. C
    The router looks up the BGP route and the BGP next hop to reach a destination in the remote AS. Then the router looks up the route to reach the BGP next hop using the IGP.
  4. D
    The routerlooks up the route and the next hop to reach a destination in the remote AS using the IGP. Then the router looks up the route to reach the next hop using BGP.
  5. E
    The router perform three routing lookups to determine the route to reach a destination in theremote AS. The first lookup is done using EBGP, the second lookup is done using IBGP, and the third lookup is done using the IGP.

Correct Answer:
C
A few different approaches are available to deal with iBGP and synchronization. We may turn on the synchronization option on our routers and wait for the IGP to have a route for the destination before its advertised to peers. Another option is to simply use a full mesh, so that iBGP convergence isnt an issue.
Clearly that isnt going to happen when a networks core needs to scale: it will implement something like reflectors that cause iBGPs full mesh to be broken.
The real alternative, if you dont enable synchronization, is to use route recursion. A recursive route lookup uses the BGP next-hopattribute to actually make a different route lookup. The IGP can use the destination network instead of the AS-path to determine where it gets sent. Even if the iBGP hasnt converged, the routers will still know how to get to that network, since it will exist in the router it was advertised from, who will know the next-hop.

Question #24
Which reserved AS number or range of numbers is used for backward compatibility between old BGP peers using 16-bit AS number and new BGP peers using
32-bit AS number?
  1. A
    AS 65001 to 65535
  2. B
    AS 65512 to 65535
  3. C
    AS 12345
  4. D
    AS 23456
  5. E
    AS 64001

Correct Answer:
D
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6554/ps6599/4byte_asnios.pdf
New Reserved AS#

AS_TRANS = AS #23456 -
2-byte placeholder fora 4-byte AS number
Used for backward compatibility between OLD and NEW BGP speakers

Question #25
Which BGP attribute is a set of generic tags that can be used to signal various routing policies between BGP routers?
  1. A
    AS path
  2. B
    MED
  3. C
    weight
  4. D
    communities
  5. E
    route tags

Correct Answer:
D
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a00801475b2.shtml

Previous Questions Next Questions

All Pages