Cisco 642-883 Braindumps 2021

NEW QUESTION 1
A network engineer cannot connect different routers by eBGP using peer groups. Which two actions establish an adjacency between both routers? (Choose two.)

• A. Ensure that the peer group statements match across all routers.
• B. Ensure that ebgp-multihop is configured.
• C. Ensure that the remote-as statement is configured with the correct peer AS.
• D. Configure a weight value that is lower than the default value of 32768.
• E. Specify the weight attribute first.

Answer: BC

NEW QUESTION 2
Which two statements about a transit AS are correct? (Choose two.)

• A. A transit AS has eBGP connection(s) to only one external AS.
• B. Routes between ASs are always exchanged via eBGP.
• C. A transit AS uses an IGP like OSPF or ISIS to propagate the external networks within the transit AS.
• D. Core routers within a transit AS normally use default routing to reach the external networks.
• E. iBGP sessions can be established between non directly connected routers.

Answer: BE

NEW QUESTION 3
A service provider is about to purchase more IPv4 address space. Which organization can facilitate this purchase?

• A. APNIC
• B. IETF
• C. USANOG
• D. IEEE
• E. NANOG

Answer: A

NEW QUESTION 4
Refer to the exhibit.

R2 does not have R1 1.1.1.1/32 subnet in its BGP table. Which issue can be causing this problem?

• A. There is no route-reflector configuration in AS 100.
• B. IPv4 address-family isnot enabled on R1.
• C. R2 does not have next-hop-self for a XR4 iBGP session.
• D. XR4 drops any update coming from R1 because there is no RPL policy applied.

Answer: D

NEW QUESTION 5
Refer to the exhibit.

A service provider (AS65000) is interconnected to two upstream providers (ISP 1 neighbor IP 192.168.1.1 and ISP 2 neighbor IP 192.168.1.2) via a single link in a peering exchange. Which option can an engineer use to implement nonproprietary policies to make ISP 1 the preferred link for incoming and outgoing traffic from the local SP?

• A. route-map outgoing permit 10set-as –path prepend 65000 65000 65000route-map incoming permit 10set local-preference 1000router bgp 65000neighbor 192.168.1.1 route- map incoming outneighbor 192.168.1.1 route-map outgoing in
• B. route-map outgoing permit 10set metric 100route-map incoming permit 10set weight 100router bgp 65000neighbor 192.168.1.1 route-map incoming inneighbor 192.168.1.1 route-map outgoing out
• C. route-map outgoing permit 10set-as –path prepend 65000 65000 65000route-map incoming permit 10set local-preference 1000router bgp 65000neighbor 192.168.1.1 route- map incoming inneighbor 192.168.1.2 route-map outgoing out
• D. set-as –path prepend 65000 65000 65000route-map incoming permit 10set weight 100router bgp 65000neighbor 192.168.1.1 route-map incoming inneighbor 192.168.1.1 route-map outgoing out

Answer: A

NEW QUESTION 6
What are three common problems that can cause a BGP neighbor state to toggle between the idle state and the active state? (Choose three.)

• A. BGP network command misconfiguration
• B. route policy misconfiguration
• C. AS number misconfiguration
• D. route map misconfiguration
• E. BGP neighbor peering to wrong IP address
• F. IGP routing problem: not able to reach the source IP address of the BGP open packet

Answer: CEF

NEW QUESTION 7
How many total OSPF virtual links are configured in this multiarea OSPF network which supports both OSPFv2 and OSPFv3 for IPv4 and IPv6 routing?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: B

Explanation: #Show running-config | include virtual – check how many router having “virtual “ entry

NEW QUESTION 8
Which four statements are correct regarding IS-IS operations? (Choose four.)

• A. By default, Level 1 routers within an IS-IS area do not carry any routing information external to the area to which they belon
• B. They use a default route to exit the area.
• C. Summarization should be configured on the Level 2 routers, which injects the Level 2 routes into Level 1.
• D. IS-IS supports "route leaking" in which selected Level 2 routes can be advertised by a Level 1/Level 2 router into Level 1.
• E. The IS-IS backbone is a contiguous collection of Level 1 capable routers, each of which can be in a different area.
• F. 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.
• G. Cisco IOS XR Software supports multitopology for IPv6 IS-IS unless single topology is explicitly configured in IPv6 address-family configuration mode.

Answer: ACEF

Explanation: http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.0/routing/configuration/guide/rc3isis.html#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.

NEW QUESTION 9
When configuring Cisco IOS route maps, which command allows the route map processing to jump to another statement instead of exiting?

• A. jump
• B. next
• C. set
• D. continue
• E. goto

Answer: D

Explanation: Match Operations With Continue Clauses
If a match clause does not exist in the route-map entry but a continue clause does, the continue clause will be automatically executed and go to the specified route-map entry. If a match clause exists in a route-map entry, the continue clause is executed only when a successful match occurs. When a successful match occurs and a continue clause exists, the route map executes the set clauses and then goes to the specified route-map entry. If the next route map contains a continue clause, the route map will execute the continue clause if a successful match occurs. If a continue clause does not exist in the next route map, the route map will be evaluated normally. If a continue clause exists in the next route map but a match does not occur, the route map will not continue and will “fall through” to the next sequence number if one exists.
Set Operations With Continue Clauses
Set clauses are saved during the match clause evaluation process and executed after the route-map evaluation is completed. The set clauses are evaluated and executed in the order in which they were configured. Set clauses are only executed after a successful match occurs, unless the route map does not contain a match clause. The continue statement proceeds to the specified route-map entry only after configured set actions are performed. If a set action occurs in the first route map and then the same set action occurs again, with a different value, in a subsequent route map entry, the last set action may override any previous set actions that were configured with the same set command unless the set command permits more than one value. For example, the set as-path pretend command permits more than one autonomous system number to be configured.

NEW QUESTION 10
What is function of the RP/0/RSP0/CPU0:PE1(config-ospf)#distance Cisco IOS-XR command?

• A. To modify the administrative distance of the OSPF routes
• B. To modify the default seed metric of the OSPF external routes
• C. To modify the OSPF default reference bandwidth
• D. To modify the OSPF cost

Answer: A

Explanation: http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.8/routing/command/reference/rr38osp f.pdf

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NEW QUESTION 11
A network engineer wants to set the local preference to 100 for the specific BGP community sets of 100:1, 101:1, and 102:1. Which option can the engineer use to implement this through RPL, where the BGP community set list is made by the name of lowpri-communities?

• A. route-policy ch-prefif community matches lowpri-communities then set local-preference 100endifend-policy
• B. route-policy ch-prefif community eq lowpri-communities then set local-preference 100endifend-policy
• C. route-policy ch-prefif community matches-any lowpri-communities then set local-preference 100endifend-policy
• D. route-policy ch-prefif community neq lowpri-communities then set local-preference 100endifend-policy

Answer: C

NEW QUESTION 12
In comparing IS-IS with OSPF, a Level-1-2 IS-IS router is similar to which kind of OSPF router?

• A. ASBR on a normal OSPF area
• B. ASBR on NSSA
• C. ABR on totally stubby OSPF area
• D. ABR on stubby OSPF area
• E. ABR on a normal OSPF area

Answer: C

NEW QUESTION 13
Refer to the BGP and route map configurations exhibit.

When the "setas" route map is applied to the 10.1.1.2 neighbor, the 10.1.1.2 neighbor is not able to receive all the required BGP routes from this router. What could be the problem?

• A. The BGP session was cleared using the clear ip bgp command after the route map was applied.
• B. The test1 or test2 prefix-list is misconfigured.
• C. There is no pass action configured within the route map.
• D. The route map is missing the route-map setas permit 30 statement.

Answer: D

NEW QUESTION 14
Refer to the Cisco IOS show command output shown in the exhibit.

Which of the following statements is correct?

• A. The best path to 10.2.10.1/32 was chosen because of the AS path.
• B. The best path to 10.2.10.1/32 was chosen because of the weight.
• C. The best path to 10.2.10.1/32 was chosen because of the local preference.
• D. The best path to 10.2.10.1/32 was chosen because of the MED.
• E. The best path to 10.2.10.1/32 was chosen because of the route origin.

Answer: B

NEW QUESTION 15
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

NEW QUESTION 16
What is recursive lookup in BGP and how does it work?

• A. The router looks up the EBGP route and the EBGP next hop to reach a destination in the remote A
• B. Then the router looks up the route to reach the EBGP next hop using the IBGP.
• C. The router looks up the IBGP route and the IBGP next hop to reach a destination in the remote A
• D. Then the router looks up the route to reach the IBGP next hop using the EBGP.
• E. The router looks up the BGP route and the BGP next hop to reach a destination in the remote A
• F. Then the router looks up the route to reach the BGP next hop using the IGP.
• G. The router looks up the route and the next hop to reach a destination in the remote AS using the IG
• H. Then the router looks up the route to reach the next hop using BGP.
• I. The router perform three routing lookups to determine the route to reach a destination in the remote A
• J. The first lookup is done using EBGP, the second lookup is done using IBGP, and the third lookup is done using the IGP.

Answer: C

Explanation: 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 it’s advertised to peers. Another option is to simply use a full mesh, so that iBGP convergence isn’t an issue.
Clearly that isn’t going to happen when a network’s core needs to scale: it will implement something like reflectors that cause iBGP’s full mesh to be broken.
The real alternative, if you don’t enable synchronization, is to use route recursion. A recursive route lookup uses the BGP next-hop attribute 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 hasn’t 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.

NEW QUESTION 17
Refer to the exhibit.

Routers B and C in transit AS 200 are the exit points toward AS 100 and AS 300. Router B is running Cisco IOS XR and Router C IOS XE. Internally, AS 200 runs OPSF only for internal routing. Which two methods can an engineer use to ensure proper reachability between AS 100 and AS 300 for the needed routes? (Choose two.)

• A. Router B: router ospf 200redistribute bgp 200 tag 20router bgp 200address-family ipv4 unicast redistribute ospf 200 metric-type 2
• B. Router B: router ospf 200redistribute bgp 200router bgp 200address-family ipv4 unicast redistribute ospf 200
• C. Router C: router ospf 200redistribute bgp 200 metric-type 1 subnets tag 200router bgp 200 address-family ipv4 redistribute ospf 200
• D. Router C: router ospf 200redistribute bgp 200 metric-type 1 subnets tag 200router bgp 200 address-family ipv4redistribute ospf 200 match external 2
• E. Router C: router ospf 200redistribute bgp 200 metric-type 1 subnets tag 200router bgp 200 address-family ipv4redistribute ospf 200 route-map match-tag match external route-map match-tag deny 10match tag 200

Answer: AD

NEW QUESTION 18
Which two features are specific only to Tier 3 providers? (Choose two.)

• A. interconnects with Tier Level 1 and Tier Level 2 ISPs in public peering points
• B. only purchases transit from other networks to reach the Internet
• C. purchases transit and pays settlements to other service providers
• D. uses strict route filtering to allow only customer and local routes to be sent to upstream providers
• E. receives a full Internet routing table via BGP from its upstream provider, which it can use for load-balancing traffic

Answer: BD

NEW QUESTION 19
A network engineer is configuring IS-IS in Cisco IOS XR. Where is BFD configured?

• A. RP/0/RSP0/CPU0:router(config-isis-if)#
• B. RP/0/RSP0/CPU0:router(config)#
• C. RP/0/RSP0/CPU0:router(config-bfd)#
• D. RP/0/RSP0/CPU0:router(config-isis-if-af)#

Answer: A