Cisco 640-878 Dumps 2021

NEW QUESTION 1
Which Cisco platform runs the Cisco IOS XE operating system?

• A. Cisco ASR9K
• B. Cisco CRS
• C. Cisco 12000 GSR
• D. Cisco ASR1K
• E. Cisco ME 3400
• F. Cisco ISR-G2

Answer: D

Explanation: http://www.cisco.com/en/US/prod/collateral/routers/ps9343/product_bulletin_c25-448387.html

NEW QUESTION 2
Which three are common ISP access network technologies? (Choose three.)

• A. DSL
• B. Cable modem
• C. DWDM
• D. MPLS
• E. PON
• F. MP-BGP

Answer: ABE

Explanation: http://blog.ioshints.info/2010/02/passive-optical-networks.html- PON

NEW QUESTION 3
Which two statements about carrier-grade NAT are true? (Choose two.)

• A. It conserves IPv4 addresses.
• B. A service provider issues private IP addresses to its customers.
• C. A service provider translates the private IP address of its customer to another private IP address.
• D. It is implemented on the CE and PE routers.
• E. It is designed to simplify IPv6 addressing.

Answer: AB

Explanation: http://www.cisco.com/en/US/docs/routers/crs/software/crs_r3.9.1/cg_nat/configuration/guide/cgc39 1cgn.html#wp1268988
Carrier Grade NAT Overview
Carrier Grade Network Address Translation (CGN) is a large scale NAT that is capable of providing private IPv4 to public IPv4 translation in the order of millions of translations to support several hundred thousand subscribers and bandwidth throughput of at least 10 Gbps full-duplex.
CGN is a workable solution to the IPv4 address depletion problem while offering a way for service provider subscribers and content providers to implement a graceful transition to IPv6. CGN employs network address and port translation (NAPT) methods to aggregate many private IP addresses into fewer public IPv4 addresses. For example, a single public IPv4 address with a pool of 32 K port numbers supports 320 individual private IP subscribers assuming each subscriber requires 100 ports (for example, each TCP connection needs one port number). A CGN requires IPv6 to assist with the transition from IPv4 to IPv6.

NEW QUESTION 4
Within an MPLS domain, which table is used by the label switch routers to make forwarding decisions when a labeled packet is received?

• A. FIB
• B. RIB
• C. LFIB
• D. LIB
• E. CEF

Answer: C

Explanation:
http://www.cisco.com/en/US/docs/ios-xml/ios/mp_ldp/configuration/12-4m/mp-ldp-12-4m-book.pdf

NEW QUESTION 5
Select and Place:

Answer:

Explanation:

NEW QUESTION 6
Which first-hop router redundancy protocol uses the active virtual gateway to assign a virtual MAC address to the active virtual forwarders?

• A. HSRP
• B. VRRP
• C. GLBP
• D. FHRP

Answer: C

Explanation: http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html

NEW QUESTION 7
What layer of the IP NGN Model does the Customer Element and the Carrier Ethernet exist?

• A. Service Layer
• B. Network Layer
• C. Application Layer
• D. Operational Layer

Answer: B

NEW QUESTION 8
ISPs use which protocol to establish peering sessions in an Internet exchange point environment?

• A. LDP
• B. IS-IS
• C. BGP
• D. OSPF

Answer: C

NEW QUESTION 9
Which three statements about OSPFv2 or OSPFv3 authentication are true? (Choose three.)

• A. On Cisco IOS XR platforms, OSPFv3 authentication can be configured at the OSPF routing process, area, or interface level.
• B. OSPF authentication on Cisco IOS and IOS XE platforms can be configured per area or per interface.
• C. On Cisco IOS and IOS XE and IOS XR platforms, the authentication key can only be configured per interface.
• D. OSPFv3 uses IPsec for authentication and encryption.
• E. On Cisco IOS XR platforms, the OSPF authentication that is configured for the area overrides the authentication that is configured for the interface.
• F. On Cisco IOS and IOS XE platforms, the two OSPFv2 authentication methods that are supported are MD5 and SHA1.

Answer: ABD

Explanation: http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.7/routing/configuration/guide/rc37ospf.html

NEW QUESTION 10
Topology Diagram:

Select and Place:

Answer:

Explanation:

NEW QUESTION 11
Refer to the exhibit.

Which three statements about MPLS LDP operations are true?

• A. The incoming label for 10.2.10.1/32 is 16010 (which is allocated by the local router), and theoutgoing label is 22 (as advertised by the next-hop router).
• B. The 16003 and 16010 labels are learned from the 192.168.112.40 LDP neighbor.
• C. The ImpNull outgoing label for the 192.168.102.0/24 network means that the outgoing label should be removed when sending packets to the 192.168.112.40 next-hop router, when the incoming label is 16003.
• D. The ImpNull outgoing label for the 192.168.102.0/24 network means that the local router has not received a label for that network from its neighbor.
• E. The Unlabeled outgoing label for 10.10.10.100/32 indicates that a label pop is required when sending packets to the 10.10.10.1 next-hop router.
• F. The outgoing label of 22 for 10.2.10.1/32 is learned from the 192.168.112.40 LDP neighbor.

Answer: ACF

Explanation: http://www.cisco.com/en/US/docs/ios/12_2t/12_2t2/feature/guide/ldp_221t.html

NEW QUESTION 12
Which Cisco IOS-XR command is used to unpack a package on the local router?

• A. install boot
• B. install commit
• C. install add
• D. install package

Answer: C

NEW QUESTION 13
Refer to the exhibit.

The access list has been configured on the Gi0/0/0/0 interface in the inbound direction. Which two packets that are sourced from 172.16.1.1 TCP port 1050, if they are routed to the Gi0/0/0/0 interface, will be permitted? (Choose two)

• A. destination IP address: 10.10.192.201, destination TCP port: 80
• B. destination IP address: 10.10.193.255, destination TCP port: 80
• C. destination IP address: 10.10.196.1, destination TCP port: 80
• D. destination IP address: 10.10.195.254, destination TCP port: 23
• E. destination IP address: 10.10.193.145, destination TCP port: 23
• F. destination IP address: 10.10.197.32, destination TCP port: 23

Answer: AB

NEW QUESTION 14
The permit 172.16.32.0 0.0.15.255 access-list entry permits exactly which IP address range?

• A. 172.16.32.0 to 172.16.47.255
• B. 172.16.32.0 to 172.16.48.255
• C. 172.16.32.0 to 172.16.62.255
• D. 172.16.32.0 to 172.16.63.255
• E. 172.16.32.0 to 172.16.64.255
• F. 172.16.32.0 to 172.16.255.255

Answer: A

NEW QUESTION 15
When is a route-policy configuration needed on a Cisco IOS XR router using RPL?

• A. when enabling an IGP routing protocol configuration
• B. when enabling an EBGP peering configuration
• C. when enabling an IBGP peering configuration
• D. when enabling route redistribution
• E. when enabling an LDP peering configuration

Answer: B

Explanation: http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.7/routing/configuration/guide/rc37rpl.pdf

NEW QUESTION 16
Which configuration error within an AS can cause a Cisco IOS XR router to not announce certain
prefixes to its EBGP peers?

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

Answer: A

NEW QUESTION 17
Topology:

Select and Place:

Answer:

Explanation:

NEW QUESTION 18
Select and Place:

Answer:

Explanation:

NEW QUESTION 19
Your switch network has been configured to support multiple VLANs. In order for the users on one VLAN to communicate with users on another VLAN, which additional configuration is required?

• A. Enable a routing protocol like EIGRP on a router or on a Layer 3 capable switch
• B. Enable inter-VLAN routing on a router or on a Layer 3 capable switch
• C. Enable a switch virtual interface on the router, using the interface vlan global configuration command
• D. Enable a switch virtual interface on the switch, using the encapsulation dot1q
• E. subinterface configuration command
• F. Enable IP routing on a Layer 2 switch

Answer: B

NEW QUESTION 20





Hot Area:

Answer:

Explanation:
vlan 80
Use the "show spanning-tree mst" command on each switch to see the vlans mapped to each MST.