Exam code : 640-878
Exam name : Building Cisco Service Provider Next-Generation Networks, Part 2Which spanning-tree mode can be used to map several VLANs to a singlespanning-tree
Which spanning-tree mode uses the name command to configure a region name?
Which procedure is used as thelast resort disaster recovery procedure to completely
replace the currently installed IOS XR software on Cisco IOS XR routers?
C. install recovery
D. install rollback
E. install add and install activate
Which file extension indicates abootable installation file in Cisco IOS XR software?
C:\Documents and Settings\user-nwz\Desktop\1.JPG
When configuring an ACL entry, which network and wildcard mask matches only IP
addresses 10.8.144.0to 10.8.151.255?
A. 10.8.144.0 0.0.3.255
B. 10.8.144.0 0.0.7.255
C. 10.8.144.0 0.0.15.255
D. 10.8.144.0 0.0.252.255
E. 10.8.144.0 0.0.248.255
F. 10.8.144.0 0.0.240.255
Which IP addresses are matched by the permit 192.168.80.640.0.0.15 access-list entry?
A. 192.168.80.64 to 192.168.80.255
B. 192.168.80.64 to 192.168.80.96
C. 192.168.80.64 to 192.168.80.95
D. 192.168.80.64 to 192.168.80.80
E. 192.168.80.64 to 192.168.80.79
Which two statements aboutNAT444 are true? (Choose two.)
A. NAT444 packets are translated three times.
B. NAT packets traverse three IPv4 addressing domains.
C. NAT444 needs to work together with DNS64.
D. There are two types of NAT444 (stateful or stateless).
E. NAT is performedby the CPE and also by the service provider router.
Carrier-grade NAT (CGN), also known as large-scale NAT (LSN), is an approach to IPv4
network design in which end sites, in particular residential networks, are configured with
private network addresses that are translated to public IPv4 addresses by middlebox
network address translator devices embedded in the network operator's network, permitting
the sharing of small pools of public addresses among many end sites. Thisshifts the NAT
function and configuration thereof from the customer premises to the Internet service
Carrier-grade NAT has been proposed as an approach for mitigating IPv4 address
Critics of carrier-grade NAT argue the following aspects:
Like any form of NAT, it breaks the end-to-end principle.
It has significant security, scalability, and reliability problems, by virtue of being stateful.
It makes record keeping for law-enforcement operations more difficult.
It makes itimpossible to host services on well known ports.
It does not solve the IPv4 address exhaustion problem when a routable IP address is
needed, such as in web hosting.
One use scenario of CGN can be described as NAT444, because some customer's
connectionsto public servers would pass through three different IPv4 addressing domains:
the customer's own private network, the carrier's private network, and the public Internet.
Another CGN scenario is Dual-Stack Lite, in which the carrier's network uses IPv6 andthus
only two IPv4 addressing domains are needed.
Refer to the exhibit.
The access list has been configured on the Gi0/0/0/0 interface in the inbound direction.
Which four packets that are sourced from 10.1.1.1 TCP port 1060, if theyare routed to the
Gi0/0/0/0 interface, will be permitted? (Choose four)
A. destination IP address: 192.168.15.37, destination TCP port: 8080
B. destination IP address: 192.168.15.41, destination TCP port: 8080
C. destination IP address: 192.168.15.49, destination TCP port: 8080
D. destination IP address: 192.168.15.36, destination TCP port: 80
E. destination IP address: 192.168.15.46, destination TCP port: 80
F. destination IP address: 192.168.15.49, destination TCP port: 80
Which two statements about NAT64 are true? (Choose two.)
A. NAT64 packets traverse two IPv4 addressing domains.
B. NAT64 packets are translated two times.
C. There are two types of NAT64 (stateful or stateless).
D. NAT is performed by the CPE and also by the service provider edge router.
E. The DNS64 server embeds the IPv4 address from the DNS A record with a
preconfigured IPv6 translation prefix.
Answer: C, E