Cisco Exam #642-821: BCRAN Exam (Transcender, set 2)
Brush up on your knowledge of WAN connection technologies for remote access between enterprise sites for the CCNP exam with these nine sample questions.
courtesy of Transcender
Question:
1. Which command should you use to configure a line to accept both PPP and SLIP encapsulation?
2. Which numerical code signifies a CHAP-failure message type in a CHAP result?
3. Which reference point is placed between a NT1 and a LT on a subscriber line?
4. How many B channels make up an ISDN PRI connection in Europe?
5. Which traffic shaping term refers to the clock/port speed of the connection to the Frame Relay cloud and specifies the rate at which traffic flows into or out of the network?
6. Which command should you use to enable Frame Relay traffic shaping on an interface?
7. Which of the following is a routing strategy that can be used on a Dial-on-Demand Routing (DDR) network to control the update interval of distance vector routing protocols?
a. static
b. dynamic
c. snapshot
d. dialer filtering
8. You must configure a router to issue AT commands to a remote host during callback. Which command should you use to configure this functionality?
a. Router(config)# ppp callback accept
b. Router(config)# ppp callback initiate
c. Router(config)# callback forced-wait 60
d. Router(config-line)# script callback test
9. What is the function of a NAT router?
a. Translates globally unique IP addresses into local addresses before sending the packet to the outside network
b. Translates globally unique IP addresses into global addresses before sending the packet to the outside network
c. Translates external addresses into globally unique IP addresses before sending the packet to the outside network
d. Translates internal local addresses into globally unique IP addresses before sending the packet to the outside network
1. async mode interactive
2. 04
3. U
4. 30
5. local access rate
6. frame-relay traffic-shaping
7. Answer C is correct. Snapshot routing is a routing strategy that can be used on a DDR network to control the update interval of distance vector routing protocols. Snapshot routing uses a client-server model to control the routing table updates between the DDR routers. During a DDR connection, the client router and server router exchange routing tables and then enter a quiet period. Once the established quiet period elapses, the client and server again exchange routing tables. This method of updating routing tables saves a considerable amount of bandwidth because distance vector routing protocols often transmit their entire routing table in 10- to 60-second intervals.
Static routes, which are defined for connecting the DDR routers, are entered manually on each DDR router and do not control the update interval of DDR routers. The use of static routes eliminates the need for DDR routers to broadcast routing updates and tables over the DDR connection. When dynamic routing protocols are used, routing updates flow between the DDR routers once the DDR connection is made. Dynamic routing can be used with snapshot routing to cache routes learned by dynamic routing protocols, which allows the automation of static routing maintenance. Dialer filtering uses access control lists (ACLs) to classify all packets traversing a DDR connection as either interesting or uninteresting. Dialer filtering cannot be used to control the update interval of distance vector routing protocols.
8. Answer D is correct. The script-callback test command specifies that the test chat script be used during callback. Chat scripts can be used for a variety of tasks, including reconfiguring modems.
To require the router to initiate a callback to a remote host, you must use the ppp callback initiate command.
To allow a remote host to request a callback from the router, you must use the ppp callback accept command.
The callback-forced wait 60 command requires the router to wait 60 seconds before a callback is initiated.
9. Answer D is correct. A NAT router translates internal local addresses into globally unique IP addresses before sending the packet to the outside network. Its main function is not to convert global IP addresses into local addresses, but it can forward a transmission to the proper internal address once a transmission is received.
One disadvantage of NAT is that it does not allow for end-to-end IP traceability of transmissions.
A NAT router introduces switching path delays. Therefore, it does not improve the bandwidth at which a user can transmit data.
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