Implement and verify WAN links

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These questions are based on 642-816 – Interconnecting Cisco Networking Devices Part 2.


Objective: Implement and verify WAN links
Sub-Objective: Troubleshoot WAN implementation issues


Single Answer, Multiple Choice


Which of the following Dial on Demand Routing (DDR) commands allows a five-minute delay before disconnecting a call?



  1. The dialer idle-timeout 5 command
  2. The dialer idle-timeout 300 command
  3. The dialer load-threshold 5 command
  4. The dialer load-threshold 300 command


B. The dialer idle-timeout 300 command


The dialer idle-timeout 300 command allows a five-minute delay before disconnecting a call. This command specifies the number of idle seconds before a call is disconnected. The syntax for the command is as follows:


dialer idle-timeout seconds


The default number of seconds for the dialer idle-timeout seconds command is 120 seconds. As long as interesting traffic is crossing the connection, the timeout value is reset to 120 or equal to idle-timeout value. Noninteresting traffic does not reset the timer. Once the timer reaches 0, the DDR connection is terminated.


The dialer idle-timeout 5 option is incorrect. The dialer idle-timeout command uses seconds, not minutes, to specify the idle time before a call is disconnected.


The dialer load-threshold 5 and dialer load threshold 300 options are incorrect. The dialer load-threshold command is used to set the maximum amount of interface load before the dialer places another call. It does not specify the number of idle minutes or seconds before a call is disconnected. This command allows you to perform load balancing across the two B-channels on your Basic Rate Interface (BRI). This feature is also referred to as bandwidth on demand (BOD). For example, your router makes a phone call on the first B-channel of your BRI, and after a period of time, you exceed the 64 Kbps bandwidth available on this channel. By default, your traffic would experience congestion, and in the worse case would be dropped. To deal with this temporary burst of traffic, you can have your router bring up the second B-channel to handle the burst, and once the traffic falls back to 64 Kbps or lower, drop the connection on the second B-channel.


CCNA Self-Study CCNA ICND Exam Certification Guide, Chapter 10: ISDN and Dial-on-Demand Routing, p. 345.

Cisco Support > Cisco IOS Software Releases 12.1 T > Dialer Idle Timer Inbound Traffic Configuration

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