Using an Internal ISDN PRI Module

Problem

You want to configure an internal ISDN PRI module.

Solution

You can configure an ISDN PRI controller module by using the controller T1 command set as follows:

Router8#configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Router8(config)#isdn switch-type primary-dms100
Router8(config)#controller T1 0
Router8(config-controlle)#framing esf
Router8(config-controlle)#clock source line primary
Router8(config-controlle)#linecode b8zs
Router8(config-controlle)#pri-group timeslots 1-24
Router8(config-controlle)#exit
Router8(config)#end
Router8#

 

Discussion

The configuration for an ISDN PRI controller module is different from the configuration for a regular internal T1 module that we discussed in Recipe 16.3. But the basic parameters such as defining the framing, line coding, and so forth are similar.

In this example, we have also defined two ISDN-specific options. The first is to set the ISDN switch type to be a Nortel DMS 100 device:

Router8(config)#isdn switch-type primary-dms100

There are several other primary rate ISDN switch types available. If your ISDN vendor uses National ISDN switches, you would replace this command with the following:

Router8(config)#isdn switch-type primary-ni

Cisco has made a concerted effort to make the primary-ni option effectively switch independent in newer IOS releases. There are still some problems with some of the less common switch types, but, for the most part, you should be able to use primary-ni with PRI circuits from most ISDN vendors.

Note that it is often necessary to reboot the router after changing the ISDN switch type to ensure that the change takes effect.

The other ISDN-specific command in this configuration example is the pri-group command:

Router8(config-controlle)#pri-group timeslots 1-24

In this case, we have simply defined the available ISDN B channels to be on channels 1 through 24, inclusive.

See Also

Recipe 16.3