Understanding ISDN PRI Operation for Channelized Interfaces

The Dual-Port Channelized T1/E1/ISDN PRI PIM provides support for ISDN PRI services such as dial-in at the central office, callback from the central office, and primary or backup network connections from branch offices. You can install channelized T1/EI/ISDN PRI PIMs and ISDN BRI PIMs and configure both ISDN PRI and ISDN BRI service on the same J Series device.

On a J Series device with Dual-Port Channelized T1/E1/ISDN PRI PIMs, you can configure each port for either T1, E1, or ISDN PRI service, or for a combination of ISDN PRI and either channelized T1 or E1 service. You can configure up to 23 time slots in a channelized T1 PRI interface and up to 30 time slots in a channelized E1 PRI interface as B-channels. Each B-channel supports 64 Kbps of traffic. The unconfigured time slots can be used as regular DS0 interfaces on top of the T1 or E1 physical layer.

You must also explicitly configure a D-channel for signaling purposes: time slot 24 on a channelized T1 interface and time slot 16 on a channelized E1 interface.

In addition, you can configure the following options:

• B-channel allociation order—This setting controls the allocation of free B-channels for dial-out calls. Values include ascending (allocating from the lowest-numbered to highest-numbered) and descending (the default).
• Switch type—The following ISDN switch types are compatible with J Series devices:
  • ATT5E—AT&T 5ESS
  • ETSI—NET3 for the UK and Europe
  • NI2—National ISDN-2
  • NTDMS-100—Northern Telecom DMS-100
  • NTT—NTT Group switch for Japan
• Q.931 timers—Q.931 is a Layer 3 protocol for the setup and termination of connections. The default value for each timer is 10 seconds, but can be configured between 1 and 65,536 seconds.
• Dialer pool—The dialer pool priority has a range from 1 to 255, with designating lowest-priority interfaces and 255 designating the highest-priority interfaces.
• Trace options