BACP PortMaster 3 (TM)-to-Ascend Pipeline Configuration Example

Background:

The Ascend Pipeline family of products is widely deployed throughout the world as dial-in customer premises equipment (CPE) devices to ISPs. The Pipeline family can use the two channels of a BRI dynamically to maintain a 56Kbps or 64Kbps connection and bring up the second channel on an as-needed basis to create a 112Kbps or 128Kbps connection. To enable this dynamic bandwidth allocation (DBA), the Pipeline product relies on the central site device to provide information, which is then used by the Pipeline to bring up and tear down the second channel as needed. 

In a situation like the following where all Ascend gear is used, the protocol that provides the information to the Pipeline is Multichannel Protocol Plus (MP+) and is Ascend's proprietary bandwidth on demand (BOD) protocol: 

        _________
       |         |     ISDN      __________
       |   MAX   | _---------_  |          |
       |_________+/     MP+   \ | Pipeline |
                               -+__________|

Lucent PortMaster Solution:

In many cases, the central site device is a PortMaster 3 (PM3): 

      _________
     |         |     ISDN      __________
     |   PM3   +--------------+          |
     |_________|     BACP     | Pipeline |
                              |__________|

Because MP+ is proprietary to Ascend, a team of vendors created an alternate protocol to provide the same information. The Bandwidth Allocation Control Protocol BACP includes the Bandwidth Allocation Protocol (BAP). BACP allows the Pipeline family to use its BOD features no matter what the central site vendor is. At the time this document was written, the Lucent InterNetworking Systems is the only known central site vendor with BACP support. 

Supported/Tested Platforms:

BACP with BAP, a new feature in ComOS 3.8, works on all PortMaster products able to run this version of ComOS. BACP interoperability has been tested with the Pipeline 50 running version 5.1Ap9 or greater of the Ascend operating system. 

PortMaster Implementation And Configuration:

Because BACP and BAP are both negotiated protocols that are active by default, they require no special commands to turn them on. However, unless you are using the "Call-ID" feature, you must set directory numbers on each ISDN port on the PortMaster so that it can offer a second number to dial to the Pipeline. 

To do so, use the following command: Example: Command> set s0 directory 5105551212

Once BACP is negotiated and the target bandwidth is reached, a BAP packet is sent out from the Pipeline requesting another channel. The PortMaster responds with a free channel's directory number, and the call is bundled with the original channel using Multilink PPP. 

Lucent's ComOS implementation of BACP follows RFC 2125. 

"Called-ID" Feature:

BACP supports local exchanges telephone numbers. If a long-distance BACP user is configured to dial a local exchange phone number, the PortMaster looks at the "Called-ID" value when a second channel is requested. In this configuration, you must not set directory numbers on ISDN ports. 

Note - The PortMaster 3 supports "Called-ID" with a PRI configuration only. 

If you have a channelized T1 configuration, directory numbers are required. 

Ascend Configuration:

  1. You must configure BACP on the Pipeline as follows by enabling it from the "PPP Options" menu: 
    2. Mod Config -> Ethernet -> PPP Options -> BACP=Yes

    below is a correction, though it is unverified. 

    Ethernet -> Answer -> PPP Options -> BACP=Yes
  2. Then in the connection profile, you must set the encapsulation of the link as follows for Multilink PPP: 
    3. Ethernet -> Connections -> <profile name> -> Encaps=MP
  3. Finally, you must enable BACP as follows in the "Encaps Options..." menu: 
    4. Ethernet -> Connections -> <profile name> -> Encaps
Options...-> BACP=Yes