Configuring an ISU for use with a Cisco Router

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    Article ID: 1652
    Q&A

     

     

      Configuring an ISU for use with a Cisco Router


     

    Q:

    Using ADTRAN ISUs With Cisco Routers

     

     

    A:

    Introduction

    This document outlines how to configure ADTRAN ISU terminal adapters (TAs) to work with Cisco routers. The configuration of both the router and the ISU depends on the application. The applications discussed here are

    • a connection between two ADTRAN ISUs using BONDING Mode 1
    • a 128k connection to a router using Multilink PPP
    • a dial backup connection.

    Before You Begin Your Setup

    • For some applications, the ADTRAN ISU is required to support synchronous Multilink PPP. The ISUs that support synchronous MP include the ISU Express (part numbers 1200081L5, 1200081L6, and 1202081 L6), ISU 2x64 (1200051L1 and 1200051L2), and the second generation ISU 128 (1202029L2 and 1202029L3).
    • To use Multilink PPP on a Cisco router, the software revision of the ISU must be up to date.

     

    Setting Up the ISU

    This configuration is used when the ISU connects to another ISU or other device that supports BONDING Mode 1. It is assumed that V.25 dialing is used (i.e., there is a Dialer Inbandstatement in the Cisco configuration). If your application uses DTR dialing, refer to Dial Backup Connection later in this Technical Support Note. Only the relevant options are addressed here.

    Configuration of the ISU:

     

    Dial Options = V.25 HDLC Flags
    Bit Rate = 128000 (112000 for 56k calls)
    CTS Options = Follows RTS
    DTR Options = Idle When Off
    DSR Options = Off Idle + Test
    Protocol = BONDING Mode 1

    For a one B channel connection, change the Bit Rate accordingly and change Protocol to Clear Channel.

    Connection To A Router Using Multilink PPP

    This configuration is for dialing into a router (or Internet service) that supports Multilink PPP. Again, it is assumed that V.25 dialing is used. If your application uses DTR dialing, refer to Dial Backup Connection later in this Technical Support Note.

    Configuration of the ISU:

     

    Dial Options = V.25 HDLC Flags
    Bit Rate = 128000 (112000 for 56k calls)
    CTS Options = Follows RTS
    DTR Options = Idle When Off
    DSR Options = Off Idle + Test
    Protocol = PPP async/sync
    Method = Multilink PPP

    If there is a second number to dial, store it in Stored Number 1. This option is found in the Dial menu, under the Store/Review # option.

     

    When configuring the Cisco Router:

     

    In the relevant serial interface, there must be a Dialer Inband statement containing the number to be dialed. There should also be a Dialer Map statement mapping the appropriate network address to the serial port.

    Dial Backup Connection

    This configuration is generally used for a dial backup connection to T1 or Frame Relay. It is assumed that the Cisco device initiating the dial backup connection is using a Dialer DTRcommand to initiate the call. The configurations will differ slightly depending on whether the desired connection is to be 56/64k or 112/128k, as well as whether the unit initiates or answers the call.

    Configuration of the ISU:

     

    Dial Options = Front Panel (select Disabled on the ISU Express)
    Bit Rate = (Select the appropriate bit rate according to your bandwidth requirements)
    CTS Options = Forced CTS
    DTR Options = Dial #0 If On (dialing unit only)
    DTR Options = Ignore DTR (answering unit only)
    DSR Options = Off Idle + Test
    Protocol = (Use Clear Channel for a single B channel, or use BONDING or Multilink PPP for two B channels)

    On the dialing unit, store the dialing number in Stored Number 0. This option is found in the Dial menu, under the Store/Review # option. If you are using Multilink PPP, store the second phone number to dial in Stored Number 1. If no number is stored in Stored Number 1, the same phone number is dialed to establish the second link.

    If you experience any problems using your ADTRAN product, please contact ADTRAN Technical Support.