New User: How do you configure a Cisco 1721 router with a new T-1 line?

Posted on 2005-04-13
Last Modified: 2013-12-12
I have a new T-1 line and Cisco 1721 router.  I would like to configure the router with the new T-1. Where do I start?
Question by:veyron55
    LVL 79

    Expert Comment

    You  need to have an IP address for the T1 interface
    You need to know the encapsulation (PPP | Frame-relay | HDLC)
    Is this an Internet connection? You need default gateway
    Do you have a firewall behind the router, or is this your security router/firewall?
    Do you have the internal WIC-T1-DSU module, or are you using an external CSU/DSU?

    Basic config example
      interface serial 0/0
        ip address a.b.c.d
        no shutdown

     sho interface serial 0/0
    Look for indications : line is UP | DOWN   protocol is UP | DOWN
    Looking for UP | UP
    LVL 79

    Accepted Solution

    Any luck? Do you need more information?

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