Can I use 2 aux ports to practice DDR?

Discussion in 'Cisco' started by dwhkt, Dec 21, 2004.

  1. dwhkt

    dwhkt Guest


    My goal is to use 2 aux ports (possibly on 2610's) to practice
    Dial-on-demand. Instead of using ISDN WIC and ISDN simulator, is it
    possible to just use the 2 aux ports? Sample config would be nice.

    dwhkt, Dec 21, 2004
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  2. dwhkt

    Liam Guest

    You could use a roll-over cable to make it work.

    I've got it working a few months ago.
    I did it something like this. You could try to copy paste it. Don't know if
    it truly works. You can't really dial with it.
    If you want to dial, you should try to get a home-phone central (?) here in
    the netherlands we have a device called a homevox (you can connect 5 phones
    (or modems) to it. I used it for my BCRAN exam. You can connect two modems
    to your routers the normal way, and then use some standard phonecable to
    connect the modems to the homevox, et voila, you have your own internal
    telephone network.

    Here's the config. I think this worked for me. You could try it.

    conf t
    line aux 0
    speed 38400
    flowcontrol hardware
    transport input all
    int async 1
    ip add
    async mode dedicated
    no shut
    Liam, Dec 21, 2004
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  3. or you could use two modems if you have two phone lines, much more
    realistic. DDR on a back-to-back cable doesn't really teach you
    You can get some good dial on demand practice, but you need to be
    aware that async DDR and ISDN DDR each have their own foibles and
    bugs. I have no idea what you need for whatever certification test,
    but in the real world you'll need to know both. There are sample
    configs on CCO and on my website and all over the web.

    You'll also find that the bugs differ with the IOS release and
    hardware platform. For example, I working on resolving a bug right
    now in 12.3 where dialer watch on the AUX port fails to dial. Its
    a little tricky because the Async dialer watch is backup for a
    56K ISDN link which is backup for 128K MLPPP ISDN which is backup
    for a T1. If all links are dead, the async port will dial until
    it connects. But any time the async call drops, there is a high
    probability that the router will not try to call again!

    Just for grins, consider the following: The failure only occurs with IOS
    12.3, IOS 12.2 works just fine. The failure does not occur on a 17xx
    router, only on a 26xx. The failure does not occur when using a
    WIC-1B-S/T in the 2610, only with a WIC-1B-U (guess which my ISDN
    emulator requires and which is used in production...).

    Good luck and have fun!
    Vincent C Jones, Dec 21, 2004
  4. dwhkt

    Liam Guest

    I know,

    So i adviced him to try to find something like a home telephone central.
    Like an el-cheapo homevox (about 30?) connect your modems and you can dial.
    It's got 5 ports so you can dial to multiple locations.

    I guess you also have things like that in the USA.
    But, if you haven't got anything, you could use a back-to-back to at least
    connect the two via an AUX port.


    Liam, Dec 21, 2004
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