ISDN Failover

Discussion in 'Cisco' started by Gary, Oct 28, 2003.

  1. Gary

    Gary Guest

    We have an ISDN line backing up a T1 in the event of failure

    Does this look about right for the ISDN in standby

    lobal ISDN Switchtype = basic-net3
    SDN BRI0 interface
    dsl 0, interface ISDN Switchtype = basic-net3
    Layer 1 Status:
    DEACTIVATED
    Layer 2 Status:
    Layer 2 NOT Activated
    Layer 3 Status:
    0 Active Layer 3 Call(s)
    Activated dsl 0 CCBs = 0
    The Free Channel Mask: 0x80000003
    Total Allocated ISDN CCBs = 0

    Interface IP-Address OK? Method Status
    Protocol
    BRI0 unassigned YES unset standby mode down
    BRI0:1 unassigned YES unset administratively down down
    BRI0:2 unassigned YES unset administratively down down
    Dialer1 x.x.x.1 YES unset up up
    Ethernet0 x.x.x.1 YES NVRAM up up
    Serial0 x.x.x.1 YES unset up up

    Is there a way to test the dialup without taking the serial line down ?

    Thanks
    Gary
    Gary, Oct 28, 2003
    #1
    1. Advertising

  2. On Tue, 28 Oct 2003 10:03:27 -0500, Gary wrote:
    > We have an ISDN line backing up a T1 in the event of failure
    >
    > Does this look about right for the ISDN in standby
    >
    > lobal ISDN Switchtype = basic-net3
    > SDN BRI0 interface
    > dsl 0, interface ISDN Switchtype = basic-net3
    > Layer 1 Status:
    > DEACTIVATED
    > Layer 2 Status:
    > Layer 2 NOT Activated
    > Layer 3 Status:
    > 0 Active Layer 3 Call(s)
    > Activated dsl 0 CCBs = 0
    > The Free Channel Mask: 0x80000003
    > Total Allocated ISDN CCBs = 0
    >
    > Interface IP-Address OK? Method Status
    > Protocol
    > BRI0 unassigned YES unset standby mode down
    > BRI0:1 unassigned YES unset administratively down down
    > BRI0:2 unassigned YES unset administratively down down
    > Dialer1 x.x.x.1 YES unset up up
    > Ethernet0 x.x.x.1 YES NVRAM up up
    > Serial0 x.x.x.1 YES unset up up
    >
    > Is there a way to test the dialup without taking the serial line down ?


    What is your configuration ?

    Normally you will use routing to failover to the ISDN when the
    serial line is down - but if that is the case, the above is wrong,
    as the ISDN line is down on layer 1

    /Jesper

    --
    Jesper Skriver, CCIE #5456, FreeBSD committer
    Jesper Skriver, Oct 28, 2003
    #2
    1. Advertising

  3. Gary

    Ivan Ostres Guest

    "Gary" <> wrote in message
    news:7zvnb.2494$Re.1151@lakeread06...
    > We have an ISDN line backing up a T1 in the event of failure
    >
    > Does this look about right for the ISDN in standby
    >
    > lobal ISDN Switchtype = basic-net3
    > SDN BRI0 interface
    > dsl 0, interface ISDN Switchtype = basic-net3
    > Layer 1 Status:
    > DEACTIVATED


    There's something very wrong with physical layer. Faulty BRI card? bad
    cable? NT dead? (some external NT's require external power). Try connecting
    ISDN phone to line and see if it's working. If not, line is bad. If it works
    check cable and BRI int.

    Ivan
    Ivan Ostres, Oct 28, 2003
    #3
  4. Gary

    Ivan Ostres Guest

    "Ivan Ostres" <> wrote in message
    news:bnm3mr$12hffo$-berlin.de...
    > "Gary" <> wrote in message
    > news:7zvnb.2494$Re.1151@lakeread06...
    > > We have an ISDN line backing up a T1 in the event of failure
    > >
    > > Does this look about right for the ISDN in standby
    > >
    > > lobal ISDN Switchtype = basic-net3
    > > SDN BRI0 interface
    > > dsl 0, interface ISDN Switchtype = basic-net3
    > > Layer 1 Status:
    > > DEACTIVATED

    >
    > There's something very wrong with physical layer. Faulty BRI card? bad
    > cable? NT dead? (some external NT's require external power). Try

    connecting
    > ISDN phone to line and see if it's working. If not, line is bad. If it

    works
    > check cable and BRI int.
    >
    > Ivan
    >
    >


    Reply to my own post.. real smart. Is this correct ISDN type? (net3). Where
    in Europe are you?

    Ivan
    Ivan Ostres, Oct 28, 2003
    #4
  5. Gary

    Gary Guest

    "Ivan Ostres" <> wrote in message
    news:bnm3q0$12cgf9$-berlin.de...
    > "Ivan Ostres" <> wrote in message
    > news:bnm3mr$12hffo$-berlin.de...
    > > "Gary" <> wrote in message
    > > news:7zvnb.2494$Re.1151@lakeread06...
    > > > We have an ISDN line backing up a T1 in the event of failure
    > > >
    > > > Does this look about right for the ISDN in standby
    > > >
    > > > lobal ISDN Switchtype = basic-net3
    > > > SDN BRI0 interface
    > > > dsl 0, interface ISDN Switchtype = basic-net3
    > > > Layer 1 Status:
    > > > DEACTIVATED

    > >
    > > There's something very wrong with physical layer. Faulty BRI card? bad
    > > cable? NT dead? (some external NT's require external power). Try

    > connecting
    > > ISDN phone to line and see if it's working. If not, line is bad. If it

    > works
    > > check cable and BRI int.
    > >
    > > Ivan
    > >
    > >

    >
    > Reply to my own post.. real smart. Is this correct ISDN type? (net3).

    Where
    > in Europe are you?
    >
    > Ivan
    >
    >

    England
    Gary, Oct 28, 2003
    #5
  6. Gary

    Tim Thorne Guest

    "Gary" <> wrote:

    >Is there a way to test the dialup without taking the serial line down ?


    If you're using the same routable subnet over ISDN, then no. If not,
    first make sure your default route doesn't point down the BRI or
    Dialer interface or you'll kill your traffic when you bring up the
    interface. Find something pingable on your ISPs network. Set a default
    route to that IP down the Dialer or BRI interface. Remove the backup
    config from the serial interface then ping the ISP host. That should
    be all you need to test ISDN backup.

    Tim
    Tim Thorne, Oct 28, 2003
    #6
  7. Gary

    Gary Guest

    "Tim Thorne" <> wrote in message
    news:...
    > "Gary" <> wrote:
    >
    > >Is there a way to test the dialup without taking the serial line down ?

    >
    > If you're using the same routable subnet over ISDN, then no. If not,
    > first make sure your default route doesn't point down the BRI or
    > Dialer interface or you'll kill your traffic when you bring up the
    > interface. Find something pingable on your ISPs network. Set a default
    > route to that IP down the Dialer or BRI interface. Remove the backup
    > config from the serial interface then ping the ISP host. That should
    > be all you need to test ISDN backup.
    >
    > Tim

    Am using the same routable space but can add a small subnet for the BRI -
    WHat commands are required please.

    Thx
    Gary
    Gary, Oct 29, 2003
    #7
  8. Gary

    Tim Thorne Guest

    "Gary" <> wrote:
    >"Tim Thorne" <> wrote:
    >> "Gary" <> wrote:
    >>
    >> >Is there a way to test the dialup without taking the serial line down ?

    >>
    >> If you're using the same routable subnet over ISDN, then no. If not,
    >> first make sure your default route doesn't point down the BRI or
    >> Dialer interface or you'll kill your traffic when you bring up the
    >> interface. Find something pingable on your ISPs network. Set a default
    >> route to that IP down the Dialer or BRI interface. Remove the backup
    >> config from the serial interface then ping the ISP host. That should
    >> be all you need to test ISDN backup.

    >
    >Am using the same routable space but can add a small subnet for the BRI -
    >WHat commands are required please.


    You'll need to talk to your ISP and have your radius (or whatever)
    account adjusted to use a different subnet before you do anything. I
    don't think you'll be able to apply the smaller subnet to the dialer
    interface because it'll overlap with the eth or ser ifs. Could you ask
    them for a test subnet you could use for a couple of hours or perhaps
    you could use one of their dynamic IPs? Anyway, assign an IP from the
    other subnet to the dialer interface then apply a static route for the
    ISP host:

    ip route <isp host/32> dialer0

    Ping the host and the bri should dial.

    Tim
    Tim Thorne, Oct 30, 2003
    #8
  9. Gary

    Andre Beck Guest

    Jesper Skriver <> writes:
    > On Tue, 28 Oct 2003 10:03:27 -0500, Gary wrote:
    > > Layer 1 Status:
    > > DEACTIVATED
    > > Layer 2 Status:
    > > Layer 2 NOT Activated

    >
    > Normally you will use routing to failover to the ISDN when the
    > serial line is down - but if that is the case, the above is wrong,
    > as the ISDN line is down on layer 1


    Actually this doesn't need to mean anything bad. The BRI NT, when not
    noticing any L2 activity for some time, is free to shut itself down
    for power savings. If a call is coming in, it will be awakened. If the
    TE wants to place a call, it can wake up the NT the usual way (INFO1-4
    as in I.430). When powered down, the BRI is indeed PHY_DEACTIVATED, and
    this is not a failure.

    To Gary:

    The only real test to see whether a dial backup works is to use it.
    May be done late at night, but it should be done. You don't know
    whether a dialer will succeed even if BRI is up on L1-L3. It may well
    fail during dialing. The remote side might not answer. There are
    hundreds of possible problems with the private and the public network
    from failing PBXes, PBXes with access control over public networks that
    are out of B-channels up to similar problems at the remote end. Even if
    you prove the dialer works out of band (just plug an independent network
    on top of it, dial and try to ping), you still have to verify that it
    still does in the backup case (prove whether the failover logic, that
    might be backup interface, dialer watch, floating static, ospf demand-
    circuit or whatever, really kicks in) *and* that the routing takes over
    to the dial line. Even more, you need to verify that in case the primary
    leased line comes back, the dialer really drops *and* the routing goes
    back to the leased line *only*. So get a service time window, cut the
    T1 and look what happens. Replug it and again look what happens. It's
    the only way to be sure. Redundancy has its cost - that procedure is
    one part of it.

    --
    The _S_anta _C_laus _O_peration
    or "how to turn a complete illusion into a neverending money source"

    -> Andre "ABPSoft" Beck +++ ABP-RIPE +++ Dresden, Germany, Spacetime <-
    Andre Beck, Oct 31, 2003
    #9
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. BobCov
    Replies:
    3
    Views:
    565
    Andre Beck
    Nov 21, 2003
  2. Alec Waters
    Replies:
    0
    Views:
    1,487
    Alec Waters
    Jun 9, 2004
  3. Marcus
    Replies:
    0
    Views:
    1,094
    Marcus
    Oct 11, 2004
  4. sync
    Replies:
    0
    Views:
    542
  5. Pit
    Replies:
    0
    Views:
    1,115
Loading...

Share This Page