Trouble with serial interface or line?

Discussion in 'Cisco' started by Thread7@hotmail.com, Oct 28, 2005.

  1. Guest

    I inherited management of a Cisco 3640 and I only have a basic
    knowledge of Cisco. We currently have a new customer with a leased
    line setup but the interface on our 3640 at the Telco office says "Line
    Protocol Down". The Telco has checked the line but says everything is
    fine. We have several other sites that work just fine. They all run
    out of the same cable on the back of the E1 channelized card. I have
    looked at the configuration but everything seems correct and very
    straightforward.
    The only thing I could think to try is do a "shut" on the interface and
    then a "no shut". After doing this, the "sh int s2/0:8" command
    actually shows the "line protocol is up", but it only lasts maybe 15
    seconds. Then it goes to "line protocol is down" again.
    I will do a "show int" on a good site and this problem site to see if
    anyone has ideas for me.

    Serial2/0:8 is up, line protocol is down
    Hardware is DSX1
    Description: "Non-Working Site"
    Internet address is 204.142.197.201/30
    MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
    reliability 255/255, txload 1/255, rxload 1/255
    Encapsulation HDLC, loopback not set
    Keepalive set (10 sec)
    Last input never, output 00:00:05, output hang never
    Last clearing of "show interface" counters never
    Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
    Queueing strategy: weighted fair
    Output queue: 0/1000/64/0 (size/max total/threshold/drops)
    Conversations 0/1/256 (active/max active/max total)
    Reserved Conversations 0/0 (allocated/max allocated)
    Available Bandwidth 96 kilobits/sec
    5 minute input rate 0 bits/sec, 0 packets/sec
    5 minute output rate 0 bits/sec, 0 packets/sec
    0 packets input, 0 bytes, 0 no buffer
    Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
    0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    14421 packets output, 349138 bytes, 0 underruns
    0 output errors, 0 collisions, 4811 interface resets
    0 output buffer failures, 0 output buffers swapped out
    1 carrier transitions
    Timeslot(s) Used:30-31, Transmitter delay is 0 flags

    Serial2/0:7 is up, line protocol is up
    Hardware is DSX1
    Description: "Working Site"
    Internet address is 204.142.197.197/30
    MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
    reliability 255/255, txload 21/255, rxload 93/255
    Encapsulation HDLC, loopback not set
    Keepalive set (10 sec)
    Last input 00:00:01, output 00:00:00, output hang never
    Last clearing of "show interface" counters never
    Input queue: 0/75/2/0 (size/max/drops/flushes); Total output drops: 0
    Queueing strategy: weighted fair
    Output queue: 0/1000/64/0 (size/max total/threshold/drops)
    Conversations 0/27/256 (active/max active/max total)
    Reserved Conversations 0/0 (allocated/max allocated)
    Available Bandwidth 96 kilobits/sec
    5 minute input rate 47000 bits/sec, 9 packets/sec
    5 minute output rate 11000 bits/sec, 8 packets/sec
    404054 packets input, 115782707 bytes, 0 no buffer
    Received 16864 broadcasts, 0 runts, 0 giants, 0 throttles
    2 input errors, 0 CRC, 2 frame, 0 overrun, 0 ignored, 1 abort
    389221 packets output, 170896813 bytes, 0 underruns
    0 output errors, 0 collisions, 2 interface resets
    0 output buffer failures, 0 output buffers swapped out
    1 carrier transitions
    Timeslot(s) Used:19-20, Transmitter delay is 0 flags

    This is the relevant area of the configuration.
    ---------------
    controller E1 2/0
    framing NO-CRC4
    channel-group 1 timeslots 1-4
    channel-group 2 timeslots 5-6
    channel-group 3 timeslots 9-12
    channel-group 4 timeslots 13-16
    channel-group 5 timeslots 7-8
    channel-group 6 timeslots 17-18
    channel-group 7 timeslots 19-20
    channel-group 8 timeslots 30-31

    interface Serial2/0:7
    description "Working Site"
    ip address 204.142.197.197 255.255.255.252
    !
    interface Serial2/0:8
    description "Non-Working Site"
    ip address 204.142.197.201 255.255.255.252
    ------------

    Thanks a lot for any suggestions.
     
    , Oct 28, 2005
    #1
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  2. just a thought:

    is the remote router cisco or from a different vendor?
    if the latter applies, you might want to opt for
    ppp encapsulation - hdlc is cisco proprietary.

    cheers,

    sven


    wrote:
    > I inherited management of a Cisco 3640 and I only have a basic
    > knowledge of Cisco. We currently have a new customer with a leased
    > line setup but the interface on our 3640 at the Telco office says "Line
    > Protocol Down". The Telco has checked the line but says everything is
    > fine. We have several other sites that work just fine. They all run
    > out of the same cable on the back of the E1 channelized card. I have
    > looked at the configuration but everything seems correct and very
    > straightforward.
    > The only thing I could think to try is do a "shut" on the interface and
    > then a "no shut". After doing this, the "sh int s2/0:8" command
    > actually shows the "line protocol is up", but it only lasts maybe 15
    > seconds. Then it goes to "line protocol is down" again.
    > I will do a "show int" on a good site and this problem site to see if
    > anyone has ideas for me.
    >
    > Serial2/0:8 is up, line protocol is down
    > Hardware is DSX1
    > Description: "Non-Working Site"
    > Internet address is 204.142.197.201/30
    > MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
    > reliability 255/255, txload 1/255, rxload 1/255
    > Encapsulation HDLC, loopback not set
    > Keepalive set (10 sec)
    > Last input never, output 00:00:05, output hang never
    > Last clearing of "show interface" counters never
    > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
    > Queueing strategy: weighted fair
    > Output queue: 0/1000/64/0 (size/max total/threshold/drops)
    > Conversations 0/1/256 (active/max active/max total)
    > Reserved Conversations 0/0 (allocated/max allocated)
    > Available Bandwidth 96 kilobits/sec
    > 5 minute input rate 0 bits/sec, 0 packets/sec
    > 5 minute output rate 0 bits/sec, 0 packets/sec
    > 0 packets input, 0 bytes, 0 no buffer
    > Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
    > 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    > 14421 packets output, 349138 bytes, 0 underruns
    > 0 output errors, 0 collisions, 4811 interface resets
    > 0 output buffer failures, 0 output buffers swapped out
    > 1 carrier transitions
    > Timeslot(s) Used:30-31, Transmitter delay is 0 flags
    >
    > Serial2/0:7 is up, line protocol is up
    > Hardware is DSX1
    > Description: "Working Site"
    > Internet address is 204.142.197.197/30
    > MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
    > reliability 255/255, txload 21/255, rxload 93/255
    > Encapsulation HDLC, loopback not set
    > Keepalive set (10 sec)
    > Last input 00:00:01, output 00:00:00, output hang never
    > Last clearing of "show interface" counters never
    > Input queue: 0/75/2/0 (size/max/drops/flushes); Total output drops: 0
    > Queueing strategy: weighted fair
    > Output queue: 0/1000/64/0 (size/max total/threshold/drops)
    > Conversations 0/27/256 (active/max active/max total)
    > Reserved Conversations 0/0 (allocated/max allocated)
    > Available Bandwidth 96 kilobits/sec
    > 5 minute input rate 47000 bits/sec, 9 packets/sec
    > 5 minute output rate 11000 bits/sec, 8 packets/sec
    > 404054 packets input, 115782707 bytes, 0 no buffer
    > Received 16864 broadcasts, 0 runts, 0 giants, 0 throttles
    > 2 input errors, 0 CRC, 2 frame, 0 overrun, 0 ignored, 1 abort
    > 389221 packets output, 170896813 bytes, 0 underruns
    > 0 output errors, 0 collisions, 2 interface resets
    > 0 output buffer failures, 0 output buffers swapped out
    > 1 carrier transitions
    > Timeslot(s) Used:19-20, Transmitter delay is 0 flags
    >
    > This is the relevant area of the configuration.
    > ---------------
    > controller E1 2/0
    > framing NO-CRC4
    > channel-group 1 timeslots 1-4
    > channel-group 2 timeslots 5-6
    > channel-group 3 timeslots 9-12
    > channel-group 4 timeslots 13-16
    > channel-group 5 timeslots 7-8
    > channel-group 6 timeslots 17-18
    > channel-group 7 timeslots 19-20
    > channel-group 8 timeslots 30-31
    >
    > interface Serial2/0:7
    > description "Working Site"
    > ip address 204.142.197.197 255.255.255.252
    > !
    > interface Serial2/0:8
    > description "Non-Working Site"
    > ip address 204.142.197.201 255.255.255.252
    > ------------
    >
    > Thanks a lot for any suggestions.
    >
     
    Sven Juergensen, Oct 28, 2005
    #2
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  3. Guest

    The remote router is just a Cisco 2501. I keep thinking it is some
    problem at the main router 3640 end though. To narrow down the problem
    I telnetted into the remote Cisco 2501 at the working site and rebooted
    it. Then on the 3640 I constantly checked the sh int s2/0:7 for two
    minutes while the remote 2501 was rebooting. It said "Line protocol is
    up" the whole time.

    Therefore, even if the remote router is turned off, it seems like it
    does not affect the serial interface at the main 3640 router. So for
    my non-working site, it seems like it should not be a problem at the
    remote 2501.
     
    , Oct 28, 2005
    #3
  4. Guest

    I should also say that the 2501 at the customer site says both the
    serial interface and line protocol are up.
     
    , Oct 28, 2005
    #4
  5. jem12475 Guest

    Have you done any testing with the telco?
     
    jem12475, Oct 28, 2005
    #5
  6. Guest

    Yes, and the Telco says everything is fine from his end. He has been
    out to the site and can send data across the line.
     
    , Oct 29, 2005
    #6
  7. <> wrote in message
    news:...

    > The only thing I could think to try is do a "shut" on the interface and
    > then a "no shut". After doing this, the "sh int s2/0:8" command
    > actually shows the "line protocol is up", but it only lasts maybe 15
    > seconds. Then it goes to "line protocol is down" again.


    Right: The line is assumed up when it comes up, but after 3 missed
    keepalives (30 seconds) the line is marked as "protocol down" meaning it
    cannot pass traffic.


    > I will do a "show int" on a good site and this problem site to see if
    > anyone has ideas for me.
    >
    > Serial2/0:8 is up, line protocol is down
    > Hardware is DSX1
    > Description: "Non-Working Site"

    [...]
    > Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
    > 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
    > 14421 packets output, 349138 bytes, 0 underruns


    Packets are sent, nothing received back. Telco issue, most likely they have
    logically crossed timeslots.

    Serial 2/0:8 is channel group 8 (timeslots 30-31, 2x64k channels, 128k
    total). Have the telco report to you where they think the timeslots are
    mapped on the other side.

    This is not rocket science. Te telco is at fault if it suddenly stopped
    working.

    If the remote side is saying serial interface and line protocol are up for
    more than the first thirty seconds, it is connected SOMEWHERE, but not to
    the timeslots and circuit you are expecting. They need to tell you where
    they have mapped the 128k virtual circuit.

    Remember rule #1 of telcos. They lie.
     
    Phillip Remaker, Nov 1, 2005
    #7
  8. Guest

    Maybe you have clocking problem please check it and set a new clocking
    rate. Then you should see your error lists .
    look you have many error resets on your interface this says that your
    link is not suitable for service. you could check your line by
    Multimeter for test that is it stable ? and is your link has a fix
    resistance or not. if you checked them and your problem wasn't solved
    notify me again.
     
    , Nov 1, 2005
    #8
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