here's a FECN question for the network techs in the room...

Discussion in 'Computer Security' started by Dood, Dec 21, 2004.

  1. Dood

    Dood Guest

    I've got a router with a full T-1 plugged in. I've configured traffic
    shaping and FULL CIR. I've confirmed with Bell South that they are set
    to FULL CIR on there side also. So supposedly both sides are set for
    full T-1 CIR. My problem is the fact that my router is seeing approx
    5000 FECNs per hour, even when I show 30 to 40 percent utilization on
    my line. I've configured my router to throttle back when it recieves
    FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
    link inbetween my CSU and my router. I've run captures and history
    samples and benchmark utilization. I've tasked Bell South to tell me
    which frame switch is sending my router the FECN's, but so far no
    luck. Has anyone else experienced anything like this? I could be
    wrong, but if both sides are set to FULL CIR, I don't think I should
    see FECNs even if I oversubsribe my circuit. Both sides should be
    transmitting and recieving at the same speed.

    Any input is greatly appriciated, Peace.

    Network Dood.
     
    Dood, Dec 21, 2004
    #1
    1. Advertising

  2. Dood

    donnie Guest

    On Tue, 21 Dec 2004 00:14:04 GMT, (Dood) wrote:

    >I've got a router with a full T-1 plugged in. I've configured traffic
    >shaping and FULL CIR. I've confirmed with Bell South that they are set
    >to FULL CIR on there side also. So supposedly both sides are set for
    >full T-1 CIR. My problem is the fact that my router is seeing approx
    >5000 FECNs per hour, even when I show 30 to 40 percent utilization on
    >my line. I've configured my router to throttle back when it recieves
    >FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
    >link inbetween my CSU and my router. I've run captures and history
    >samples and benchmark utilization. I've tasked Bell South to tell me
    >which frame switch is sending my router the FECN's, but so far no
    >luck. Has anyone else experienced anything like this? I could be
    >wrong, but if both sides are set to FULL CIR, I don't think I should
    >see FECNs even if I oversubsribe my circuit. Both sides should be
    >transmitting and recieving at the same speed.
    >
    >Any input is greatly appriciated, Peace.
    >
    >Network Dood.

    #####################
    What router are you using? Athough it appears to be a telco problem,
    you might want to hear what the router manufacturer has to say.
    donnie.
     
    donnie, Dec 21, 2004
    #2
    1. Advertising

  3. Dood wrote:

    > I've got a router with a full T-1 plugged in. I've configured traffic
    > shaping and FULL CIR. I've confirmed with Bell South that they are set
    > to FULL CIR on there side also. So supposedly both sides are set for
    > full T-1 CIR. My problem is the fact that my router is seeing approx
    > 5000 FECNs per hour, even when I show 30 to 40 percent utilization on
    > my line. I've configured my router to throttle back when it recieves
    > FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
    > link inbetween my CSU and my router. I've run captures and history
    > samples and benchmark utilization. I've tasked Bell South to tell me
    > which frame switch is sending my router the FECN's, but so far no
    > luck. Has anyone else experienced anything like this? I could be
    > wrong, but if both sides are set to FULL CIR, I don't think I should
    > see FECNs even if I oversubsribe my circuit. Both sides should be
    > transmitting and recieving at the same speed.
    >
    > Any input is greatly appriciated, Peace.
    >
    > Network Dood.


    First a couple of things. If you are using Frame Relay on a T1 (physical)
    you can NOT over subscribe (over 1.54 Mbs). Remember you can only go as
    fast as the physical layer permits. In other words try to get more than
    1.54 Mbs on a T1 is NOT possible.

    Second, you should look at the stats on the physical (T1) and data link
    (Frame Relay) layers. Look for errors on both. It is posssible that you
    have some sort of error that is causing packet loss.

    Michael
     
    Michael J. Pelletier, Dec 21, 2004
    #3
  4. Dood

    Dood Guest

    On Mon, 20 Dec 2004 22:58:11 -0800, "Michael J. Pelletier"
    <> wrote:

    >Dood wrote:
    >
    >> I've got a router with a full T-1 plugged in. I've configured traffic
    >> shaping and FULL CIR. I've confirmed with Bell South that they are set
    >> to FULL CIR on there side also. So supposedly both sides are set for
    >> full T-1 CIR. My problem is the fact that my router is seeing approx
    >> 5000 FECNs per hour, even when I show 30 to 40 percent utilization on
    >> my line. I've configured my router to throttle back when it recieves
    >> FECNs instead of shutdown. I have a WAN Sniffer inline on my serial
    >> link inbetween my CSU and my router. I've run captures and history
    >> samples and benchmark utilization. I've tasked Bell South to tell me
    >> which frame switch is sending my router the FECN's, but so far no
    >> luck. Has anyone else experienced anything like this? I could be
    >> wrong, but if both sides are set to FULL CIR, I don't think I should
    >> see FECNs even if I oversubsribe my circuit. Both sides should be
    >> transmitting and recieving at the same speed.
    >>
    >> Any input is greatly appriciated, Peace.
    >>
    >> Network Dood.

    >
    >First a couple of things. If you are using Frame Relay on a T1 (physical)
    >you can NOT over subscribe (over 1.54 Mbs). Remember you can only go as
    >fast as the physical layer permits. In other words try to get more than
    >1.54 Mbs on a T1 is NOT possible.
    >
    >Second, you should look at the stats on the physical (T1) and data link
    >(Frame Relay) layers. Look for errors on both. It is posssible that you
    >have some sort of error that is causing packet loss.
    >
    >Michael


    Thanks for the input guys. I've had the router vendor, Nortel,
    conferenced with Bell South, and according to Nortel, my router is
    configured correctly for full CIR on a T-1. According to Bellsouth I'm
    not oversubscribing my circuit. Most of the day the router sits at 30
    to 40 percent utilization. I'm not seeing errors increment anywhere I
    look. I'm using Sniffer and Ethereal to look, and both are reporting
    the same data as far as utilization on the pipe goes. I just keep
    seeing FECNs from the cloud which tells my router to throttle back.
    Bell South has run stress tests and found "nothing wrong". One
    Bellsouth guy even told me the FECNs must be coming from my router. I
    had to very calmly explain to him that I don't own a piece of hardware
    capable of generating FECNs, Frame switches generate FECNs. Sometimes
    you wonder where they get there techs from. I wonder how much they
    pay? I'm gonna swap the router out as soon as I can to rule out that
    possibilty, even though I really don't think my routers the issue. I
    think there is congestion somewhere in the frame cloud that Bell south
    needs to fix.
     
    Dood, Dec 22, 2004
    #4
  5. Dood

    donnie Guest

    On Wed, 22 Dec 2004 00:33:57 GMT, (Dood) wrote:

    > I'm gonna swap the router out as soon as I can to rule out that
    >possibilty, even though I really don't think my routers the issue. I
    >think there is congestion somewhere in the frame cloud that Bell south
    >needs to fix.

    ##########################
    You're probably right, but I thought I would mention the router anway.
    Swaping the router is a good test.
    donnie
     
    donnie, Dec 22, 2004
    #5
    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. mauro
    Replies:
    3
    Views:
    3,496
    John Agosta
    Jun 3, 2004
  2. Igor Mamuzic

    FR BECN/FECN packets count

    Igor Mamuzic, Nov 6, 2005, in forum: Cisco
    Replies:
    3
    Views:
    769
    Igor Mamuzic
    Nov 8, 2005
  3. Guest
    Replies:
    2
    Views:
    461
    127.0.0.1
    Jun 3, 2004
  4. Computer Tool Kits for Network Techs

    , Feb 19, 2004, in forum: Computer Information
    Replies:
    0
    Views:
    575
  5. Giuen
    Replies:
    0
    Views:
    996
    Giuen
    Sep 12, 2008
Loading...

Share This Page