[c-nsp] Serial link CTS=down link UP

[Marcelo Zilio]

Hi,

Debug keeps showing the following messages. I don't think is much helpfull.

Router#debug serial interface
Router#
000083: Dec 18 08:53:17.521 BST: Serial0/1/0(out): StEnq, myseq 61, yourseen
60, DTE up
000084: Dec 18 08:53:17.533 BST: Serial0/1/0(in): Status, myseq 61, pak size
19
Router#
000085: Dec 18 08:53:27.521 BST: Serial0/1/0(out): StEnq, myseq 62, yourseen
61, DTE up
000086: Dec 18 08:53:27.537 BST: Serial0/1/0(in): Status, myseq 62, pak size
14
Router#
000087: Dec 18 08:53:37.521 BST: Serial0/1/0(out): StEnq, myseq 63, yourseen
62, DTE up
000088: Dec 18 08:53:37.537 BST: Serial0/1/0(in): Status, myseq 63, pak size
14
As far as I could see CTS is always down. It is not flapping.

I'm talking to the Service Provider guys. I'll let you know the results.
Thanks for all responses!
On Thu, Dec 17, 2009 at 4:18 PM, Michael K. Smith - Adhost <
mksmith at adhost.com> wrote:

>  > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > bounces at puck.nether.net] On Behalf Of Marcelo Zilio
> > Sent: Thursday, December 17, 2009 10:04 AM
> > To: cisco-nsp at puck.nether.net
> > Subject: [c-nsp] Serial link CTS=down link UP
> >
> > Hi,
> >
> > Has anyone seen this in serial interfaces before?
> > Link is UP and traffic is going through, however router shows CTS=down
> > besides a lot CRCs/Input Errors.
> > It doesn't make sense to me the parameter which should advise that the
> > link
> > is "ready to go" is DOWN while there is traffic on it.
> > Users are complaining some application are slow.
> >
> > The router is a Cisco 2811 IOS 12.4(15)T10.
> >
> > Router#sh int s0/1/0
> > Serial0/1/0 is up, line protocol is up
> >   Hardware is GT96K Serial
> >   MTU 1500 bytes, BW 256 Kbit/sec, DLY 20000 usec,
> >      reliability 255/255, txload 40/255, rxload 42/255
> >   Encapsulation FRAME-RELAY IETF, loopback not set
> >   Keepalive set (10 sec)
> >   CRC checking enabled
> >   LMI enq sent  48, LMI stat recvd 48, LMI upd recvd 0, DTE LMI up
> >   LMI enq recvd 0, LMI stat sent  0, LMI upd sent  0
> >   LMI DLCI 0  LMI type is ANSI Annex D  frame relay DTE  segmentation
> > inactive
> >   FR SVC disabled, LAPF state down
> >   Broadcast queue 0/64, broadcasts sent/dropped 7/0, interface
> > broadcasts 0
> >   Last input 00:00:00, output 00:00:00, output hang never
> >   Last clearing of "show interface" counters 00:07:55
> >   Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops:
> 0
> >   Queueing strategy: dual fifo
> >   Output queue: high size/max/dropped 0/256/0
> >   Output queue: 0/128 (size/max)
> >   30 second input rate 43000 bits/sec, 68 packets/sec
> >   30 second output rate 41000 bits/sec, 78 packets/sec
> >      34746 packets input, 2956769 bytes, 0 no buffer
> >      Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
> >      602 input errors, 602 CRC, 433 frame, 107 overrun, 0 ignored, 323
> > abort
> >      43237 packets output, 3308125 bytes, 0 underruns
> >      0 output errors, 0 collisions, 0 interface resets
> >      0 unknown protocol drops
> >      0 output buffer failures, 0 output buffers swapped out
> >      0 carrier transitions
> >      DCD=up  DSR=up  DTR=up  RTS=up  *CTS=down*
> >
> With all those errors I would say you have a physical layer problem or a
> clocking issue.  Perhaps the CTS is flapping between up and down and
> you're catching it on the down.  What happens if you debug the
> interface?
>
> Regards,
>
> Mike
>