T1 Circuit issues

senthilkumarmani · ‎03-20-2013

Hi Experts,

I am seeing bursty errors and slip secs in my serial interface..T1 circuit is connected to it.. I checked with ISP and they dont see any issues from their side and we have checked the local cable between deamrc and router, no issues seen.
Do i need to check anything else from my end. Please advice.

Thanks,
Arun

vmiller · ‎03-20-2013

start with a show controllers for the imodule involved.

Did this curcuit ever work correctly?

How is the circuit clock defined?

senthilkumarmani · ‎03-20-2013

started facing issue with this circuit in recent time.. Here is the clock settings

Network Clock Configuration
---------------------------
Priority Clock Source Clock State Clock Type

10 Backplane GOOD PLL

Current Primary Clock Source
---------------------------
Priority Clock Source Clock State Clock Type

10 Backplane GOOD PLL

Framing is ESF, Line Code is B8ZS, Current clock source is line,

paolo bevilacqua · ‎03-20-2013

network-clock-select 1 t1 /x/y/z

anisaini · ‎03-20-2013

use network-clock-select and network clock participate commad which can remove any slip errors.

senthilkumarmani · ‎03-20-2013

this would fix this issue?.. i dont have any idea about this.. could you please shed more light on this..

senthilkumarmani · ‎03-20-2013

Here is the network clock output.

Network Clock Configuration
---------------------------
Priority Clock Source Clock State Clock Type

10 Backplane GOOD PLL

Current Primary Clock Source
---------------------------
Priority Clock Source Clock State Clock Type

10 Backplane GOOD PLL

Jose Bogantes · ‎03-20-2013

Hello Senthil,

Can you please gather the following outputs?

show run | sec network-clock
show controller T1

Regards.

senthilkumarmani · ‎03-20-2013

network clock has not been configured.. i have attached controller output..

Jose Bogantes · ‎03-20-2013

Hi Senthil,

The commands "network-clock-select" and "network-clock-participate" are not useful if your card is a WIC-1DSU-T1-V2 or an HWIC-1DSU-T1. Please gather the following output instead:

show service-module
show interface serial x/x/x ( affected one )

It is recommended to check if the command "service-module t1 clock source internal" appears under the affected interface. Most of the time, ISPs provide clocking so using "clock source internal" on your end will trigger clocking issues for both ends are providing clocking. Just to confirm.

Regards.

senthilkumarmani · ‎03-20-2013

Please find the output below,

Serial0/0/0 is up, line protocol is up
Hardware is GT96K with integrated T1 CSU/DSU
Description: MPLS WAN TO PE ROUTER
Internet address is 68.176.92.26/30
MTU 1500 bytes, BW 1544 Kbit/sec, DLY 20000 usec,
     reliability 255/255, txload 2/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 3d00h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 84
Queueing strategy: Class-based queueing
Output queue: 0/1000/0 (size/max total/drops)
30 second input rate 10000 bits/sec, 7 packets/sec
30 second output rate 18000 bits/sec, 9 packets/sec
     2453122 packets input, 891355767 bytes, 0 no buffer
     Received 25956 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     3205022 packets output, 646173890 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=up
----------------------------------------------------------------

Service-module:

Interface Serial0/0/0
Module type is T1/fractional
    Hardware revision is 1.1, Software revision is 20091019,
    Image checksum is 0x44F2D8, Protocol revision is 0.1
Receiver has no alarms.
Framing is ESF, Line Code is B8ZS, Current clock source is line,
Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.
Last module self-test (done at startup): Passed
Last clearing of alarm counters 3d00h
    loss of signal        :    0,
    loss of frame         :    0,
    AIS alarm             :    0,
    Remote alarm          :    0,
    Module access errors :    0,
Total Data (last 96 15 minute intervals):
    0 Line Code Violations, 0 Path Code Violations
    2147482131 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
    0 Errored Secs, 2147413235 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Data in current interval (27 seconds elapsed):
    0 Line Code Violations, 0 Path Code Violations
    0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
    0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Jose Bogantes · ‎03-21-2013

Hi Senthil,

The clock configuration looks fine but the T1 has accumulated many Slips and Bursty Err Secs. I do not see problems related to input errors though but I can see that the counters were cleared 3 days ago. I recommend clearing the counters (clear counters) to check if the Slips and Bursty Err Secs are still increasing. Please monitor the T1 (using the show service-module command) to know if the errors are still increasing. If after 30 minutes you still find the same Slips and Bursty Err Sec, I recommend performing a hardward lookback test to isolated the issue. You need a lookback plug, setting encapsulation HDLC, configuring clock source internal and an IP address under the interface (any IP address for it is just for testing). Finally, you should clear counters and run extended pings towards the IP address you configured under the affected interface. Continue checking counters by using the "show service-module" command. You can find more information on the loopback test in the following link:

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00800a754b.shtml#csudsu_hw

If you do not see errors after the test, I recommend to get the ISP involved again for you will have evidence to confirm that the card is not related to the errors.

Hope it helps.

Regards.