Clock Source Errors

[g.oridota]

Can any one Please asssit :

I've got a POS link on a 7609 Flexwan Module connecting via a Sonet Network connecting to a remote 12410 GSR.

Problem is: i have configured both ends to clock from Line but the OSR keeps reverting back to internal.

with the show controller command , it indicates a change back to internal , Reason S1.

Has anyone had this problem before ? any suggestion ?

What exactly is the S1 Error ?

Find below output of Show controller:

SHOSR01#sh controllers pos 7/0/0 details

POS7/0/0

SECTION

LOF = 1 LOS = 1 BIP(B1) = 4843

LINE

AIS = 1 RDI = 1 FEBE = 6321445 BIP(B2) = 2105609

PATH

AIS = 22 RDI = 22 FEBE = 193111 BIP(B3) = 206445

PLM = 5 UNEQ = 10 TIM = 0 TIU = 0

LOP = 0 NEWPTR = 699 PSE = 4053218 NSE = 21

Active Defects: None

Active Alarms: None

Alarm reporting enabled for: SF SLOS SLOF B1-TCA LAIS LRDI B2-TCA PAIS PLOP PRDI B3-TCA

Line alarm trigger delay = 100 ms

Path alarm trigger delay = 100 ms

Framing: SONET

APS

COAPS = 6 PSBF = 1

State: PSBF_state = False

Rx(K1/K2): 00/00 Tx(K1/K2): 00/00

Rx Synchronization Status S1 = 0F

S1S0 = 02, C2 = CF

Remote aps status (none); Reflected local aps status (none)

CLOCK RECOVERY

RDOOL = 0

State: RDOOL_state = False

PATH TRACE BUFFER: STABLE

Remote hostname : ESGSR01

Remote interface: POS1/0

Remote IP addr : 10.136.24.13

Remote Rx(K1/K2): F9/FF Tx(K1/K2): 08/00

50CE4880: 45534753 52303100 00000000 ESGSR01.....

50CE4890: 00000000 00000000 00000000 504F5331 ............POS1

50CE48A0: 2F300000 00000000 00003130 2E313336 /0........10.136

50CE48B0: 2E32342E 31330000 00004639 46463038 .24.13....F9FF08

50CE48C0: 30300D0A 00..

BER thresholds: SF = 10e-3 SD = 10e-6

TCA thresholds: B1 = 10e-6 B2 = 10e-6 B3 = 10e-6

Clock source: internal

Clock source changed to : internal Reason : S1

[ebreniz]

Rx Synchronization Status S1 = 0F " indicate Don't Use for synchronization regarding to the standard ITU G.704:

As noted above the "show controller" output seems to indicate that the clock source was indeed set to be internal..

http://www.cisco.com/en/US/products/hw/optical/ps2006/products_installation_and_configuration_guide_chapter09186a00800eaae0.html#14283

So the root cause of the issue is SPA is not ignoring Rx Synchronization Status S1 and changing clock source to internal

[g.oridota]

Hi

Thanks .

I actually digged up a command " fos flag s1 ignore " which seems to change the clocking back to line.

Apparently on some Cisco IOS , the Router reverts to Internal if it recieves an S1 bit ???

Question is : is it safe to ignore the S1 Bit ?

[s.schlegel]

Hi,

although I'm a little late and you solved the problem on your own this information could be helpful.

The S1 byte indicates the clock quality in sdh/sonet networks. You received 0xf (1111) which is known as "don't use for synchronization" in sdh world. So it should be investigated why the connected sdh-equipment sends oxf. Most probably the sdh-equipment will have a clock-problem itself or it is just misconfigured. If you ignore the s1 byte you will clock from a line which should not be used for clocking in sdh world. but I think this won't bring you in trouble because the clock you receive will be good enough for the pos interface.

Further information of how clocking works can be found here:

http://www.cisco.com/en/US/tech/tk482/tk607/technologies_tech_note09186a0080094bb9.shtml

If you don't want to use the ignore s1 byte command you could try to fix the problem in the sdh network. If you receive a better S1 byte (as for example 0x2 or 0x4) you would be on the safe side.

best regards

Sebastian

[s.schlegel]

Hi,

I was talking about sdh networks because I wasn't aware of the fact you were using SONET. So replace all sdh in my last post by SONET in order to fit my answer to your question.

br

Sebastian