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New Member

slip secs

Dear experts,

what is the cause of occuring slip secs in T1 controller and how do we eliminate it ? this has totally ruined our fax transmissions.

I realy do appriciate if anyone help me in this regard.

Best Regards,

Hall of Fame Super Gold

Re: slip secs

what router is that ?

Assuming it is an ISR with VWIC-xxx

controller t1 x/y

clock source line

network-clock-partecipate wic x

network-clock-select 1 x


Re: slip secs

For one, you need to know where you should be getting the clock from. For instance, if you have a Point to Point T-1 you will need to provide the clock on one end of the circuit. If you don't know where the clock should come from you can always play around with the settings. Set the routers on both end of the T-1 to pull the clock off the line. Still see slips? Set one end of the T-1 to clock source internal.

See if that helps

New Member

Re: slip secs

those guy's are correct, I'm assuming this a PRI on an mft T1 card. there are network clock select and metwork clock participate commands that you are probably missing...what kind of hardware router/ t1 card are u using?

New Member

Re: slip secs

many thanks to your replies,

The hardware is a 3662 router with a 12.3(15)

IOS and 4 NMHDV-2T1 modules with mft cards loaded on each module.

the T1 interfaces are connected to CAC channel banks and no clock source commands are configured under the T1 controlers.

please advise how should we configure the commands you recommanded and also a brief

symptom of what is happening.

By the way I have another question,

Does anybody know the OID of a dial-peer active connctions ?

Best Regards,


New Member

Re: slip secs


you can look these up and try to find the solution that fits your environment. Look up these two commands and see where they fit in for you. In it's most basic form

The following example on a Cisco 3660 specifies the slot number that participates in network clocking and selects port E1 5/0:

Router(config)# network-clock-participate s lot 5

Router(config)# network-clock-select 1 E1 5/0