Showing results for 
Search instead for 
Did you mean: 

6608 T1/PRI Total Rx RTP Lost Pkts

Level 1
Level 1

We've seen some noise issues on calls on our CUCM. 

We have 3 PRI/T1 with our service provide Paetec.  And 2 PRI and 1 T1 set up between our Rolm 9751 and CUCM. 

All PRI/T1 have high numbers of Total Rx RPT lost pkts (over 4 billions each) when looking at device status.  Occasionally I can catch a Total Rx RPT lost pkts on specific ports when looking at the PORT status, but mostly these run clean.  As usage increases on a PRI, the rate of lost pkts increases too.

1.  Is there a way to clear the device Total RX RPT lost pkts counts?

2.  Is there a correlation between the Device Total RX RPT lost pkts and the noisy calls we're hearing?

3.  Where do I look to resolve this.

I do not see errors on the Rolm 9751 side of the PRI's.

Thank you.

Frank Kirstein

3 Replies 3

VIP Alumni
VIP Alumni


6608 getting old now.

Your problem is probably due to poor "CLOCKIN" configuration,

Hopefully your ROLM 9751 is attached somewhere to the PSTN/ISDN network and sould be deriving its clock from the there.

So if you select your PSTN links to clock from "NETWORK"  then clock the ROLM links from "SPAN 1 to 8" so that they are synched with the PSTN links , basically all clocks should be locked as one.

Hopefully this will stop your received errors



Regards, Alex. Please rate useful posts.

Thank you Alex.  I'll change the clocking source and see what I end up with. 

Hi Alex,

It took awhile, but I now have all the PRIs set to 1 clock source.  Paetec to our Rolm 9751 T1 to Span 7 on the 6608.  All the PRI on the CCM from Paetec and internally get the clock from Span 7.  Traffic looked clean for about 2 hours, than 1 Lost Pkt followed by 246 lost packets, and finally, 4 billion.  I actually caught a Port status which shows port 22 with RTP Sent Pkts of 318, RTP Rcvd pkts of 318 and Lost RX pkts of 4294901760.   All of our PRI/T1 show lost pkts of over 4 billion. 

Any ideas?

Thanks all.