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Knowledge Base

The solution of a PRI Problem

Publication Date:  2012-07-27  |   Views:  205  |   Downloads:  0  |   Author:  shaobin  |   Document ID:  EKB0000007982

Contents

Issue Description

Users can't dial in and always get busy tone.

Alarm Information

no

Handling Process

Analyse the ISDN Q921 and Q931 message

Root Cause

Serial0:15 N->U Len=38 02 01 02 02 08 02 00 07 05 A1 04 03 90 90 A3 18 03 A1 83 81 1E 02 82 81 70 0C A1 30 32 31 32 35 35 30 37 30 30 30 N->U:sapi=00 tei=00 c/r=1 I ns=01 nr=01 p=0 Serial0:15 U->N Len=4 02 01 01 04 U->N:sapi=00 tei=00 c/r=1 RR nr=02 p/f=0 Serial0:15 N->U DL_I_DATA_IND CES = 1 cr= 02 00 07 SETUP *sn_com=a1 *bearer=04 03 90 90 a3 *chan_id=18 03 a1 83 81 *prog_ind=1e 02 82 81 *called_n=70 0c a1 30 32 31 32 35 35 30 37 30 30 30 Serial0:15 CC<-Q931: PRIM_SETUP_IND CCIndex=0xffff L3Index=0x0 PortID=0x1d800b0 CES=0x1 *SN_COM=a1 *bearer=04 03 90 90 a3 *chan_id=18 03 a1 83 81 *prog_ind=1e 02 82 81 *called_n=70 0c a1 30 32 31 32 35 35 30 37 30 30 30 CC: Device(DDR) rejected incomming call for SERVICE dismatch ?bearer=04 03 90 90 a3?mean the service type of this call.The detailed description is below: 04 00000100 mean this unit is the carrying capacity information unit 03 00000011 mean the length of this unit 90 10010000 the first bit is the extend bit,don't consider it here,the same below 00 CCITT standardized coding as described below0 10000 3.1 kHz audio 90 10010000 00 Circuit mode 10000 64 kbit/s a3 10100011 01 Layer 1 Information 00011 Recommendation G.711 A-law Our router can't support call of 3.1kHz now.So there is information as below: CC: Device(DDR) rejected incomming call for SERVICE dismatch Conclusion:The customer dial with analog modem not the ISDN terminal as they said.

Suggestions

ISP---Quidway2630---PSTN---User The customer use Quidway2630 to accept users dialing in.The Quidway2630 connect to the AT&T Switch via E1 PRI.