[cisco-nas] Overlap dialing on modem

[Bernhard Schmidt]

Hi everyone,

we have a serious problem with overlap dialing on our AS5350XM with IOS 
12.4(5a). The box is used to terminate a couple (two at the moment) E1s 
from our carrier (block 35831[7-9]...) and route the calls to the 
integrated modem, integrated fax, a channelbank (with another E1) or to 
the central PBX with SIP.

We have enabled overlap-receiving on both incoming E1s

interface Serial3/0:15
  description DTAG-S2M
  no ip address
  encapsulation ppp
  dialer rotary-group 1
  dialer-group 1
  trunk-group DTAG-PSTN
  isdn switch-type primary-net5
  isdn overlap-receiving
  isdn overlap-receiving calltypes all
  isdn incoming-voice modem
  isdn send-alerting
  isdn sending-complete

For the dialin number (3583190..) we have the following dialpeer defined:

dial-peer data 101 pots
  description Dialin
  incoming called-number 3583190..

If the number is dialed en-block it works fine

Feb 14 14:15:19 CET: ISDN Se3/0:15 Q931: RX <- SETUP pd = 8  callref = 
0x02F1
         Bearer Capability i = 0x8090A3
                 Standard = CCITT
                 Transfer Capability = Speech
                 Transfer Mode = Circuit
                 Transfer Rate = 64 kbit/s
         Channel ID i = 0xA18382
                 Preferred, Channel 2
         Calling Party Number i = 0x2181, '8974140493'
                 Plan:ISDN, Type:National
         Called Party Number i = 0xC1, '358319000'
                 Plan:ISDN, Type:Subscriber(local)
         High Layer Compat i = 0x9181
[...]
    Result=Success(0) after DP_MATCH_INCOMING_DNIS; Incoming Dial-peer=101
Feb 14 14:15:19 CET: PM_ST_MODEM(2/16): modem call_duration_started = 
4294967296000
Feb 14 14:15:19 CET: ISDN Se3/0:15 Q931: TX -> CALL_PROC pd = 8  callref 
= 0x82F1
         Channel ID i = 0xA98382
                 Exclusive, Channel 2
Feb 14 14:15:19 CET: ISDN Se3/0:15 Q931: TX -> ALERTING pd = 8  callref 
= 0x82F1
Feb 14 14:15:19 CET: PM_ST_MODEM: Incoming modem calling number: 8974140493
Feb 14 14:15:19 CET: PM_ST_MODEM: Incoming modem called number: 358319000
Feb 14 14:15:19 CET: ISDN Se3/0:15 Q931: TX -> CONNECT pd = 8  callref = 
0x82F1
Feb 14 14:15:19 CET: ISDN Se3/0:15 Q931: RX <- CONNECT_ACK pd = 8 
callref = 0x02F1

we get the usual modem noise and everything works fine

With overlap dialing, the call gets routed to the correct dialpeer and 
the line gets connected, but there is no modem noise at all:

Feb 14 14:16:50 CET: ISDN Se3/0:15 Q931: RX <- SETUP pd = 8  callref = 
0x02F2
         Bearer Capability i = 0x8090A3
                 Standard = CCITT
                 Transfer Capability = Speech
                 Transfer Mode = Circuit
                 Transfer Rate = 64 kbit/s
         Channel ID i = 0xA1839F
                 Preferred, Channel 31
         Calling Party Number i = 0x2181, '8974140493'
                 Plan:ISDN, Type:National
         Called Party Number i = 0xC1, '358319'
                 Plan:ISDN, Type:Subscriber(local)
         High Layer Compat i = 0x9181
[...]
Feb 14 14:16:50 CET: //-1/xxxxxxxxxxxx/DPM/dpAssociateIncomingPeerCore:
    Result=MORE_DIGITS_NEEDED(1) After All Match Rules Attempt
Feb 14 14:16:52 CET: ISDN Se3/0:15 Q931: RX <- INFORMATION pd = 8 
callref = 0x02F2
         Called Party Number i = 0xC1, '0'
                 Plan:ISDN, Type:Subscriber(local)
[...]
Feb 14 14:16:52 CET: //-1/xxxxxxxxxxxx/DPM/dpAssociateIncomingPeerCore:
    Result=MORE_DIGITS_NEEDED(1) After All Match Rules Attempt
Feb 14 14:16:54 CET: ISDN Se3/0:15 Q931: RX <- INFORMATION pd = 8 
callref = 0x02F2
         Called Party Number i = 0xC1, '0'
                 Plan:ISDN, Type:Subscriber(local)
[...]
Feb 14 14:16:54 CET: //-1/xxxxxxxxxxxx/DPM/dpAssociateIncomingPeerCore:
    Result=MORE_DIGITS_NEEDED(1) After All Match Rules Attempt
Feb 14 14:16:55 CET: ISDN Se3/0:15 Q931: RX <- INFORMATION pd = 8 
callref = 0x02F2
         Called Party Number i = 0xC1, '0'
                 Plan:ISDN, Type:Subscriber(local)
Feb 14 14:16:55 CET: //-1/xxxxxxxxxxxx/DPM/dpAssociateIncomingPeerCore:
    Calling Number=, Called Number=358319000, Voice-Interface=0x66310370,
    Timeout=FALSE, Peer Encap Type=ENCAP_VOICE, Peer Search Type=Invalid,
    Peer Info Type=DIALPEER_INFO_SPEECH
Feb 14 14:16:55 CET: //-1/xxxxxxxxxxxx/DPM/dpAssociateIncomingPeerCore:
    Result=Success(0) after DP_MATCH_INCOMING_DNIS; Incoming Dial-peer=101


as you can see Incoming Dial-peer=101 is there on both occasions.

Any idea where to look for the problem?

Regards,
Bernhard