[Serusers] SER has problems matching ACKs to replies
Maxim Sobolev
sobomax at portaone.com
Tue Apr 8 16:56:17 CEST 2003
Sorry, further investigation shown that this particular problem was
caused by the typo in our fix for hashing function (one found in 0.8.10
didn't bother to strip insignificant chars from call-id and cseq number).
I've fixed that and the problem gone.
However, we have another problem with ACK matching. The problem is that
we are using propiertary module which queries billing engine via Radius
and uses its replies to rewrite URI. Since it isn't practical to run
that query on each request received, we are only performing it on
INVITEs, which is fine as long as the next hop is always B2BUA that
only cares about method URI in INVITE requests and ignores it in any
subsequent requests. The typical sequence looks like the following:
1. ATA->SER:
INVITE xyz at foo.bar
2. SER->BILLING
please expand xyz
3. BILLING->SER
xyz expands to 123456
4. SER->B2BUA (t_relay_to())
INVITE 123456 at foo.bar
Everything is fine when INVITE transaction ends with a 200 OK, in this
case ATA generates ACK to acknowelege 200 OK using information from
that 200 OK, i.e. `ACK 123456 at foo.bar', not `ACK xyz at foo.bar'. The problem
happens if transaction ends with 4xx error, or is cancelled by the
originating party, in this case ATA acknoweleges receipt of final negative
response with `ACK xyz at foo.bar' so that tm module is unable to match ACK
to original INVITE.
Do you have any ideas how to properly solve this problem without
introducing steps (2) and (3) above for every ACK request as well?
It would be inacceptable for us since each BILLING query means
extra database access, therefore is puting extra load on the system
and degrading its performance (normal call involves 2 ACKs, so that
there would be 3 db accesses instead of 1).
I think that it should be possible to resolve the problem by modifying
tm module to match ACKs for non-200 replies to original uri in INVITE
instead to rewriten one. What do you think? Is there any potential
problems with this approach?
-Maxim
On Mon, Apr 07, 2003 at 10:41:31PM +0200, Jiri Kuthan wrote:
> Maxim,
>
> neither did I find a reason why the ACK is not matched. I might be
> wrong but my guess is that it is a config issue -- are you sure it
> enters t_relay in your script?
>
> -Jiri
>
> At 09:19 PM 4/7/2003, Maxim Sobolev wrote:
> >Folks,
> >
> >I found that in the stateful mode, SER is having troubles matching
> >ACKs to negative replies when Vovida B2BUA (1.5.0) is used as one
> >UA, while Cisco ATA 186 as another one. Following is a dump of the
> >session illustrating the problem. As you can see, SER keeps
> >retransmiting 480, despite receiving properly formed ACKs. Does
> >anybody have any ideas what the problem might be?
> >
> >-Maxim
> >P.S. I am also seeing in the logs the following warnings:
> >
> >Apr 7 12:05:28 demo ser[86090]: WARNING: sip_msg_cloner: header body ignored: 4096
> >
> >
> >B2BUA->SER
> >
> >INVITE sip:16045215277 at demo.portaone.com:5060;transport=udp;user=phone SIP/2.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >cisco-GUID: 200546447-2237180178-1764455078-2518034476
> >CSeq: 2 INVITE
> >Max-Forwards: 10
> >Expires: 300
> >Contact: <sip:380442466396 at 64.180.102.72:5061;user=phone>
> >User-Agent: PortaSIP (030401b)
> >Content-Type: application/sdp
> >Content-Length: 309
> >o=380442466396 20916528 20916528 IN IP4 192.168.1.20
> >s=ATA186 Call
> >c=IN IP4 193.111.9.226
> >t=0 0
> >m=audio 14000 RTP/AVP 4 8 0 101
> >a=rtpmap:4 G723/8000/1
> >a=rtpmap:8 PCMA/8000/1
> >a=rtpmap:0 PCMU/8000/1
> >a=rtpmap:101 telephone-event/8000
> >a=fmtp:101 0-15
> >a=direction:active
> >a=oldmediaip:192.168.1.20
> >
> >SER->B2BUA
> >
> >SIP/2.0 100 trying -- your call is important to us
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Sip EXpress router (0.8.10 (i386/freebsd))
> >Content-Length: 0
> >
> >SER->ATA
> >
> >INVITE sip:16045215277 at 172.17.1.127:5060;user=phone;transport=udp SIP/2.0
> >Record-Route: <sip:16045215277 at 64.180.102.72;branch=0>
> >Via: SIP/2.0/UDP 64.180.102.72;branch=z9hG4bK56f9.3c3c97acad0bdb329284be13e26ccc54.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >cisco-GUID: 200546447-2237180178-1764455078-2518034476
> >CSeq: 2 INVITE
> >Max-Forwards: 9
> >Expires: 300
> >Contact: <sip:380442466396 at 64.180.102.72:5061;user=phone>
> >User-Agent: PortaSIP (030401b)
> >Content-Type: application/sdp
> >Content-Length: 309
> >o=380442466396 20916528 20916528 IN IP4 192.168.1.20
> >s=ATA186 Call
> >c=IN IP4 193.111.9.226
> >t=0 0
> >m=audio 14000 RTP/AVP 4 8 0 101
> >a=rtpmap:4 G723/8000/1
> >a=rtpmap:8 PCMA/8000/1
> >a=rtpmap:0 PCMU/8000/1
> >a=rtpmap:101 telephone-event/8000
> >a=fmtp:101 0-15
> >a=direction:active
> >a=oldmediaip:192.168.1.20
> >
> >ATA->SER
> >
> >SIP/2.0 100 Trying
> >Via: SIP/2.0/UDP 64.180.102.72;branch=z9hG4bK56f9.3c3c97acad0bdb329284be13e26ccc54.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Cisco ATA 186 v2.15 ata18x (030401b)
> >Content-Length: 0
> >
> >ATA->SER
> >
> >SIP/2.0 183 Session Progress
> >Via: SIP/2.0/UDP 64.180.102.72;branch=z9hG4bK56f9.3c3c97acad0bdb329284be13e26ccc54.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Cisco ATA 186 v2.15 ata18x (030401b)
> >Content-Length: 201
> >Content-Type: application/sdp
> >o=16045215277 1110 1110 IN IP4 172.17.1.127
> >s=ATA186 Call
> >c=IN IP4 64.180.102.72
> >t=0 0
> >m=audio 10000 RTP/AVP 4 101
> >a=rtpmap:4 G723/8000/1
> >a=rtpmap:101 telephone-event/8000
> >a=fmtp:101 0-15
> >
> >SER->B2BUA
> >
> >SIP/2.0 183 Session Progress
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Cisco ATA 186 v2.15 ata18x (030401b)
> >Content-Length: 221
> >Content-Type: application/sdp
> >o=16045215277 1110 1110 IN IP4 172.17.1.127
> >s=ATA186 Call
> >c=IN IP4 64.180.102.72
> >t=0 0
> >m=audio 10000 RTP/AVP 4 101
> >a=rtpmap:4 G723/8000/1
> >a=rtpmap:101 telephone-event/8000
> >a=fmtp:101 0-15
> >a=direction:active
> >
> >ATA->SER
> >
> >SIP/2.0 480 Temporarily Not Available
> >Via: SIP/2.0/UDP 64.180.102.72;branch=z9hG4bK56f9.3c3c97acad0bdb329284be13e26ccc54.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Cisco ATA 186 v2.15 ata18x (030401b)
> >Content-Length: 0
> >
> >SER->B2BUA
> >
> >SIP/2.0 480 Temporarily Not Available
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Cisco ATA 186 v2.15 ata18x (030401b)
> >Content-Length: 0
> >
> >B2BUA->SER
> >
> >ACK sip:16045215277 at demo.portaone.com:5060;transport=udp;user=phone SIP/2.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 ACK
> >Max-Forwards: 70
> >Content-Length: 0
> >
> >SER->ATA
> >
> >ACK sip:16045215277 at 172.17.1.127:5060;user=phone;transport=udp SIP/2.0
> >Via: SIP/2.0/UDP 64.180.102.72;branch=z9hG4bKbc52.5db2fe1211adfdd0d5db3db6e2295344.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 ACK
> >Max-Forwards: 69
> >Content-Length: 0
> >
> >SER->B2BUA
> >
> >SIP/2.0 480 Temporarily Not Available
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Cisco ATA 186 v2.15 ata18x (030401b)
> >Content-Length: 0
> >
> >B2BUA->SER
> >
> >ACK sip:16045215277 at demo.portaone.com:5060;transport=udp;user=phone SIP/2.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 ACK
> >Max-Forwards: 70
> >Content-Length: 0
> >
> >SER->ATA
> >
> >ACK sip:16045215277 at 172.17.1.127:5060;user=phone;transport=udp SIP/2.0
> >Via: SIP/2.0/UDP 64.180.102.72;branch=z9hG4bKbc52.5db2fe1211adfdd0d5db3db6e2295344.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 ACK
> >Max-Forwards: 69
> >Content-Length: 0
> >
> >SER->B2BUA
> >
> >SIP/2.0 480 Temporarily Not Available
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 INVITE
> >Server: Cisco ATA 186 v2.15 ata18x (030401b)
> >Content-Length: 0
> >
> >B2BUA->SER
> >
> >ACK sip:16045215277 at demo.portaone.com:5060;transport=udp;user=phone SIP/2.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 ACK
> >Max-Forwards: 70
> >Content-Length: 0
> >
> >SER->ATA
> >
> >ACK sip:16045215277 at 172.17.1.127:5060;user=phone;transport=udp SIP/2.0
> >Via: SIP/2.0/UDP 64.180.102.72;branch=z9hG4bKbc52.5db2fe1211adfdd0d5db3db6e2295344.0
> >Via: SIP/2.0/UDP 64.180.102.72:5061
> >To: <sip:121 at 64.180.102.72;user=phone>;tag=2698540533
> >From: <sip:380442466396 at 64.180.102.72:5061;user=phone>;tag=4505a91c4165b3ffb1b4df0ff79c2904
> >Call-ID: 3135130751 at 192.168.1.20
> >CSeq: 2 ACK
> >Max-Forwards: 69
> >Content-Length: 0
> >
> >[the last 3 repeat until timeout hits]
> >_______________________________________________
> >Serusers mailing list
> >serusers at lists.iptel.org
> >http://lists.iptel.org/mailman/listinfo/serusers
>
> --
> Jiri Kuthan http://iptel.org/~jiri/
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