[Serusers] Problem with ACK

[Greger V. Teigre]

Are you sure that the ACK stops at ser?  The ACKs should just flow through 
ser.  I have seen a similar problem with XLite where Cisco drops the ACK 
because XLite there is a bug in XLIte's Via parsing.  This is a Cisco 
gateway appending an x-route-tag to via.  Turn on debugging (ALL) on Cisco 
and check if it drops the ACK due to wrong/no branch info in Via.
g-)

Amozurrutia Jesus wrote:
> I'm implementing the scenario shown below.
>
>   ___      ______
>  / 0 \ ---/      \   |
>   /_\     | ATA1 |---|    ____     _  _  _  _     _____
>           \______/   |   /    \   / \/ \/ \/ \   /     \
>                      |---| FW |---|  IP Net  |---| CCM |
>                      |   \____/   \_/\_/\_/\_/   \_____/
>                      |             |        |
>                      |             |        |
>                                    |        |
>                                   ---      ---
>                                  /   \    /   \
>                                  |NAT|    |SER|
>                                  |-T |    |   |
>                                  \___/    \___/
>
> When calling between the CCM (Cisco CallManager) and the ATA, SER
> simply ignores the call ACK.
> The ACK looks like:
>
>  ACK sip:5559853979*sip1.mcm.net.mx=X.X.71.2+17081 at X.X.81.92:5063
>  SIP/2.0 Via: SIP/2.0/UDP  X.X.67.218:5060;branch=z9hG4bK29b2c750
>  From: "5559852600" <sip:5559852600 at X.X.67.218>;tag=16781758
>  To: <sip:5559853979 at mcm.net.mx>;tag=2602576443
>  Date: Tue, 30 Nov 2004 23:53:15 GMT
>  Call-ID: fef8ed00-1da1612d-24d-da4334c8 at X.X.67.218
>  Route: <sip:5559853979 at X.X.81.94;ftag=16781758;lr>
>  Max-Forwards: 70
>  CSeq: 101 ACK
>  Content-Length: 0
>
> The call flow:
>
>     CallManager         SIP Server             ATA
>          |                   |                   |
>          |-- INVITE -------->|                   |
>          |<-- trying --------|                   |
>          |                   |-- INVITE -------->|
>          |                   |<-- Trying --------|
>          |                   |<-- Ringing -------|
>          |<-- Ringing -------|                   |
>          |                   |<-- OK ------------|
>          |<-- OK ------------|                   |
>          |-- ACK ----------->|                   |
>          |                   |<-- OK ------------|
>          |<-- OK ------------|                   |
>          |-- ACK ----------->|                   |
>          |                   |<-- OK ------------|
>          |<-- OK ------------|                   |
>          |-- ACK ----------->|                   |
>          |                   |<-- OK ------------|
>          |<-- OK ------------|                   |
>          |-- ACK ----------->|                   |
>          |                   |<-- OK ------------|
>                ......
>
> My guess is that SER does not accept the URI
> "5559853979*sip1.mcm.net.mx=X.X.71.2+17081 at X.X.81.92:5063" because it
> contains "*+=" signs ore something similar.
> When calling from ATA - ATA there is no preoblem because ATAs
> construct the ACK message different (URI and Rote flipped).
>
> Any ideas?
>
> Thanks in advance,
>
> Jesus
>
>
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