SIPp: Cancel scenario 487 before 200 - sip

Question

I'm trying to simulate how to deal when 487 comes before 200 in cancel scenario. But i get "Aborting call on unexpected message for Call-Id while sending (index 5), received 'ACK sip:service#192.168.1.20:5060 SIP/2.0" error.
this is my server.
<scenario name="Basic UAS responder">
<recv request="INVITE" crlf="true">
</recv>
<send>
<![CDATA[
SIP/2.0 100 Trying
[last_Via:]
[last_From:]
[last_To:]
[last_Call-ID:]
[last_CSeq:]
Contact: <sip:[local_ip]:[local_port];transport=[transport]>
Content-Length: [len]
]]>
</send>
<send>
<![CDATA[
SIP/2.0 180 Ringing
[last_Via:]
[last_From:]
[last_To:];tag=[call_number]
[last_Call-ID:]
[last_CSeq:]
Contact: <sip:[local_ip]:[local_port];transport=[transport]>
Content-Length: [len]
]]>
</send>
<recv request="CANCEL">
</recv>
<send>
<![CDATA[
SIP/2.0 487 Request Terminated
[last_Via:]
[last_From:]
[last_To:]
[last_Call-ID:]
CSeq: [cseq] INVITE
Contact: <sip:[local_ip]:[local_port];transport=[transport]>
Content-Length: [len]
]]>
</send>
<send>
<![CDATA[
SIP/2.0 200 OK
[last_Via:]
[last_From:]
[last_To:]
[last_Call-ID:]
[last_CSeq:]
Contact: <sip:[local_ip]:[local_port];transport=[transport]>
Content-Length: [len]
]]>
</send>
<!--pause milliseconds="4000"/-->
<recv request="ACK"
crlf="true">
</recv>
</scenario>
this is my client
<scenario name="UAC Cancel">
<send retrans="500">
<![CDATA[
INVITE sip:[service]#[remote_ip]:[remote_port] SIP/2.0
Via: SIP/2.0/[transport] [local_ip]:[local_port];branch=[branch]
To: <sip:[service]#[remote_ip]:[remote_port]>
From: <sip:sipp#[local_ip]:[local_port]; tag=[call_number]
Call-ID: [call_id]
CSeq: [cseq] INVITE
Contact: sip:sipp#[local_ip]:[local_port]
Max-Forwards: 70
Content-Length: [len]
]]>
</send>
<recv response="100" optional="true">
</recv>
<recv response="180">
</recv>
<pause milliseconds="4000"/>
<send>
<![CDATA[
CANCEL sip:[service]#[remote_ip]:[remote_port] SIP/2.0
[last_Via:]
To: sip:[service]#[local_ip]:[local_port]>[peer_tag_param]
From: sip:sipp#[local_ip]:[local_port];tag=[call_number]
Call-ID: [call_id]
[last_CSeq:]
Contact: sip:sipp#[local_ip]:[local_port]
Max-Forwards: 70
Content-length: [len]
]]>
</send>
<recv response="200" optional="true">
</recv>
<recv response="487" next="cancelACK">
</recv>
<label id="cancelACK"/>
<send>
<![CDATA[
ACK sip:[service]#[remote_ip]:[remote_port] SIP/2.0
[last_Via:]
To: <sip:[service]#[remote_ip]:[remote_port]>[peer_tag_param]
From: <sip:sipp#[local_ip]:[local_port];tag=[call_number]
Call-ID: [call_id]
CSeq: [cseq] ACK
Contact: sip:sipp#[local_ip]:[local_port]
Max-Forwards: 70
Content-Length: [len]
]]>
</send>
<pause milliseconds="3000"/>
</scenario>

Answer 1

Looks to me like you'll have a problem with the way your are using [last_Via:].
The CANCEL request from the UAC should have a new branch parameter in its Via header since it's a new transaction.
Also the OK response to the INVITE request being generated by the UAS is going to use the Via header from the CANCEL request.
Since the Via header is critical for SIP transaction matching it's understandable that sipp is complaining when it is not able to match things up properly.