[OpenSER-Users] The Via Header of CANCEL Message

[Klaus Darilion]

Looks like it is defined clearly and openser is not 100% standard conform.

regards
klaus

fancy wrote:
> Hi Klaus:
> RFC 3665 page 54 line 4:
>    A CANCEL constructed by a
>    client MUST have only a single Via header field value matching the
>    top Via value in the request being cancelled.
> 
> and RFC 3665 at page 53:
>    CANCEL is referred to as a "hop-by-hop" request, since it is
>    responded to at each stateful proxy hop.
> 
> and RFC 3665 at page 21:
>    Client: A client is any network element that sends SIP requests
>          and receives SIP responses.  Clients may or may not interact
>          directly with a human user.  User agent clients and proxies are
>          clients.
> 
> So, for my opinion, the role of proxy in this case of RFC 3665 section 3.8 is a client when it sends CANCEL message to Bob.
> 
> If I misunderstand any RFC meanings, please correct me.
> Thank you very much.
> 
> Best Regards,
> Fangyu Ling
> 
> 
>> fancy wrote:
>>> According to RFC 3665 section 3.8 and RFC 3261 section 9,
>>> there is only one via header in CANCEL message
>>> (message F11, F13 at page 72 of RFC 3665).
>> Hi!
>>
>> I could find it in RFC 3665, but not in 3261. Where exactly in RFC 3261
>> is mentioned that the CANCEL has only 1 Via header?
>>
>> Further, the example has only one Via header - but I could not find any
>> definition if this is a MUST or not.
>>
>>> How can I remove the 2nd via header?
>> You would have to modify tm module and change the code which generates
>> the CANCEL message.
>>
>> regards
>> klaus
>>