Sip Implementors

Keerthi Srinivasan | 1 Aug 2012 09:00

Unknown transport in Via Header

All,

Can anyone help in unknown transport in Via Header

1. If the Proxy / Registrar received the below message.

      OPTIONS sip:user <at> example.com SIP/2.0
      To: sip:user <at> example.com
      From: <sip:caller <at> example.com>;tag=323
      Max-Forwards: 70
      Call-ID:  transports.kijh4akdnaqjkwendsasfdj
      Accept: application/sdp
      CSeq: 60 OPTIONS
*      Via: SIP/2.0/UNKNOWN t4.example.com;branch=z9hG4bKasd0f3en*
      l: 0

What could be the response?

2. If the Proxy / Registrar received the below message.

      OPTIONS sip:user <at> example.com SIP/2.0
      To: sip:user <at> example.com
      From: <sip:caller <at> example.com>;tag=323
      Max-Forwards: 70
      Call-ID:  transports.kijh4akdnaqjkwendsasfdj
      Accept: application/sdp
      CSeq: 60 OPTIONS
*       Via: UNKNOWN/2.0/UDP t4.example.com;branch=z9hG4bKasd0f3en*
      l: 0

(Continue reading)

headers

Brett Tate | 1 Aug 2012 12:55

Re: Unknown transport in Via Header

> Can anyone help in unknown transport in Via Header
> 
> 1. If the Proxy / Registrar received the below message.
> 
>       OPTIONS sip:user <at> example.com SIP/2.0
>       To: sip:user <at> example.com
>       From: <sip:caller <at> example.com>;tag=323
>       Max-Forwards: 70
>       Call-ID:  transports.kijh4akdnaqjkwendsasfdj
>       Accept: application/sdp
>       CSeq: 60 OPTIONS
> *      Via: SIP/2.0/UNKNOWN t4.example.com;branch=z9hG4bKasd0f3en*
>       l: 0
> 
> What could be the response?

It is an abnormal situation; thus the UAS can basically act however it wants.  Returning a 400 using received
transport (obviously not the unknown transport) and not updating Via's transport would hopefully get
the problem noticed/fixed.

> 2. If the Proxy / Registrar received the below message.
> 
> 
>       OPTIONS sip:user <at> example.com SIP/2.0
>       To: sip:user <at> example.com
>       From: <sip:caller <at> example.com>;tag=323
>       Max-Forwards: 70
>       Call-ID:  transports.kijh4akdnaqjkwendsasfdj
>       Accept: application/sdp
>       CSeq: 60 OPTIONS

(Continue reading)

headers

Brez Borland | 1 Aug 2012 14:18

Re: Unknown transport in Via Header

See inline..

On Wed, Aug 1, 2012 at 8:00 AM, Keerthi Srinivasan <
keerthivarmansrinivasan <at> gmail.com> wrote:

> All,
>
> Can anyone help in unknown transport in Via Header
>
> 1. If the Proxy / Registrar received the below message.
>
>       OPTIONS sip:user <at> example.com SIP/2.0
>       To: sip:user <at> example.com
>       From: <sip:caller <at> example.com>;tag=323
>       Max-Forwards: 70
>       Call-ID:  transports.kijh4akdnaqjkwendsasfdj
>       Accept: application/sdp
>       CSeq: 60 OPTIONS
> *      Via: SIP/2.0/UNKNOWN t4.example.com;branch=z9hG4bKasd0f3en*
>       l: 0
>
> What could be the response?
>

"RFC 3261, Section 25.1 Basic Rules" defines the transport as one of the
following:
-------------------------
transport         =  "UDP" / "TCP" / "TLS" / "SCTP"
                     / other-transport
-------------------------

(Continue reading)

headers

Worley, Dale R (Dale | 1 Aug 2012 22:22

Re: Unknown transport in Via Header

> From: Keerthi Srinivasan [keerthivarmansrinivasan <at> gmail.com]
> 
> Can anyone help in unknown transport in Via Header

Of course, there is no way to send a response to the request, because
the element cannot determine how to contact the sender.

There is probably no better choice than dropping the message.

I suggest you contact the vendor identified in the User-Agent header
and tell them of this bug.

Dale