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Remove attribute

9 posts · Brekeke SIP Server Forum

caronte506 Original post
1. Brekeke Product Name and version: Brekeke SIP Server , Version 2.4.8.6 Standard

2. Java version: 1.6.0_01

3. OS type and the version: Linux 2.6.18-4-686

4. UA (phone), gateway or other hardware/software involved:

5. Select your network pattern from http://www.brekeke-sip.com/bbs/network/ ... terns.html :

6. Your problem:

I am trying to send calls to a gateway/softwitch but they are rejected with SIP/2.0 400 Bad Request.
Error-Info: <sip:X@A.B.C.D>;cause="[line 034] SIP syntax error"

Looks like it is a bug on the software, they suggest to remove the "a=rtcp:3550" attribute"

Any idea of how?

Thanks
taitan
> they suggest to remove the "a=rtcp:3550" attribute"

Let you explain why it is the bug.
caronte506
What they let me know is that they are not parsing this a=rtcp:3550 attribute correctly.

They think it is due a bug on the running software of their equipment.

That bug was fixed in the next software version (In my case I have to stay with the current version).

This is the CQ posted in the next software release:

The issue was that the grammar for "a=rtcp:.." also picked up "a=rtcp-xr:.."causing parser error. The code has been modified to fix this issue such that the grammar for "a=rtcp:.." does not pick up:"a=rtcp-rx:..". As a result, ignoring the unknown SDP attribute.

This is why they asked me to ask brekeke to remove that attribute.
taitan
It is still lack of information...

What kind of SIP device are you using?
Do you know who added "a=rtcp" attribute?

Generally, "a=rtcp" attribute is added by UAC.
caronte506
Looks like the problems was on the sip client.

I am using Sonus Gateway/Softwitch <--> Brekeke SIP Server <--> SIP client

I was using the client 3CX Phone, after switching to X-Lite 4 the problem is gone.

Thanks for your help.
taitan
if you create a session plugin, the following routine can remove "a=rtcp" attribute before the server forwards INVITE packets.

Code: 

Sdp  sdpContent = (Sdp)( Content.getContent( sippacket.content, Sdp.CONTENT_TYPE ) ) ;
  if ( sdpContent != null ) {

    // Media descriptions
    if ( sdpContent.tblDescMedia != null ) {

      SdpDescription  descMedia ;
      int  n ;
      int  m = sdpContent.tblDescMedia.size() ;  // number of medias

      // loop with each media
      for ( n = 0; n < m; ++n ) {
        // get media description
        descMedia = (SdpDescription)( sdpContent.tblDescMedia.get( n ) ) ;
        descMedia.removeValue( "a=rtcp" ) ;
      }

    }
  }
skb007
Hi ,

We are using a legacy platform not currently supported by vendor. Our platform is having a problem with the following SDP it receives from UAC. "a=sendrecv" is present as session attribute not as media attribute.

v=0
o=user1 53655765 2353687637 IN IP4 192.168.2.178
s=-
c=IN IP4 192.168.2.178
a=sendrecv
t=0 0
m=audio 24940 RTP/AVP 8 101
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15

I tried your plugin but it removes the attributes defined in the media section only. How can I change the code to remove the session attribute. I want to remove "a=sendrecv" from the above SDP.
Ericcc
You can get the object of Session description from the method sdpContent.takeSessionDesc().

So the code will be like this.

Code: 

Sdp  sdpContent = (Sdp)(Content.getContent(sippacket.content,Sdp.CONTENT_TYPE)) ;
if ( sdpContent != null ) {

    SdpDescription  sd = sdpContent.takeSessionDesc() ;
    if ( sd != null ) {
        sd.removeValue("a=sendrecv") ; 
    }

}
skb007
Appreciate your valuable response.
You guys rock...!!!