6 Feb
2017
6 Feb
'17
2:24 p.m.
Hi Daniel,
I send you the pcap files on both client and server side.
Analyse this files, I see the packet can not "reassemble" INVITE message
at server side:
- At client.pcapng, it can detect 6 and 7th packets are one.
- But on server.pcap, it can not "reassemble" 18 and 21st packets.
I just explain as my understand. If you have any information, please ask me.
I think the problem relate the MTU - fragmentation. But I'm not sure about
this.
Thank you for support !
Regards,
Hai Bui
On Sun, Jan 22, 2017 at 4:33 PM, Hai Bui Duc Ha <hai.bui(a)htklabs.com> wrote:
Hi Daniel,
Thank for your advice.
I will capture and analyze the call log on both client and kamailio to
check the packet size.
Regards,
Hai Bui
On Fri, Jan 20, 2017 at 3:38 PM, Daniel-Constantin Mierla <
miconda(a)gmail.com> wrote:
--
Hai Bui
VoIP engineer, Cvoice team, HTK-HCM Office
Mobile: +84-165-618-9876
On 19/01/2017 22:56, Daniel-Constantin Mierla wrote:
Hello,
On 19/01/2017 10:48, Hai Bui Duc Ha wrote:
Hi Daniel,
Thank you for reply.
On Tue, Jan 17, 2017 at 6:05 PM, Daniel-Constantin Mierla <
miconda(a)gmail.com> wrote:
--
Hai Bui
VoIP engineer, Cvoice team, HTK-HCM Office
Mobile: +84-165-618-9876
Hello,
apparently I missed the follow ups on this discussion, dragged in by
other topics on mailing list.
Can you get the pcap with all the traffic taken on kamailio server for
the call (from initial invite to the end of the
call)?
I send you the pcap at enclosed file. You can see the packet *No.5 *, it
missing SIP message body:
* Media Attribute (a): rtpmap:8 PCMA/8000*
* Media Attribute (a): rtpmap:101 telephone-event/8000*
* Media Attribute (a): fmtp:101 0-16*
I expect that content length is mismatching or
there is a '\0' inside
the sdp.
Can you explain me more about this ?
TCP is a stream protocol, meaning that the application (kamailio) need to
read and parse to figure out the end of a SIP message. The state machine as
per RFC requires the application to read and identify the Content-Length
header, take its value, read until the end of headers is found (an empty
line) and from there on read as much as the value of Content-Length to get
the body and consider the end of message there.
If the sending application puts a lower value in the Content-Length than
the number of chars in the body, the rest remains in the buffer and the
receiving application (kamailio) attempts to parse a new SIP message.
The other thing I was thinking of was the presence of '\0' which marks
the end of string in C.
I will look at the pcap very soon and see what I find there.
The problem is the value of Content-Lenght set by the client -- it is set
only to the size that it is view as part of the invite. A bit later the
client sends more sdp, but exceeding the size sent in C-L header. That part
of SDP remains as garbage.
So there is a bug in client app.
Cheers,
Daniel
--
Daniel-Constantin Mierlawww.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio World Conference - May 8-10, 2017 - www.kamailioworld.com