[SR-Users] [Kamailio-Users] Relaying NOTIFY UDP messages over TCP

[Pascal Maugeri]

Hi Daniel

Just to let you know I followed your advice and we deployed kamailio 3.0.1.
We are still doing several tests, but I can say already we don't have
anymroe errors with tcp connections ...

Cheers
Pascal


On Fri, Mar 12, 2010 at 6:04 PM, Daniel-Constantin Mierla <miconda at gmail.com
> wrote:

> Hello,
>
>
> On 03/11/2010 05:58 PM, Iñaki Baz Castillo wrote:
>
>> 2010/3/11 Pascal Maugeri<pascal.maugeri at gmail.com>:
>>
>>
>>> Does such NOTIFY go to a TCP registered user? Of course if there is
>>>> not an existing TCP connection between Kamailio and the final natted
>>>> user then it's not possible to send such NOTIFY.
>>>>
>>>>
>>>>
>>> Do you mean that the user is sending "transport=tcp" in his Contact
>>> header ?
>>>
>>>
>> This must be present in the initial SUBSCRIBE. However if the client
>> is behind NAT and uses TCP it's required some way to mantain the
>> keepalive in the router, if not a future NOTIFY could not arrive. A
>> common approach is the client sending some TCP data through the
>> existing connection (i.e.<CRLF><CRLF>  as defined in defat-oubound,
>> now RFC XXXX).
>>
>>
> I have seen clients sending registration over UDP requiring to be contacted
> via TCP.
>
> To be sure it registers via TCP check the configuration of the phone and
> watch the sip traffic with ngrep (or ethereal) to see the transport layer
> protocol.
>
> Connecting from server to a client behind nat is possible only if you have
> port forwarding on your nat box to phone IP address. Therefore, if the phone
> connects via tcp it must keep the connection open. If for some reason it
> closes, it must re-open it. Otherwise it becomes unreachable.
>
> In the server side there are lot of tcp options to tune the behavior and
> optimize. I do suggest using version 3.0 for a much improved TCP
> architecture and implementation (including asynchronous tcp -- in case you
> deal with lot of tcp connections, then this saves you).
>
> http://www.kamailio.org/dokuwiki/doku.php/core-cookbook:3.0.x#tcp_parameters
>
> Worth to mention as well that you can change the value of tcp parameters at
> runtime without need to restart (e.g., connecting timeout, send timeout,
> etc) using sercmd.
>
> Cheers,
> Daniel
>
> --
> Daniel-Constantin Mierla
> Kamailio SIP Router Masterclass, Berlin, March 22-26, 2010
> * http://www.asipto.com/index.php/sip-router-masterclass/
>
>
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