[OpenSIPS-Users] using TCP/TLS in a large scale deployment

[Bogdan-Andrei Iancu]

Hi George,

There are advantages and disadvantages for each protocol you use:

UDP is much lighter as protocol for the OS (100K UDP end points -> only 
one socket, 100K TCP end points -> 100K sockets) and also for the 
application (OpenSIPS) - managing TCP connection is more resource 
intensive rather than UDP sockets

UDP also have some advantages as it a framed protocol - a SIP packages 
and delimited at protocol level (in a single datagram), while in TCP, 
where everything is streamed, the reading application cannot "see" at 
transport level where a SIP package end and a new one starts - it has to 
do SIP parsing just to figure out where it ends.

Nevertheless, TCP has better NAT penetration (as it is connection 
oriented) - this is why all mobile devices do prefer TCP over UDP.
Also UDP has problems when comes to size, as it is limited to 65K (not 
to mention poor UDP fragmentation on several stacks) - again, TCP solves 
this problem as it is stream oriented.

Best regards,

Bogdan-Andrei Iancu
OpenSIPS Founder and Developer
http://www.opensips-solutions.com

On 12.09.2014 17:13, george wu wrote:
> I am not sure if I should start another thread or not.
> I have similar question.
> The client is android linphone. it says it needs to send keep-alive 
> message for firewall traversal.
> For tcp it only needs to send every 10 minutes while for udp it needs 
> to send every 10 seconds.
> It is obviously tcp is much better for the clients.
> However from thread here, it is better to use udp.
>
> Now can anybody give me some clue how to do tradeoff between tcp and udp.
> Thanks.
>
> George
>
>
>
>
>
> At 2014-09-12 09:38:04, "Bogdan-Andrei Iancu" <bogdan at opensips.org> wrote:
>
>     Hi Jayesh,
>
>     There are 2 aspects here :
>         - first, configure proper limits when starting OpenSIPS - like
>     max number of fds per process, etc.
>         - secondly, when comes to opensips itself, you need to look into :
>             * enough memory (TCP uses a lot)
>             * set proper timeouts in TCP (connect, write, read
>     timeouts) to avoid blocking
>             * properly handle the TCP lifetime to get to a compromise
>     between the number of ongoing connections and seting/closing
>     connections
>             * really good control over when OpenSIPS should open new
>     TCP conns - you can do this from script, depending on the target
>     (like never try to open conns towards end-user, let them connect
>     to you).
>
>     Regards,
>
>     Bogdan-Andrei Iancu
>     OpenSIPS Founder and Developer
>     http://www.opensips-solutions.com
>
>     On 10.09.2014 14:55, Jayesh Nambiar wrote:
>>     Hello,
>>     I am in process of designing opensips which can handle a million
>>     users, hypothetically 200,000 registrations and 500CPS capacity.
>>     I've been reading a lot and learnt that TCP design is blocking
>>     and not suitable for huge volumes.
>>     My requirement was to have TLS between endpoints and Opensips and
>>     hence riding over TCP is the only option. I needed some expert
>>     suggestions on what things should be taken care of when planning
>>     a large deployment over TCP.
>>     I have built similar stuff on UDP and I trust it heavily as it
>>     has performed perfectly as expected. But when it comes to TCP I'm
>>     a bit clueless.
>>     I've read about lot of global parameters that is now available
>>     for asynchrous tcp operations. Is it really helpful when planning
>>     for scalable environments??
>>
>>     Thanks for any suggestions !!
>>
>>     W/regards,
>>     Jayesh
>>
>>
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>
>
>
>
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