Sip & Ims

ron_darrell

Hi,

I may be phrasing this incorrectly but I'm trying to help a friend out and neither of us know a huge amount about this. Basically he's doing a project incorporating IMS and the SIP protocol for a mobile device. Originally he told me it was a java project so I offered to help if I could but now he's been told he needs a JR180 library for the SIP function calls. The link he's been given to download the library only gives access to the API and supporting documentation. Does anyone know where he can get his hands on the JR180 library or is he being sent up the garden path? (i.e. does he not need this library and can he gain access to the SIP/IMS functionality by other means??)

Apologies if I haven't phrased this properly.

Regards,
-RD

matrim

There is a SIP stack as part of java but I don't know much about it. There should be information on the java site. Also check out sipcenter.com, as it has information about SIP stacks.

By the way if he wants to make SIP calls on a mobile than java may be the wrong way to go as it would probably be too slow.

ron_darrell

Java too slow? Ok didn't know that. What woudl you suggest using instead. The project is only in the early stages and he has some C++ and VB experience so if wither of those is a better idea then he still has time to change course.

Thanks for your reply
-RD

matrim

What platform is he targetting?

ron_darrell

He's using a N95 to test on so the code should be able to work on all symbian based mobiles. Can the code be written to be even more generic (i.e. run on almost any platform (I think that might be why he wants to write in Java)) ?

-RD

marco_polo

matrim wrote: »

There is a SIP stack as part of java but I don't know much about it. There should be information on the java site. Also check out sipcenter.com, as it has information about SIP stacks.

By the way if he wants to make SIP calls on a mobile than java may be the wrong way to go as it would probably be too slow.

The speed of java is really not much of an issue these days. I would be surpised if the Java 5 or 6 VMs were not up to the task especially if they used the server VM instead of the client VM. If it was java 1.3 VM then it possibly would be too slow.

However Java has made massive performance improvements over the last few releases, and aside from the much longer startup times as the JIT compiles the bytecode, once a java programming is up and running it is now very close in performance to C++ over alot of benchmarks.

http://www.idiom.com/~zilla/Computer/javaCbenchmark.html

Of course the C++ version would probably be slightly faster however if the OP and his mate know Java better and it can do the job then I would not discount that road, if they can live with slight perfromance drop.

Of course I know nothing about SIP programming so that slight performance drop coud be very important. I know Java is unsuitable for certain real time and embedded applications due to its garbage collection strategy and thread scheduling model (I would definately opt for a c++ pacemaker if I ever need one ), but is either of these a big issue for SIP programming on a mobile?

ron_darrell wrote: »

He's using a N95 to test on so the code should be able to work on all symbian based mobiles. Can the code be written to be even more generic (i.e. run on almost any platform (I think that might be why he wants to write in Java)) ?

-RD

The code would have to be recompilled to run on other devices if it was written in C++, but that would hopefully not be too problematic a task if it is written using standard C++. (Any third party libraries used would also need to be available for each platform)

matrim

marco_polo wrote: »

The speed of java is really not much of an issue these days. I would be surpised if the Java 5 or 6 VMs were not up to the task especially if they used the server VM instead of the client VM. If it was java 1.3 VM then it possibly would be too slow.

However Java has made massive performance improvements over the last few releases, and aside from the much longer startup times as the JIT compiles the bytecode, once a java programming is up and running it is now very close in performance to C++ over alot of benchmarks.

http://www.idiom.com/~zilla/Computer/javaCbenchmark.html

Of course the C++ version would probably be slightly faster however if the OP and his mate know Java better and it can do the job then I would not discount that road, if they can live with slight perfromance drop.

Java would be fine for a server side platform, in fact some of the big SIP providers use Java EE for their server platform. It would be ok for a PC client also. The issue with java would be the fact that it is on a mobile platform, you could probably get away with it for just SIP signalling, but I don't think it would be good enough for RTP (audio) encoding.

matrim

ron_darrell wrote: »

He's using a N95 to test on so the code should be able to work on all symbian based mobiles. Can the code be written to be even more generic (i.e. run on almost any platform (I think that might be why he wants to write in Java)) ?

-RD

There's a SIP stack build into the Nokia S60 devices that he may be able to use as a starter if he only wanted to target Nokia. (check out forum.nokia.com )

There are also multi platform SIP stacks available but I don't have the names to hand.

HarrierJoe

If you've tried numerous times and failed it may be your operator's fault. I understand that Vodafone has disabled all SIP-based functionality on the N95 when the branded it because they'll not make any money if you were given the choice of a network vs. wlan-based phone call.