I'm new to SIP/VoIP programming. I want to implement a SIP server mainly for registering and proxing. I know to start from scratch is foolishness, but then what options do I have? I have been doing google-ing for a couple of days, and I got some few options to work with-
SIP JAIN
SIPServlet
Please comment on these items and some related materials. It would be helpful if someone can comment on the programming languages that suits SIP best, for all I'm more inclined towards Java.
Regards,
There are already some Open Source SIP proxy / registrars available: OpenSIPS and Kamailio. Both are written in C.
Do you have any specific need for writing a SIP proxy from scratch? Maybe you could extend one of the available ones to suit your needs?
Related
Sorry for my ignorance , but this subject has been stressing me for days
I currently read in a book about networks that there is a UseNet that is like a blog , but uses a different protocol to communicate
My question is, when I'm developing a software, can I decide which application protocol will it work?
the TOR browser, I read that .onion sites use a different protocol than HTTP, how is this possible?
We first need to break up your question. There are protocols implemented in operating systems (low-level protos) and those implemented in applications (high-level protos).
What makes early high-level protos so interesting, like Usenet and SNMP, is that they are not dependent on low-level protocols. Basically they just need the operating system to provide a mechanism for streaming data to come to/from the machine they want to speak to. You can see that Usenet's protocol's , UUCP, code can handle TCP or serial connections.
My question is, when I'm developing a software, can I decide which application protocol will it work?
Yes, you ask the OS for your low-level protocol and you then implement your high level protocol in you application. You can also layer protocols ontop of one another.
the TOR browser, I read that .onion sites use a different protocol than HTTP, how is this possible?
While not a TOR expert, general proxy protocols like SOCKS, use TCP at a low level to connect to their first proxy and then using higher level protocols encrypt HTTP requests so they bounce around several proxies.
this is a very high level answer, you can absolutely implement a low-level protocol in an application. I am just speaking to the most common examples
We are thinking about writing a softphone app. It would basically be a component of a system that has calls queued up from a database. It would interface with a LINUX server which has Asterisk installed.
My first question is
Whether we should write the softphone at all or just buy one?
Secondly, if we do,
what base libraries should be use?
I see SIP Sorcery on CodePlex. More than anything, I am looking for a sense of direction here. Any comments or recommendations would be appreciated.
The answer would depend on the capabilities you have in your team and the place you see your core value and the essence of the service you provide.
In most cases, I'd guess that you don't really care about SIP or doing anything fancy with it that require access to its low level. In such a case, I'd recommend getting a ready-made softphone - either a commercial one or an open source one. I'd go for a commercial one, as it will give you the peace of mind as to its stability and assistance with bug fixing and stuff.
To directly answer your question, one of the many open source softphones are likely to fit your needs, and allow slight modifications as needed. Under most open source licenses there is no obligation to distribute your code as long as you only use it internally (do not distribute the binary.)
Trying to guess what you are trying to do, it sounds like a call center like scenario, so one of the many call queue implementations out there might fit your needs.
I had to write an own softphone and I found a great guide how to achieve it. In the guide there are 10 steps provided for having an own softphone (voip-sip-sdk.com on page 272)
I found it useful and maybe you will find it as well.
I am trying to write a iPhone group chatting/message-board app which will have a backend component. I expect users to register with our system and start posting messages on chatrooms/message-boards. These message-boards can have more than 2 individuals, must support real time notifications and should be accessible from any other clients (like web) as well.
I stumbled upon http://code.google.com/p/xmppframework/ . I realize that XMPP is a very attractive proposition for our needs but I am seriously worried about the infrastructure complexities and scale issues. Besides, XMPP has way too much to offer for my needs. Looks like, XMPP might be the only choice for my pleasure in pain, but I wanted to see what you experts have to say on this.
Any thoughts?
Thanks,
My advice is: whichever protocol you're choosing, do not try to invent your own protocol. Go for XMPP or if you can find an alternative which you find more compelling, use that. Especially if there's already a nice framework for you to use. Why ? Because a single developer new to a field is seldom smarter than a bunch of people with experience ;-) Make use of other peoples' experience by using an established protocol, and make use of existing frameworks to avoid coding mistakes and investing a lot of time to solve a problem yet again that was already solved.
That being said, XMPP is widely deployed and thus would make for a good choice if you later plan to write additional clients for other platforms or want to have third-party clients connect to your server.
I would like to ask a question about network communication.
The Question is:
A server uses the socket interface on the Lunix platform,
and a client uses Winock on the Windows platform.
Can they communicate?
Explain briefly.
I guess the answer is NO.
I guess it is due to the compatibility between 2 different socket interface?!
But I am not sure my estimation is right or not.
So, I hope someone could give me some comments about this questions.
Thank you very much!
Not right at all.
The APIs are different, but both sockets create packets written to a standard format described in RFC 793 and lots of subsequent revisions and additions.
Follow that packet format, and implementations written for different platforms and in different languages will talk to each other.
This is the magic of the internet.
I want to try developing an XMPP server component using XEP-0114: Jabber Component Protocol.
Which server do you recommend and why? I'm talking about ease of development, community support, documentation, examples, etc.
That's a hard question to answer, because I doubt there are many developers involved in developing across multiple XMPP projects and languages.
I can throw out a few personal perceptions but... I could be off-base!
What you're really looking for is which libraries would be recommended for component development. All the servers support the component protocol, so all you really need is a socket connection to the server and some helper routines to make the repetitive stuff like message parsing easier.
Where the server might matter is if you need tighter integration.
For example if you want your component to scale the same way as Ejabberd then you'll probably want to use exmpp.
If you need to deploy your component alongside Openfire into Java only enterprises, then you'll probably want to use smack.
If you are familiar with Python and want to prototype quickly use Wokkel.
I don't think documentation is going to be great for any of the libraries (haven't looked at them all though!) but that shouldn't be a huge burden. All you really need a good book on how the XMPP protocol works and then some sample code from the library and it's fairly easy to move on from there.
For an easy-to-use testing server I like openfire. Good instructions, easy to hook in components, and a good web interface for administration. Debugging is more of a "tail -f" on the logfiles, slightly java-ish.
I've used XCP professionally, but that's really for commercial use. It works well but if that's not your target deployment it's not worth the effort. I'm not sure if you can buy it separately any more.
I tried using ejabberd and I gave up quickly. I found the documentation for setup and administration awful. The config files are not self describing and there's no good walk through on the ejabberd site. It may be able to even fry my eggs in the morning for breakfast, but I couldn't get past install with the time I'd allotted to it.
For Openfire, there is something called Whack, which is a Java library for creating server components (XEP-0114).
Since the communication is over sockets, I presume the same code should work for any well designed XMPP server (such as ejabberd). However, I have only tested it with Openfire and it works quite well.