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New Member

UDP streaming instead of RTP streaming

Hi, I able to make RTP streaming by using xml services and  "RTPTx:......."  i get the streaming result and the protocol is RTP. But instead of using RTP as the streamming protocol, is it possible to making the transmit protocol as UDP without the rtp header?

22 REPLIES

UDP streaming instead of RTP streaming

Hi,

why whould you do that?

G.

New Member

UDP streaming instead of RTP streaming

Hi gergely,

Because i have a  system that only can receive UDP packet, there is so difficult to change the system. So instead of changing the system, is it possible to change the protocol from RTP to UDP on cisco ip phone ?

UDP streaming instead of RTP streaming

No.

New Member

UDP streaming instead of RTP streaming

how about the ip phone transmit a single UDP message to any destination?

UDP streaming instead of RTP streaming

I don't understand. What are you trying to achieve?

G.

UDP streaming instead of RTP streaming

You do know that RTP is transmitted over UDP...?

GTG

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UDP streaming instead of RTP streaming

GTG, I thought so. But I was wrong. RTP may be transmitted over TCP as well (see the Wikipedia article).

Anyway, the OP wants to send raw UDP packets _without_ the RTP header.

G.

UDP streaming instead of RTP streaming

From what I've seen, Cisco use UDP for RTP transmission.

Yeah, I saw their request for raw audio without the RTP header. The OP's gonna have to ammend their listening software to extract the audio from the UDP/RTP stream. (Wireshark does it quite well )

GTG

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New Member

UDP streaming instead of RTP streaming

Ya, hope someone can help, to change the RTP streamming into UDP streamming.

A.

UDP streaming instead of RTP streaming

Cisco phones send RTP (within UDP). Get used to it.

G.

New Member

UDP streaming instead of RTP streaming

I agree with your statement, the difference is only the 12 byte RTP header, is there a way to strip the 12 bytes rtp header on the server side?

UDP streaming instead of RTP streaming

Hi,

what server side?

You are talking directly to the Cisco phone. There's no configurable parameter of doing that.

You'll have to do that on your side.

G.

New Member

UDP streaming instead of RTP streaming

Hi,

Ok, do on my side, can u describe what was the step, so that i can achieve that?

A.

UDP streaming instead of RTP streaming

I don't know. You'll have to implement something on a very low level, between the interface and the user process.

I would probably match and intercept such packets with iptables, take the payload and retransmit.

G.

New Member

Re: UDP streaming instead of RTP streaming

Are you mean program or configure something inside the cisco ip phone?

Re: UDP streaming instead of RTP streaming

You can't configure the Cisco phone to do that.

Yes, you'll have to write a program that strips the RTP header. Meaning you intercept the packet, disassemble, take the payload, assemble a raw UDP packet, send.

G.

New Member

Re: UDP streaming instead of RTP streaming

Can the program implement inside the Cisco ip phone?

Re: UDP streaming instead of RTP streaming

If you are a hacker, then yes. :-)

New Member

UDP streaming instead of RTP streaming

Lol.... i just want to strip the packet header before the packet transmit ....  but where and how to implement? Someone Please provide guideline... Thanks

UDP streaming instead of RTP streaming

aikbee chew wrote:

Lol.... i just want to strip the packet header before the packet transmit

You can't !!!!

GTG

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UDP streaming instead of RTP streaming

Come on. Everything is possible. Think positive.

I already gave him instructions:

1. intercept the packet,

2. disassemble packet,

3. take the payload,

4. create a shiny new UDP packet and send it.

For a moment I thought iptables "mangle" can do that, but I was wrong. Probably so probably libnetpcap. With jNetPcap, to be more precise.

G.

Re: UDP streaming instead of RTP streaming

aikbee chew wrote:

Can the program implement inside the Cisco ip phone?

NO, NO, NO, NO, NO !

The handsets are sealed, black boxes, as far as you are concerned. If they don't do what you want them to do, either buy other boxes, or write your own software running on your own systems to do the necessary stuff.

GTG

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