Icecast Streaming Media Server

[kai4711]

Hi Guys,

i am using a dedicated Rootserver streaming an audio programme.

When we started the stream I first used shoutcast and it worked fine, with full load of the server. Up to 1000 listeners, about 70Mbit/s...

Then I wanted to switch to Icecast and it worked fine until the provider cutted of the line when we reached about 50 Mbits/s and told us we are making a DDos out of our server. That happend sometimes, so I switched back to shoutcast and it works fine with heavy load...

So I checked the difference and noticed about the TCP-Packet size, and the Shoutcast sizes seems to be twice the shoutcasts... so shoutcast has twice the packets per second at the same bitrate... so our provider thinks we are DDos-ing.....

I didnt find any solutions or information how to configure it...
Can anybody help me?

best regards,
Kai

[karlH]

Can you be clearer on the issue in question. Is this an ogg stream or not, and are we to assume this is 2.3.1?

If it were a direct comparison to shoutcast then it's probably a non-ogg stream and for that we try to collect the incoming stream into blocks of 1400 bytes (just under the commonly used 1500 MTU). The blocking prevents small writes by the source client causing large protocol overhead waste.

I'm not sure on what your are seeing but if shoutcast is generating smaller packets then surely that increases overhead.

karl.

[kai4711]

Yes its 2.3.1 and its MP3.

I think Shoutcast uses larger packets, so it has less packets per Second.
So I am searching for something making the Icecast-Packets larger... (or another solution that my provider will not detect icecast-load as outgoing DDos.. )

Thank you in advance,
Kai

Edit: Damn, its 2.2.0...

[karlH]

The packets should be a little over 1400 bytes, how much bigger do you want them?

karl.

[kai4711]

twice?

I know that my provider doesnt detect the shooutcast stream as Outgoing-DDos.
When we can say Icecast to have the same packet-structure I hope I can use IC on the server, which is the better streamingserver I think.

Thank you!
Kai

PS: I benchmarked Shoutcast and Icecast at 64kbit/s with 500 listeners ~ 30Mbit/s
Shoutcast: 3.8k packets per second
Icecast: 8K packets per second

[karlH]

Can you provide a tcpdump capture of both sessions, 1 listener should suffice. We would need to know exactly what is going on.

karl.

[kai4711]

Can you tell me how to filter the relevant information or do you want the whole echo of tcpdump?

Can you say me how to use? Echo to file?
I am a novice to tcpdump...

Edit:
So I created 2 Dumps filtered by the ports of icecast/shoutcast...
I sent it to you via email...


Thank you,
Kai

[karlH]

Just to follow up on this for others. The actual installation was icecast 2.2.0 which did have an issue of small packet writes, 2.3.1 does not.

karl.