[Icecast-dev] Help

Rücker Thomas thomas.ruecker at tieto.com
Thu Sep 27 06:31:09 PDT 2012


On 27/09/12 12:45, renato fringuello wrote:
> I took some radios from yp.xml 2 days ago, but today someone (like
> http://streaming207.radionomy.com/AngeFM) answers to me :
> "The file you requested could not be found"
> what's the problem?
> They doesn't exist anymore? They are off now and they could be on later?

Yes, yp.xml is a snapshot of the streams that exist at the given time.
You should refresh your cached copy every now and then to be up to date. 
As said previously don't do this too often. I'd guess if your cached 
copy is older than e.g. 60min and the user does something that requires 
the list, it should be safe to download a fresh copy.


GENERAL WARNING (nothing personal):
As said before I'd like to avoid situations where we get some popular 
software where each client will download the list every 5 minutes.
To give everyone reading this list an idea what this could mean:
- 500 copies active at a given time
- Polling every 5min
- XML size (compressed): 500 kByte / uncompressed: 5 MByte
- resulting bandwidth usage (compressed): 7 Megabit/s; uncompressed: 70 
For just /one/ misbehaving software.

For comparison the current average bandwidth of the /whole/ dir.xiph.org 
server is 7Megabit/s (most of it due to uncompressed downloads)

Now consider a well behaved software:
- 100000 copies active at a given time, install base in the millions.
- Updates only when it really needs the list (e.g. the user opens the 
'Internet streams' dialogue)
- When it needs the list it doesn't update more often than every e.g. 60min
- Uses RFC2616 compliant compression
30 requests per hour, 400kbit/s effective bandwidth usage.
(Those numbers are actually educated guesses based on real usage 
statistics of dir.xiph.org)

Thanks for listening,


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