Internet radio problem

[timr]

I am having a problem trying to receive internet radio.

My setup is 2Mb residential line with Zyxel wireless DSL modem/router.

If I try RTE or BBC it is unusable. Real Player shows anything from 60% to 95% packet loss. While I get the same variability in bandwidth that others report in this forum, I get this packet loss all the time on RTE or BBC – I can get download speeds of 190KB/s at the same time.

Neighbors using Eirocm get perfect audio quality.

If it try WFMU-FM 91.1/Jersey City, NJ; 90.1/Hudson Valley, NY – it is perfect.

So:

it is not a raw bandwidth problem – see download speeds,
it is not a server problem – see Eircom neighbours’ experience
It is probably (?) not something specific to audio streams - see WFMU-FM 91.1/Jersey City, NJ; 90.1/Hudson Valley, NY

BT TS are next to useless – all they do is blame my internal equipment whne they do bother to answer the phone.

Anyone get any suggestions? Similar experiences?

I would really love to be able to get radio on my machine.

Thanks

[Sean]

What it seems like is that BT is throttling the port real player uses. Both the RTE and BBC streams use real audio, where as the WFMU-FM radio uses MP3 audio by default. From my experience, an MP3 stream is also less sensitive to jitter and latency than real audio, especially when I use to listen to streams using a satellite based ISP. It is also possible that the real audio streams are using a UDP connection, which is more sensitive to packet loss than a TCP connection. As far as I'm aware of, MP3 only streams by TCP.

To start with, run a speed test here to see what packet loss and average jitter are reported for the VoIP test, as this VoIP test will give an idea of how well your connection handles UDP audio streaming. To give a comparison, both my home Digiweb and work Eircom DSL connections report a jitter of 1.7ms and packet loss of 0.0% when I last checked today.

[timr]

Thanks Sean,

my results are all over the shop - right now I can't even run the test - the VOIP test is not finishing. But this is a different issue I suspect.

I have seen results with < 1ms jitter and others of ~10ms. I'll try it again when it becomes usable and post results.

Cheers
Tim

[timr]

Hi

I just re-ran that speed test during the quiet of the day. The jitter reading was 0.7ms with 0% packet loss. RTE & BBC radio still sound like a tin can and real player reports ~70%packet loss.

I ran Wireshark and it looks like it is using UDP. I also see a number of:

"destination un-reachable, host administratively prohibited"

messages back to RealPlayer from RTE. I am not sure I understand this as the port that is being quoted is the sameport that is being used all of the time. Also the frequency of the unreachable messages is more liek 10% rather than 70%.

Tim

[timr]

on second thoughts and a somewhat more thorough examination the "destination unreachable" messages do look to be the cause - the frequency is much higher than I originally said - at least 50%

I also checked BBC and see the same pattern there.

[Sean]

After trying some further tests with real streams here, I did find that for some strange reason, if I block incoming TFTP taffic, this will prevent most real streams from playing at all here. While I know you are able to get an intermittent connection, one thing I do know is that the ZyXEL router BT provides is configured to block incoming TFTP connections by default.

Assuming you have not already tried changing your router's security settings, to remove this TFTP block, go into the the router web configuration, into "Security" within "Advanced Setup" and then remove the tick from the option "TFTP". When you apply this change, the router will re-establish the DSL connection, so it may take a minute or two before you are back. After this, give the RTE and BBC streams a try.

[timr]

Thanks Sean

I think I may have a different model modem/router - Mine is a P-660HW-D1. When I go to the security tab I ahve sub options of FIrewall & Content Filter. I see no protocol lists anywhere.

Tim