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View Full Version : 20Kb/sec bandwith used and it's not even playing anything?



jnolen
2005-12-13, 18:14
Hi Folks,

I just got two new SB3s and I set them up last night. They're working well overall, and are a noticable improvement over my SB1s.

However, I've noticed that anytime I have the SlimServer running, it appears to be pumping out about 20Kb/sec of SOMETHING, even tho both SB3s are stopped or powered-off (with the red "power" button, not actually unplugged).

I don't suppose it's really hurting anything, but I just want to know -- what the heck is it doing?

Thanks,
Jonathan

mrfantasy
2005-12-13, 18:43
Are you running a power off screensaver (say, the date and time?) That's gonna cause a bit of data. 20Kbps sounds like a lot but I have never really tested it.

jnolen
2005-12-13, 18:51
Looks like Date&Time was the culprit.

That seems crazy. I can't imagine what's using that much bandwith. You shouldn't need to check the time server more than once a minute or so.

Oh well, at least I have an answer. Thanks!

mrfantasy
2005-12-13, 19:20
Remember the Squeezebox is dependent on SlimServer for everything on the display. Time on the boxes changes once a second, and it thus has to transmit once a second. I'm guessing it has to transmit the entire display every second, not just the changed parts. 320x32=10240 bits/sec. 2 players makes 20Kbps.

Hey, there you go.

m1abrams
2005-12-13, 19:25
Remember the Squeezebox is dependent on SlimServer for everything on the display. Time on the boxes changes once a second, and it thus has to transmit once a second. I'm guessing it has to transmit the entire display every second, not just the changed parts. 320x32=10240 bits/sec. 2 players makes 20Kbps.

Hey, there you go.

This would be my guess as well. The sueezebox just displays whatever is sent to it. From what I can tell it does not have an internal clock, which is why it goes blank when it loses server contact.

seanadams
2005-12-13, 19:53
Who cares about 20Kb/s on a LAN?

MrC
2005-12-13, 20:06
I don't think that measurement is correct anyway. I have two units, and they are both running superdatetime. I'm only seeing 2-4k / second bandwidth.

jnolen
2005-12-13, 20:18
Who cares about 20Kb/s on a LAN?

Well, like I said: I didn't think it was hurting anything, I was just curious what it was doing. It's all cool with me.

Phil Karn
2005-12-13, 21:40
seanadams wrote:
> Who cares about 20Kb/s on a LAN?

Nobody, at least not on a LAN. But it can be a problem if your
Squeezebox and its server are separated by a shared wide area network.

The Squeezeboxnetwork server appears designed to minimize network
overhead, e.g., by updating the clock only every minute.

I once took my Squeezebox to work and had it tunnel back home over SSH.
It worked, but the overhead was rather high and I didn't want to put
that much continuous load on my DSL uplink. It seems better to just take
your music with you.

Phil

seanadams
2005-12-13, 23:24
seanadams wrote:
> Who cares about 20Kb/s on a LAN?

Nobody, at least not on a LAN. But it can be a problem if your
Squeezebox and its server are separated by a shared wide area network.

The Squeezeboxnetwork server appears designed to minimize network
overhead, e.g., by updating the clock only every minute.

I once took my Squeezebox to work and had it tunnel back home over SSH.
It worked, but the overhead was rather high and I didn't want to put
that much continuous load on my DSL uplink. It seems better to just take
your music with you.

Phil

Fair enough.

I think you can easily disable the seconds display though. (?)

eq72521
2005-12-14, 09:19
Fair enough.

I think you can easily disable the seconds display though. (?)

Yes, you can, but I'm not sure it makes a difference. When I first set up my SB1 early this year, I noticed (admittedly only by the blinking lights on the Ethernet switch, I did not measure) that there was network traffic with the SB turned off and displaying the basic Date/Time "screensaver". Thinking I'd save some bandwidth by only displaying down to the minutes (but knowing it really doesn't matter anyway, just being curious and a bit AR), I changed the screensaver thus. However, the switch lights continued to blink at the same rate. I don't have the server on now to check, but I think that I just changed it back to display seconds anyway. From this, I imagine that the Date/Time screensaver updates every second, paying no heed to whether the display has actually changed. I haven't perused the source though, so I could certainly be way off here.

Triode
2005-12-14, 12:24
SB2/SB3 will suppress sending the same screen data to the player. Hence there is only one display frame per minute if you turn off the seconds display. A display frame for SB2/3 is ~1290 bytes.

SB1 and Slimp3 will send a display frame once per second in date time mode. [this is because SB1 firmware requires an update every few seconds - SB2/3 uses tcp keepalives instead] So a graphic display SB1 generates most traffic in Date Time mode. Display frame for SB1-G is ~570 bytes.

20 kbps is nothing though - try my network test plugin (in 6.5) this uses display frames to generate far more traffic - up to 5Mbps..

eq72521
2005-12-15, 08:57
SB2/SB3 will suppress sending the same screen data to the player. Hence there is only one display frame per minute if you turn off the seconds display. A display frame for SB2/3 is ~1290 bytes.

SB1 and Slimp3 will send a display frame once per second in date time mode. [this is because SB1 firmware requires an update every few seconds - SB2/3 uses tcp keepalives instead] So a graphic display SB1 generates most traffic in Date Time mode. Display frame for SB1-G is ~570 bytes.

20 kbps is nothing though - try my network test plugin (in 6.5) this uses display frames to generate far more traffic - up to 5Mbps..

Ahh, that explains it then. Shortly after posting yesterday and thinking about it, I rather suspected something like this. Thanks.