What sustained speed does SL usually download at for you?

I'm just curious to find out what sort of sustained download rates fellow Residents of Second Life are getting when they're inworld.

A good way to test is to go into a very dense area like a mall packed with textures or a busy club with many other avatars around, and quickly hit Ctrl-Shift-1 to bring up the STATISTICS BAR on the righthand side of your screen and have a look. It's easy to read, just look what it says to Bandwidth and sum that out over time using the expanded red readout (click on the Bandwidth section and it should change).

For me, I sometimes peak at 900 kbps, but this quickly drops and the average sustained rate is more like 600 kbps. I've talked to several Residents with superfast connections and good pingtimes and they report similar sustained rates in the 550 kbps-650 kbps range, far below their maximum throughput.

This was done in Da Boom, just under the Edge. What happened was I fell under the big pyramid and then flew up, bumping the floor and so a lot of things came into my field of view and started loading. Typical scenario, nothing esoteric here. This picture has been contrasted but not retouched otherwise. Typical display. Note how most of the dots are indeed in the 550-650 level, apart from a couple anomalies on the far edges.



On a side note.... I wonder why this is? If we can set Network prefs Maximum Bandwidth to 1000 kbps, why does it do this? Is it due to overhead or a hard limit set or something else?

This isn't meant to be scientific, but rather, anecdotal retelling of individual experiences. Thanxies!

Anyone who'd like to express their findings on this?

Most graciously appreciated... thanxies.

I have managed to peak much higher, just tried it in preview and got upto about 1050kbps, but then it soon falls down to about 600-700kbps even though im still waiting for objects and textures to rez, once the objects are rezzed now its at 300-500, still waiting for some textures to load and it seems to be hovering there, still waiting for textures to load, textures never finished loading

This is not a good subject for me Im on a 3.5 meg line.. and i pay over 120 usd a month and the shit doesnt work half the time.. But mine sticks around like 300. I guess thats relative?

Yea i think 300 seems about normal activity range, peaking when rezzing, if you watch the debug options you'll see that behind the scenes that the sim is throttling back your connection, im not exactly sure why its doing that, if you've set your speed it should just be happy with that, it never throttles up above that limit. and yes i have a faster line speed than the bandwidth limit, which can be annoying especially as i have a higher ping which can slow things down if something has to keep requesting and acknowledging

One explanation for the observed phenomena is that SL is continually expanding and contracting the transmitted bandwitdth to you behind the scenes. You can find when and how it is doing this by looking for lines like:

2005-10-17T23:35:17Z INFO Sending throttle settings, total BW 120000
2005-10-17T23:31:49Z INFO Sending throttle settings, total BW 140000
2005-10-17T23:35:16Z INFO Sending throttle settings, total BW 180000
2005-10-17T23:31:48Z INFO Sending throttle settings, total BW 210000
2005-10-17T23:35:15Z INFO Sending throttle settings, total BW 240000
2005-10-17T23:31:37Z INFO Sending throttle settings, total BW 280000
2005-10-17T23:35:13Z INFO Sending throttle settings, total BW 300000
2005-10-17T23:31:36Z INFO Sending throttle settings, total BW 350000
2005-10-17T23:35:10Z INFO Sending throttle settings, total BW 360000
2005-10-17T23:31:35Z INFO Sending throttle settings, total BW 420000
2005-10-17T23:35:08Z INFO Sending throttle settings, total BW 480000
2005-10-17T23:31:34Z INFO Sending throttle settings, total BW 490000
2005-10-17T23:35:05Z INFO Sending throttle settings, total BW 540000
2005-10-17T23:31:33Z INFO Sending throttle settings, total BW 560000
2005-10-17T23:34:39Z INFO Sending throttle settings, total BW 600000
2005-10-17T23:31:32Z INFO Sending throttle settings, total BW 630000
2005-10-17T23:31:24Z INFO Sending throttle settings, total BW 700000

which were excerpted from one SecondLife.log file containing 270 such messages. The window is also opened like so:

2005-10-17T23:31:47Z INFO Easing network throttle to 280000

So the bandwidth you set under Preferences->Network sets an upper bound on how much SL will try to send you, but SL will reduce that as it sees fit to - in this case to 17% of the upper bound. As the throttling tends to happen after warning messages of lost or out of sequence packets, I suspect it tightens the window in response to loss.

Or, for the truly geeky, SL seems to be implmenting a proprietary variant of TCP rate control on top of the UDP substrate. This has the advantage of allowing datagram speed service without the TCP reliable session constraints. The disadvantage is that TCP's flow control is not simple and if done poorly can exhibit wild hysteresis.

Huggbees!

When I goto a very high prim/texture area, I usually get between 600-1200KPBS It seems to hover around the 800-950 range the most, but I have seen higher averages.

I have a 4 meg pipe but my results are similar. Keep in mind most all website DLs are rarely above 300kbps for any sustained amount of time, the fact SL can manage 600 is a feat in itself.

Thanxies for sharing your experiences... I have a better idea of what I might expect now.

Mal, nice tech analysis.

Please forgive me for having posted analysis that may have indicated that there was router congestion at Linden Lab's Data Center. I was clearly mistaken as was indicated in a recent Hotline to Linden response:I offer my humble apologies for suggesting that there could be a fault at Linden Lab rather than at the globally dispersed ISPs dozens of players. I withdraw my hypothesis as it was clearly refuted and I shall not assert such again in the future.