Maximum Bandwidth? Custom Port Connection?

Hello friends.

With no presumption I know it all, I make SL Video Tutorials desirous to ensure no mis-information is publicized. That said, I dare to ask two questions, answers to which (in definitive terms) are elusive.

l. MAXIMUM BANDWIDTH

The Preference slider allows from 50 to 1500 kbps with (I believe), a default value of 300.

Here's what I know:

- I know the difference between a kilobit (kb) and a kilobyte (kB).
- I know my download speed is ~6700 kbps
- I know my upload speed is ~700 kbps
- I know these values have been tested at various servers across the US.
- I know it is recommended one adjust the slider to slightly less than known bandwidth.
- I know it is recommended to reduce bandwidth if packet loss becomes problematic.
- I know I am unskilled in matters of networking.

Here's what I wonder:

The range suggests we are dealing with upload (not download) speeds, although that doesn't make sense to me altogether.

Can someone please comment on this?

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2. CUSTOM PORT CONNECTION

Here's what I know:

- Separate instances of SL sharing the same IP address may benefit from forcing an alternate port.
- Those behind an NAT (Network address Translation) router may require a port change
- Those with various firewall configurations may require a port change.
- This is a UDP (User Datagram Protocol) and not a TCP connection.

Here's what I wonder:

Is this for upload only. or will the port change also re-route download data?

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Please forgive my ignorance, with TIA for the valued and appreciated commentary.

--
Amras

It is not often that a question stumps the forum group mind. I can only surmise that yours is too technical for most of us (including me).

I. No, I think download is the key thing here. You have very good bandwidth compared to many if not most of us. Lucky you. If you can crank it all the way up without packet loss, then you should go for it.

There is a less frequently mentioned upload adjustment, too. Seems like you might increase that, too, to 128.

I suppose you might be fast enough to out pace your computer.

As an aside, I think LL should mandate that all LL staff connect at speeds that are slower than the average of the customer base.

II. First, not all of SL is UDP based. There is TCP as well, and I think they are trying to move away from UDP as time goes by.

My understanding is that the port number deal is for outgoing only. The reply will go to wherever the request came from.

regarding your first question, it's download rate, I believe. Keep in mind, not everyone has a cable connection with 6+ megs down. And when SL was first developing, that was a lot rarer than it is today.

@ Lee: Thank you sir/madam. It was amusing to have zero replies and I thank you for diving in. Although my connectivity is good, some have much better. Mine is a business connection, at least. And yes, I can go full bore (1500) without but occasional packet loss which I attribute to network issues.

Regarding UDP, it's my understanding that the "Custom Port Connection" option is indeed a UDP player and not TCP. A list of ports SL uses is published to help seeing which are UDP and which are TCP. Here it is:

"Second Life needs to connect to ports 443/TCP, 12035/UDP, 12036/UDP, 12043/TCP, and 13000-13050/UDP. You should configure your firewall to allow outbound traffic on those ports, and related inbound traffic. "

NOTE: It is the 13000-13050 port that's adjustable in Preferences.

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@Retsuki: I agree with your comment and count my connectivity blessings although I pay more than USD$100/mo to connect at those somewhat comparitively lackluster speeds.

For the record, I use http://speedtest.net for measurements.

#1 - Maximum Bandwidth

It's download speed.

If the max upload speed that your ISP provides you is 700kps, setting the max bandwidth on the SL client to 1500kbs won't and can't increase the max upload bandwidth that your ISP provides to you. They're the ones capping your upload speed.

Good point Rooke, and absolutely correct.

Throttling upload speeds is the tool an ISP uses to prevent "John Q home user" from operating a halfway decent (read p2p) server.

I'll throw this out there also ... something I did to speed up my client.

First, my client computer has a static IP address on the network. In the router, I have the option to assign priority network traffic to specific IP addresses, so I have the client computer max priority. That means when competing for bandwidth, the SL client PC takes priority on traffic. I also configured the router to give priority for specific ports ... yup, the ones that SL uses. Then I set the SL client to use a specific port, and again in the router listed that as a priority traffic port.

My gameplay was significantly improved.