[ender2002]

I am using bittorrent with a computer that has airport. The web-speed is fine, so is mail and everything else. The only problem is that compared to using the ethernet directly connected to computer, the speed through airport is a huge fraction. I have download speeds of 1 kb/s compared to 130 kb/s. I have the ports open and I have heard that you need to "direct" or mirror the correct address to the airport bs(?). I have no clue what the exact problem is. Any help?

[car1son]

I played with BitTorrent a little. A clever technology for distributing the load of large downloads off of a single server. However, I was surprised that it still worked pretty well when I was connected through Airport or a Router without special config (below).

You may need to set up port forwarding in the Airport to get better thruput. This will let other BT users on the net to connect to your Mac (without getting blocked out by the Airport's NAT.)

To set that up, you need to:

Use your System Preferences / Network to change the Airport config for TCP/IP from "DHCP" to "Manually", and assigning your Mac a static IP address (e.g. 10.0.1.201). You'll aslo need to assign a subnet mask (255.255.255.0 should work), the Router's IP = the Airport's LAN-side IP address (probably 10.0.1.1 - check it on the "Select Base Station" window), and manually enter your ISP's DNS server(s) IP addresses. (You might want to designate this as a different Location, and make sure it still connects to the net after applying that change, so it's easy to go back to your original settings.)

Then use Airport Admin Utility, Port Mapping tab, to forward all the BT port addresses (the same you have open in the firewall) to your 10.0.1.201 IP address. The airport will need a restart to apply, then make sure browser still works.

That should allow external BT users to connect to you, as well as you connect to them.

[ender2002]

Do i just invent an IP #?

Also, in the port mapping tab, i have to add the ports to forward. It says public and private ports, and has the ip number in the middle of them. I know i have to have ports 6881 to 6889 open in order to have BT working. Do i put in 9 different entries?

example:

public port: 6881
ip: 10.0.1.201
private port: 6881

this is what i am putting in that "add" dialog box that slides down. However, I think i am competely wrong. Is this right?

[car1son]

You can't quite make up "any" IP number - it needs to be one on your subnet. The Airport is usually set up with DHCP so it allocates dynamic IP addresses to its clients. It typically uses 10.0.1.1 for itself (thus, the value to manually configure as the Router in your Network System Preference) and then assigns the first client 10.0.1.2, the next 10.0.1.3, etc, in a range to 10.0.1.200. The value 10.0.1.201 is intended to avoid conflicts with any dynamically-allocated IP addresses (it should be unique on your LAN, so if you assign a static IP address to a second wireless client, pick a different number, such as 10.0.1.202.) (The "subnet mask" of 255.255.255.0 is consistent with this IP assignment scheme - i.e., the first 3 fields are the same for all systems on the LAN.)

If you join someone else's wireless network, you may need to switch the config back to DHCP or assign your Mac a different IP address to avoid conflict with that wireless LAN's assignments. Using a different Location for that LAN configuration can make the switch-over painless.

Other routers use different subnet numbering. E.g., the LinkSys models I've seen use 192.168.1.nnn, so if you had a LinkSys wireless router you'd want to fit into that assignment scheme. (The easiest thing to do is connect once with DHCP and observe the assigned IP, mask, and router values in the Network preference pane; then manually assign something compatible. Or you could look in the router's manual.)

Yes, if BT uses 9 ports, then you need to give 9 Airport Port Map entries, one for each port, as in your example. (Some routers can be configured to map a range of ports, but Airport doesn't.)

[ghporter]

Originally posted by ender2002:
I am using bittorrent with a computer that has airport. The web-speed is fine, so is mail and everything else. The only problem is that compared to using the ethernet directly connected to computer, the speed through airport is a huge fraction. I have download speeds of 1 kb/s compared to 130 kb/s. I have the ports open and I have heard that you need to "direct" or mirror the correct address to the airport bs(?). I have no clue what the exact problem is. Any help?

You have to keep in mind that any 802.11b networking, AirPort Included, will max out at 11Mbps, while your ethernet goes up to at least 100Mbps (1000Mbps if you have a gigabyte card).

So, yes, with a wireless connection you will get at most 10% of the gross throughput of a wired connection. If you have AirPort Extreme, you max out at 54Mbps, which is about half of your 100BaseT ethernet connection.

These are theoretical maximums! Your actual performance will be significantly lower! There is more overhead on a wireless connection because the system is managing more different variables, and if you don't have sufficient signal strength or quality, your throughput will fall as well.

Comparing gross bit throughput of wireless and wired connections is like comparing oranges and kumquats; they are both citrus fruits (network connections), but you get different qualities out of them (mobility versus speed-or eating the flesh versus eating the skin).

[car1son]

My actual performance is considerably lower: Bittorrent or not, I've found that with my DSL connection, Airport (snow, 802.11b), TiBook500 and OS X 10.2.6, it tastes the same whether I eat the flesh or the skin. NetStat shows me topping out at a little over 100 KB/s on wireless Airport or wired directly to the DSL "modem". That's with FTP, large eMail, newsreaders, Bittorrent, etc. (Since my CPU doesn't max out there, I assume that's a throttle in my DSL speed.)

BitTorrent does a distributed download: you simultaneously download parts a single file from multiple "peers" while simultaneously providing uploads of other parts of the file you have already received to the same or other peers. Peers reward you for data you send them with more data sent to you - so it's to your advantage to facilitate uploads as well as downloads by letting peers connect to you as well as connecting to them. Thus, the BitTorrent readMe suggests to increase thruput by opening the firewall/NAT to let them connect.

[ghporter]

Originally posted by car1son:
My actual performance is considerably lower: Bittorrent or not, I've found that with my DSL connection, Airport (snow, 802.11b), TiBook500 and OS X 10.2.6, it tastes the same whether I eat the flesh or the skin. NetStat shows me topping out at a little over 100 KB/s on wireless Airport or wired directly to the DSL "modem". That's with FTP, large eMail, newsreaders, Bittorrent, etc. (Since my CPU doesn't max out there, I assume that's a throttle in my DSL speed.)

That sounds awfully slow for DSL--Oh! My numbers were in kilobits, and you used a "B" meaning kilobytes! Ok. That works a little better! Not great, but better. Depending on who your DSL provider is and the condition of your lines, you may be capped or you may be getting the best you can from your connection.

Yes, this does have something to do with BitTorrent! With a saturated connection, you can't provide many connections, and/or all of the multiple connections you're running will be very slow. So if your connection is only getting you about 800kbps (note the "b" meaning bits), and you have four concurrent, two way connections, each up or down link will have about 100kbps max. That's of course an average, and your upload may be significantly slower than that. But consider also that if your upload seems slow, BitTorrent may actually consider you to have a very slow overall connection, and not feed you download data as fast (or from as fast a server) as it might otherwise.

Also, since your DSL maxes out at less than 10BaseT's maximum rate, you're probably not going to see much more of a difference from your ethernet connection than maybe a bit of latentcy with your wireless connection.

[voodoo]

I managed to get BitTorrent to work with my Airport Extreme basestation and my SMC Barricade ADSL modem/router.

My setup is like this:

Teh Intarweb
-->SMC Barricade ADSL modem/router
---->AirPort Extreme Station
------>My Mac

Both the Modem/router and AirPort Base Station have built in firewalls. That sucks when you don't want them eh?

Step no1 is to turn off the IP distribution of the AirPort Base Station. It is done by choosing the proper radio button in the AirPort Admin Utility setup where you choose what kind of DHCP and NAT you want to use. Bottom line: I don't want to use any of that since I don't need it and it is redundant because there is a firewall in the modem. When you turn this off the AirPort becomes a straight wireless bridge between the modem and your Mac.

Step no 2 is to set the port forwarding on the modem. That is very simple on the Barricade, you just enter the advanced setup on the web interface and choose the Virtual Server options. There you enter the ports you want open (ports between 6881 and 6889) and the IP address that your Mac is set up with.

Your Mac has to be allocated the IP number that was set to use those ports in the Barricade setup. Then all is well

[badtz]

Originally posted by car1son:
(Some routers can be configured to map a range of ports, but Airport doesn't.)

is there a reason why airport doesn't do this?

I've always wondered why this hasn't been implemented

[Ice33]

Did anyone else notice that since the last Apple security update the download speeds on an airport to bittorrent have dropped? I was able in the past to get up to speeds of 150Kb/sec but since that last update I have dropped to no more than 20K. All I know is that this has effected my download speeds but not uploads which still top off around 50kb/sec.

I do not have an ABS but rather a 2wire DSL modem/base station which I did not have to previously do any port forwarding to. So I am at a loss as to how to use the web base configure screen to get this accomplished.

[iPond317]

Just did what was recommended above by turning on the port mapping and setting a static IP and WOW! Just freakin' wow! I went from averaging 20-50 KiB/s to a staggering ~130 KiB/s... Thanks for the tip!

[Zim]

Originally posted by GHPorter:
You have to keep in mind that any 802.11b networking, AirPort Included, will max out at 11Mbps, while your ethernet goes up to at least 100Mbps (1000Mbps if you have a gigabyte card).

Uh, yeah, but he's only trying to get 130kB/s... or ~1.3 Mbps. 11 Mbps should be plenty, and even the 10% of that should be almost as good.

I'd suspect that what's going on is that the Airport is firewalling the other users from his machine.. since they can't get from him, they won't give to him. So its not that his throughput is bad, its just that he now has MUCH less to be downloading.

I dunno what ports BT uses, but he should enable port-forwarding.

Mike

[ghporter]

Originally posted by Zim:
Uh, yeah, but he's only trying to get 130kB/s... or ~1.3 Mbps. 11 Mbps should be plenty, and even the 10% of that should be almost as good.

I think the problem is that BitTorrent really likes to establish a bazillion concurrent connections, and that stresses (sometimes saturates) wireless network hardware. Even with a ton of connections running, there's only so much computer power to find, move and confirm the data going through the connection, and that is the real limiting factor.

I believe BitTorrent has settings for how many concurrent connections it will establish, but I don't know anything about configuring it.