Wireless
Motivation
The UW wireless network has a couple of major deficiencies:
- Weak signal in MC 3036, preventing some laptops from connecting
- Aggressive throttling of bandwith, even to wired systems within the club office
The second point is quite important: UW's wireless will begin to throttle high bandwith connections after a minute or two, decreasing bandwith slowly from 1MB/s or more down to 100KB/s or less. Members can expect to sit in the office for an hour or more if they want to download many packages off of the CSC mirror.
To work around this problem we have an access point in the Computer Science Club.
Configuration
- ESSID: csc-wireless
- AP: 00:0B:86:3E:54:F0
- Network: auth3net (129.96.192.0/23)
Clients must authenticate to the Network Authentication Applicance (NAA) as with uw-wireless, in accordance with this IST policy, points #2 through #4.
Technical Overview
The AP connects to acesulfame-potassium through a secondary NIC. On acesulfame-potassium, the following decision is made:
- IP packets destined for mathstudentorgsnet are brouted with SNAT to wireless-nat.csclub.uwaterloo.ca
- All other ethernet frames are bridged to auth3net
The network is identical to connection through uw-wireless in all respects, except for the special treatment of mathstudentorgs traffic. This special treatment bypasses uw-wireless throttling for machines on our network.
Wireless Performance
Tests were done on a 700MB Ubuntu ISO at an off peak time.
- uw-wireless
- Initial speed: 1.3MB/s
- Final speed: 40KB/s
- Time: aborted after 27 minutes (got bored) with 67% remaining, ETA increased steadily throughout
mike@freyr:/tmp$ time wget http://mirror.csclub.uwaterloo.ca/ubuntu-releases/7.10/ubuntu-7.10-desktop-i386.iso --23:54:09-- http://mirror.csclub.uwaterloo.ca/ubuntu-releases/7.10/ubuntu-7.10-desktop-i386.iso Resolving mirror.csclub.uwaterloo.ca... 129.97.134.71 Connecting to mirror.csclub.uwaterloo.ca|129.97.134.71|:80... connected. HTTP request sent, awaiting response... 302 Found Location: http://citric-acid.csclub.uwaterloo.ca/iso/ubuntu-gutsy/ubuntu-7.10-desktop-i386.iso [following] --23:54:09-- http://citric-acid.csclub.uwaterloo.ca/iso/ubuntu-gutsy/ubuntu-7.10-desktop-i386.iso Resolving citric-acid.csclub.uwaterloo.ca... 129.97.134.37 Connecting to citric-acid.csclub.uwaterloo.ca|129.97.134.37|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 729608192 (696M) [application/x-iso9660-image] Saving to: `ubuntu-7.10-desktop-i386.iso' 11% [===> ] 86,583,824 377K/s eta 13m 34ss 33% [========================> ] 241,791,104 39.5K/s eta 55m 48s real 27m40.165s user 0m1.008s sys 0m4.252s
- csc-wireless
- Initial speed: 1.83MB/s
- Final speed: 1.93MB/s
- Time: aborted after 6 minutes (ran out of disk) with 10% remaining, steady progress
--00:27:07-- http://mirror.csclub.uwaterloo.ca/ubuntu-releases/7.10/ubuntu-7.10-desktop-i386.iso Resolving mirror.csclub.uwaterloo.ca... 129.97.134.71 Connecting to mirror.csclub.uwaterloo.ca|129.97.134.71|:80... connected. HTTP request sent, awaiting response... 302 Found Location: http://citric-acid.csclub.uwaterloo.ca/iso/ubuntu-gutsy/ubuntu-7.10-desktop-i386.iso [following] --00:27:07-- http://citric-acid.csclub.uwaterloo.ca/iso/ubuntu-gutsy/ubuntu-7.10-desktop-i386.iso Resolving citric-acid.csclub.uwaterloo.ca... 129.97.134.37 Connecting to citric-acid.csclub.uwaterloo.ca|129.97.134.37|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 729608192 (696M) [application/x-iso9660-image] Saving to: `ubuntu-7.10-desktop-i386.iso' 1% [> ] 14,380,544 1.83M/s eta 6m 29s 33% [========================> ] 243,488,896 1.92M/s eta 4m 46s 65% [=================================================> ] 475,945,024 1.90M/s eta 2m 21s 91% [=====================================================================> ] 670,317,304 1.93M/s in 6m 5s Cannot write to `ubuntu-7.10-desktop-i386.iso' (No space left on device). real 6m4.935s user 0m2.124s sys 0m11.161s
While these are quite unscientific, they do demonstrate the huge performance advantage of csc-wireless. I will repeat them without aborting, when I have time.