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How does an ISP load balance?

David_W
Rising Star
Posts: 2,291
Thanks: 29
Registered: 19-07-2007

How does an ISP load balance?

Silly question, but best place to ask is an ISP forum! Cheesy

Anyhow, I play FFXI, and this month they are due to release another content patch, oh the joy. A few hundred thousand people trying to download lots of files at the same time. The congestion on this is awful, it can take 2+ days just to be able to get the files downloaded, not including the hours spent waiting for you to actually be able to connect to the update server just to check for the updates.

So, if F9 had to serve say, 150 files, for a grand total of 30MB total size, to 500,000 people, where all 500,000 people first had to go through a check to see if they require the patch (every time you log into the game, it checks if you need update, so the update checker is always being hammered), and then download each of the files 1 at a time (dont ask why they dont make it one large file, probably cause of the PS2 owners in American and Japan), how would F9 do it, to make sure the servers were not trashed and people could download the patch files quickly, without it taking two days?
4 REPLIES
N/A

How does an ISP load balance?

There are a number of ways which this can be done.

The most popular way (I think anyway) is to use a dedicated box, or cluster of boxes which use layer 2-7 load balancing for virtual IP addresses. You add say, 500 addresses of servers onto the load balancer, which contain the files you need. These servers are spread across a network, and are attached to a SAN infrastucture, using block disk writes, so the data is transferred fast. You assign 1 virtual address to the load balancer, and depending on which server is available/has the best latency/less cpu usage/best network - you attach to the client to that server to get the files.

Some load balancers, like the F5 models, can use differnet protocols like http, ftp, ssh, ssl etc etc etc. Sans should be connected via hba fibre channel cards to get the best transfer rate.
N/A

How does an ISP load balance?

Steam (Valve) seem to be doing a good job of that sort of thing for now. It appears they have lots of servers of their own all over as well as many partnered companies (some of which only serve select users) all over the world.

http://www.steampowered.com/status/status.html
http://www.steampowered.com/status/content_servers.html

With nearly 2.5m unique user logons on average per month, regular automatic patches (few k to tens of megs), and whole games (just released Day of Defeat source) and utilities hundreds of megs in size available for download they do quite well imo - download speeds are usually 500kbits-1.5mbits, but can be higher/lower.

...90.3 million gaming hours on average per month... just think if that was put to good use!
N/A

How does an ISP load balance?

Gaming IS a good use... who told you otherwise :shock: :roll: :lol:
David_W
Rising Star
Posts: 2,291
Thanks: 29
Registered: 19-07-2007

How does an ISP load balance?

From looking at steam (I got half life 2 btw, game rocks Cheesy) it appears to use a decentralised system where the capacity is spready by nation and through multiple download servers within the nations, so capacity is a bit different.

FFXI has one server in one location (Japan), by one server I mean 1 IP address with the many world servers and patch servers behind it. Everyone from EU/NA/JP all goes via the one IP address, so its this which is the bone of contention I think.

Its like our lovely ADSL, at 50:1 contention if everyone were to cap it, the system would collapse, so I'm guessing FFXI has its own contention ratio, after all they dont expect people in the EU to be on prime time JP and vice versa, but when patch day comes, the silly Yanks stay up till 5am just to download the patches which messes up the staggered contended ratio.