Hacking at Random
Hacking happens

Roger Dingledine
Day Friday - 2009-08-14
Room The Birthday Tent
Start time 21:00
Duration 01:00
ID 33
Event type Lecture
Language used for presentation English

Why Tor is slow

and what we're doing about it

Many of you have probably tried Tor, and then stopped because you found it too slow. Now that Tor has several hundred thousand users, our original design decisions are showing their age. We need to figure out and deploy some major changes if we want the Tor network to scale up to the million-user mark.

Problem #1 is that Tor's congestion control does not work well. We need to come up with ways to let "quiet" streams like web browsing co-exist better with "loud" streams like bulk transfer. Problem #2 is that some Tor users simply put too much traffic onto the network relative to the amount they contribute, so we need to work on ways to limit the effects of those users and/or provide priority to the other users. Problem #3 is that the Tor network simply doesn't have enough capacity to handle all the users that want privacy on the Internet. We need to develop strategies for increasing the overall community of relays, and consider introducing incentives to make the network more self-sustaining.

In this talk I'll walk through these problems and more: why we think these are the right problems to solve, and how we're solving them.