4 ms·

Here's Van Jacobson's 1988 paper on slow start and other congestion avoidance algorithms. It's really worth reading to understand what was happening: https://cs

Here's Van Jacobson's 1988 paper on slow start and other congestion avoidance algorithms. It's really worth reading to understand what was happening: https://cs162.eecs.berkeley.edu/static/readings/jacobson-congestion.pdf https://cs162.eecs.berkeley.edu/static/readings/jacobson-con... It's personally fascinating to me because in about 1984/5 I was working on a local area network and with a friend 'invented' a connection-oriented protocol that used counters to spot dropped packets (because of Ethernet collisions) and request retransmission. We successfully overloaded the network of about 16 machines using this algorithm as it went crazy retransmitting and upping the collision rate and we began worked on very similar algorithms to fix this (but didn't get that far because had A levels to do).

mhandley 9y ago
I bet anyone who has worked on congesion control has war stories to tell. With me, it was when we were working on TFRC around 2001: https://tools.ietf.org/html/rfc3448 https://tools.ietf.org/html/rfc3448 We were testing tweaks to the algorithm, sending traffic from a university in Germany (where my colleague came from) to our lab in Berkeley. We knew something had gone wrong when we could no longer access the Internet from our lab over the 10Mb/s microwave link due to 90% packet loss. The problem was how to shut down the sender in Germany, and it was 4am there. Even bypassing our microwave problems, we could see that there was also 90% packet loss on the 100Mb/s link out of the university in Germany - the sender was clearly sending around a gigabit - so we couldn't just ssh in. It took us quite a while to find the number of an old-hashioned dial-up modem inside the university and dial in from Berkeley to shut the sender down. Turns out my colleague had inverted the rate function in the code, and when loss increased, it sent faster.
tptacek 9y ago
I've always wondered how much of this stuff really comes from Raj Jain and CUTE, which I think predates it and has the many of the same ideas in it.
- jgrahamc 9y ago
  I know that myself and Petr were working totally in isolation just trying stuff out. We did what we could but it sure would have been helpful to have some clues :-)

mhandley 9y ago

I bet anyone who has worked on congesion control has war stories to tell. With me, it was when we were working on TFRC around 2001: https://tools.ietf.org/html/rfc3448 https://tools.ietf.org/html/rfc3448 We were testing tweaks to the algorithm, sending traffic from a university in Germany (where my colleague came from) to our lab in Berkeley. We knew something had gone wrong when we could no longer access the Internet from our lab over the 10Mb/s microwave link due to 90% packet loss. The problem was how to shut down the sender in Germany, and it was 4am there. Even bypassing our microwave problems, we could see that there was also 90% packet loss on the 100Mb/s link out of the university in Germany - the sender was clearly sending around a gigabit - so we couldn't just ssh in. It took us quite a while to find the number of an old-hashioned dial-up modem inside the university and dial in from Berkeley to shut the sender down. Turns out my colleague had inverted the rate function in the code, and when loss increased, it sent faster.

tptacek 9y ago

I've always wondered how much of this stuff really comes from Raj Jain and CUTE, which I think predates it and has the many of the same ideas in it.

jgrahamc 9y ago
I know that myself and Petr were working totally in isolation just trying stuff out. We did what we could but it sure would have been helpful to have some clues :-)