4 ms·

Is it really faster to do a whole FIN / ACK / FIN / ACK / SYN / SYNACK / ACK every N bytes? How much does this sort of traffic shaping typically throttle, and h

Is it really faster to do a whole FIN / ACK / FIN / ACK / SYN / SYNACK / ACK every N bytes? How much does this sort of traffic shaping typically throttle, and how long does it typically give a connection? Can this be easily parallelized? I'll bet it could.

ch4ch4 10y ago
Comcast had a feature called "Powerboost" (http://www.dslreports.com/faq/14520 http://www.dslreports.com/faq/14520) that would let you burst up 100mbit or something for the first 20MB of a file. I'm not sure if this is still being offered, but I bet it would be awesome with Hellcat.
- wmf 10y ago
  Because Powerboost and similar systems are per-customer instead of per-TCP-connection, Hellcat cannot bypass them.
- dylz 10y ago
  I think that might be a bit outdated since it refers to DOCSIS1, and I haven't ever received a package offer from Comcast before below 200Mbps or so
  - waspleg 10y ago
    In my area, I have the highest tier of Comcast service (residential) at 75 mbps.
mjevans 10y ago
If N is large enough, maybe. However this assumes that the state of the traffic shaping system is per connection. If it's per site<>client or just client<>net over a duration then this wouldn't help. Reminds me a lot of hierarchical token bucket filters and letting clients burst over their normal allocation as long as there was spare bandwidth (then squeezing them when others woke up and wanted to use bandwidth as well).
lelandbatey 10y ago
This exact tool is one I've wanted for a while, since I've had the exact scenario of trying to download a file only for the download to slow by 10x after several seconds. In such scenarios, I'm able to download the file 10x faster by manually restarting with --continue every time the speed drops.
minaguib 10y ago
Not only is the handshake expensive, but TCP has something called "slow start" which effectively artificially limits the rate of data in the beginning of the connection till the network capacity is discovered. An ideal N would be high enough where the cost of the TCP handshake and slow-start are minimal, but small enough not to trip the traffic shaper to downgrade the connection from the fast flow to the slower one.
- jakobegger 10y ago
  Is slow start really still in use? I'm not too familiar with congestion control algorithms, but I thought that TCP stacks have moved beyond that...
cheerioty 10y ago
You can make up for that with parallizing

ch4ch4 10y ago

Comcast had a feature called "Powerboost" (http://www.dslreports.com/faq/14520 http://www.dslreports.com/faq/14520) that would let you burst up 100mbit or something for the first 20MB of a file. I'm not sure if this is still being offered, but I bet it would be awesome with Hellcat.

wmf 10y ago
Because Powerboost and similar systems are per-customer instead of per-TCP-connection, Hellcat cannot bypass them.
dylz 10y ago
I think that might be a bit outdated since it refers to DOCSIS1, and I haven't ever received a package offer from Comcast before below 200Mbps or so
- waspleg 10y ago
  In my area, I have the highest tier of Comcast service (residential) at 75 mbps.

mjevans 10y ago

If N is large enough, maybe. However this assumes that the state of the traffic shaping system is per connection. If it's per site<>client or just client<>net over a duration then this wouldn't help. Reminds me a lot of hierarchical token bucket filters and letting clients burst over their normal allocation as long as there was spare bandwidth (then squeezing them when others woke up and wanted to use bandwidth as well).

lelandbatey 10y ago

This exact tool is one I've wanted for a while, since I've had the exact scenario of trying to download a file only for the download to slow by 10x after several seconds. In such scenarios, I'm able to download the file 10x faster by manually restarting with --continue every time the speed drops.

minaguib 10y ago

Not only is the handshake expensive, but TCP has something called "slow start" which effectively artificially limits the rate of data in the beginning of the connection till the network capacity is discovered. An ideal N would be high enough where the cost of the TCP handshake and slow-start are minimal, but small enough not to trip the traffic shaper to downgrade the connection from the fast flow to the slower one.

jakobegger 10y ago
Is slow start really still in use? I'm not too familiar with congestion control algorithms, but I thought that TCP stacks have moved beyond that...

cheerioty 10y ago

You can make up for that with parallizing