Parts of the internet keep on disappearing on me

[Shachar Shemesh]

On 01/24/2013 02:44 PM, E.S. Rosenberg wrote:
>
>
> When you enable timestamps they don't match so the packet is discarded, this could be due to the ISP fiddling with the packets on the way.
I know what timestamp is, and what it is used for. I have not, yet,
rebooted to see whether this does not happen when the problem is
dormant. What I told Shimi was that I want as much information as
possible, and since he seems to know a bit about it, I would like to
hear it all.

It is not enough to say "the ISP is fiddling with the packets". I want
to know fiddling how. Changing the timestamp might be done by some
brain-dead QoS in order to fool the TCP congestion mechanism. In my
case, the timestamp moved backward by 2948. This might be done by a
traffic shaping mechanism in order to make the RTT seem longer, and thus
give them more time to do other manipulations of the traffic.

One example is, if they want to slow down the connection, they need to
make the rount trip time seem longer. Otherwise, my TCP/IP stack might
assume that the packet was lost, and perform a retransmit. If you bear
in mind that they are after reducing my bandwidth usage, you will see
how that is bad for them.

So, as you can see, there are valid reasons to find out not just what is
happening, but also why, before I call and yell at them.

Shachar

-- 
Shachar Shemesh

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.cs.huji.ac.il/pipermail/linux-il/attachments/20130124/26676d26/attachment-0001.html>