[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
Observed bandwidth doubled?
This is my first message to this list. I've tried searching for the
answer to my question in the archives, but I couldn't find it.
I run a Tor non-exit relay, named DigitalBrains. Bandwidth is shaped and
prioritized by Linux, with the HTB scheduler in the 2.6 kernel. The
maximum token rate is 750,000 bits/s. To be completely exact, the
iproute2 command that shapes my TOR traffic is:
# tc class add dev eth0 parent 1:1 classid 1:12 htb rate 80Kbit quantum
1600 ceil 750Kbit
It will borrow tokens when there is no higher-priority traffic. This is
the upstream traffic, i.e., away from the server. Downstream traffic is
Now, if I don't enter any shaping configuration in my torrc, the
observed bandwidth in the server descriptor happily doubles that rate:
-- from descriptor --
bandwidth 5242880 10485760 151973
-- end --
I've seen this more often than not. Checking the torstatus pages (f.e.
,), the actual rate in the graphs is limited to what the token
bucket dictates (obviously, I'd almost say).
Can anybody explain why the observed rate is so much higher than the
And more importantly: am I hurting the performance of the network when I
let this situation continue? Should I enter a MaxAdvertisedBandwidth of,
MaxAdvertisedBandWidth 91 KBytes
In that figure, I assumed that KBytes means kibibytes; it almost
corresponds to 750,000 bits/s.
For completeness' sake, the machine is a Debian Squeeze i686 running Tor
0.2.0.34-1. It's behind an ADSL connection. If you need more info, I'll
gladly supply it.
Thanks in advance,
PS: I accidentally pulled the power cord of the TOR machine today while
working on it, so the current stats might be a bit different from what
they usually are.