dd-wrt router firmware QoS troubleshooting

Posted by Jeff Atwood on Super User See other posts from Super User or by Jeff Atwood
Published on 2010-10-03T16:49:35Z Indexed on 2012/09/06 15:41 UTC
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I've been using the dd-wrt firmware on my router and I like it a lot!

But -- I'm not sure the quality of service (QoS) is working on it. I have it set up as follows:

  • http, port 80 -- Premium
  • bittorrent, port 6969 -- Bulk
  • https, port 443 -- Premium
  • dns, port 53 -- Premium

Per the QoS documentation, these levels are:

bandwidth is allocated based on the following percentages of uplink and downlink values for each class:

  • Exempt: 100mbps - ignores global limits.
  • Premium: 75% - 100%
  • Express: 15% - 100%
  • Standard: 10% - 100%
  • Bulk: 1.5% - 100%

This doesn't entirely seem to work, though -- with busy torrents going I get major pauses in my web browsing which sucks!

The QoS documentation gives some steps to check the QoS ...

What you'll be interested to look at will be the first set of source and destination IP, including the port numbers. Next the presence of l7proto and the "mark" field. The entries indicate the current live connection QoS priority applied on them based on the "mark" field. The "mark" values correspond to the following

  • Exempt: 100
  • Premium: 10
  • Express: 20
  • Standard: 30
  • Bulk: 40
  • (no QoS matched): 0

You may see "mark=0" for some l7proto service even though they are in configured in the list of QoS rules. This may mean that the layer 7 pattern matching system didn't match a new or changed header for that protocol. Custom service on port matches will usually take care of these.

On port 6969 (bittorrent) I see a weird mixture of stuff with mark=0 and mark=40 like so

cat /proc/net/ip_conntrack

udp  17 105 src=98.162.182.42 dst=1.2.3.4 sport=64512 dport=6969 packets=3 bytes=290 src=10.0.0.2 dst=98.162.182.42 sport=6969 dport=64512 packets=4 bytes=202 [ASSURED] mark=0 secmark=0 use=1
tcp  6 117 TIME_WAIT src=98.248.173.174 dst=1.2.3.4 sport=51114 dport=6969 packets=12 bytes=704 src=10.0.0.2 dst=98.248.173.174 sport=6969 dport=51114 packets=10 bytes=440 [ASSURED] mark=40 secmark=0 use=1
tcp  6 598 ESTABLISHED src=165.132.128.201 dst=1.2.3.4 sport=57218 dport=6969 packets=8024 bytes=9919881 src=10.0.0.2 dst=165.132.128.201 sport=6969 dport=57218 packets=4211 bytes=239607 [ASSURED] mark=0 secmark=0 use=1
tcp  6 586 ESTABLISHED src=68.46.9.24 dst=1.2.3.4 sport=64688 dport=6969 packets=6 bytes=490 src=10.0.0.2 dst=68.46.9.24 sport=6969 dport=64688 packets=8 bytes=944 [ASSURED] mark=40 secmark=0 use=1
udp 17 45 src=222.254.228.38 dst=1.2.3.4 sport=25438 dport=6969 packets=5 bytes=454 src=10.0.0.2 dst=222.254.228.38 sport=6969 dport=25438 packets=3 bytes=154 [ASSURED] mark=0 secmark=0 use=1

( full file visible at http://pastebin.com/AZE6EtWm )

I've been playing around with this log for a little while and I can't see any patterns!

Why is some port 6969 bittorrent traffic tagged mark=0 (not matched) by dd-wrt's QoS while others are tagged mark=40 (Bulk) .. any ideas?

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