[Cake] WAN ingress rate with concurrent downloads

Georgios Amanakis g_amanakis at yahoo.com
Sun Oct 30 12:43:11 EDT 2016

Dear All,

I think Sebastian's theory has a weak point. 

> Again I believe you just show bit-torrent misbehaving ...

I can easily reproduce this behaviour if one LAN-host downloads
multiple files using TCP (e.g. 2 or more kernels simultaneously from ht

> For me this looks like bwmon accounts the incoming packets before
> cake sees and drops them ...

If only one download takes place then the bandwidth bmon reports on
WAN-ingress is the same as the limit set in cake. I don't think that
bmon accounts the incoming packets before cake sees them. Furthermore,
Wireshark reports that all bittorrent traffic in my case are TCP
packets, and reports the same bandwidth usage as bmon on WAN-ingress. 

The only way I have found that WAN-ingress limit is obeyed, is using
act_police with the in-kernel bandwidth estimator (i.e. tc filter add
dev enp0s13 parent ffff: protocol all estimator 10msec 80msec u32 match
u32 0 0 police avrate 3300kbit drop flowid :1). But then there is an
discrepancy between WAN-ingress and LAN-egress (i.e. WAN-ingress is at
~400kbytes/s and LAN-egress on the host running bittorrent is
~220kbytes/s). Unfortunately I cannot see the bandwidth my cable-modem
syncs at (I searched the web-interface but did not find it; it is a
Comcast-provided Arris TG1682G).

Noah, could you try and see what happens if instead of bittorrent a
LAN-host downloads multiple files using TCP?

Thank you all for your feedback,

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