My short cake crash course

cake_debian.txt

#Set cake as qdisc and bbr as your congestion control (either from shell or add them to sysctl.conf or your OS equivalent)

sysctl net.core.default_qdisc=cake
sysctl net.ipv4.tcp_congestion_control=bbr

#Replace the root qdisc to cake diffserv4 (we get 4 distinct queues this way). Replace enp0231f6 with your interface name:

/sbin/tc qdisc replace root dev enp0s31f6 cake ethernet diffserv4 wash

#Check output. Queue priority (from lowest to highest) is bulk<best effort<video<voice. It should be similar to below one:

tc -s qdisc show dev enp0s31f6

qdisc cake 8028: root refcnt 2 bandwidth unlimited diffserv4 triple-isolate nonat wash no-ack-filter split-gso rtt 100.0ms noatm overhead 38 mpu 84
 Sent 110902499451704 bytes 2245544728 pkt (dropped 258725334, overlimits 0 requeues 3815608646)
 backlog 0b 0p requeues 3815608646
 memory used: 5786310b of 15140Kb
 capacity estimate: 0bit
 min/max network layer size:           21 /    1500
 min/max overhead-adjusted size:       84 /    1538
 average network hdr offset:           14

                   Bulk  Best Effort        Video        Voice
  thresh           0bit         0bit         0bit         0bit
  target          5.0ms        5.0ms        5.0ms        5.0ms
  interval      100.0ms      100.0ms      100.0ms      100.0ms
  pk_delay          5us         34us         27us          4us
  av_delay          2us          3us          2us          0us
  sp_delay          0us          0us          0us          0us
  backlog            0b           0b           0b           0b
  pkts       3507231516   3192674174     97009583      2322085
  bytes    74953140009638 36196052900705 134675833305    246350387
  way_inds   3124849622   3685021084       560217        11411
  way_miss     26110415     11746396       724773       503043
  way_cols       329469       110845            0            0
  drops       253089563      5635584          187            0
  marks         2665014       138610            0            0
  ack_drop            0            0            0            0
  sp_flows           85            4            4            1
  bk_flows            2            1            0            0
  un_flows            0            0            0            0
  max_len         69278        69278        66616          590
  quantum          1514         1514         1514         1514
  
#Add iptables rules
iptables -t mangle -N set_dscp_prio_bulk
iptables -t mangle -N set_dscp_prio_besteffort
iptables -t mangle -N set_dscp_prio_video
 
#Plex source ports + http server source port
iptables -t mangle -A OUTPUT -o enp0s31f6 -p udp -m multiport --sports 443,32400,32401 -j set_dscp_prio_video
iptables -t mangle -A OUTPUT -o enp0s31f6 -p tcp -m multiport --sports 443,32400,32401 -j set_dscp_prio_video
#Deluge is listening on port 8999 for torrent traffic
iptables -t mangle -A OUTPUT -o enp0s31f6 -p udp -m udp --sport 8999 -j set_dscp_prio_besteffort
iptables -t mangle -A OUTPUT -o enp0s31f6 -p tcp -m tcp --sport 8999 -j set_dscp_prio_besteffort
#Rtorrent is listening on port 64333 for torrent traffic
iptables -t mangle -A OUTPUT -o enp0s31f6 -p udp -m udp --sport 64333 -j set_dscp_prio_bulk
iptables -t mangle -A OUTPUT -o enp0s31f6 -p tcp -m tcp --sport 64333 -j set_dscp_prio_bulk

#Now we add the mark so that cake assigns the traffic to the correct queue:
iptables -t mangle -A set_dscp_prio_besteffort -j DSCP --set-dscp 0x00
iptables -t mangle -A set_dscp_prio_besteffort -j ACCEPT
iptables -t mangle -A set_dscp_prio_bulk -j DSCP --set-dscp 0x08
iptables -t mangle -A set_dscp_prio_bulk -j ACCEPT
iptables -t mangle -A set_dscp_prio_video -j DSCP --set-dscp 0x18
iptables -t mangle -A set_dscp_prio_video -j ACCEPT

#Check output real time and see the counters increasing:
watch -t tc -s qdisc show dev enp0s31f6