QoS with MAC filtering

nospam@example.com (KaBuTe) — Sat, 17 May 2008 12:12:00 +0200

Problem: Collapsed Network with high load and dynamic IPs (DHCP server working)

Answer: Implement QoS using tc and MAC filtering (with the u32 classifier reading the header of the packet).

I'll use a script to show how it works:

#!/bin/bash

#Maximum bitrate, for example 9Mbit/sec
MAXRATE=9Mbit

#Assured minimum bitrate per PC, for example 3 Mbit/sec
MINRATE=3Mbit

ALG=htb

#Network Interface to balance
IFACE=eth1

case "$1" in

start)

#Creation of the root and the classes as usual, 3 classes (min: 3Mbit/sec, max: 9Mbit/sec)
tc qdisc add dev $IFACE root handle 1: htb default 12
tc class add dev $IFACE parent 1: classid 1:1 htb rate $MAXRATE ceil $MAXRATE
tc class add dev $IFACE parent 1:1 classid 1:10 htb rate $MINRATE ceil $MAXRATE
tc class add dev $IFACE parent 1:1 classid 1:11 htb rate $MINRATE ceil $MAXRATE
tc class add dev $IFACE parent 1:1 classid 1:12 htb rate $MINRATE ceil $MAXRATE

#PC to filter by MAC (for example: 11:22:AA:BB:33:44), see command bellow
#tc filter add dev $IFACE protocol ip parent 1:1 prio 1 u32 match u16 0x0800 0xFFFF at -2 match u32 0x(8 last "digits" of the MAC) 0xFFFFFFFF at -12 match u16 0x(4 first "digits" of the MAC) 0xFFFF at -14 flowid 1:12

tc filter add dev $IFACE protocol ip parent 1:1 prio 1 u32 match u16 0x0800 0xFFFF at -2 match u32 0xaabb3344 0xFFFFFFFF at -12 match u16 0x1122 0xFFFF at -14 flowid 1:12

;;

show)

tc -s qdisc ls dev $IFACE

;;
esac

KaBuTe - Dummy Hacker - Redes

QoS with MAC filtering