Load balance tiga modem di satu router (Ubuntu)

#!/bin/sh

# Dapet dari makassar-slackers.org
# moga-moga bisa ;-D

# Parameter Speedy 1
T1=speedy1
IF1=eth1
IP1=192.168.1.2
GW1=192.168.1.1
NET1=192.168.1.0/24

# Parameter speedy 2
T2=speedy2
IF2=eth2
IP2=192.168.2.2
GW2=192.168.2.1
NET2=192.168.2.0/24

# Parameter Speedy 3
T3=speedy3
IF3=eth3
IP3=192.168.3.2
GW3=192.168.3.1
NET3=192.168.3.0/24

ip route add $NET1 dev $IF1 src $IP1 table $T1
ip route add default via $GW1 table $T1
ip route add $NET2 dev $IF2 src $IP2 table $T2
ip route add default via $GW2 table $T2
ip route add $NET3 dev $IF3 src $IP3 table $T3
ip route add default via $GW3 table $T3

ip route add $NET1 dev $IF1 src $IP1
ip route add $NET2 dev $IF2 src $IP2
ip route add $NET3 dev $IF3 src $IP3

ip rule add from $IP1 table $T1
ip rule add from $IP2 table $T2
ip rule add from $IP3 table $T3

# +-------------------------------------------------------------+
# | Buat Admin |
# | Edit baris dibawah kalo ada modem yang tidak connect |
# | By Sadlie |
# +-------------------------------------------------------------+

# Jalan pake 3 modem -> IF1, IF2, & IF3
# kalo semua modem bisa dipake
ip route add default scope global nexthop via $GW1 dev $IF1 weight 1 nexthop via $GW2 dev $IF2 weight 1 nexthop via $GW3 dev $IF3 weight 1

# Jalan pake 2 modem -> IF1 & IF2
# kalo hanya modem 1 & 2 yang bisa dipake
# ip route add default scope global nexthop via $GW1 dev $IF1 weight 1 nexthop via $GW2 dev $IF2 weight 1

# Jalan pake 2 modem -> IF1 & IF3
# kalo hanya modem 1 & 3 yang bisa dipake
# ip route add default scope global nexthop via $GW1 dev $IF1 weight 1 nexthop via $GW3 dev $IF3 weight 1

# Jalan pake 2 modem -> IF2 & IF3
# kalo hanya modem 2 & 3 yang bisa dipake
# ip route add default scope global nexthop via $GW2 dev $IF2 weight 1 nexthop via $GW3 dev $IF3 weight 1