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Link Load-Balancing (LLB) Example

The Network Setup

Link load balancing network configuration (Master/Backup)
Link load balancing network configuration (Master/Backup)

The internal network parameters are 10.11.12.0/24, the balancer network parameters 172.17.2.0/24. VRRP advertisements should be sent out on both networks, a separate address space 10.11.12.0/24 is used for that purpose.

The default route of all clients and also of the optional internal router shown on the left is the “network virt” address of the internal network (10.11.12.71 in this example).

The ipforwarding parameter has to be enabled for Link Load Balancing (“set ipforwarding 1”).

The module chaing “vrrp,arp,ping,hc,master,llb” activates the Link Load-Balancing functionality.

The IPv4 default route on hosts in network 10.11.12.0/24 should point to 10.11.12.56, which is represented by VRRP.

The LB1 Configuration File

// configuration taken Fri Apr 26 14:36:39 2013
// BalanceNG 3.446 (created 2013/04/26)
hostname LB1
modules vrrp,arp,ping,hc,master,llb
set {
 ipforwarding 1
 vrrppreempt 1
 vrrppreemptts 8
} 
interface 1 {
 name eth1
 access raw
} 
interface 2 {
 name eth2
 access raw
 trackval 10
} 
interface 3 {
 name eth3
 access raw
 trackval 10
} 
register interfaces 1,2,3
vrrp {
 vrid 64
 priority 200
 network 2
 tracking enable
} 
network 1 {
 addr 172.17.2.0
 mask 255.255.255.0
 real 172.17.2.55
 virt 172.17.2.56
 nat outside
 interface 3
} 
network 2 {
 addr 10.11.12.0
 mask 255.255.255.0
 real 10.11.12.55
 virt 10.11.12.56
 nat inside
 interfaces 1,2
} 
register networks 1,2
enable networks 1,2
server 1 {
 name "BalanceNG LLB Router"
 ipaddr any
 method session
 targets 1,2,3,4
} 
register server 1
enable server 1
target 1 {
 name "Link 1"
 ipaddr 172.17.2.1
 ping 10.11.12.1,5,20
} 
target 2 {
 name "Link 2"
 ipaddr 172.17.2.2
 ping 10.11.12.2,5,20
} 
target 3 {
 name "Link 3"
 ipaddr 172.17.2.3
 ping 10.11.12.3,5,20
} 
target 4 {
 name "Link 4"
 ipaddr 172.17.2.4
 ping 10.11.12.4,5,20
} 
register targets 1,2,3,4
enable targets 1,2,3,4
// end of configuration

The LB2 Configuration File

// configuration taken Fri Apr 26 14:36:43 2013
// BalanceNG 3.446 (created 2013/04/26)
hostname LB2
modules vrrp,arp,ping,hc,master,llb
set {
 ipforwarding 1
 vrrppreempt 1
 vrrppreemptts 8
} 
interface 1 {
 name eth1
 access raw
} 
interface 2 {
 name eth2
 access raw
 trackval 10
} 
interface 3 {
 name eth3
 access raw
 trackval 10
} 
register interfaces 1,2,3
vrrp {
 vrid 64
 priority 200
 network 2
 tracking enable
} 
network 1 {
 addr 172.17.2.0
 mask 255.255.255.0
 real 172.17.2.57
 virt 172.17.2.56
 nat outside
 interface 3
} 
network 2 {
 addr 10.11.12.0
 mask 255.255.255.0
 real 10.11.12.57
 virt 10.11.12.56
 nat inside
 interfaces 1,2
} 
register networks 1,2
enable networks 1,2
server 1 {
 name "BalanceNG LLB Router"
 ipaddr any
 method session
 targets 1,2,3,4
} 
register server 1
enable server 1
target 1 {
 name "Link 1"
 ipaddr 172.17.2.1
 ping 10.11.12.1,5,20
} 
target 2 {
 name "Link 2"
 ipaddr 172.17.2.2
 ping 10.11.12.2,5,20
} 
target 3 {
 name "Link 3"
 ipaddr 172.17.2.3
 ping 10.11.12.3,5,20
}
target 4 {
 name "Link 4"
 ipaddr 172.17.2.4
 ping 10.11.12.4,5,20
}
register targets 1,2,3,4
enable targets 1,2,3,4
// end of configuration