Cisco Systems 78-11741-02 manual IOS SLB Stateless Backup Configuration Example, IPC-157

Configuring Server Load Balancing

Configuration Examples

standby 1 timers 5 15 standby 1 name Web-Group

interface FastEthernet 41

ip address 2.0.0.1 255.0.0.0

router eigrp 1 network 1.0.0.0 network 2.0.0.0

The standby ip interface configuration command enables HSRP and establishes 1.0.0.3 as the IP address of the virtual router. The configurations of both Layer 3 switches include this command so that both switches share the same virtual IP address. The number 1 establishes Hot Standby group 1. (If you do not specify a group number, the default is group 0.) The configuration for at least one of the Layer 3 switches in the Hot Standby group must specify the IP address of the virtual router; specifying the IP address of the virtual router is optional for other routers in the same Hot Standby group.

The standby preempt interface configuration command allows the Layer 3 switch to become the active switch when its priority is higher than all other HSRP-configured switches in this Hot Standby group. The configurations of both switches include this command so that each can be the standby Layer 3 switch for the other switch. The number 1 indicates that this command applies to Hot Standby group 1. If you do not use the standby preempt command in the configuration for a Layer 3 switch, that switch cannot become the active Layer 3 switch.

The standby priority interface configuration command sets the HSRP priority of the Layer 3 switch to 110, which is higher than the default priority of 100. Only the configuration of Device A includes this command, which makes Device A the default active Layer 3 switch. The number 1 indicates that this command applies to Hot Standby group 1.

The standby authentication interface configuration command establishes an authentication string whose value is an unencrypted eight-character string that is incorporated in each HSRP multicast message. This command is optional. If you choose to use it, each HSRP-configured Layer 3 switch in the group should use the same string so that each switch can authenticate the source of the HSRP messages that it receives. The number 1 indicates that this command applies to Hot Standby group 1.

The standby timers interface configuration command sets the interval (in seconds) between hello messages (called the hello time) to 5 seconds, and sets the interval (in seconds) that a Layer 3 switch waits before it declares the active Layer 3 switch to be down (called the hold time) to 8 seconds. (The defaults are 3 and 10 seconds, respectively.) To modify the default values, you must configure each Layer 3 switch to use the same hello time and hold time. The number 1 indicates that this command applies to Hot Standby group 1.

The standby name interface configuration command associates the IOS SLB interface with an HSRP group name (in this case, Web-Group), previously specified on an inservice (virtual server) command. The number 1 indicates that this command applies to Hot Standby group 1.

IOS SLB Stateless Backup Configuration Example

The following commands enable the HSRP standby group 100 IP address, priority, preempt, and timers; and configures a name and authentication for Device A in Figure 26:

standby 100 ip 172.20.100.10 standby 100 priority 110 standby 100 preempt standby 100 timers 5 15 standby 100 name Web_group1 standby 100 authentication Secret exit

Cisco IOS IP Configuration Guide

IPC-157