VRRP

VRRP

Description

The Virtual Router Redundancy Protocol (VRRP) is a standards-based alternative to HSRP, defined in IETF standard RFC 2338. This section is brief, highlighting only the differences between HSRP and VRRP.

VRRP provides one redundant gateway address from a group of routers. The active router is called the master router , whereas all others are in the backup state . The master router is the one with the highest router priority in the VRRP group.

VRRP group numbers range from 0 to 255; router priorities range from 1 to 254. (254 is the highest, 100 is the default.)

The virtual router MAC address is of the form 0000.5e00.01xx, where xx is a two-digit hex VRRP group number.

VRRP advertisements are sent at 1-second intervals. Backup routers optionally can learn the advertisement interval from the master router.

By default, all VRRP routers are configured to preempt the current master router if their priorities are greater.

VRRP sends its advertisements to the multicast destination address 224.0.0.18 (VRRP), using IP protocol 112.

VRRP vs HSRP

* The router with standby IP address same as the interface IP address will set its priority to 255 automatically and always be the master router whenever possible.

Gateway Addressing

Switch(config-if)# vrrp group ip ip-address [secondary]

Authentication

Switch(config-if)# vrrp group authentication string

Show Command

Switch# show vrrp [ brief ]

Switch-A# show vrrp brief
Interface Grp Pri Time Own Pre State  Master addr    Group addr
Vlan50    1   200 3218     Y   Master 192.168.1.10   192.168.1.1
Vlan50    2   100 3609         Backup 192.168.1.11   192.168.1.2
Switch-A#
Switch-B# show vrrp brief
Interface Grp Pri Time Own Pre State  Master addr    Group addr
Vlan50    1   100 3609         Backup 192.168.1.10   192.168.1.1
Vlan50    2   200 3218     Y   Master 192.168.1.11   192.168.1.2
Switch-B#

Switch-A# show vrrp

Switch-A# show vrrp
Vlan50 - Group 1
  State is Master
  Virtual IP address is 192.168.1.1
  Virtual MAC address is 0000.5e00.0101
  Advertisement interval is 1.000 sec
  Preemption is enabled
    min delay is 0.000 sec
  Priority is 200
  Authentication is enabled
  Master Router is 192.168.1.10 (local), priority is 200
  Master Advertisement interval is 1.000 sec
  Master Down interval is 3.218 sec

Vlan50 - Group 2
  State is Backup
  Virtual IP address is 192.168.1.2
  Virtual MAC address is 0000.5e00.0102
  Advertisement interval is 1.000 sec
  Preemption is disabled
  Priority is 100
  Authentication is enabled
  Master Router is 192.168.1.11, priority is 200
  Master Advertisement interval is 1.000 sec
  Master Down interval is 3.609 sec (expires in 2.977 sec)
Switch-A#

Switch# show vrrp brief all

Switch# show vrrp interface type member/module/number

Properties

Per-interface Properties

priority

Description: Priority
Values: 1 to 254
Default: 100
Command:

Switch(config-if)# vrrp group priority level

timers

Description: Advertisement timer
Values:
Default: 1 second Command:

Switch(config-if)# vrrp group timers advertise [ msec ] interval

A router can also be set to learn the advertisement interval from the master router by the following command.

Switch(config-if)# vrrp group timers learn

preempting

Description: Preempting Values: [Enabled | Disabled]
Default: Enabled
Command:

Switch(config-if)# vrrp group preempt [delay seconds]

track

Description: Track an object
Values:
Default:
Command:

Switch(config-if)# vrrp group track object-number [decrement priority]

Example

Configuring Load Balancing with VRRP

Switch-A(config)# interface vlan 50
Switch-A(config-if)# ip address 192.168.1.10 255.255.255.0
Switch-A(config-if)# vrrp 1 priority 200
Switch-A(config-if)# vrrp 1 ip 192.168.1.1
Switch-A(config-if)# vrrp 2 priority 100
Switch-A(config-if)# no vrrp 2 preempt
Switch-A(config-if)# vrrp 2 ip 192.168.1.2

Switch-B(config)# interface vlan 50
Switch-B(config-if)# ip address 192.168.1.11 255.255.255.0
Switch-B(config-if)# vrrp 1 priority 100
Switch-B(config-if)# no vrrp 1 preempt
Switch-B(config-if)# vrrp 1 ip 192.168.1.1
Switch-B(config-if)# vrrp 2 priority 200
Switch-B(config-if)# vrrp 2 ip 192.168.1.2