Configuring VRRP

This chapter describes how to configure the Virtual Router Redundancy Protocol (VRRP) on a switch

This chapter includes the following sections:

Information About VRRP

VRRP allows for transparent failover at the first-hop IP router, by configuring a group of routers to share a virtual IP address. VRRP selects a master router in that group to handle all packets for the virtual IP address. The remaining routers are in standby and take over if that the master router fails.

This section includes the following topics:

VRRP Operation

A LAN client can determine which router should be the first hop to a particular remote destination by using a dynamic process or static configuration. Examples of dynamic router discovery are as follows:

  • Proxy ARP—The client uses Address Resolution Protocol (ARP) to get the destination it wants to reach, and a router will respond to the ARP request with its own MAC address.
  • Routing protocol—The client listens to dynamic routing protocol updates (for example, from Routing Information Protocol [RIP]) and forms its own routing table.
  • ICMP Router Discovery Protocol (IRDP) client—The client runs an Internet Control Message Protocol (ICMP) router discovery client.

The disadvantage to dynamic discovery protocols is that they incur some configuration and processing overhead on the LAN client. Also, in the event of a router failure, the process of switching to another router can be slow.

An alternative to dynamic discovery protocols is to statically configure a default router on the client. Although, this approach simplifies client configuration and processing, it creates a single point of failure. If the default gateway fails, the LAN client is limited to communicating only on the local IP network segment and is cut off from the rest of the network.

VRRP can solve the static configuration problem by enabling a group of routers (a VRRP group) to share a single virtual IP address. You can then configure the LAN clients with the virtual IP address as their default gateway.

Figure 21-1 shows a basic VLAN topology. In this example, Routers A, B, and C form a VRRP group. The IP address of the group is the same address that was configured for the Ethernet interface of Router A (10.0.0.1).

Figure 21-1 Basic VRRP Topology

 

Because the virtual IP address uses the IP address of the physical Ethernet interface of Router A, Router A is the master (also known as the IP address owner). As the master, Router A owns the virtual IP address of the VRRP group router and forwards packets sent to this IP address. Clients 1 through 3 are configured with the default gateway IP address of 10.0.0.1.

Routers B and C function as backups. If the master fails, the backup router with the highest priority becomes the master and takes over the virtual IP address to provide uninterrupted service for the LAN hosts. When router A recovers, it becomes the router master again. For more information, see the “VRRP Router Priority and Preemption” section.

Note Packets received on a routed port destined for the VRRP virtual IP address will terminate on the local router, regardless of whether that router is the master VRRP router or a backup VRRP router. This includes ping and Telnet traffic. Packets received on a Layer 2 (VLAN) interface destined for the VRRP virtual IP address will terminate on the master router.

VRRP Benefits

The benefits of VRRP are as follows:

  • Redundance—Enables you to configure multiple routers as the default gateway router, which reduces the possibility of a single point of failure in a network.
  • Load Sharing—Allows traffic to and from LAN clients to be shared by multiple routers. The traffic load is shared more equitably among available routers.
  • Multiple VRRP groups—Supports up to 255 VRRP groups on a router physical interface if the platform supports multiple MAC addresses. Multiple VRRP groups enable you to implement redundancy and load sharing in your LAN topology.
  • Multiple IP Addresses—Allows you to manage multiple IP addresses, including secondary IP addresses. If you have multiple subnets configured on an Ethernet interface, you can configure VRRP on each subnet.
  • Preemption—Enables you to preempt a backup router that has taken over for a failing master with a higher priority backup router that has become available.
  • Advertisement Protocol—Uses a dedicated Internet Assigned Numbers Authority (IANA) standard multicast address (224.0.0.18) for VRRP advertisements. This addressing scheme minimizes the number of routers that must service the multicasts and allows test equipment to accurately identify VRRP packets on a segment. IANA has assigned the IP protocol number 112 to VRRP.
  • The benefits of VRRPv3 are as follows:

– Interoperability in multi-vendor environments.

– Support for the IPv4 and IPv6 address families.

Multiple VRRP Groups

You can configure up to 255 VRRP groups on a physical interface. The actual number of VRRP groups that a router interface can support depends on the following factors:

  • Router processing capability
  • Router memory capability

In a topology where multiple VRRP groups are configured on a router interface, the interface can act as a master for one VRRP group and as a backup for one or more other VRRP groups.

Figure 21-2 shows a LAN topology in which VRRP is configured so that Routers A and B share the traffic to and from clients 1 through 4. Routers A and B act as backups to each other if either router fails.

Figure 21-2 Load Sharing and Redundancy VRRP Topology

 

This topology contains two virtual IP addresses for two VRRP groups that overlap. For VRRP group 1, Router A is the owner of IP address 10.0.0.1 and is the master. Router B is the backup to router A. Clients 1 and 2 are configured with the default gateway IP address of 10.0.0.1.

For VRRP group 2, Router B is the owner of IP address 10.0.0.2 and is the master. Router A is the backup to router B. Clients 3 and 4 are configured with the default gateway IP address of 10.0.0.2.

VRRP Router Priority and Preemption

An important aspect of the VRRP redundancy scheme is the VRRP router priority because the priority determines the role that each VRRP router plays and what happens if the master router fails.

If a VRRP router owns the virtual IP address and the IP address of the physical interface, this router functions as the master. The priority of the master is 255.

Priority also determines if a VRRP router functions as a backup router and the order of ascendancy to becoming a master if the master fails.

When the master switch and the backup switches have the same priority value, the backup switch has a higher IP address, and initially the master switch is up. In this scenario, when the backup switch comes up, it should not disturb the state of master switch. Only when the master switch goes down, the backup switch becomes the master switch.

For example, if router A, the master in a LAN topology fails, VRRP must determine if backups B or C should take over. If you configure router B with priority 101 and router C with the default priority of 100, VRRP selects router B to become the master because it has the higher priority. If you configure routers B and C with the default priority of 100, VRRP selects the backup with the higher IP address to become the master.

VRRP uses preemption to determine what happens after a VRRP backup router becomes the master. With preemption enabled by default, VRRP will switch to a backup if that backup comes online with a priority higher than the new master. For example, if Router A is the master and fails, VRRP selects Router B (next in order of priority). If Router C comes online with a higher priority than Router B, VRRP selects Router C as the new master, even though Router B has not failed.

If you disable preemption, VRRP will only switch if the original master recovers or the new master fails.

VRRP Advertisements

The VRRP master sends VRRP advertisements to other VRRP routers in the same group. The advertisements communicate the priority and state of the master. Cisco NX-OS encapsulates the VRRP advertisements in IP packets and sends them to the IP multicast address assigned to the VRRP group. Cisco NX-OS sends the advertisements once every second by default, but you can configure a different advertisement interval.

VRRP Authentication

VRRP supports the following authentication mechanisms:

  • No authentication
  • Plain text authentication

VRRP rejects packets in any of the following cases:

  • The authentication schemes differ on the router and in the incoming packet.
  • Text authentication strings differ on the router and in the incoming packet.

VRRPv3

VRRP version 3 (VRRPv3) enables a group of switches to form a single virtual switch in order to provide redundancy and reduce the possibility of a single point of failure in a network. The LAN clients can then be configured with the virtual switch as their default gateway. The virtual switch, representing a group of switches, is also known as a VRRPv3 group.

Virtualization Support

VRRP supports virtual routing and forwarding (VRF) instances. By default, Cisco NX-OS places you in the default VRF unless you specifically configure another VRF.

If you change the VRF membership of an interface, Cisco NX-OS removes all Layer 3 configuration, including VRRP.

For more information, see Chapter14, “Configuring Layer 3 Virtualization”

Licensing Requirements for VRRP

The following table shows the licensing requirements for this feature:

 

Product
License Requirement

Cisco NX-OS

VRRP requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide.

Note Make sure the LAN Base Services license is installed on the switch to enable Layer 3 interfaces.

Guidelines and Limitations

VRRP has the following configuration guidelines and limitations:

  • You cannot configure VRRP on the management interface.
  • When VRRP is enabled, you should replicate the VRRP configuration across switches in your network.
  • We recommend that you do not configure more than one first-hop redundancy protocol on the same interface.
  • You must configure an IP address for the interface that you configure VRRP on and enable that interface before VRRP becomes active.
  • Cisco NX-OS removes all Layer 3 configurations on an interface when you change the interface VRF membership, port channel membership, or when you change the port mode to Layer 2.
  • When you configure VRRP to track a Layer 2 interface, you must shut down the Layer 2 interface and reenable the interface to update the VRRP priority to reflect the state of the Layer 2 interface.
  • VRRPv3 has the following configuration guidelines and limitations:

– VRRPv3 is not intended as a replacement for existing dynamic protocols. VRRPv3 is designed for use over multi-access, multicast, or broadcast-capable Ethernet LANs.

– VRRPv3 is supported only on Ethernet and Fast Ethernet interfaces, bridge group virtual interfaces (BVIs), and Gigabit Ethernet interfaces as well as on Multiprotocol Label Switching (MPLS) virtual private networks (VPNs), VRF-aware MPLS VPNs, and VLANs.

– When VRRPv3 is in use, VRRPv2 is unavailable. To configure VRRPv3, you must disable any VRRPv2 configuration.

– Use VRRPv3 millisecond timers only where absolutely necessary and with careful consideration and testing. Millisecond values work only under favorable circumstances. The millisecond timer values are compatible with third-party vendors, as long as they also support VRRPv3.

Default Settings

Table 21-1 lists the default settings for VRRP parameters.

 

Table 21-1 Default VRRP Parameters

Parameters
Default

advertisement interval

1 second

authentication

No authentication

preemption

Enabled

priority

100

VRRP feature

Disabled

VRRPv3

Disabled

VRRPv3 secondary address matching

Enables

VRRPv3 timers advertise

1000 milliseconds

Configuring VRRP

This section includes the following topics:

Note If you are familiar with the Cisco IOS CLI, be aware that the Cisco NX-OS commands for this feature might differ from the Cisco IOS commands that you would use.

Enabling the VRRP Feature

You must globally enable the VRRP feature before you can configure and enable any VRRP groups.

To enable the VRRP feature, use the following command in global configuration mode:

 

Command
Purpose

feature vrrp

 

Example :

switch(config)# feature vrrp

Enables VRRP.

To disable the VRRP feature and remove all associated configuration, use the following command in global configuration mode:

 

Command
Purpose

no feature vrrp

 

Example :

switch(config)# no feature vrrp

Disables the VRRP feature.

Configuring VRRP Groups

You can create a VRRP group, assign the virtual IP address, and enable the group.

You can configure one virtual IPv4 address for a VRRP group. By default, the master VRRP router drops the packets addressed directly to the virtual IP address because the VRRP master is only intended as a next-hop router to forward packets. Some applications require that Cisco NX-OS accept packets addressed to the virtual router IP. Use the secondary option to the virtual IP address to accept these packets when the local router is the VRRP master.

Once you have configured the VRRP group, you must explicitly enable the group before it becomes active.

BEFORE YOU BEGIN

Ensure that you configure an IP address on the interface (see the “Configuring IPv4 Addressing” section.

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. no switchport

4. vrrp number

5. address ip-address [ secondary ]

6. no shutdown

7. (Optional) show vrrp

8. (Optional) copy running-config startup-config

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface - type slot/port

 

Example:

switch(config)#

switch(config-if)# interface ethernet 1/2

Enters interface configuration mode.

Step 3

no switchport

 

Example:

switch(config-if)# no switchport

Configures the interface as a Layer 3 routed interface.

Step 4

vrrp number

 

Example:

switch(config-if)# vrrp 250

switch(config-if-vrrp)#

Creates a virtual router group. The range is from 1 to 255.

Step 5

address ip-address [ secondary ]

 

Example:

switch(config-if-vrrp)# address 192.0.2.8

Configures the virtual IPv4 address for the specified VRRP group. This address should be in the same subnet as the IPv4 address of the interface.

Use the secondary option only if applications require that VRRP routers accept the packets sent to the virtual router’s IP address and deliver to applications.

Step 6

no shutdown

 

Example :

switch(config-if-vrrp)# no shutdown

switch(config-if-vrrp)#

Enables the VRRP group. Disabled by default.

Step 7

show vrrp

 

Example:

switch(config-if-vrrp)# show vrrp

(Optional) Displays VRRP information.

Step 8

copy running-config startup-config

 

Example:

switch(config-if-vrrp)# copy running-config startup-config

(Optional) Saves this configuration change.

Configuring VRRP Priority

The valid priority range for a virtual router is from 1 to 254 (1 is the lowest priority and 254 is the highest). The default priority value for backups is 100. For switches whose interface IP address is the same as the primary virtual IP address (the master), the default value is 255.

BEFORE YOU BEGIN

Ensure that you have enabled the VRRP feature (see the “Configuring VRRP” section).

Ensure that you have configured an IP address on the interface (see the “Configuring IPv4 Addressing” section.

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. no switchport

4. vrrp number

5. shutdown

6. priority leve l [ forwarding-threshold lower lower-value upper upper-value ]

7. no shutdown

8. (Optional) show vrrp

9. (Optional) copy running-config startup-config

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface-type slot/port

 

Example:

switch(config)# interface ethernet 1/2

switch(config-if)#

Enters interface configuration mode.

Step 3

no switchport

 

Example:

switch(config-if)# no switchport

Configures the interface as a Layer 3 routed interface.

Step 4

vrrp number

 

Example:

switch(config-if)# vrrp 250

switch(config-if-vrrp)#

Creates a virtual router group.

Step 5

shutdown

 

Example :

switch(config-if-vrrp)# shutdown

switch(config-if-vrrp)#

Disables the VRRP group. Disabled by default.

Step 6

priority level [ forwarding-threshold lower lower-value upper upper-value ]

 

Example:

switch(config-if-vrrp)# priority 60 forwarding-threshold lower 40 upper 50

 

Sets the priority level used to select the active router in an VRRP group. The level range is from 1 to 254. The default is 100 for backups and 255 for a master that has an interface IP address equal to the virtual IP address.

Step 7

no shutdown

 

Example :

switch(config-if-vrrp)# no shutdown

switch(config-if-vrrp)#

Enables the VRRP group. Disabled by default.

Step 8

show vrrp

 

Example:

switch(config-if-vrrp)# show vrrp

(Optional) Displays a summary of VRRP information.

Step 9

copy running-config startup-config

 

Example:

switch(config-if-vrrp)# copy running-config startup-config

(Optional) Saves this configuration change.

Configuring VRRP Authentication

You can configure simple text authentication for a VRRP group.

BEFORE YOU BEGIN

Ensure that the authentication configuration is identical for all VRRP switches in the network.

Ensure that you have enabled the VRRP feature (see the “Configuring VRRP” section).

Ensure that you have configured an IP address on the interface (see the “Configuring IPv4 Addressing” section.

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. no switchport

4. vrrp number

5. shutdown

6. authentication text password

7. no shutdown

8. (Optional) show vrrp

9. (Optional) copy running-config startup-config

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface-type slot/port

 

Example:

switch(config)# interface ethernet 1/2

switch(config-if)#

Enters interface configuration mode.

Step 3

no switchport

 

Example:

switch(config-if)# no switchport

Configures the interface as a Layer 3 routed interface.

Step 4

vrrp number

 

Example:

switch(config-if)# vrrp 250

switch(config-if-vrrp)#

Creates a virtual router group.

Step 5

shutdown

 

Example :

switch(config-if-vrrp)# shutdown

switch(config-if-vrrp)#

Disables the VRRP group. Disabled by default.

Step 6

authentication text password

 

Example:

switch(config-if-vrrp)# authentication md5 prd555oln47espn0 spi 0x0

Assigns the simple text authentication option and specifies the keyname password. The keyname range is from 1 to 255 characters. We recommend that you use at least 16 characters. The text password is up to eight alphanumeric characters.

Step 7

no shutdown

 

Example :

switch(config-if-vrrp)# no shutdown

switch(config-if-vrrp)#

Enables the VRRP group. Disabled by default.

Step 8

show vrrp

 

Example:

switch(config-if-vrrp)# show vrrp

(Optional) Displays a summary of VRRP information.

Step 9

copy running-config startup-config

 

Example:

switch(config-if-vrrp)# copy running-config startup-config

(Optional) Saves this configuration change.

Configuring Time Intervals for Advertisement Packets

You can configure the time intervals for advertisement packets.

BEFORE YOU BEGIN

Ensure that you have enabled the VRRP feature (see the “Configuring VRRP” section).

Ensure that you have configured an IP address on the interface (see the “Configuring IPv4 Addressing” section.

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. no switchport

4. vrrp number

5. shutdown

6. advertisement-interval seconds

7. no shutdown

8. (Optional) show vrrp

9. (Optional) copy running-config startup-config

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface-type slot/port

 

Example:

switch(config)# interface ethernet 1/2

switch(config-if)#

Enters interface configuration mode.

Step 3

no switchport

 

Example:

switch(config-if)# no switchport

Configures the interface as a Layer 3 routed interface.

Step 4

vrrp number

 

Example:

switch(config-if)# vrrp 250

switch(config-if-vrrp)#

Creates a virtual router group.

Step 5

shutdown

 

Example :

switch(config-if-vrrp)# shutdown

switch(config-if-vrrp)#

Disables the VRRP group. Disabled by default.

Step 6

advertisement-interval seconds

 

Example:

switch(config-if-vrrp)# advertisement-interval 15

Sets the interval time in seconds between sending advertisement frames. The range is from 1 to 254. The default is 1 second.

Step 7

no shutdown

 

Example :

switch(config-if-vrrp)# no shutdown

switch(config-if-vrrp)#

Enables the VRRP group. Disabled by default.

Step 8

show vrrp

 

Example:

switch(config-if-vrrp)# show vrrp

(Optional) Displays a summary of VRRP information.

Step 9

copy running-config startup-config

 

Example:

switch(config-if-vrrp)# copy running-config startup-config

(Optional) Saves this configuration change.

Disabling Preemption

You can disable preemption for a VRRP group member. If you disable preemption, a higher-priority backup router will not take over for a lower-priority master router. Preemption is enabled by default.

BEFORE YOU BEGIN

Ensure that you have enabled the VRRP feature (see the “Configuring VRRP” section).

Ensure that you have configured an IP address on the interface (see the “Configuring IPv4 Addressing” section.

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. no switchport

4. vrrp number

5. shutdown

6. no preempt

7. no shutdown

8. (Optional) show vrrp

9. (Optional) copy running-config startup-config

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface-type slot/port

 

Example:

switch(config)# interface ethernet 1/2

switch(config-if)#

Enters interface configuration mode.

Step 3

no switchport

 

Example:

switch(config-if)# no switchport

Configures the interface as a Layer 3 routed interface.

Step 4

vrrp number

 

Example:

switch(config-if)# vrrp 250

switch(config-if-vrrp)#

Creates a virtual router group.

Step 5

no shutdown

 

Example :

switch(config-if-vrrp)# no shutdown

Enables the VRRP group. Disabled by default.

Step 6

no preempt

 

Example:

switch(config-if-vrrp)# no preempt

Disables the preempt option and allows the master to remain when a higher-priority backup appears.

Step 7

no shutdown

 

Example :

switch(config-if-vrrp)# no shutdown

Enables the VRRP group. Disabled by default.

Step 8

show vrrp

 

Example:

switch(config-if-vrrp)# show vrrp

(Optional) Displays a summary of VRRP information.

Step 9

copy running-config startup-config

 

Example:

switch(config-if-vrrp)# copy running-config startup-config

(Optional) Saves this configuration change.

Configuring VRRP Interface State Tracking

Interface state tracking changes the priority of the virtual router based on the state of another interface in the switch. When the tracked interface goes down or the IP address is removed, Cisco NX-OS assigns the tracking priority value to the virtual router. When the tracked interface comes up and an IP address is configured on this interface, Cisco NX-OS restores the configured priority to the virtual router (see the “Configuring VRRP Priority” section).

Note For interface state tracking to function, you must enable preemption on the interface.

Note VRRP does not support Layer 2 interface tracking.

BEFORE YOU BEGIN

Ensure that you have enabled the VRRP feature (see the “Configuring VRRP” section).

Ensure that you have configured an IP address on the interface (see the “Configuring IPv4 Addressing” section.

Ensure that you have enabled the virtual router (see the “Configuring VRRP Groups” section).

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. no switchport

4. vrrp number

5. shutdown

6. track interface type number priority value

7. no shutdown

8. (Optional) show vrrp

9. (Optional) copy running-config startup-config

DETAILED STEPS

 

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface-type slot/port

 

Example:

switch(config)# interface ethernet 1/2

switch(config-if)#

Enters interface configuration mode.

Step 3

no switchport

 

Example:

switch(config-if)# no switchport

Configures the interface as a Layer 3 routed interface.

Step 4

vrrp number

 

Example:

switch(config-if)# vrrp 250

switch(config-if-vrrp)#

Creates a virtual router group.

Step 5

shutdown

 

Example :

switch(config-if-vrrp)# shutdown

switch(config-if-vrrp)#

Disables the VRRP group. Disabled by default.

Step 6

track interface type number priority value

 

Example:

switch(config-if-vrrp)# track interface ethernet 2/10 priority 254

Enables interface priority tracking for a VRRP group. The priority range is from 1 to 254.

Step 7

no shutdown

 

Example :

switch(config-if-vrrp)# no shutdown

switch(config-if-vrrp)#

Enables the VRRP group. Disabled by default.

Step 8

show vrrp

 

Example:

switch(config-if-vrrp)# show vrrp

(Optional) Displays a summary of VRRP information.

Step 9

copy running-config startup-config

 

Example:

switch(config-if-vrrp)# copy running-config startup-config

(Optional) Saves this configuration change.

Configuring VRRPv3

Enabling VRRPv3

You must globally enable the VRRPv3 feature before you can configure and enable any VRRPv3 groups.

To enable the VRRPv3 feature, use the following command in global configuration mode:

 

Command
Purpose

feature vrrpv3

 

Example :

switch(config)# feature vrrpv3

Enables VRRP version 3. The no form of this command disables VRRPv3 in a VDC.

If VRRPv2 is currently configured, use the no feature vrrp command in global configuration mode to remove the VRRPv2 configuration and then use the feature vrrpv3 command to enable VRRPv3.

Configuring VRRPv3 Groups

You can create a VRRPv3 group, assign the virtual IP address, and enable the group.

You can configure one virtual IPv4 address for a VRRPv3 group. By default, the master VRRPv3 router drops the packets addressed directly to the virtual IP address because the VRRPv3 master is only intended as a next-hop router to forward packets. Some applications require that Cisco NX-OS accept packets addressed to the virtual router IP. Use the secondary option to the virtual IP address to accept these packets when the local router is the VRRPv3 master.

Note After you have configured the VRRPv3 group, you must explicitly enable the group before it becomes active.

BEFORE YOU BEGIN

  • Ensure that the VRRPv3 feature is enabled.
  • Ensure that you configure an IP address on the interface.

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. vrrpv3 number address-family { ipv4 | ipv6 }

4. (Optional) address ip-address [ primary | secondary ]

5. (Optional) description description

6. (Optional) match-address

7. (Optional) preempt [delay minimum seconds ]

8. (Optional) priority level

9. (Optional) timers advertise interval

10. (Optional) vrrpv2

11. (Optional) shutdown

12. (Optional) show fhrp [ interface-type interface-number] [verbose]

13. (Optional) copy running-config startup-config

DETAILED STEPS

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface - type slot/port

 

Example:

switch(config)# interface ethernet 2/1

switch(config-if)#

Enters interface configuration mode.

Step 3

[no] vrrpv3 number address-family { ipv4 | ipv6 }

 

Example:

switch(config-if)# vrrpv3 5 address-family

ipv4

switch(config-if-vrrpv3-group)#

Creates a VRRPv3 group and enters VRRPv3 group configuration mode. The range is from 1 to 255.

The no form of this command removes all configuration defined within the submode.

Step 4

[no] address ip-address [ primary | secondary ]

 

Example:

switch(config-if-vrrpv3-group)# address

100.0.1.10 primary

(Optional) Specifies a primary or secondary IPv4 or IPv6 address for the VRRPv3 group.

Note To utilize secondary IP addresses in a VRRPv3 group, you must first configure a primary IP address on the same group.

Step 5

[no] description description

 

Example:

switch(config-if-vrrpv3-group)# description

group3

(Optional) Specifies a description for the VRRPv3 group. You can enter up to 80 alphanumeric characters.

Step 6

[no] match-address

 

Example:

switch(config-if-vrrpv3-group)# match-address

(Optional) Matches the secondary address in the advertisement packet against the configured address.

Step 7

[no] preempt [ delay minimum seconds ]

 

Example:

switch(config-if-vrrpv3-group)# preempt

delay minimum 30

(Optional) Enables preemption of a lower priority master switch with an optional delay. The range is from 0 to 3600.

Step 8

[no] priority level

 

Example:

switch(config-if-vrrpv3-group)# priority 3

(Optional) Specifies the priority of the VRRPv3 group. The range is from 1 to 254.

Step 9

[no] timers advertise interval

 

Example:

switch(config-if-vrrpv3-group)# timers advertise 1000

(Optional) Sets the advertisement timer in milliseconds. The range is from 100 to 40950.

Note Cisco recommends that you set this timer to a value greater than or equal to 1 second.

Step 10

[no] vrrpv2

 

Example:

switch(config-if-vrrpv3-group)# vrrpv2

(Optional) Enables support for VRRPv2 simultaneously, to ensure interoperability with devices that support only VRRPv2.

Note VRRPv2 compatibility mode is provided to allow an upgrade from VRRPv2 to VRRPv3. This is not a full VRRPv2 implementation and should be used only to perform an upgrade.

Step 11

[no] shutdown

 

Example :

switch(config-if-vrrp3-group)# shutdown

(Optional) Disables VRRP configuration for the VRRPv3 group.

Step 12

show fhrp [ interface-type interface-number ] [verbose]

 

Example:

switch(config-if-vrrp3-group)# show fhrp port-channnel 101 verbose

(Optional) Displays First Hop Redundancy Protocol (FHRP) information.

Use the verbose keyword to view detailed information.

Step 13

copy running-config startup-config

 

Example:

switch(config-if-vrrp3-group)# copy running-config startup-config

(Optional) Saves this configuration change.

Configuring the Delay Period for FHRP Client Initialization

You can configure the delay period for the initialization of FHRP clients.

Note In all FHRP protocols, we do not recommend to use aggressive timers as they cause CPU spikes and they result in increased control packet flow. In case of VRRPv3, you should configure sufficient interface delay/reload delay for proper failover of the VRRP nodes.

To configure this feature, use the following command in interface configuration mode:

 

Command
Purpose

fhrp delay {[ minimum ] | [ reload ] seconds }

 

Example :

switch(config)# fhrp delay minimum 34

Specifies the delay period for the initialization of FHRP clients. The range is from 0 to 3600 seconds.

The minimum keyword configures the delay period after an interface becomes available.

The reload command configures the delay period after the device reloads.

Configuring VRRPv3 Control Groups

You can configure a VRRPv3 control group.

BEFORE YOU BEGIN

  • Ensure that the VRRPv3 feature is enabled.
  • Ensure that you configure an IP address on the interface.

SUMMARY STEPS

1. configure terminal

2. interface interface-type slot/port

3. ip address ip-address mask [ secondary ]

4. vrrpv3 number address-family { ipv4 | ipv6 }

5. (Optional) address ip-address [ primary | secondary ]

6. (Optional) shutdown

7. (Optional) show fhrp [ interface-type interface-number] [verbose]

8. (Optional) copy running-config startup-config

DETAILED STEPS

Command
Purpose

Step 1

configure terminal

 

Example:

switch# configure terminal

switch(config)#

Enters global configuration mode.

Step 2

interface interface - type slot/port

 

Example:

switch(config)# interface ethernet 2/1

switch(config-if)#

Enters interface configuration mode.

Step 3

[no] ip address ip-address mask [ secondary]

 

Example:

switch(config-if)# ip address 209.165.200.230 255.255.255.224

Configures the IP address on the interface.

Note You can use the secondary keyword to configure additional IP addresses on the interface.

Step 4

[no] vrrpv3 number address-family { ipv4 | ipv6 }

 

Example:

switch(config-if)# vrrpv3 5 address-family

ipv4

switch(config-if-vrrpv3-group)#

Creates a VRRPv3 group and enters VRRPv3 group configuration mode. The range is from 1 to 255.

Step 5

[no] address ip-address [ primary | secondary ]

 

Example:

switch(config-if-vrrpv3-group)# address

209.165.200.227 primary

(Optional) Specifies a primary or secondary IPv4 or IPv6 address for the VRRPv3 group.

Step 6

[no] shutdown

 

Example :

switch(config-if-vrrp3-group)# shutdown

(Optional) Disables VRRP configuration for the VRRPv3 group.

Step 7

show fhrp [ interface-type interface-number ] [verbose]

 

Example:

switch(config-if-vrrp3-group)# show fhrp port-channnel 101 verbose

(Optional) Displays First Hop Redundancy Protocol (FHRP) information.

Use the verbose keyword to view detailed information.

Step 8

copy running-config startup-config

 

Example:

switch(config-if-vrrp3-group)# copy running-config startup-config

(Optional) Saves this configuration change.

Verifying the VRRPv2 Configuration

To display the VRRPv2 configuration information, perform one of the following tasks:

 

Command
Purpose

show vrrpv2

Displays the VRRP status for all groups.

show vrrpv2 vr group-number

Displays the VRRP status for a VRRP group.

show vrrp v2 vr number interface interface-type port configuration

Displays the virtual router configuration for an interface.

show vrrp v2 vr number interface interface-type port status

Displays the virtual router status for an interface.

show fhrp [ interface-type interface-number] [verbose]

Displays First Hop Redundancy Protocol (FHRP) information.

show interface interface-type

Displays the virtual router configuration for an interface.

Verifying the VRRPv3 Configuration

See the following table for information on the fields in the show vrrpv3 command output:

Command
Purpose

>

Redirect it to a file

>>

Redirect it to a file in append mode

all

All VRRPV3 information

brief

Brief output

detail

Detail output

ethernet

Ethernet IEEE 802.3z

internal

Internal command

ipv4

IPv4

ipv6

IPv6

loopback

Loopback interface

port-channel

Port Channel interface

statistics

Statistics output

Vlan

VLAN interface

|

Pipe command output to filter

For example, use the show vrrpv3 statistics command to display the VRRPv3 statistics:

# show vrrpv3 statistics

Displaying VRRP Statistics

To display VRRP statistics, use the following commands:

 

Command
Purpose

show vrrp vr number interface interface-type port statistics

Displays the virtual router information.

show vrrp statistics

Displays the VRRP statistics.

Use the clear vrrp vr command to clear the IPv4 VRRP statistics for a specified interface.

Use the clear vrrp ipv4 command to clear all the statistics for the specified IPv4 virtual router.

Configuration Examples for VRRPv2

In this example, Router A and Router B each belong to three VRRPv2 groups. In the configuration, each group has the following properties:

  • Group 1:

– Virtual IP address is 10.1.0.10.

– Router A will become the master for this group with priority 120.

– Advertising interval is 3 seconds.

– Preemption is enabled.

  • Group 5:

– Router B will become the master for this group with priority 200.

– Advertising interval is 30 seconds.

– Preemption is enabled.

  • Group 100:

– Router A will become the master for this group first because it has a higher IP address (10.1.0.2).

– Advertising interval is the default 1 second.

– Preemption is disabled.

Router A

interface ethernet 1/0

no switchport

ip address 10.1.0.2/16
no shutdown
vrrpv2 1
priority 120
authentication text cisco
advertisement-interval 3
address 10.1.0.10
no shutdown
vrrpv2 5
priority 100
advertisement-interval 30
address 10.1.0.50
no shutdown
vrrpv2 100
no preempt
address 10.1.0.100
no shutdown

Router B

interface ethernet 1/0

no switchport

ip address 10.2.0.1/2
no shutdown
vrrpv2 1
priority 100
authentication text cisco
advertisement-interval 3
address 10.2.0.10
no shutdown
 
vrrpv2 5
priority 200
advertisement-interval 30
address 10.2.0.50
no shutdown
vrrpv2 100
no preempt
address 10.2.0.100
no shutdown
 

Configuration Example for VRRPv3

See the following configuration example for VRRPv3.

 
interface Vlan20
vrrpv3 10 address-family ipv4
timers advertise 1000
priority 100
preempt
match-address
no vrrpv2
address 20.1.1.1 primary
address 20.1.1.5 secondary
vrrpv3 10 address-family ipv6
timers advertise 1000
priority 100
preempt
match-address
no vrrpv2
address fe80::1 primary
address 2011::5

Additional References

For additional information related to implementing VRRP, see the following sections:

Related Documents

Related Topic
Document Title

Configuring the Hot Standby Routing Protocol

Chapter 20, “Configuring HSRP”

VRRP CLI commands

Cisco Nexus 3000 Series Command Reference