VRRP

The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that provides for automatic assignment of available IP routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork.

The protocol achieves this by creating virtual routers, which are an abstract representation of multiple routers (that is, a master and backup routers, acting as a group). The default gateway of a participating host is assigned to the virtual router instead of a physical router. If the physical router that is routing packets on behalf of the virtual router fails, another physical router is selected to automatically replace it. The physical router that is forwarding packets at any given time is called the master router.

VRRP provides information on the state of a router, not the routes processed and exchanged by that router. Each VRRP instance is limited, in scope, to a single subnet. It does not advertise IP routes beyond that subnet or affect the routing table in any way.

Routers have a priority of between 1-255 and the router with the highest priority becomes the master. The configurable priority value ranges from 1-254, the router which owns the interface IP address as one of its associated IP addresses has the priority value 255. When a planned withdrawal of a master router is to take place, its priority can be lowered, which means a backup router will preempt the master router status rather than having to wait for the hold time to expire.NVIDIA Onyx supports IPv4 in VRRP version 2, and IPv6 in VRRP version 3.

Load Balancing

To create load balancing between routers participating in the same VR, it is recommended to create 2 (or more) VRs. Each router will be a master in one of the VRs, and a backup to the other VR(s). A group of hosts should be configured with Router 1’s virtual address as the default gateway, while the second group should be configured with Router 2’s virtual address.

Configuring VRRP

The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that provides for automatic assignment of available IP routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork.The protocol achieves this by creating virtual routers, which are an abstract representation of multiple routers (that is, a master and backup routers, acting as a group). The default gateway of a participating host is assigned to the virtual router instead of a physical router. If the physical router that is routing packets on behalf of the virtual router fails, another physical router is selected to automatically replace it. The physical router that is forwarding packets at any given time is called the master router.VRRP provides information on the state of a router, not the routes processed and exchanged by that router. Each VRRP instance is limited, in scope, to a single subnet. It does not advertise IP routes beyond that subnet or affect the routing table in any way.Routers have a priority of between 1-255 and the router with the highest priority becomes the master. The configurable priority value ranges from 1-254, the router which owns the interface IP address as one of its associated IP addresses has the priority value 255. When a planned withdrawal of a master router is to take place, its priority can be lowered, which means a backup router will preempt the master router status rather than having to wait for the hold time to expire.

Preconditions

Enable IP routing functionality. Run:

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            switch (config)# ip routing

Enable the desired VLAN. Run:
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            switch (config)# vlan 20
        
```
Warning

The VLAN cannot be the same one configured for the MLAG IPL, if MLAG is used.

Add this VLAN to the desired interface. Run:

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            switch (config)# interface ethernet 1/1
switch (config interface ethernet 1/1)# switchport access vlan 20

Create a VLAN interface. Run:

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            switch (config)# interface vlan 20

Apply IP address to the VLAN interface.

For IPv4, do the following.

On one of the switches, run:

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            switch (config interface vlan 20)# ip address 20.20.20.20 /24

On the other switch, run:

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            switch (config interface vlan 20)# ip address 20.20.20.30 /24

For IPv6, apply IPv6 address to the VLAN interface.

On one of the switches, run:

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            switch (config interface vlan 20) # ipv6 address 2001::20 /64

On the other switch, run:

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            switch (config interface vlan 20) # ipv6 address 2001::30 /64

Enable the interface. Run:

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            switch (config interface vlan 20)# no shutdown

Configuring VRRP

Enable VRRP protocol globally. Run:

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            switch (config)# protocol vrrp

Create a virtual router group for an IP interface. Up to 255 VRRP IDs are supported. Run:

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            switch (config interface vlan 20)# vrrp 100

Set the VIP address.

For IPv4, run:

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            switch (config interface vlan 20 vrrp 100)# address 20.20.20.40

For IPv6, run:

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             switch (config interface vlan 20 vrrp 100) # address 2001::40

Influence the election of the master in the VR cluster make sure that the priority of the desired master is the highest. Note that the higher IP address is selected in case the priority of the routers in the VR are the same. Select the priority. Run:
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            switch (config interface vlan 20 vrrp 100)# priority 200
        
```

The advertisement interval should be the same for all the routers within the VR. Modify the interval. Run:

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            switch (config interface vlan 20 vrrp 100)# advertisement-interval 2

The authentication text should be the same for all the routers within the VR. Configure the authentication text. Run:
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            switch (config interface vlan 20 vrrp 100)# authentication text my-password
        
```
Warning

This option is not supported in VRRP IPv6.
Use the preempt command to enable a high-priority backup virtual router to preempt the low-priority master virtual router. Run:
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            switch (config interface vlan 20 vrrp 100)# preempt
        
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Disable VRRP. Run:

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            switch (config interface vlan 20 vrrp 100)# shutdown

Warning

The configuration will not be deleted, only the VRRP state machine will be stopped.

Verifying VRRP

Display VRRP brief status. Run:

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            switch (config) # show vrrp
Interface  VR         Admin State      Priority   Adv-Intvl   Preempt    State      VR IP addr
-----------------------------------------------------------------------------------------------------------
Vlan20     100        Enabled           100        1          Enabled    Master     20.20.20.40
Vlan20     100        Enabled           100        1          Enabled    Master     2001::40

Display VRRP detailed status. Run:

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            switch (config) # show vrrp detail
VRRP Admin State: Enabled
 
Vlan20 - Vrrp 100:
  Instance Admin State         : Enabled
  State                        : Master
  State v6                     : Master
  Virtual IP Address           : 20.20.20.40
  Virtual IPv6 Address         : 2001::40
  Priority                     : 100
  Advertisement interval(sec)  : 1
  Preemption                   : Enabled
  Virtual MAC Address          : 00:00:5e:00:01:64
  Primary IP Address           : 20.20.20.20
  Master router                : 20.20.20.20
  Virtual MAC Address v6       : 00:00:5e:00:02:64
  Primary IP Address v6        : ::
  Master router v6             : 2001::20
  Master priority              : 100
  Master advertisement interval: 1

Display VRRP statistic counters. Run:

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            switch (config) # show vrrp statistics
Invalid packets:                    0
Too short:                          0
Transitions to Master:              1
Total received:                     0
Bad TTL:                            0
Failed authentication:              0
Unknown authentication:             0
Conflicting authentication:         0
Conflicting Advertise time:         0
Conflicting Addresses:              0
Received with zero priority:        0
Sent with zero priority:            0
Invalid packets v6:                 0
Too short v6:                       0
Transitions to Master v6:           1
Total received v6:                  0
Bad TTL v6:                         0
Conflicting Advertise time v6:      0
Conflicting Addresses v6:           0
Received with zero priority v6:     0
Sent with zero priority v6:         0

Additional Reading and Use Cases

For more information about this feature and its potential applications, please refer to the following community post:

HowTo Configure VRRP on Ethernet Switches

VRRP Commands

protocol vrrp

	protocol vrrp no protocol vrrp Enables VRRP globally and unhides VRRP related commands. The no form of the command deletes all the VRRP configuration and hides VRRP related commands.
Syntax Description	N/A
Default	no protocol vrrp
Configuration Mode	config
History	3.3.4500
Example	switch (config)# protocol vrrp
Related Commands
Notes

clear vrrp statistics

	clear vrrp statistics Clears VRRP statistics.
Syntax Description	N/A
Default	N/A
Configuration Mode	config
History	3.3.4500
Example	switch (config)# clear vrrp statistics
Related Commands
Notes

	vrrp <number> no vrrp <number> Creates a virtual router group on this interface and enters a new configuration mode. The no form of the command deletes the VRRP instance and the related configuration.
Syntax Description	number	A VRRP instance number Range: 1-255
Default	N/A
Configuration Mode	config interface vlan
History	3.3.4500
	3.6.8100	Updated parameter range
	3.7.1100	Updated Syntax and notes
Example	switch (config interface vlan 10)# switch (config interface vlan 10 vrrp 10)#
Related Commands
Notes	A maximum total of 64 VRRP instances are supported per switch system.

address

	address <ip-address> [secondary] no address [<ip-address> [secondary]] Sets virtual router IP address (primary and secondary). The no form of the command deletes the IP address from the VRRP interface.
Syntax Description	ip-address	The virtual IP address
Syntax Description	secondary	A secondary IP address for the virtual router
Default	N/A
Configuration Mode	config vrrp interface
History	3.3.4500
History	3.9.1000	Added support IPv6 address
Example	switch (config vrrp 100)# address 10.10.10.10 switch (config vrrp 100)# address 10.10.10.11 secondary switch (config vrrp 100)# address 10.10.10.12 secondary switch (config vrrp 100)# address 2001::40 switch (config vrrp 100)# address 2001::41 secondary
Related Commands
Notes	The virtual address can be either from the interface’s primary or secondary subnet This command is the enabler of the protocol. Therefore, set all the protocol parameters initially and only then set the ip-address. There are up to 20 IP addresses associated with the VRRP instance. One primary and up to 19 secondary ip-addresses. If the configured IP address is the same as the interface IP address, this switch automatically owns the IP address (priority 255) For IPv6, the OS will auto-generate link-local virtual IP. Up to 19 IPv6 addresses are allowed to be associated with the VRRP instance—one primary address and up to 18 secondary addresses. IPv4 and IPv6 addresses are allowed to be configured on the same VRRP instance.

shutdown

	shutdown no shutdown Disables the virtual router. The no form of the command enables the virtual router (stops the VRRP state machine).
Syntax Description	N/A
Default	Enabled (no shutdown)
Configuration Mode	config vrrp interface
History	3.3.4500
Example	switch (config vrrp 100)# shutdown
Related Commands
Notes

priority

	priority <level> no priority Sets the priority of the virtual router. The no form of the command resets the priority to its default.
Syntax Description	level	The virtual router priority level Range: 1-254
Default	100
Configuration Mode	config vrrp interface
History	3.3.4500
Example	switch (config vrrp 100)# priority 200
Related Commands
Notes	The higher IP address is selected as master if the priority of the routers in the VR are the same To influence the election of the master in the VR cluster make sure that the priority of the desired master is the higher

preempt

	preempt no preempt Sets virtual router preemption mode. The no form of the command disables the virtual router preemption.
Syntax Description	N/A
Default	Enabled (preempt)
Configuration Mode	config vrrp interface
History	3.3.4500
Example	switch (config vrrp 100)# preempt
Related Commands
Notes	To set this router as backup for the current virtual router master, preempt must be enabled.

authentication text

	authentication text <password> no authentication text Sets virtual router authentication password and enables authentication. The no form of the command disables the authentication mechanism.
Syntax Description	password	The virtual router authentication password
Default	Disabled
Configuration Mode	config vrrp interface
History	3.3.4500
History	3.9.1000	Updated notes
Example	switch (config vrrp 100)# authentication text mypassword
Related Commands
Notes	The password string must be up to 8 alphanumeric characters This option is not supported in VRRP IPv6 instance

advertisement-interval

	advertisement-interval <seconds> no advertisement-interval Sets the virtual router advertisement-interval. The no form of the command resets the parameter to its default.
Syntax Description	seconds	The virtual router advertisement-interval in seconds Range: 1-255
Default	1
Configuration Mode	config vrrp interface
History	3.3.4500
Example	switch (config vrrp 100)# advertisement-interval 10
Related Commands
Notes

show vrrp

	show vrrp [interface <type> <number>] [vr <id>] Displays VRRP brief configuration and status.
Syntax Description	interface <type> <number>	Filters the output to a specific interface type and number
Syntax Description	vr <id>	Filters the output to a specific virtual router Range: 1-10
Default	N/A
Configuration Mode	Any command mode
History	3.3.4500
History	3.9.1000	Added support for VRRP IPv6 instance
Example	switch (config) # show vrrp Interface VR Admin State Priority Adv-Intvl Preempt State VR IP addr ------------------------------------------------------------------------------ Vlan20 100 Enabled 100 1 Enabled Master 20.20.20.40 Vlan20 100 Enabled 100 1 Enabled Master 2001::40
Related Commands
Notes

show vrrp detail

	show vrrp detail [interface <type> <number>] [vr <id>] Displays detailed VRRP configuration and status.
Syntax Description	interface <type> <number>	Filters the output to a specific interface type and number
Syntax Description	vr <id>	Filters the output to a specific virtual router Range: 1-255
Default	N/A
Configuration Mode	Any command mode
History	3.3.4500
	3.6.5000	Updated example
	3.6.8008	Updated example
	3.9.1000	Added support for VRRP IPv6 instance
Example	switch (config) # show vrrp detail VRRP Admin State: Enabled Vlan20 - Vrrp 100: Instance Admin State : Enabled State : Master State v6 : Master Virtual IP Address : 20.20.20.40 Virtual IPv6 Address : 2001::40 Priority : 100 Advertisement interval(sec) : 1 Preemption : Enabled Virtual MAC Address : 00:00:5e:00:01:64 Primary IP Address : 20.20.20.20 Master router : 20.20.20.20 Virtual MAC Address v6 : 00:00:5e:00:02:64 Primary IP Address v6 : :: Master router v6 : fe80::ba59:9fff:fea6:6988 Master priority : 100 Master advertisement interval: 1 Associated IP Addresses: 20.20.20.41 Associated IPv6 Addresses: 2001::41
Related Commands
Notes

show vrrp statistics

	show vrrp statistics [interface <type <number>] [vr <id>] [all] Displays VRRP counters.
Syntax Description	interface <type> <number>	Filters the output to a specific interface type and number
Syntax Description	vr <id>	Filters the output to a specific virtual router Range: 1-255
Default	N/A
Configuration Mode	Any command mode
History	3.3.4500
	3.6.5000	Updated example
	3.9.1000	Updated example
Example	switch (config) # show vrrp statistics Invalid packets: 0 Too short: 0 Transitions to Master: 0 Total received: 0 Bad TTL: 0 Failed authentication: 0 Unknown authentication: 0 Conflicting authentication: 0 Conflicting Advertise time: 0 Conflicting Addresses: 0 Received with zero priority: 0 Sent with zero priority: 0 Invalid packets v6: 0 Too short v6: 0 Transitions to Master v6: 0 Total received v6: 0 Bad TTL v6: 0 Conflicting Advertise time v6: 0 Conflicting Addresses v6: 0 Received with zero priority v6: 0 Sent with zero priority v6: 0
Related Commands
Notes

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