VRRP

by | Oct 15, 2013 | High Availability, Routing | 0 comments

Virtual Router Redundancy Protocol or VRRP is an open standard that eliminates a single point of failure inherent in the static default routed environment. VRRP specifies an election protocol that dynamically assigns responsibility for a virtual router. It’s a First Hop Routing protocol just like it’s cousin HSRP. VRRP is very similar in nature to HSRP with a few exception. VRRP is an open standard as opposed to proprietary nature of HSRP. Because of the open nature, VRRP can be configured to run between a Cisco Router and a Juniper Router for example.

RFC

Priority

  • Priority 1 – 255
  • Default 100

Multicast Address

  • Hello Messages every 3 seconds
  • Dead Interval at 10 seconds
  • Address = 224.0.0.18
  • UDP Port = 8888
  • Protocol = 112

Features

  • Primary Router in the Group is called the Master Router
  • There is one virtual IP addressed shared between Gateways
  • Virtual MAC: 0000.5E00.01XX where XX is hex VRRP Group number
  • The real IP address of an interface can be used as opposed to virtual
  • The ability to preempt is the event of failure
  • Priority range 0 – 255
  • Multicast address – 224.0.0.18

Lets start off by getting the ISP interfaces up and running…

ISP(config)#
ISP(config)#interface Serial0/0
ISP(config-if)#description R1
ISP(config-if)#ip address 10.0.1.1 255.255.255.252
ISP(config-if)#exit
ISP(config)#
ISP(config)#
ISP(config)#interface Serial0/1
ISP(config-if)#description R2
ISP(config-if)#ip address 10.0.2.1 255.255.255.252
ISP(config-if)#exit
ISP(config)#

Now lets take a quick look at the status of the ISP interfaces 

ISP#show ip interface brief | include up

Interface   IP-Address    OK?     Method   Status     Protocol
Serial0/0   10.0.1.1      YES     manual   up         up
Serial0/1   10.0.2.1      YES     manual   up         up

Lets get the Interfaces up and running on Router R1

R1(config)#
R1(config)#interface Serial0/0
R1(config-if)#description ISP
R1(config-if)#ip address 10.0.1.2 255.255.255.252
R1(config-if)#exit
R1(config)#
R1(config)#
R1(config-if)#interface Ethernet1/0
R1(config-if)#ip address 172.17.0.1 255.255.255.0
R1(config-if)#duplex full
R1(config-if)#speed 100
R1(config-if)#vrrp 1 ip 172.17.0.3
R1(config-if)#vrrp 1 priority 2
R1(config-if)#exit
R1(config)#

Lets take a quick look at thee status of the Interfaces on Router R1

R1#show ip interface brief | include up

Interface    IP-Address  OK   Method  Status  Protocol
Serial0/0    10.0.1.2    YES  manual  up      up
Ethernet1/0  172.17.0.1  YES  manual  up      up

Lets check out the VRRP Interface status on Router R1

R1#show vrrp interface e1/0

Ethernet1/0 - Group 1
State is Master
Virtual IP address is 172.17.0.3
Virtual MAC address is 0000.5e00.0101
Advertisement interval is 1.000 sec
Preemption enabled
Priority is 2
Master Router is 172.17.0.1 (local), priority is 2
Master Advertisement interval is 1.000 sec
Master Down interval is 3.992 sec

Lets a take brief look at the VRRP status on Router R1

R1#show vrrp brief

Interface  Grp Pri Time Own Pre  State  Master addr Group addr
Et1/0      1   2   3992     Y    Master 172.17.0.1  172.17.0.3

Lets get the ISP Serial Interface on Router R2 up and running

R2(config)#
R2(config)#interface Serial0/0
R2(config-if)#description ISP
R2(config-if)#ip address 10.0.2.2 255.255.255.252
R2(config-if)#exit
R2(config)#

Lets take a quick look at the Interface status on Router R2

R2#show ip interface brief | include up

Interface    IP-Address  OK?  Method  Status Protocol
Serial0/0    10.0.2.2    YES  manual  up     up
Ethernet1/0  172.17.0.2  YES  manual  up     up

Lets get VRRP up and running on Router R2 Ethernet Interface

R2(config)#
R2(config)#interface Ethernet1/0
R2(config-if)#ip address 172.17.0.2 255.255.255.0
R2(config-if)#duplex full
R2(config-if)#speed 100
R2(config-if)#vrrp 1 ip 172.17.0.3
R2(config-if)#vrrp 1 priority 1
R2(config-if)#exit
R2(config)#

Now that VRRP is up and running on Router R2 lets take a look at Interface status

 R2#show vrrp interface e1/0

 Ethernet1/0 - Group 1
 State is Backup
 Virtual IP address is 172.17.0.3
 Virtual MAC address is 0000.5e00.0101
 Advertisement interval is 1.000 sec
 Preemption enabled
 Priority is 1
 Master Router is 172.17.0.1, priority is 2
 Master Advertisement interval is 1.000 sec
 Master Down interval is 3.996 sec (expires in 3.872 sec)

Lets take a brief look at the VRRP status on Router R2

R2#show vrrp brief 

Interface Grp Pri Time Own Pre State  Master addr Group addr
Et1/0     1    1    3996   Y   Backup 172.17.0.1  172.17.0.3

Virtual Router Redundancy Protocol much like HSRP is an election protocol that dynamically assigns responsibility between one or more Routers within a VRRP Group utilizing virtual or real IP addresses on a LAN. This allows several Routers on a multiaccess to provide redundancy.

I hope you found this post on VRRP helpful and informative. Be sure to let me know what you think by leaving suggestions, and feedback in the comments section below. You can find out more about these and other articles be checking out recent posts and archives. To learn more about me be sure to check out the About page. And as always thanks again for visiting The Packet.

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