Virtual Router Redundancy Protocol (VRRP)

Virtual Router Redundancy Protocol (VRRP) is an open protocol (not a proprietary protocol). It introduces the concept of the virtual router to improve the redundancy of the default gateway of hosts.

This article checks the uses and importance of VRRP.

One commenter, Frank, asked about how VRRP ensures the Network Redundancy. Another reader, Kevin Thomas, asked about using a virtual router in this protocol. Let me answer both here.

According to VRRP, a virtual router (VR) is not just a physical router but includes the master and backup routers.

This VR concept ensures that if one router fails, another will take the charge immediately. However, at a time, only one master acts as the default gateway, and the master informs the backup routers of its current status.

The backup router will take place in the position of the master if the master becomes unavailable.

Ronald asked me if he could configure a Cisco router with VRRP. Cisco uses a different protocol, HSRP.

Virtual Router Redundancy Protocol is an open-source protocol similar to Cisco's proprietary protocol, the Hot Standby Router Protocol (HSRP). However, both protocols are not compatible despite their similarities.

You have learned the basics of VRRP. Let us check how to configure the Virtual Router Redundancy Protocol.

Kanaka Raj, a young network engineer, wanted a tutorial on configuring VRRP. I guess the steps below will help him learn it.

1. The Virtual Router (VR) works as the default gateway of hosts.

2. A group of physical routers comes under VR, but only one master at a time.

3. The master router informs backup routers of its current status (all the time).

4. When the master fails, one backup router assumes the role of master.

5. The concept of VirtualRuter by Virtual Router Redundancy Protocol improves network redundancy.

6. The MAC address of the VR must be in this format: 00-00-5E-00-01-XX.

7. The IP address used for multicast is 224.0.0.18.

You have learned the basics of the Virtual Router Redundancy Protocol and its application in a network.

You have learned the basics of VRRP. For further studies, I recommend the following tutorials from Cisco and Juniper.

1. https://www.juniper.net/documentation/us/en/software/junos/high-availability/topics/topic-map/vrrp-understanding.html
2. https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipapp_fhrp/configuration/15-mt/fhp-15-mt-book/fhp-vrrp.html
3. https://www.cisco.com/c/en/us/td/docs/routers/crs/software/crs_r4-0/addr_serv/configuration/guide/ic40crs1book_chapter10.html