Friday, January 4, 2013

Difference between HSRP and VRRP


HSRP stands for Hot Standby Routing Protocol. VRRP stands for Virtual Route Rendundancy Protocol. The differences between HSRP versus VRRP are very slight especially when looking at the basic configuration side by side. But under the covers there are some significant differences. The end result, however is still the same.
 
If a router fails you need a standby router to become the active gateway and forward packets to the next hop

Here's a break down that compares the major differences between the two protocols.

HSRP Versus VRRP Comparison Table

HSRPVRRP
PropietaryStandards based
RFC 2281RFC 3768
Separate IP Address needed for the VirtualCan use the physical IP Address of the Virtual, if needed, saving IP space.
One Master, all other routers are backupOne Master, One Standby, all others are listening
More familiar to most network engineersLess familiar - yet very similar
Can track an interface for failoverCan track an interface for failover (depending on operating system and version)
All HSRP routers use multicast hello packets to 224.0.0.2 (all routers) for version 1 or 224.0.0.102 for version 2.All VRRP routers use IP protcol number 112 (vrrp) to communicate via multicast IP address 224.0.0.18
All virtual router must use MAC address 0000.0c07.acXX where XX is the group ID.All virtual routers must use 00-00-5E-00-01-XX as its Media Access Control (MAC) address

Configuration differences between HSRP and VRRP

 
The differences between both VRRP and HSRP, especially on a Cisco router are very slight. If your familiar with Configuring HSRP you can easily understand VRRP commands. Configuring VRRP on Juniper as well as other network equipment can vary significantly depending on the devices. Many load balancers also support VRRP and their configuration is specific to each of these devices.
 
Here are some configuration examples as seen on a Cisco router:
 
HSRP Configuration Example

R1(config)# interface GigE 0/1
R1(config-if)# ip address 192.168.1.2 255.255.255.0
R1(config-if)# standby 1 ip 192.168.1.1
R1(config-if)# standby 1 priority 200
R1(config-if)# standby 1 preempt

R2(config-if)# ip address 192.168.1.3 255.255.255.0
R2(config-if)# standby 1 ip 192.168.1.1
R2(config-if)# standby 1 preempt


 

VRRP Configuration Example

R1(config)# interface GigE 0/1
R1(config-if)# ip address 192.168.1.2 255.255.255.0
R1(config-if)# vrrp 1 ip 192.168.1.1
R1(config-if)# vrrp 1 priority 110

R2(config)# interface GigE 0/1
R2(config-if)# ip address 192.168.1.3 255.255.255.0
R2(config-if)# vrrp 1 ip 192.168.1.1

Notice the lack of a preempt command. This isn't necessary for VRRP. It's enabled by default.
As you can see there sin't a big difference between the two protocols. The primary difference between HSRP versus VRRP would be that HSRP is proprietary to Cisco and can only be used on Cisco devices. VRRP is a standards based protocol and is vendor independant allow some flexibility when choosing network devices.
 

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