Wednesday, December 01, 2004

What's the difference between HSRP and VRRP?

In short, the answer is "Not much!" (By the way, both are even worth
the same amount of points in Scrabble.)

HSRP (Hot Standby Router Protocol) is a Cisco method of router
redundancy. VRRP (Virtual Router Redundancy Protocol) is an industry
standard that operates on multiple vendors' routers.

VRRP is spelled out in RFC 2338, which notes VRRP's similarity to both
Cisco's HSRP and to DEC's IPSTB (IP Standby Protocol). The features and
functions are very similar.

VRRP can offer HMAC-based authentication as a security feature as well
as the password-level protection that HSRP offers. HSRP will always use
authentication. If not specified, the default value is "cisco." Go
figure.

VRRP timing intervals are, by default, faster than HSRP. The priority
level and default as well as pre-empt capabilities are "virtually"
identical between the two. VRRP allows for multiple IP addresses to be
assigned at one time, where HSRP utilizes separate groups to accomplish
this. While VRRP utilizes ICMP redirects to assist in the failover
process, HSRP specifically prohibits their use.

And though HSRP was put into RFC status with RFC 2281, it never
received full adoption. Both router protocols use local-link multicast
addresses to pass information:

HSRP = 224.0.0.2
VRRP = 224.0.0.18

For a little historical background, HSRP was created in 1994 and was
published in an RFC in March 1998. VRRP got its own RFC a month later,
in April 1998.

For further information, check out:

HSRP: http://www.faqs.org/rfcs/rfc2281.html
VRRP: http://www.faqs.org/rfcs/rfc2338.html

CREDITS : Last but not the least i need to say that i picked up so detail explanation from a article by Scott Morris who is a quad CCIE and it can be read here.

Nitin



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