Redundancy Madness

I like redundancy solutions -- they're fun to configure. Conceptually they are simple. I think the complexity arises when they are used for load balancing. For the CCNP, Cisco press presents three redundancy technologies: HSRP, VRRP, and GLBP. Here's a breakdown of each:

HSRP (Hot Standby Routing Protocol)

-Cisco proprietary
-uses a default hello timer of 3 seconds with a hold timer of 10 seconds
-can load balance using multiple HSRP isntances or 'groups'

VRRP (Virtual Routing Redundancy Protocol)

-open standard
-faster timers than HSRP by default -- hello=1 second, hold timer = 3 seconds

GLBP ( Gateweay Load Balancing Protocol)

- Cisco proprietary also
-just like HSRP except it's designed for easier load balancing because it allows an active-active configuration

That's the bare basics of all three. In the following week I will have a series of posts that delve into the various complexities of these three redundancy protocols..