What is the difference between HSRP & GLBP?

In basic HSRP configuration one active router does all the forwarding for all its hosts, and the standby router is simply used only if the active router fails. Load balancing with HSRP requires the creation of two HSRP groups.

GLBP has the redundant gateways which share multiple virtual MAC addresses. Both routers are considered active for any given subnet and the load balancing can be usually configured in three ways:

-Round-robin—GLBP cycles through the virtual MAC addresses sent in ARP replies, load balancing the traffic across all the routers.

-Weighted—The primary router uses the advertised weight for secondary routers to decide the load that will be directed to them.

-Host dependent—GLBP uses the MAC address of the host to determine which virtual MAC address to direct the host to use. This algorithm guarantees that a host gets the same virtual MAC address if the number of virtual forwarders does not change.