Gateway Load Balancing Protocol
As a admirable generalization, the Aperture Load-Balancing Protocol (GLBP) can be admired as
an another to both HSRP and VRRP, in that GLBP additionally provides a basal absence gateway
as the ambition for hosts on an Ethernet. The capital aberration amid the protocols is that both
HSRP and VRRP baddest an alive router, and the standby routers are not acclimated at all.
GLBP uses the aforementioned assumption for the basal IP abode as the absence gateway, but uses
more than one basal MAC abode to bind this to. This has the appulse of acceptance hosts to
select altered routers as the absence aperture while still application the basal IP abode that guarantees
GLBP is actual agnate to HSRP, afar from the actuality that added than one MAC abode will be
used to map to the basal IP address. It may be adamantine to see why you should accept to use GLBP,
given the actuality that HSRP has such a ample following. In fact, the load-sharing accommodation of GLBP,
while actual useful, can about be accomplished by HSRP if you accept several VLANs to support, as
each VLAN can be configured with its own absence aperture mapped to a altered HSRP group.
Nonetheless, back application HSRP in a distinct VLAN environment, and with a distinct absence gateway
address, it is accurate that alone one router will be forwarding in the group. GLBP will change that.
The architecture of the GLBP accumulation is actual simple in basal networks, but in ample networks where
you crave assorted groups, time charge be taken to accede how altered groups can interact.
Remember to plan your absolute agreement beforehand, because this protocol
starts active as anon as it is enabled.
Many of the commands that you accept apparent in HSRP accept a alongside central GLBP, so don’t
expect any surprises in the abutting sections.