Gateway Load Balancing Protocol
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Gateway Load Balancing Protocol (GLBP) is a Cisco proprietary protocol that attempts to overcome the limitations of existing redundant router protocols by adding basic load balancing functionality.
In addition to being able to set priorities on different gateway routers, GLBP also allows a weighting parameter to be set. Based on this weighting (compared to others in the same virtual router group), ARP requests will be answered with MAC addresses pointing to different routers. Thus, load balancing is not based on traffic load, but rather on the number of hosts that will use each gateway router.
GLBP assigns the primary router as the Active Virtual Gateway (AVG) and the secondary router as the Active Virtual Forwarder (AVF). There can be multiple AVFs.
By default, GLBP routers use the local multicast address 224.0.0.102 to send hello packets to their peers every 3 seconds over UDP 3222 (source and destination).
[edit] See also
- VRRP Virtual router redundancy protocol
- HSRP Cisco proprietary router redundancy solution
- Common Address Redundancy Protocol
