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| 6.2 |  | Implementing Router Redundancy in a Switched Network |
| 6.2.5 |  | Gateway Load Balancing Protocol (GLBP) |

Like HSRP and VRRP, GLBP supplies a method of providing nonstop path redundancy for IP by sharing protocol and MAC addresses between redundant gateways. GLBP also allows a group of routers to share the load of the default gateway on a LAN. This improves performance by facilitating better use of network resources when multiple upstream paths are available and increases reliability and network availability removing the single point of failure, the first-hop router. GLBP enables a router to automatically assume the forwarding function of another router in the group if there is a failure in any other gateway router.

GLBP is supported on the following hardware platforms:

- Cisco 2600 series routers
- Cisco 3620 router
- Cisco 3640 router
- Cisco 7200 series routers
- Cisco 7500 series routers
- Cisco Catalyst 6000 MSFC
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Troubleshooting GLBP
GLBP allows traffic from a single common subnet to go through multiple redundant gateways while using a single virtual IP address. It provides the same level of first-hop failure recovery capability as provided by HSRP and VRRP.

Cisco IOS Software contains show and debug commands to allow network operators to determine the status of GLBP. These commands are useful for verifying the operation of GLBP and verifying that the design goals are being met relative to tracked objects and forwarder states.

Use the show glbp command to display GLBP operational information and statistics.