Home » Cisco » 350-080 » Which GLBP timer can be tuned to prevent unnecessary GLBP state changes during a switchover or ISSU?
In a Cisco Nexus 7000 platform configured with GLBP, which GLBP timer can be tuned to prevent unnecessary GLBP state changes during a switchover or ISSU?
A. GLBP redirect timer
B. GLBP forwarder pre-empt delay minimum timer
C. GLBP hold timer
D. GLBP pre-empt delay minimum timer
E. GLBP extended hold timer
F. GLBP nonstop forwarding timer
Correct Answer: E
Explanation/Reference:
Explanation:
GLBP supports high availability through stateful restarts and stateful switchovers. A stateful restart occurs when the GLBP process fails and is restarted. A stateful switchover occurs when the active supervisor switches to the standby supervisor. Cisco NX-OS applies the run-time configuration after the switchover.
If GLBP hold timers are configured for short time periods, these timers might expire during a controlled switchover or in-service software upgrade (ISSU). GLBP supports extended non-stop forwarding (NSF) to temporarily extend these GLBP hold timers during a controlled switchover or ISSU.
With extended NSF configured, GLBP sends hello messages with the extended timers. GLBP peers update their hold timers with these new values. The extended timers prevent unnecessary GLBP state changes during the switchover or ISSU. After the switchover or ISSU event, GLBP restores the hold timers to their original configured values. If the switchover fails, GLBP restores the hold timers after the extended hold timer values expire.
Reference: http://www.cisco.com/c/en/us/td/docs/switches/datacenter/sw/5_x/nx-os/unicast/configuration/guide/l3_cli_nxos/l3_glbp.html (High Availability and Extended Nonstop Forwarding)