Ietf rfc and internet draft support – Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) User Manual
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Multi-Service IronWare Routing Configuration Guide
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OSPF graceful restart
times until a configured maximum delay time value is reached or no event occurs (which resets the
router to the initial hold time). The maximum value is then held until the hold time expires without a
topology change event occurring. At any time that a hold time expires without a topology change
event occurring, the router reverts to the initial hold value and begins the process all over again.
For example if you set the initial delay timer to 100 milliseconds, the hold timer to 300 and the
maximum hold timer to 2000 milliseconds, the following would occur:
If a topology change occurs the initial delay of 100 milliseconds will be observed. If a topology
change occurs during the hold time of 300 milliseconds the hold time is doubled to 600
milliseconds. If a topology change event occurs during the 600 millisecond period, the hold time is
doubled again to 1200 milliseconds. If a topology change event occurs during the 1200
millisecond period, the hold time is doubled to 2400 milliseconds. Because the maximum hold
time is specified as 2000, the value will be held at 2000. This 2000 millisecond period will then
repeat as long as topology events occur within the maximum 2000 millisecond hold time. When a
maximum hold time expires without a topology event occurring, the router reverts to the initial delay
time and the cycle repeats as described.
The purpose of this feature is to use longer SPF scheduling values during network topology
instability.
Configuration of this feature is described in
“Configuring OSPF shortest path first throttling”
IETF RFC and internet draft support
The implementation of OSPF Graceful Restart supports the following IETF RFC:
•
RFC 3623: Graceful OSPF Restart
NOTE
A secondary management module must be installed for the device to function as a graceful restart
device. If the device functions as a graceful restart helper device only, there is no requirement for a
secondary management module.
For details on how to configure OSPF Graceful Restart, refer to