Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 773)

Multi-Service IronWare Routing Configuration Guide 745
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IPv6 IS-IS Multi-Topology
The transition option allows the network to undergo transition from IPv6 IS-IS single-topology mode
to IPv6 IS-IS MT mode. By default, the transition mode is off.
The [no] form of the command disables the transition support.
Configuring the IS-IS IPv6 PSPF exponential back-off feature
The exponential back-off mechanism allows you to schedule PSPF processing for IPv6 IS-IS MT. An
initial-hold-time interval is the wait time after an LSP change until the first PSPF calculation.
Optionally, this value is followed by another configurable variable called the exponential-hold-time
interval that is used as a wait time between the first and second PSPF calculations.
The exponential-hold-time interval is increased in multiples of two until it reaches the maximum
hold time as configured by the max-hold-time variable. Once reached, the maximum hold time
remains the hold interval between PSPF calculations until there are no further changes in the
network. When there are no network changes in a hold down period, the gap between PSPF
calculations returns to the initial-hold-time interval and the process begins again.
If the initial-hold-time interval is configured without an exponential-hold-time, the max-hold-time
variable is used for the second and all subsequent intervals.
If the initial-hold-time and exponential-hold-time intervals are not configured, the max-hold-time
variable is used for the first and all subsequent intervals.
To configure the minimum time between the two consecutive partial route calculations for IPv6
IS-IS MT, enter the following command under the IPv6 unicast address family configuration level.
Brocade(config-isis-router-ipv6u)# partial-spf-interval 60 1000 5000
Syntax: [no] partial-spf-interval max-hold-time initial-hold-time exponential-hold-time
The max-hold-time variable specifies the maximum hold time between two Partial Shortest Path
First (PSPF) calculations. The range is from 0 through 120000 milliseconds. The default value is
5000 milliseconds.
The initial-hold-time variable is an optional value that specifies the hold time after an LSP change
until the first PSPF calculation. The range is from 0 through 120000 milliseconds. The default
value is 2000 milliseconds.
The exponential-hold-time variable is an optional value that specifies the hold time between the
first and second PSPF calculations. The range is from 0 through 120000 milliseconds. The default
value is 5000 milliseconds.
The [no] form of the command resets all parameters to their default values.
Changing the SPF timer
You can configure the minimum time between two consecutive SPF computations for IPv6 IS-IS MT,
by entering the following command under the IPv6 unicast address family configuration level.
Brocade(config-isis-router-ipv6u)# spf-interval 5 2000 2000
Syntax: [no] spf-interval max-hold-time initial-hold-time exponential-hold-time
The max-hold-time variable specifies the maximum time gap between consecutive SPF
calculations. The range is from 0 through 120 seconds. The default value is five seconds.