Brocade Virtual ADX Switch and Router Guide (Supporting ADX v03.1.00) - Manual (Page 276)

262 Brocade Virtual ADX Switch and Router Guide
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Filtering
8
Protocols are automatically notified when a route filter is created, deleted or modified. In addition,
when a protocol is notified of a filter change, appropriate steps are taken to apply the new or
updated filter to existing routes.
Commands for dynamic route filter updating
In order to allow multiple filter updates to be processed together by applications, the device waits
10 seconds by default before notifying applications of the filter change. You can force an
immediate update notification or modify the time delay from when a change is made to a route
filter to when the protocols are notified.
Route filter update delay settings can be configured using the commands shown here.
Setting a time delay for route filter update notification
Set the amount of time that the device waits before sending filter additions and modification
notification to protocols using the following command.
Virtual ADX(config)# filter-change-update-delay 100
Syntax: [no] filter-change-update-delay delay-time
The delay-time variable specifies the amount of time in seconds that the device waits before
sending filter addition and modification notification to protocols. The valid range is 0 to 600
seconds. If you set the value to 0, filter change notifications will not be automatically sent to
protocols. The default value is 10 seconds.
NOTE
Debugging of route filtering can be done using the debug route-filters command.
NOTE
There may be delays in sending route filter change notifications to applications, and delays in
applying the new or updated filter to all existing routes retroactively. However any new routes or
changes to existing routes will be subject to the new filters.
Filter update delay and BGP
The filter-changes-update-delay command applies only to changes of filters that are already used
or referenced by applications. If the content of a filter is changed, the new filter action takes effect
after filter-changes-update-delay for existing routes. The notification delay does not apply to
situations where the usage or reference of a filter is changed in a protocol.
For example, the following BGP neighbor command sets or changes the route-map filter on a
neighbor:
Virtual ADX(config-bgp)# neighbor x.x.x.x route-map map_abc out
In this case, the router applies the route-map “map_abc” to the peer immediately, and
automatically applies the new route-map filter retroactively to existing routes.
NOTE
The auto-update action for a BGP peer filter is newly introduced in release 3.5. In previous releases,
a user needs to manually issue the clear ip bgp neighbor x.x.x.x soft out command to cause the
router to apply the new route-map retroactively to existing routes.
The general guideline is to define a policy first, then apply it to a BGP peer.