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Ospf abr type 3 lsa filtering, Usage guidelines, Changing the lsa pacing interval – Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) User Manual

Page 231: Usage and configuration guidelines

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Multi-Service IronWare Routing Configuration Guide

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Adding additional parameters

Usage guidelines

The pacing interval is inversely proportional to the number of LSAs the device is refreshing and
aging. For example, if you have approximately 10,000 LSAs, decreasing the pacing interval
enhances performance. If you have a very small database (40 – 100 LSAs), increasing the pacing
interval to 10 – 20 minutes might enhance performance slightly.

Changing the LSA pacing interval

To change the LSA pacing interval, use the following CLI method.

To change the LSA pacing interval to two minutes (120 seconds), enter the following command.

Brocade(config-ospf-router)# timers lsa-group-pacing 120

Syntax: [no] timers lsa-group-pacing secs

The secs parameter specifies the number of seconds and can be from 10 – 1800 (30 minutes).
The default is 240 seconds (four minutes).

To restore the pacing interval to its default value, enter the following command.

Brocade(config-ospf-router)# no timers lsa-group-pacing

OSPF ABR type 3 LSA filtering

OSPF ABR Type 3 LSA filtering increases the ability of an ABR that is running the OSPF protocol to
filter type 3 link-state advertisements (LSAs) that are sent between different OSPF areas. Only
packets with specified prefixes will be sent from one area to another area and all packets with
other prefixes will be prohibited.

Type 3 LSAs refer to summary links and are sent by ABRs to advertise destinations outside the
area. OSPF ABR Type 3 LSA filtering gives the administrator improved control of route distribution
between OSPF areas.

Usage and configuration guidelines

The “area prefix-list” command is only applicable to the ABRs. If the router is not an ABR
the configuration is accepted however it will start working only after router is made ABR.

With this feature enabled in the “in” direction, all type 3 LSAs originated by the ABR to this
area, based on information from all other areas, are filtered by the prefix list. Type 3 LSAs
that were originated as a result of the area range command in another area are treated
like any other type 3 LSA that was originated individually. Any prefix that does not match an
entry in the prefix list is implicitly denied.

With this feature enabled in the “out” direction, all type 3 LSAs advertised by the ABR,
based on information from this area to all other areas, are filtered by the prefix list. If the
area range command has been configured for this area, Type 3 LSAs that corresponds to
the area range command are treated like any other type 3 LSA.

Prefixes that are not permitted by the prefix list are implicitly denied.

The following table displays the behavior for prefix list configurations