Configuring Import and Export Policies for Network Summaries

By default, OSPF uses network-summary link-state advertisements (LSAs) to transmit route information across area boundaries. Each area border router (ABR) floods network-summary LSAs to other routers in the same area. Beginning with JUNOS Release 9.1, you can configure export and import policies for OSPFv2 and OSPFv3 that enable you to control how network-summary LSAs, which contain information about interarea OSPF prefixes, are distributed and generated. For OSPFv3, the LSA is referred to as the interarea prefix LSA and performs the same function as a network-summary LSA performs for OSPFv2. An ABR originates an interarea prefix LSA for each IPv6 prefix that must be advertised into an area.

The export policy enables you to specify which summary LSAs are flooded into an area. The import policy enables you to control which routes learned from an area are used to generate summary LSAs into other areas. You define a routing policy at the [edit policy-options policy-statement policy--name] hierarchy level. As with all OSPF export policies, the default for network-summary LSA export policies is to reject everything. Similarly, as with all OSPF import policies, the default for network-summary LSA import policies is to accept all OSPF routes. For more information about configuring policies, see the JUNOS Policy Framework Configuration Guide.

To apply an export routing policy for OSPFv2 that affects which network-summary LSAs are flooded into an area, include the network-summary-export [ policy-names ] statement:

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

To apply an import routing policy for OSPFv2 that affects which routes learned from an area are used to generate network-summary LSAs, include the network-summary-import [ policy-names] statement:

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

To apply an export routing policy for OSPFv3 that affects which interarea prefix LSAs are flooded into an area, include the inter-area-prefix-export [ policy-names ] statement:

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

To apply an import routing policy for OSPFv3 that affects which routes learned from an area are used to generate interarea prefix LSAs, include the inter-area-prefix-import [ policy-names ] statement:

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

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