Inter-AS Traffic Engineering Requirements

The proper establishment and functioning of inter-AS traffic engineered LSPs depend on the following network requirements, all of which must be met:

• All ASs are under control of a single service provider.
• OSPF is used as the routing protocol within each AS, and EBGP is used as the routing protocol between the ASs.
• ASBR information is available inside each AS.
• EBGP routing information is distributed by OSPF, and an IBGP full mesh is in place within each AS.
• Transit LSPs are not configured on the inter-AS links, but are configured between entry and exit point ASBRs on each AS.
• The EBGP link between ASBRs in different ASs is a direct link and must be configured as a passive traffic engineering link under OSPF. The remote link address itself, not the loopback or any other link address, is used as the remote node identifier for this passive link. For more information about OSPF passive traffic engineering mode configuration, see Configuring OSPF Passive TE Mode.

In addition, the address used for the remote node of the OSPF passive traffic engineering link must be the same as the address used for the EBGP link. For more information about OSPF and BGP in general, see the JUNOS Routing Protocols Configuration Guide.

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