Enabling BGP to Carry CLNS Routes

Connectionless Network Service (CLNS) is a Layer 3 protocol similar to IP version 4 (IPv4). CLNS uses network service access points (NSAPs) to address end systems. This allows for a seamless AS based on ISO NSAPs.

Note: CLNS is supported for the J Series Services Router only.

A single routing domain consisting of ISO NSAP devices are considered to be CLNS islands. CLNS islands are connected together by VPNs.

You can configure BGP to exchange ISO CLNS routes between PE routers connecting various CLNS islands in a VPN using multiprotocol BGP extensions. These extensions are the ISO VPN NLRIs.

To enable MP-BGP to carry CLNS VPN NLRIs, include the iso-vpn statement:

To limit the number of prefixes from a peer, include the prefix-limit statement. To specify a routing table group, include the rib-group statement.

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

Each CLNS network island is treated as a separate VRF instance on the PE router.

You can configure CLNS on the global level, group level, and neighbor level.

For information on CLNS, see Configuring CLNS for IS-IS and the Junos OS Interfaces and Routing Configuration Guide.

For sample configurations, see the following sections:

• Example: Enabling CLNS Between Two Routers
• Example: Configuring CLNS Within a VPN

Example: Enabling CLNS Between Two Routers

Configure CLNS between two routers through a route reflector:

Example: Configuring CLNS Within a VPN

Configure CLNS on three PE routers within a VPN: