BGP D-PATH configuration

The D-PATH attribute is modified on transmission or processed on reception based on the local VPRN or R-VPLS configuration. The domain ID is configured per-BGP instance and the ISF_SAFI_TYPE automatically derived from the instance type that imported the original route.

The domain-id is configured at service bgp instance level as a six-byte value that includes a global admin value and a local admin value, for example, 65000:1. Domain ID configuration is supported on:

• VPRN BGP-EVPN MPLS and SRv6 instances (EVPN-IFL)
• VPRN BGP-IPVPN MPLS and SRv6 instance
• R-VPLS BGP-EVPN MPLS and VXLAN instances (EVPN-IFF only – the R-VPLS is configured with the evpn-tunnel command)
• VPRN BGP neighbors (PE-CE)
• VPRN level (for local routes)

The following is an example CLI configuration:

// domain-id configuration

*[ex:configure service vprn "blue" bgp-evpn mpls 1]
*[ex:configure service vprn "blue" bgp-evpn segment-routing-v6 1]
*[ex:configure service vprn "blue" bgp-ipvpn mpls 1]
*[ex:configure service vprn "blue" bgp-ipvpn segment-routing-v6 1]
*[ex:configure service vprn "blue" bgp]
*[ex:configure service vpls "blue" bgp-evpn routes ip-prefix]
+-- domain-id <global-field:local-field>


*[ex:configure service vprn "blue"]
A:admin@PE-2# 
+-- local-routes-domain-id <global-field:local-field>
// used as the domain-id for non-bgp routes in the VPRN.


// Example ‘a’

*[ex:configure service vprn "blue" bgp-ipvpn mpls 1]
    domain-id 65000:1

In the preceding "example 'a'", if a VPN-IPv4 route is received from a neighbor, imported in VPRN "blue" and exported to another neighbor as EVPN, the router prepends a D-PATH segment <65000:1:IPVPN> to the advertised EVPN RT5.

// Example ‘b’

*[ex:configure service vprn "blue"]
    local-routes-domain-id 65000:10

In the preceding "example 'b'", the local-routes-domain-id is configured at the vprn level. When configured, local routes (direct, static, IGP routes) are advertised with a D-PATH that contains the vprn>local-routes-domain-id.

The following additional considerations apply:

• If vprn>local-routes-domain-id is not configured, the local routes are advertised into the BGP instances with no D-PATH.
• If a VPRN BGP instance is not configured with a domain ID, the following handling applies:
  • Routes imported in the VPRN BGP instance are readvertised in a different instance without modifying the D-PATH.
  • Routes exported in the VPRN BGP instance are advertised with the D-PATH modified to include the domain ID of the instance that imported the route in the first place.
• Up to a maximum of four domain IDs per VPRN are supported. This includes domain IDs configured in the associated R-VPLS services.
• Modifying the domain IDs list initiates a route refresh for all address families associated with the VPRN.