4. Filtering
PEs and BRs may support filtering of CAR routes. For instance, filtering may only accept routes of locally configured colors. Techniques such as RT Constrain can be applied to CAR SAFI to constrain distribution and automate CAR route filtering.
5. Scaling
This section analyzes the key scale requirements from [INTENT-AWARE]:
- Intermediate node data plane should not need to scale to (Colors * PEs)
- If a node does not install colored service routes to E, it should not learn and install BGP CAR routes to (E, C)
Two key principles used to address scaling requirements are hierarchical network and routing design, and on-demand route subscription and filtering.
6. Routing Convergence
BGP CAR route convergence characteristics are similar to BGP-IP and BGP-LU. Multipath capability and hierarchical design help achieve fast convergence.
7. CAR SRv6
BGP CAR supports SRv6 encapsulation for establishing color-aware SRv6 transport paths. Both routed service SID and non-routed service SID deployment scenarios are supported.
8. CAR IP Prefix Route
CAR IP Prefix routes (Type-2 NLRI) are used for scenarios where unique IP prefixes are allocated for each intent, particularly suitable for per-intent locators in SRv6.
9. VPN CAR
VPN CAR SAFI (SAFI 84) is used to distribute intent-aware routes from different customers across provider networks while maintaining separation of customer address spaces.
Note: For complete technical details, please refer to RFC 9871 original text