EVPN Flex Cross Connect - L2 P2P VPNs can be agile as well!#

Tobias Heister (Plusnet)

• Why: RFC 9744 (EVPN Flexible Cross-Connect) is a new and important extension for L2 point-to-point service scaling in aggregation networks — directly relevant to the PM's EVPN and fabric interests.
• What: A practical explanation of how EVPN VPWS Flexible Cross-Connect (FXC, RFC 9744, March 2025) solves the PW scaling problem in aggregation networks where many ports/VLANs need to map to a single tunnel. Demonstrated with real deployment numbers: Plusnet's scenario (3 target categories, 12 AGGs per region, 24 ports per AGG) shows a 95% reduction in PW count (from 288 down to 3 per AGG). PoC-tested on Juniper and Arista with interop working. Deployed in production at Plusnet.
• How: FXC normalizes VLAN IDs across ports and maps multiple normalized VIDs to a single PW/service tunnel. Two modes: Default FXC (one route regardless of how many port/AC/VID combinations attach) vs VLAN-Signaled FXC (one route per normalized VID per instance, enabling cross-checks). This reduces both EVPN service labels and BGP signaling volume.
• Where applicable: Service providers and operators with large aggregation networks running L2 services (backhauling to BNGs or service routers). Requires vendor support for RFC 9744 (Juniper and Arista confirmed). The VLAN normalization part depends heavily on vendor L2 feature flexibility — Arista's Flex-Encap and "unmatched" features called out as particularly well-suited.