EVPN Layer 2 Attributes Extended Community

In big and complex networks, there are multiple transport domains, different devices, different services, and different link types. All these differentiations need to have some parameters for negotiations. draft-ietf-bess-rfc7432bis has defined the new "EVPN Layer 2 Attributes Extended Community," which allows for the control of Layer 2 Maximum Transmission Unit (MTU), Control Word (CW), and flow label. It helps MTU negotiation between networks, frame ordering, and increasing entropy for load-balancing accordingly.
In our test, we configured EVPN-VPWS as the overlay service and began advertising the Layer 2 Attributes Extended Community using BGP. Initially, all CW, MTU, and flow label settings were matched, ensuring that the EVPN-VPWS service was operational. Subsequently, we intentionally configured mismatches for any of the three parameters to verify that the EVPN-VPWS service would go down. No traffic was generated during the entire test.
The results are as follows:
- Arista: CW, MTU
- Arrcus: CW, Flow label, MTU
- H3C: CW, Flow label, MTU
- Ribbon: MTU