The use of MPLS tunnels provides the 7450 ESS and 7750 SR OS a way to scale the core while offering fast failover times using MPLS FRR. In environments where Ethernet services are deployed using native Ethernet backbones, Ethernet tunnels are provided to achieve the same fast failover times as in the MPLS FRR case.
The Nokia VLL implementation offers the capability to use core Ethernet tunnels compliant with ITU-T G.8031 specification to achieve 50 ms resiliency for backbone failures. This is required to comply with the stringent SLAs provided by service providers. Epipe and Ipipe services are supported.
When using Ethernet tunnels, the Ethernet tunnel logical interface is created first. The Ethernet tunnel has member ports, which are the physical ports supporting the links. The Ethernet tunnel control SAPs carry G.8031 and 802.1ag control traffic and user data traffic. Ethernet service SAPs are configured on the Ethernet tunnel. Optionally, when tunnels follow the same paths, end-to-end services may be configured with fate shared Ethernet tunnel SAPs, which carry only user data traffic and share the fate of the Ethernet tunnel port (if correctly configured).
Ethernet tunnels provide a logical interface that VLL SAPs may use just as regular interfaces. The Ethernet tunnel provides resiliency by providing end-to-end tunnels. The tunnels are stitched together by VPLS or Epipe services at intermediate points. Epipes offer a more scalable option.
For further information, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR Services Overview Guide.