Network OS Administration Guide

Supporting Network OS 6.0.1a

Part Number: 53-1003768-04

Metro VCS over a long-distance fabric

Whenever standard VCS Fabrics are interconnected through LAG/vLAG, they are not limited beyond LAG/vLAG protocol capabilities.

Metro VCS Fabrics (stretched fabrics) that are interconnected with standard fabrics are supported for distances up to 100 km.

As shown in the following figure, one side can be a Metro VCS over a long-distance fabric.

Figure 24. Metro VCS and distributed Ethernet fabrics

In all deployment with interconnects using edge ports, lossless Ethernet traffic (DCB/FCoE ) is not supported.

In order to connect two distinct VCS Ethernet fabrics between data centers, a third Metro VCS fabric can be formed, and the distinct local VCS Ethernet fabrics can connect to the Metro VCS fabric by means of Virtual Link Aggregation (vLAG).

Alternatively, the distinct VCS Ethernet fabrics in the respective data centers can be directly connected to each other by means of vLAG over xWDM up to a distance of 10 or 30 km. Wherever bit-transparency is not achievable in xWDM equipment, this solution can be successfully deployed for edge-to-edge interconnectivity (using 10G, 40G, or 100G vLAGs over multiple standard Ethernet links). This deployment is referred to as "Distributed Ethernet Fabrics using vLAG."

This implementation eliminates the need for the creation of a separate Metro VCS fabric to achieve local VCS cluster isolation while providing Layer 2 connectivity. In such a deployment, DCB/FCoE lossless Ethernet traffic is not supported.

When a port-channel from a node in one VCS spans across multiple RBridges in other VCS cluster, a vLAG is formed on the RBridges in the VCS cluster that are part of the same port-channel. For Distributed Ethernet Fabrics using vLAG over long distances, only LACP-based standard port-channels are supported. For details on how to create port-channels and vLAGs, refer to “Configuring Link Aggregation” chapter of the Network OS Layer 2 Switching Configuration Guide.