Network OS Administration Guide

Supporting Network OS 6.0.1a

Part Number: 53-1003768-04

Metro VCS overview

Metro VCS allows you to interconnect different locations and form clusters of data centers over long distance in order to provide disaster protection/recovery and load sharing.

In cases where distances are moderate, within 30km, and where either dedicated fiber or transparent wavelength services are available, the Metro VCS approach is a good and cost-effective Layer 2 interconnect solution. Due to the multi-pathing capabilities of the TRILL-based Metro VCS solution there is no issue with topology loops between multiple DC locations.

For longer distances alternative solutions are available.

  • Interconnecting separate fabrics through Layer 2 point-to-point connectivity -- Layer 2 point-to-point connectivity is used to interconnect VCS Fabrics using their Edge-Ports. If more than one Layer 2 link is needed for capacity or for redundancy reasons, link aggregation (LAG/vLAG) can be used in order to avoid loops between the VCS Fabric edge ports and allow for active/active protection.
  • Interconnecting separate fabrics through Layer 2-VPN connectivity -- VCS Fabrics are interconnected through their edge ports using Layer 2-VPN connectivity. This can be implemented with Layer 2-VPN services from Connectivity Service Providers or using VPLS functionality implemented on Brocade MLX routers.
Figure 20. Metro VCS configuration example

Both options are distance independent in relation to the speed of the protocols used (for example, LAG/vLAG is a slow protocol) and provide flat Layer 2 interconnection between multiple locations. In the case of more than two DC locations, care needs to be taken in order to avoid any topology loops.

Metro VCS details and configuration

Metro VCS allows for interconnection of different locations and allows to form clusters of data centers over metro distances (<10/30 km) in order to provide disaster protection/recovery and application load sharing.

By using Inter-Switch Links (ISLs) over longer distances (more than the standard 1000 m), Ethernet fabrics can be distributed across data centers located in geographically different locations.

Figure 21. Basic Metro VCS configuration

If more complex setups are needed within different locations, then local VCS Fabrics can be used interconnected via a stretched interconnect fabrics.

Figure 22. Complex Metro VCS configuration

Standard VCS Fabrics scaling limitations apply if Inter-Switch Links (ISLs) are used over distances of up to 1000 m. Using Inter-Switch Links (ISLs) over longer distances (more than the standard 1000 m) is currently available for 10G, 40G, and 100G ISLs and can be done in two ways:

  • Configuring long-distance ISLs (LD-ISLs) -- This is supported only on 10G ISLs does not restrict fabric topologies (such as the numbers of nodes and number of locations) beyond the standard VCS Fabric scalability. LD-ISLs can be used over distances up to 10km if lossless services (DCB, FCoE) are needed and over distances of 30km if only standard Ethernet is needed.
  • Using standard ISLs over longer distances -- This only works for restricted topologies (a maximum of 6 nodes and 3 locations) and for standard Ethernet (lossless Ethernet capabilities, such as no FCoE or lossless iSCSI, cannot be used in this case). The standard 10G ISL can be used over distances up to 30 km, and standard 40G and 100G ISLs can support distances up to 10 km.