Guidelines on DWDM Links for Network and Data

The network interfaces used must support DLPI (link level).

There must be less than 200 milliseconds of latency in the network between the data centers.

No routing is allowed for the networks between the data centers.

Routing is allowed to the third data center if a Quorum Server is used in that data center.

The maximum distance supported between the data centers for DWDM configurations is 100 kilometers.

Both the networking and Fibre Channel Data Replication can go through the same DWDM box - separate DWDM boxes are not required.

Since DWDM converters are typically designed to be fault tolerant, it is acceptable to use only one DWDM box (in each data center) for the links between each data center. However, for the highest availability, it is recommended to use two separate DWDM boxes (in each data center) for the links between each data center. If using a single DWDM box for the links between each data center the redundant standby fibre link feature of the DWDM box must be configured. If the DWDM box supports multiple active DWDM links, that feature can be used instead of the redundant standby feature.

At least two dark fibre optic links are required between each Primary data center, each fibre link routed differently to prevent the “backhoe problem.” It is allowable to have only a single fibre link routed from each Primary data center to the third location, however in order to survive the loss of a link between a Primary data center and the third data center, the network routing should be configured so that a Primary data center can also reach the Arbitrator via a route passing through the other Primary data center.

The network switches in the configuration must support DLPI (link level) packets. The network switch can be 100BaseT (TX or FX), 1000BaseT (TX or FX) or FDDI. The connection between the network switch and the DWDM box must be fibre optic.

FibreChannel switches must be used in a DWDM configuration; FibreChannel hubs are not supported. Direct Fabric Attach mode must be used for the ports connected to the DWDM link.