The Direct Link connection

The Direct Link option is a direct, private, gigabit connection between the Redundant Batch partners. This link transfers the batch redundancy system data between the two partners faster and with less traffic than using the DeltaV ACN. If the Direct Link connection fails for any reason, the batch redundancy system data is switched to the DeltaV ACN until the Direct Link connection is reestablished.

In the event of a Direct Link connection failure, the Redundant Batch communication is tried first on the DeltaV secondary ACN and then, if the secondary is not available, communication is established on the DeltaV primary ACN. Communication remains on the DeltaV ACN path found until the Direct Link connection is reestablished or the current path also fails.

Cable and NIC specifications (that is, cable lengths, cable shielding, crossover cabling and supported Ethernet cards) are the same as the DeltaV ACN. If the NICs in both partners work at 1Gb/sec or faster, you can use any type of network cable to connect them. If either of the Direct Link NICs is slower than 1 Gb/sec (this may be the case in an older DeltaV system), you must use a crossover cable for the Direct Link connection.

The Direct Link connection uses a dedicated, gigabit Ethernet card with the assigned IP address in the 10.12.x.x address range for the preferred active node and the 10.13.x.x address range for the preferred standby node.