Extended-Distance Ports; High-Availability Considerations - HP Surestore 64 - Director Switch Planning Manual

Cost Effectiveness
Cost is the secondary factor governing the choice of transceiver type and optical fiber.
Shortwave laser transceivers and multimode cable offer a less expensive solution if data
transmission distance is not critical.
Device or Cable Restrictions
The choice of transceiver and cable type may be restricted or dictated by:
• Device restrictions
Some devices may be restricted to use of only one type of transceiver (shortwave or
longwave). Refer to the device's supporting documentation for information.
•
Existing cable restrictions
The enterprise may contain only one type of fiber-optic cable (multimode or
singlemode), and the customer may be required to use the existing cables.

Extended-Distance Ports

HP supports the following director-to-director long distance connections:
• Up to ten kilometers using longwave SFP interswitch link (ISL) connections.
• Up to 100 kilometers by setting a port's buffer-to-buffer credit (BB_Credit) value to 60
and using DWDM equipment. HP supports DWDM customer-supplied equipment.

High-Availability Considerations

To provide high availability, multiple connections from a specific server, storage device, or
application should be provided. It is recommended that multiple fiber-optic cable
connections not be attached to the director through a single FPM card. Spreading
connections across multiple FPM cards eliminates an individual port or card as a single
point of failure.
To improve performance, consider having multiple connections to a device. Refer to the
device documentation to determine if this capability exists.
56 Port Connectivity and Fiber-Optic Cabling