IBM DS4700 manual SFP modules, Telco bezel

SFP modules

The storage subsystem supports a fiber optic interface for host and storage expansion enclosure connections. You must install a Small Form-factor Pluggable (SFP) module in each interface connector on the controller where a fibre optic cable is to be installed. Do not install an SFP in any port that will not have a fibre optic cable attached. Additionally, it is recommended that you remove any SFP from any port that does not have fibre optic cables attached.

The DS4700 Express Storage Subsystem host ports support 1, 2 and 4 Gbps fibre channel speeds. The DS4700 Express Storage Subsystem drive ports support only 2 and 4 Gbps fibre channel speeds.

Attention: The maximum operating speed of the fibre channel port is determined

by two factors: the speed of the SFP module that is installed and the speed of the fibre channel connection. For example, a 2-Gbps SFP that is plugged into a

4-Gbps-capable port will limit the speed of that port to a maximum of 2 Gbps. Conversely, a 4-Gbps SFP that is plugged into a 2-Gbps-capable port will limit the speed of the port to a maximum of 2 Gbps. Carefully check the SFP's IBM part number, option number, and FRU part number to identify its speed. There are no physical features that distinguish a 4 Gbps from a 2 Gbps SFP.

Figure 11 shows an example of SFP module with fiber optic cable.

Note: The SFP module and the fibre optic cable shown are for illustrative purposes only. The actual SFP module and the fibre optic cable shape may look different from the figure shown.

SFP

Module

Fiber-optic cable

Figure 11. SFP module and fiber optic cable

Telco bezel

The DS4700 Express Storage Subsystem can be ordered with a Telco bezel. The Telco bezel also contains a filter and filter retainer. The replaceable filter is fitted inside the Telco bezel and limits impurities, dust, air particles and other external contaminants from adversely impacting the chassis, electronic CRUs, and hard drive operational effectiveness. IBM recommends that you replace the filter every three months or sooner, depending on your environment. Inspect the filter periodically and replace it as required.

Chapter 1. Introduction 19