This chapter explains
 | Note: Appendix C contains a checklist for setting up the hub, with references to specific parts of this guide. |
Before cabling the hub, do the following:
Determine how the hub is to be managed: see “Determining Hub Management” in Chapter 2. Fulfill requirements for the management connection, such as cabling and IP address.
Determine the devices (storage and servers) in the loop and their physical location; see “Planning Loop Configuration” in Chapter 2.
Attach the Fibre Channel Hub feet, if they have not already been attached. Four nonskid pads (feet) are included with the hub for stability when the hub is used as a desktop unit.
Peel one of the feet of the backing and attach it at a corner of the hub case bottom, about 2.54 cm (1 inch) from the edge. Attach the other three feet in the remaining corners. See Figure 3-1.
Note: If the hub is to be rackmounted, do not attach the feet, because they cause interference. A qualified Silicon Graphics Systems Support Engineer installs the hub in a rack. Set up the Fibre Channel Hub in the spot you have selected; see “Selecting a Spot for the Hub” in Chapter 2.
Attach the power cord to the socket on the rear of the hub, as shown in Figure 3-2.
Do not power on the hub at this time; leave the power switch in the off position.
For a 10-Base-T Ethernet connection, insert an Ethernet cable into the port at the upper right of the front panel; see Figure 3-3.
Alternatively, connect the hub to an ANSI console terminal or to the serial (console) port of a PC; see Figure 3-4. See step 1 on page 27 for serial connection requirements.
Connect the other end of the cable to the ANSI console terminal or PC using the appropriate DB-9/RJ11 adapter included with the hub.
This section consists of the following:
Note the following:
Only one port of a Fibre Channel Hub can be cabled to a storage processor (SP) in a Fibre Channel RAID unit. That is, one port of a Fibre Channel Hub can be cabled to either the A or B port of a Fibre Channel RAID SP.
Only one port of a Fibre Channel Hub can be cabled to a JBOD unit. That is, one Fibre channel Hub can be cabled to either LCC A or LCC B, but not both.
To set up a loop with up to 18 nodes, you can cascade two hubs. Cascading hubs requires the optional cascade cable.
All ports are identical; each can be used for an NL_port connection or for a cascaded hub connection. For convenience, generally, ports on the front of the two hubs are cabled, as shown in Figure 3-5.
For two short loops, you can segment one hub into two loops with five ports each. Commands for segmenting and unsegmenting the hub (accomplished completely in software), are given in “Segmenting and Unsegmenting the Hub” in Chapter 4.
Follow these steps to cable the servers and storage to the hub with copper cabling:
Power off the servers and workstations (FC-AL nodes) that are to be connected to the hub, following procedures in the manuals for those systems.
Note: During normal hub operation, you can attach devices to the Fibre Channel Hub without powering them off; however, powering off these devices is recommended when you are setting up the hub connections for the first time. Cable the servers, workstations, and storage to the hub ports. You need not cable to adjacent hub ports; that is, you can skip ports when attaching cables.
Tighten the jackscrews on each DB-9 connector to ensure EMC emissions compliance and proper system operation.
To connect devices to the hub with optical cabling, you must use MIAs. Follow these steps to cable the servers and storage to the hub with fiber optic cabling:
Power off the servers and workstations (FC-AL nodes) that are to be connected to the hub, following procedures in the manuals for those systems.
Note: This step is required for fiber optic cabling. Attaching the connectors before applying power to the system confines all light within the fiber optic wave guide, which practically eliminates any potential hazard. Taking care not to touch the tips of the fiber optic cable connections, remove the protective caps from each cable's connectors and place an MIA on each connector. This connection is keyed.
Attach an MIA to each end of each cable.
Figure 3-6 shows the MIA and an optical cable connector.
Make sure the cable connectors are completely inserted into the sockets on the MIA. They can be a snug fit; a click occurs when the connectors seat properly.
Caution: Do not touch the tips of the fiber optic cable connections. If the fiber optic cable tips become dirty, clean and dry the tip of each fiber within the cable by gently rubbing the tip with a soft, lint-free cloth that has been moistened with reagent-grade isopropyl alcohol. Do not use prepared cleaning compounds, such as tape-head cleaner or denatured (rubbing) alcohol. If you do not have the proper equipment, skip this step.
Attach a fiber optic cable with MIA to each server, workstation, and storage unit you are cabling to the hub.
Tighten the jackscrews on each MIA at the DB-9 connector to ensure EMC emissions compliance and proper system operation.
Do not power on the devices at this time.
Making sure the connection is tight, connect the free ends of the fiber optic cables with MIAs to the ports of the hub. You need not cable to adjacent hub ports; that is, you can skip ports when attaching cables.
Follow these steps:
Connect the Fibre Channel Hub power cord(s) to a power source.
Turn on the Fibre Channel Hub power switch(es). On the hub(s):
The green power LED at the top left of the Ethernet port should illuminate.
The yellow LED at the bottom left of the Ethernet port should illuminate, indicating network activity.
The LED for each port should be
yellow if the device cabled to it is not yet powered on, indicating that the port is not participating in the loop (bypassed)
green if the device cabled to it is powered on
Figure 3-7 shows LED locations.
Table 3-1 outlines LED activity when the hub is powered on.
Table 3-1. LED Activity at Hub Power-On
Purpose
Location
Color or State
Meaning
Power
Left of 10-Base-T socket; top (green)
On
Power is applied
Network
Left of 10-Base-T socket; bottom
(yellow)Unlit
Low intensity, steady
High intensity, blinkingNo connection to network
Link up
Network activityFibre channel
Front panel
Yellow
GreenPort is bypassed: cabled device is not powered on
Link is establishedNote: A cable connected to a port does not constitute a valid link unless its other end is connected to a device. If the LEDs are not functioning this way, check the appropriate connection: check the cable seating, Ethernet configuration if applicable, and system configuration.
Observe the following warnings for fiber optic cabling.
Warning: Never look into the end of a fiber optic cable on a powered device with any type of magnifying device, such as a microscope, eye loupe, or magnifying glass. Such activity causes cause a permanent, irreversible burn on the retina of the eye. If the green power LED indicates that the hub is ready, power on the nodes that are not already powered on. The LED for each hub port they are connected to should be green.
If the port LEDs do not function this way, check the connections to the devices. Observe the fiber optic cabling warnings on this page.
