Installing the SuperStack II Hub 100

This chapter describes the following hub procedures:

• Unpacking the hub

• Positioning the hub

• Installing the hub

• Installing the transceiver interface modules

• Interpreting LED displays

• Using the power-up disabled option switch

• Protecting against power failure with the Advanced RPS

When unpacking the hub, follow these steps:

1 .   Open the shipping container and carefully remove its contents.

2 .   Return all packing materials to the shipping container and save it.

If the hub must be returned, ship it in its original shipping container (or one providing equivalent protection), or the warranty will be voided.

3 .   Verify that you have received all items that are shipped with the hub, as listed below. Each SuperStack II Hub 100 is shipped with the following:

• Rack mounting kit containing two brackets and four screws

• Four rubber feet for desktop placement

• AC power cord

4 .   Inspect each item for damage. If you find any omissions or damage, contact your network supplier and the carrier that delivered the package.

If you ordered one or more transceiver interface modules, they will be packaged separately from the hub. If you plan to interconnect one or more hubs, you must order the necessary hub expansion cables separately.

When deciding where to place the hub, make sure the environment meets the following conditions:

• The hub is accessible and you can easily connect the cables.

  For help in planning your network configuration, selecting the hub's location, and connecting the hub to the network, see Chapter 3. Read this material before locating the hub permanently. Additional information about required cable types and lengths is provided in Appendix B.

• The cables are away from:

  • Sources of electrical noise, such as heating, ventilating, or air conditioning equipment; radios; transmitters; and broadband amplifiers

  • Power lines and fluorescent lighting fixtures

• Water or moisture cannot enter the hub's case.

• Airflow around the unit and through the vents is not restricted. Provide a minimum of 1-inch (2.5-cm) clearance on all four sides of the unit.

• No objects are placed directly on top of any stack or unit other than another stackable device.

This section discusses hub installation. You can install the hub in a standard 19-inch rack or on a desk or table.

WARNING: 3Com strongly recommends that you install the hub stack in a rack, particularly if you intend to use more than four hubs in the stack. Each hub weighs 12 pounds (5.5 kg). The total weight of eight hubs (the maximum hub stack), plus the possible addition of one or more Advanced RPS units, would be more than 100 pounds (45.5 kg). For maximum safety, this combination of units should be installed in the lower part of a rack. If you place the equipment on a desk or table, be certain that the furniture is sturdy enough to support the weight.

Rack Mounting

The hub is supplied with two brackets and four screws for rack mounting in a standard 19-inch rack. The four rubber feet that are shipped with each hub are not used for rack mounting.

To mount two or more hubs in a rack, follow these steps:

1 .   Place one of the hubs on a level surface, with the front panel facing you.

2 .   Position a bracket over the mounting holes on one side of the unit, as shown in Figure 2-1.

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Figure 2-1 Attaching a Bracket for Rack Mounting

3 .   Insert the two screws and tighten with a screwdriver. Do not overtighten the screws.

4 .   Repeat steps 2 and 3 for the other side of the hub.

5 .   Mount the hub in the rack and secure it with suitable screws, as shown in Figure 2-2.

Figure 2-2 Rack Mounting a Single Hub

6 .   Attach brackets to both sides of the other hubs to be rack-mounted, as described in steps 2 through 4.

7 .   Insert each hub into the rack and fasten each one individually to the rack uprights, as shown in Figure 2-3.

Figure 2-3 shows a mixed hub stack that includes (from bottom to top) a Hub 100 T4, a 12-port Hub 100 TX, a 24-port Hub 100 TX, and a Hub 100 Management Unit.

Figure 2-3 Installing a Hub Stack in a Rack

8 .   Repeat steps 2 through 7 when placing additional hubs in the stack.

A single hub stack can contain up to eight units (eight hubs, or seven hubs and one Management Unit) and one or more Advanced RPS units.

9 .   For each hub, plug one end of the power cord into the AC power connector and the other end into a power source. See "Protecting Against Power Failure" for information on installing the Advanced RPS.

All LEDs should light momentarily. Verify that the PWR (power) LED remains lit, indicating that the hub is receiving power. See the sections about Hub 100 LED displays later in this chapter for more information.

See Chapter 3 for information about connecting the hub stack to the network.

Desktop Placement

If you place the hub on a desk or table, attach the supplied rubber feet to each bottom corner of the hub. If you stack additional hubs on top of the bottom one, place rubber feet on the bottom of each corner of each hub in the outline shown on the unit's base.

To prevent hubs from possibly sliding off the stack, fasten each hub to the hub below it by using the supplied brackets, as shown in Figure 2-4.

Figure 2-4 Attaching a Bracket for Desktop Placement

The SuperStack II Hub 100 chassis is equipped with a rear panel port into which you can insert an optional 3Com transceiver interface module. The transceiver interface module permits connections to a 100 Mbps Ethernet device, another hub stack, or a network backbone that is also running 100 Mbps Ethernet. The two types of compatible transceiver interface modules are described in Table 2-1 and shown in Figure 2-5.

Table 2-1 Transceiver Interface Modules

Module Type	3Com Part Number	Connector	Cable
100BASE-TX	3C252-TX	RJ-45	Category 5 UTP cable
100BASE-FX	3C262-FX	Multimode fiber SC connector	Two-strand (62.5/125 µm) fiber-optic cable

Early versions of the SuperStack II Hub 100 100BASE-FX transceiver interface module (part number 3C262-FX) are not compatible with the 3C250C-TX-12, 3C250C-TX-24, and 3C250B-TX versions of the SuperStack II Hub 100 TX, and the SuperStack II Hub 100 T4. You can identify an incompatible module by matching its assembly number (stenciled along the top of the component side of the module's circuit board) with one of the following numbers: 03-0058-000-Rev A, 03-0058-000-Rev B, or 03-0058-001-Rev A.

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Figure 2-5 Transceiver Interface Modules

CAUTION: Each module is packed in antistatic material to protect it during shipment. To avoid damaging any static-sensitive components after removal from the container, be sure to reduce any static electricity on your body. One way to do this is to touch an unpainted part of the metal chassis of the hub before removing the module from the antistatic bag. You can maintain grounding by wearing a wrist strap attached to the chassis.

To install a transceiver interface module, follow these steps:

1 .   Disconnect all power to the SuperStack II Hub 100.

a .   Disconnect the AC power cord.

b .   If you are using an Advanced RPS unit, disconnect the Advanced RPS cable from the DC input connector. You do not have to power down the entire stack to install a module in a single hub. If you are installing several modules, power down each hub before inserting its module.

2 .   Remove the blanking plate from the transceiver interface module port on the hub's rear panel by unscrewing the plate's two end screws. Keep the blanking plate for possible future use in case you remove the module.

The transceiver interface module port is shown in Figure 1-4 and Figure 1-5.

3 .   Carefully remove the transceiver interface module from its shipping container.

4 .   Slowly insert the module into the slot, being careful not to damage any of the components or connecting pins.

The module will slide into the hub following the tracks in the slot. The lettering that shows the module type must be positioned on top of the connector openings when the module is in place.

5 .   Push the module all the way in until the connector makes contact.

6 .   Tighten the two thumbscrews to seat the connector firmly.

7 .   Reattach the power cord to the hub.

8 .   Attach the proper cable to the module to make the desired network connection.

The STATUS LED shown on the hub's front panel for the thirteenth or twenty-fifth port should be on, indicating that the module is correctly installed in the rear-panel port, and that a connection exists between the port and the end node.

The SuperStack II Hub 100 TX is equipped with front panel LEDs to provide port status and hub operation information. The following sections explain these displays.

Status LEDs

The SuperStack II Hub 100 TX has either 12 or 24 dedicated RJ-45 twisted-pair ports on its front panel, as shown in Figure 1-1 and Figure 1-2. A media-flexible transceiver interface module port on the hub's rear panel provides an additional port. Each port is supplied with one status LED that provides activity and partition information. Figure 2-6 shows the port STATUS LEDs, labeled 1 through 13, located on the front panel of the 12-port Hub 100 TX.

Figure 2-6 Port STATUS LEDs for the 12-port Hub 100 TX

Figure 2-7 shows the port STATUS LEDs, labeled 1 through 25, located on the front panel of the 24-port Hub 100 TX.

Figure 2-7 Port STATUS LEDs for the 24-port Hub 100 TX

Table 2-2 interprets the meaning of the Hub 100 TX port STATUS LEDs.

Table 2-2 Hub 100 TX Port STATUS LEDs

Status	Meaning
ON	A connection exists between the port and the end node.
OFF	There is no connection between the port and the end node.
FLASHING	The port is partitioned because of excessive collisions (more than 127 consecutive collisions) or because long packets (longer than 5 milliseconds) are being sent over the network. If a port is partitioned, it is automatically reconnected to the network when the problem no longer exists.

Operation LEDs

Five additional hub operation LEDs provide environmental and repeater status information. Figure 2-8 shows the hub operation LEDs located on the hub's front panel.

Figure 2-8 Hub Operation LEDs for the Hub 100 TX

Table 2-3 interprets the meaning of the Hub 100 TX operation LEDs.

Table 2-3 Hub 100 TX Operation LEDs

LED	Color	Status	Meaning
ACTIVITY	Green	ON	The hub is receiving data.
		OFF	The hub is not receiving data.
OVERTEMP	Amber	ON	The internal temperature exceeds 158 \xa1 F (70 \xa1 C).
CLS II1	Green	ON	The hub is functioning as a Class II repeater. See "Classification of Repeaters" in Appendix B for more information about Class I and Class II repeaters.
		OFF	The hub is functioning as a Class I repeater. If the hub is in a mixed stack that includes at least one Class I repeater, the Class II LED is always OFF.
COLLISION	Amber	ON	The hub is experiencing collisions.
PWR (Power)	Green	ON	The hub is receiving power.

1 An exception to the normal status indicated by the Class II LED occurs when the Hub 100 TX is functioning as a Class II repeater in the same stack with a SuperStack II Hub 100 Management Unit (3C215A) that is turned off. In this case, the Class II LED remains off (unlit) as long as the Management Unit's power is off, even though the Hub 100 TX continues to function as a Class II repeater.

The SuperStack II Hub 100 T4 is equipped with front panel LEDs to provide port status and hub operation information. The following sections explain these displays.

Status LEDs

The SuperStack II Hub 100 T4 has 12 dedicated RJ-45 twisted-pair ports on its front panel, as shown in Figure 1-3. A media-flexible transceiver interface module port on the hub's rear panel provides a thirteenth port. Each port (including the thirteenth port) is supplied with three status LEDs that provide activity, link, and partition information. Figure 2-9 shows the port STATUS LEDs located on the hub's front panel.

Figure 2-9 Port STATUS LEDs for the Hub 100 T4

Table 2-4 interprets the meaning of the Hub 100 T4 port STATUS LEDs.

Table 2-4 Hub 100 T4 Port STATUS LEDs

LED	Color	Status	Meaning
ACTIVITY	Green	ON	The port is receiving data.
		OFF	The port is not receiving data.
LINK	Green	ON	A connection exists between the port and the end node.
		OFF	There is no connection between the port and the end node.
(continued)
PARTITION	Amber	ON	The port is partitioned because of excessive collisions (more than 127 consecutive collisions) or because long packets (longer than 5 milliseconds) are being sent over the network. If a port is partitioned, it is automatically reconnected to the network when the problem no longer exists.
		OFF	The port is not partitioned.

Operation LEDs

Three additional hub operation LEDs provide environmental and repeater status information. Unlike the Hub 100 TX, the Hub 100 T4 does not have a Class II LED on the front panel because it is a Class I repeater. See "Classification of Repeaters" in Appendix B for more information about Class I and Class II repeaters. Figure 2-10 shows the hub operation LEDs located on the hub's front panel.

Figure 2-10 Hub Operation LEDs for the Hub 100 T4

Table 2-5 interprets the meaning of the Hub 100 T4 operation LEDs.

Table 2-5 Hub 100 T4 Operation LEDs

LED	Color	Status	Meaning
OVERTEMP	Amber	ON	The internal temperature exceeds 158 \xa1 F (70 \xa1 C).
COLLISION	Amber	ON	The hub is experiencing collisions.
PWR (Power)	Green	ON	The hub is receiving power.

The Hub 100 front panel unit digital display (Figure 2-11 and Figure 2-12) provides a numeric designation for each component in a hub stack, including the Management Unit if one is present.

Figure 2-11 Unit Digital Display for the Hub 100 TX

Unit numbers are assigned dynamically as the units are plugged into the stack. The number 1 is displayed on a unit that has no other unit above it. For example, the hub (or Management Unit) that is on the top of the stack and connected by a hub expansion cable to the component immediately below it displays Unit 1. The number displayed is the unit's physical ID. A stand-alone unit also displays Unit 1.

Figure 2-12 Unit Digital Display for the Hub 100 T4

The power-up disabled option switch lets you automatically disable or enable all ports or selected ports upon power-up or reset. The switch is located to the left of the expansion connectors on the rear panel of the Hub 100. This option is intended for use with a 3Com network management unit, such as the SuperStack II Hub 100 Management Unit. Figure 2-13 shows the location of the power-up disabled option switch for the Hub 100 TX and Hub 100 T4.

Figure 2-13 Power-Up Disabled Option Switch

Table 2-6 describes the function of the power-up disabled option switch.

Table 2-6 Settings on Power-Up Disabled Option Switch

Setting	Result
D (disabled)	All ports on the hub are disabled upon power-up or reset. If a network management unit is connected, you can enable individual ports after power-up.
E (enabled)	All ports on the hub are enabled upon power-up or reset. This position is the factory default setting. If a network management unit is connected, you can disable individual ports after power-up.

If the hub is not connected to a 3Com network management unit (such as the SuperStack II Hub 100 Management Unit), leave the power-up disabled option switch in the enabled position (set to E); otherwise, all ports on the hub will remain disabled.

You can ensure fail-safe operation and constant power to all SuperStack II components by using the SuperStack II Advanced Redundant Power System (RPS) and the SuperStack II Uninterruptible Power System (UPS). Each unit must be purchased separately.

Advanced RPS

A single SuperStack II Advanced RPS (part numbers 3C16070 and 3C16071) can protect up to eight Hub 100 T4 (3C250-T4) units or four Hub 100 TX (3C250C-TX-12 and 3C250C-TX-24) units from internal power supply failures. If a SuperStack II unit's internal power fails, the Advanced RPS is capable of supplying all the unit's power needs.

The Advanced RPS chassis is rack-mountable and holds as many as eight slide-in Power Modules and an optional slide-in SNMP management module. It is fed by two independent AC lines and remains operational if one of the AC lines fails.

The Advanced RPS front panel provides LED indicators for monitoring temperature as well as power input and output status. In the event of a failure in one of the Power Modules, an alert is automatically sent to the Advanced RPS management console software.

Power Modules

At least one Power Module is required for each SuperStack II hub you want to protect. A variety of Power Module types offer different DC power outputs. For example, the Hub 100 T4 (3C250-T4) and older Hub 100 units require a 60-watt, 5-volt Power Module (3C16072), whereas the Hub 100 TX units (3C250C-TX-12 and 3C250C-TX-24) require a 100-watt, 3.3-volt module (3C16074).

The choice of Power Modules and cables depends on the mix of units in the stack. Consult your 3Com representative to obtain the Power Modules and cables that are appropriate for your Hub 100 units.

A single Advanced RPS with Power Modules configured with straight cables for "standard usage" can contain a maximum of four 100-watt Power Modules (and four 60-watt Power Modules), or eight 60-watt Power Modules. With Power Modules configured for "full redundancy" with Y cables, an Advanced RPS can contain a maximum of eight 100-watt Power Modules, supporting as many as four Hub 100 TX units (3C250C-TX-12 and 3C250C-TX-24).

Using the cable supplied with the Power Module, you connect the Power Module to the DC input connector located on the rear panel of the Hub 100 unit. (See Figure 2-14.)

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Figure 2-14 DC Input (RPS) Connector

Multiple Cabling Options

You can supply AC power and Advanced RPS DC power to the SuperStack II Hub 100 simultaneously. In the event of an AC power failure, the Hub 100 switches to DC power supplied by the Advanced RPS unit. You can also supply only DC power to the Hub 100 with the Advanced RPS unit. You can configure Advanced RPS support for your Hub 100 units in the following ways.

Standard Usage.

Disconnect your Hub 100 unit's AC power cable from the AC outlet. Use the straight DC cable supplied with the Power Module to connect the Power Module directly to the Hub 100 through the DC input (RPS) connector located on the hub's rear panel. (See Figure 2-14.)

The Hub 100 unit obtains DC power from a single Power Module instead of being powered directly from a standard AC source. If the Power Module fails, you can swap the faulty module for a new one. This swapping method requires a reset of the Hub 100 unit, as in a power cycle.

A cold Power Module will not supply power for about 5 seconds.

Managed Redundancy.

Connect your Hub 100 unit's AC power cable to a standard AC outlet. Use the straight DC cable supplied with the Power Module to connect the Power Module directly to the Hub 100 through the DC input (RPS) connector located on the hub's rear panel. (See Figure 2-14.)

If the Hub 100 unit's internal power supply fails, the Hub 100 unit automatically enables the Advanced RPS and resets, as in a power cycle.

The SuperStack II Advanced RPS User Guide contains warnings for SuperStack II products that do not have the "auto-enable feature." All of the Hub 100 products described in this guide provide auto-enable feature.

Full Redundancy.

Disconnect your Hub 100 unit's AC power cable from the AC outlet. Use a Y DC cable (ordered separately) to connect the Hub 100 unit directly to two Power Modules through the DC input (RPS) connector located on the hub's rear panel. (See Figure 2-14.) The Y cable for the Hub 100 TX is part number 3C16078; the Y cable for the Hub 100 T4 is part number 3C16079.

This configuration offers full resilience for mission-critical installations. The Hub 100 unit is powered from both Power Modules instead of being powered directly from a standard AC source. If one of the Power Modules fails, the other module takes the full load. The faulty module can be hot-swapped, returning the system to full redundancy without the need for a power reset.

Uninterruptible Power System

The SuperStack II Uninterruptible Power System (UPS) (3C16010, U.S. version) protects against building power outages, brownouts, power surges, and spikes. If primary power fails or falters for any reason, the UPS automatically provides power for as long as 7 minutes for up to four SuperStack II system units with 100-volt 50/60 Hz, 120-volt 60 Hz, or 230-volt 50/60 Hz power.

Cabling from a Hub 100 unit to a UPS unit is accomplished through the Hub 100 unit's AC power cord.

You can connect a UPS unit to an Advanced RPS unit as long as you do not exceed the maximum wattage (325 watts) for the UPS unit. To verify that the UPS unit's maximum wattage is not exceeded, calculate the total power consumption of all units connected to the Advanced RPS. If the result is less than 325 watts, your configuration is safe; if the result is higher than 325 watts, then there are too many units connected to the Advanced RPS.

To calculate the total power consumption of all units connected to the Advanced RPS, first calculate the total wattage of all the units connected to the Advanced RPS. (For example, a Hub 100 unit has a maximum power consumption of 40 watts; two Hub 100 units have a maximum power consumption of 80 watts, and so forth.)

Next, divide the total wattage of all units by 0.7, which is the efficiency rating (70%) of the Advanced RPS. If the result is less than 325 watts, your configuration is safe; if the result is higher, then there are too many units connected to the Advanced RPS.