When a stack includes at least one Class I unit, the entire stack functions as a logical Class I repeater, even though Class II units may be included in the stack. See Chapter 3 and Appendix B for more information on Class I repeaters.The 3Com® SuperStack® II Hub 100 provides connectivity between network devices. It performs the basic repeater functions of restoring signal amplitude and timing, detecting collisions, and broadcasting signals to those devices.
This guide describes the following SuperStack II Hub 100 models:
The SuperStack II Hub 100 provides the following capabilities:
The SuperStack II Hub 100 TX and SuperStack II Hub 100 T4 are members of the SuperStack II system of stackable network devices. These devices conform to the 100BASE-T Fast Ethernet standard, which is an extension of the Ethernet IEEE 802.3 specifications. The 100BASE-T standard supports the following 100 Mbps media options:
See Appendix A for a description of cable categories and specifications.
You can combine up to seven hubs in a stack (also called a hub stack) with a SuperStack II Hub 100 Management Unit; or you can combine as many as eight hubs in a stack without a Management Unit.
You can also create a mixed media stack that includes a variety of SuperStack hub models. For example, you can create a mixed stack composed of the following units:
The Hub 100 TX models described in this guide function as IEEE 802.3u Class II repeaters; the Hub 100 T4 functions as a Class I repeater; and the LinkBuilder FMS 100 TX Hub functions as a Class I repeater. When the Hub 100 TX, Hub 100 T4, and LinkBuilder FMS 100 TX Hub are mixed in a stack, the stack functions as a logical Class I repeater.
When a stack includes at least one Class I unit, the entire stack functions as a logical Class I repeater, even though Class II units may be included in the stack. See Chapter 3 and Appendix B for more information on Class I repeaters.
You can use a SuperStack II Hub 100 Management Unit (part number 3C215A) or a LinkBuilder FMS 100 Management Unit (part number 3C215) to manage an individual hub port, a single hub in a stack, or an entire hub stack. However, you cannot use a LinkBuilder FMS 100 Management Unit to manage a SuperStack II Hub 100 T4. Table 1-1 shows compatibility between SuperStack hub models and Management Units. See "SuperStack II Hub 100 Management Unit" later in this chapter for detailed information about hub management.
The SuperStack II Hub 100 is equipped with a rear panel port that permits connections to a 100 Mbps Ethernet device or a network backbone that is also running 100 Mbps Ethernet. You can insert either of two transceiver interface modules (100BASE-TX or 100BASE-FX) in the rear port. For more information, see "Installing the Transceiver Interface Modules" in Chapter 2.
You can use the SuperStack II Hub 100 as a stand-alone repeater or as a component in a hub stack. Stacking units provides the benefit of a higher port count, with the stack functioning as a single logical repeater. Up to eight units (for example, seven hubs and a Management Unit) can be connected together in a stack.
You can create a stack by using the two expansion connectors located on the rear panel to attach more components. Other stackable components include the Hub 100 Management Unit, LinkBuilder FMS 100 TX Hub, and the LinkBuilder FMS 100 Management Unit.
You can mount SuperStack II Hub 100 units in a 19-inch standard rack, or you can place them as stand-alone units on a flat surface. A rack-mounting kit is supplied with each hub.
This section describes the front and rear panels of the SuperStack II Hub 100 TX (models 3C250C-TX-12 and 3C250C-TX-24).
The 12-port Hub 100 TX (3C250C-TX-12) has 12 dedicated RJ-45 twisted-pair ports on its front panel, as shown in Figure 1-1. The Hub 100 TX uses 100BASE-TX signaling through its front-panel ports. A media-flexible transceiver interface module port on the hub's rear panel provides a thirteenth port.
Figure 1-1 Front Panel of 12-port SuperStack II Hub 100 TX (3C250C-TX-12)
Each port (including the thirteenth port) is supplied with one status LED that provides link and partition information. Five additional hub operation LEDs indicate status for power, hub activity, collision frequency, internal temperature, and Class II operation. See Chapter 2 for a description of the LEDs.
The 24-port Hub 100 TX (3C250C-TX-24) has 24 dedicated RJ-45 twisted-pair ports on its front panel, as shown in Figure 1-2. The Hub 100 TX uses 100BASE-TX signaling through 24 front-panel ports. A media-flexible transceiver interface module port on the hub's rear panel provides a twenty-fifth port.
Figure 1-2 Front Panel of 24-port SuperStack II Hub 100 TX (3C250C-TX-24)
Each port (including the twenty-fifth port) is supplied with one status LED that provides link and partition information. Five additional hub operation LEDs provide environmental and repeater status information. See Chapter 2 for a description of the LEDs.
The rear panel of the Hub 100 TX (Figure 1-3) has a slot for a 3Com transceiver interface module. The transceiver interface module provides the hub with additional media flexibility and accessibility through a thirteenth port for the model 3C250C-TX-12, or through a twenty-fifth port for model 3C250C-TX-24. You can leave this slot empty and not make use of the additional port.
Figure 1-3 Rear Panel of SuperStack II Hub 100 TX
Two types of transceiver interface modules are available for the Hub 100 TX and must be purchased separately:
For more information about using the additional port, see "Installing the Transceiver Interface Modules" in Chapter 2 and "Using Transceiver Interface Modules"in Chapter 3.
The rear panel of the hub provides a three-pronged socket for attaching a 100-240 V AC power cord. Alternatively, power can be supplied through a 3Com SuperStack II Advanced Redundant Power System (RPS) connected to the DC input connector. See "Protecting Against Power Failure" in Chapter 2 for additional information.
This section describes the front and rear panels of the SuperStack II Hub 100 T4 (3C250-T4).
The Hub 100 T4 has 12 dedicated RJ-45 twisted-pair ports on its front panel, as shown in Figure 1-4. The Hub 100 T4 uses 100BASE-T4 signaling through its front-panel ports. A media-flexible transceiver interface module port on the hub's rear panel provides a thirteenth port.
Figure 1-4 Front Panel of SuperStack II Hub 100 T4
Each port (including the thirteenth port) is supplied with three status LEDs that provide activity, link, and partition information. Three additional hub operation LEDs provide environmental and repeater status information. See Chapter 2 for a description of the LEDs.
The rear panel of the 12-port Hub 100 T4 (Figure 1-5) has a slot for a 3Com transceiver interface module, which provides the hub with additional media flexibility and accessibility through a thirteenth port. You can leave this slot empty.
Two types of transceiver interface modules are available for the Hub 100 T4 and must be purchased separately:
Figure 1-5 Rear Panel of SuperStack II Hub 100 T4
The rear panel of the hub provides a three-pronged socket for attaching a 100-240 V AC power cord. Alternatively, power can be supplied through a 3Com SuperStack II Advanced RPS connected to the DC input connector. Refer to the section "Protecting Against Power Failure" in Chapter 2 for additional information.
The SuperStack II Hub 100 supports the standard functions of an IEEE 802.3u repeater, as listed in Table 1-2.
You can add the SuperStack II Hub 100 Management Unit to a hub stack to provide full Simple Network Management Protocol (SNMP) manageability to the stack. You can connect the Management Unit to an Advanced RPS if desired. See "Protecting Against Power Failure" in Chapter 2 for more information about connecting to an Advanced RPS.
The flash EPROM software of the SuperStack II Hub 100 Management Unit or of the LinkBuilder FMS 100 Management Unit must be version 2.20 or later to manage a stack containing the following Class II Hub 100 TX models: 3C250C-TX-12 and 3C250C-TX-24. Managing a stack containing the 3C250B-TX Class II Hub 100 TX model requires flash EPROM version 2.10 or later. The most current version of the flash EPROM software can be downloaded from the 3Com bulletin board service (3ComBBS). See Appendix D for details.
If a Management Unit is included in a stack, a maximum of seven hubs is allowed in the stack. Only one Management Unit can be attached to a stack.
The SuperStack II Hub 100 TX, SuperStack II Hub 100 T4, and LinkBuilder FMS 100 TX Hub operate with the SuperStack II Hub 100 Management Unit, even when they are combined in a mixed media stack. The LinkBuilder FMS 100 Management Unit can also manage a mixed stack as long as the stack does not include a SuperStack II Hub 100 T4.
3Com recommends that you place the Management Unit at the top of the stack, and add repeater units at the bottom of the stack. Following this guideline preserves existing nonvolatile configuration information associated with the repeaters already in the stack. Placing an additional repeater unit in the middle or on top of a managed stack may force you to reconfigure parameters contained in the Management Unit's nonvolatile RAM.
For additional information on placement of the Management Unit and hub within a stack, see "Unit Digital Display" in Chapter 2 and "Hub to Management Unit" in Chapter 3.
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