Overview

Feature	Description
Hardware	Catalyst 2950-12 switch—12 10/100 Ethernet ports Catalyst 2950-24 switch—24 10/100 Ethernet ports Catalyst 2950C-24 switch—24 10/100 Ethernet ports and 2 100BASE-FX ports Catalyst 2950G-12-EI—12 10/100 Ethernet ports and 2 GBIC^¹-based Gigabit Ethernet module slots Catalyst 2950G-24-EI—24 10/100 Ethernet ports and 2 GBIC-based Gigabit Ethernet module slots Catalyst 2950G-24-EI-DC²—24 10/100 Ethernet ports and 2 GBIC-based Gigabit Ethernet module slots with DC-input power Catalyst 2950G-48-EI—48 10/100 Ethernet ports and 2 GBIC-based Gigabit Ethernet module slots Catalyst 2950T-24 switch—24 10/100 Ethernet ports and 2 10/100/1000 Ethernet ports On Catalyst 2950G-12-EI, 2950G-24-EI, 2950G-24-EI-DC, and 2950G-48-EI switches, support for these GBIC modules: 1000BASE-SX GBIC 1000BASE-LX/LH GBIC 1000BASE-ZX GBIC GigaStack GBIC
Configuration	Autonegotiates the speed and duplex settings on 10/100 ports and on 10/100/1000 ports Supports only 100-Mbps and full-duplex settings on 100BASE-FX ports Supports 8192 MAC addresses Checks for errors on a received packet, determines the destination port, stores the packet in shared memory, and then forwards the packet to the destination port
Power redundancy	Connection for an optional Cisco RPS 300 Redundant Power System (RPS) that uses AC³ input and supplies DC output to the switch

¹GBIC = Gigabit Interface Converter
²DC = direct current
³AC = alternating current

Front-Panel Description

The switch front panel contains the ports, the LEDs, and the Mode button. Figure 1-1 to Figure 1-8 show the switches.

Figure 1-1: Catalyst 2950-12 Switch

Figure 1-2: Catalyst 2950-24 Switch

Figure 1-3: Catalyst 2950C-24 Switch

Figure 1-4: Catalyst 2950G-12-EI Switch

Figure 1-5: Catalyst 2950G-24-EI Switch

Figure 1-6: Catalyst 2950G-24-EI-DC Switch

Figure 1-7: Catalyst 2950G-48-EI Switch

Figure 1-8: Catalyst 2950T-24 Switch

10/100 Ports

The 10/100 ports use RJ-45 connectors and twisted-pair cabling. The ports can connect to these devices:

10BASE-T-compatible devices, such as workstations and hubs, through standard RJ-45 connectors and two twisted-pair cabling. You can use Category 3, 4, or 5 cabling.

100BASE-TX-compatible devices, such as high-speed workstations, servers, hubs, routers, and other switches, through standard RJ-45 connectors and two or four twisted-pair, Category 5 cabling.

Note When connecting the switch to workstations, servers, and routers, be sure that the cable is a twisted-pair straight-through cable. When connecting the switch to hubs or other switches, use a twisted-pair crossover cable. Pinouts for the cables are described in "Connectors and Cables."

The 10/100 ports can be explicitly set to operate in any combination of half duplex, full duplex, 10 Mbps, or 100 Mbps. They can also be set for speed and duplex autonegotiation, compliant with IEEE 802.3U. In all cases, the cable length from a switch to an attached device cannot exceed 328 feet (100 meters).

When set for autonegotiation, a port senses the speed and duplex settings of the attached device and advertises its own capabilities. If the attached device supports autonegotiation, the port negotiates the best connection (that is, the fastest line speed that both devices support and full-duplex transmission, if the attached device supports it) and configures itself accordingly.

100BASE-FX Ports

The 100BASE-FX ports use 50/125- or 62.5/125-micron multimode fiber-optic cabling. These ports only operate at 100 Mbps in full-duplex mode.

In full-duplex mode (the default), the cable length from a switch to an attached device cannot exceed 6562 feet (2 kilometers).

You can connect a 100BASE-FX port to an SC or ST port on a target device by using one of the MT-RJ fiber-optic patch cables listed in Table 1-2. Use the Cisco part numbers in Table 1-2 to order the patch cables that you need.

Table 1-2: MT-RJ Patch Cables for 100 BASE-FX Connections

Type	Cisco Part Number
1-meter, MT-RJ-to-SC multimode cable	CAB-MTRJ-SC-MM-1M
3-meter, MT-RJ-to-SC multimode cable	CAB-MTRJ-SC-MM-3M
5-meter, MT-RJ-to-SC multimode cable	CAB-MTRJ-SC-MM-5M
1-meter, MT-RJ-to-ST multimode cable	CAB-MTRJ-ST-MM-1M
3-meter, MT-RJ-to-ST multimode cable	CAB-MTRJ-ST-MM-3M
5-meter, MT-RJ-to-ST multimode cable	CAB-MTRJ-ST-MM-5M

10/100/1000 Ports

The 10/100/1000 ports on Catalyst 2950T-24 switches use RJ-45 connectors and twisted-pair cabling. The ports can connect to these devices:

10BASE-T-compatible devices, such as workstations and hubs, through standard RJ-45 connectors and two or four twisted-pair, Category 5 cabling.
100BASE-TX-compatible devices, such as high-speed workstations, servers, hubs, routers, and other switches, through standard RJ-45 connectors and two or four twisted-pair, Category 5 cabling.

1000BASE-T-compatible devices, such as high-speed workstations, servers, hubs, routers, and other switches, through standard RJ-45 connectors and four twisted-pair, Category 5 cabling.

Note When connecting to a 1000BASE-T-compatible device, be sure to use a four twisted-pair, Category 5 cable.

The 10/100/1000 ports on Catalyst 2950T-24 switches can be explicitly set to operate at 10 or 100 Mbps in half- or full-duplex mode or at 1000 Mbps in full-duplex mode. The default duplex setting is full duplex. They can also be set for speed and duplex autonegotiation, compliant with IEEE 802.3AB. In all cases, the cable length from a switch to an attached device cannot exceed 328 feet (100 meters).

GBIC Module Ports

The GBIC module slots support these modules:

1000BASE-SX GBIC module for fiber-optic connections that cannot exceed 1804 feet (550 meters).

1000BASE-LX/LH GBIC module for fiber-optic connections that cannot exceed 32,810 feet (10 kilometers).
1000BASE-ZX GBIC module for fiber-optic connections that cannot exceed 328,100 feet (100 kilometers).
GigaStack GBIC module for creating a 1-Gbps stack configuration of up to nine supported switches. The GigaStack GBIC supports one full-duplex link (in a point-to-point configuration) or up to nine half-duplex links (in a stack configuration) to other Gigabit Ethernet devices. Using the required Cisco proprietary signaling and cabling, the GigaStack GBIC-to-GigaStack GBIC connection cannot exceed 3 feet (1 meter).

For more information about these GBICs, refer to your GBIC documentation.

LEDs

You can use the LEDs to monitor switch activity and performance. Figure 1-9, Figure 1-10, and Figure 1-11 show the location of the LEDs and the Mode button that you use to select the port mode. Changing the port mode changes the information provided by each port status LED.

All of the LEDs described in this section except the utilization meter (UTIL) are visible in the Cluster Management Suite (CMS). The Catalyst 2950 Desktop Switch Software Configuration Guide describes how to use CMS to manage individual switches and switch clusters.

Figure 1-9: LEDs on Catalyst 2950-12, 2950-24, 2950C-24, and 2950T-24 Switches

Figure 1-10: LEDs on Catalyst 2950G-12-EI, 2950G-24-EI, and 2950G-24-EI-DC Switches

Figure 1-11: LEDs on Catalyst 2950G-48-EI Switches

System LED

The system LED shows whether the system is receiving power and functioning properly. Table 1-3 lists the LED colors and meanings.

Table 1-3: System LED

Color	System Status
Off	System is not powered up.
Green	System is operating normally.
Amber	System is receiving power but is not functioning properly.

For information about the system LED colors during the power-on self-test (POST), see the "Running POST" section.

RPS LED

The RPS LED shows the RPS status. Table 1-4 lists the LED colors and meanings.

Table 1-4: RPS LED

Color	RPS Status
Off	RPS is off or is not installed.
Solid green	RPS is connected and ready to provide back-up power.
Flashing green	RPS is connected but is unavailable because it is providing power to another device (redundancy has been allocated to a neighboring device).
Solid amber	RPS is in standby mode or in a fault condition. Press the Standby/Active button on the RPS, and the LED should turn green. If it does not, the RPS fan could have failed. Contact Cisco Systems.
Flashing amber	The internal power supply in a switch has failed, and the RPS is providing power to the switch (redundancy has been allocated to this device).

For more information about the Cisco RPS 300, refer to the Cisco RPS 300 Redundant Power System Hardware Installation Guide.

Port Mode and Port Status LEDs

Each port has a port status LED, also called a port LED. These LEDs, as a group or individually, display information about the switch and the individual ports. The port modes (see Table 1-5) determine the type of information displayed.

Table 1-5: Port Mode LEDs

Mode LED	Port Mode	Description
STAT	Port status	The port status. This is the default mode.
UTIL	Switch utilization	The current bandwidth in use by the switch.
DUPLX	Port duplex mode	The port duplex mode: half duplex or full duplex.
SPEED	Port speed	The port operating speed: 10 or 100 Mbps for 10/100 ports and 10, 100, or 1000 Mbps for 10/100/1000 ports.

To select or change the port mode, press the Mode button (see Figure 1-12, Figure 1-13, and Figure 1-14) to highlight the mode that you want. Release the button to enable the highlighted mode.

Figure 1-12: Changing the Port Mode on Catalyst 2950-12, 2950-24, 2950C-24, and 2950T-24 Switches

Figure 1-13: Changing the Port Mode on Catalyst 2950G-12-EI, 2950G-24-EI, and 2950G-24-EI-DC Switches

Figure 1-14: Changing the Port Mode on Catalyst 2950G-48-EI Switches

When you change the port mode, the meanings of the port LED colors change. Table 1-6 explains how to interpret these colors.

Table 1-6: Meaning of Port LED Colors in Different Modes

Port Mode	Color	Meaning
STAT (port status)	Off	No link.
	Solid green	Link present.
	Flashing green	Activity. Port is transmitting or receiving data.
	Alternating green-amber	Link fault. Error frames can affect connectivity, and errors such as excessive collisions, CRC errors, and alignment and jabber errors are monitored for a link-fault indication.
	Solid amber	Port is not forwarding. Port was disabled by management, an address violation, or Spanning Tree Protocol (STP). Note After a port is reconfigured, the port LED can remain amber for up to 30 seconds while STP checks the switch for possible loops.
UTIL (utilization)	Green	The current backplane utilization that is displayed over the amber LED background on a logarithmic scale.
	Amber	The maximum backplane utilization since the switch was powered on.
	Green and amber	See Figure 1-15 to Figure 1-18 for details. Note If the current utilization exceeds the maximum utilization, the maximum utilization is automatically updated.
DUPLX	Off	Port is operating in half duplex.
(half or full duplex)	Green	Port is operating in full duplex.
SPEED (speed)	10/100 ports
	Off	Port is operating at 10 Mbps.
	Green	Port is operating at 100 Mbps.
	10/100/1000 ports
	Off	Port is operating at 10 Mbps.
	Green	Port is operating at 100 Mbps.
	Flashing green	Port is operating at 1000 Mbps.
	1000BASE-X GBIC module ports
	Off	Port is not operating.
	Green	Port is operating at 1000 Mbps.

For more information about GBIC LEDs, refer to your GBIC documentation.

Figure 1-15 to Figure 1-18 show the bandwidth utilization percentages displayed by the right-most LEDs.

If all LEDs on Catalyst 2950-12, 2950-24, 2950C-24, and 2950T-24 switches are green (no amber showing), the switch is using 50 percent or more of the total bandwidth. If the far-right LED is off, the switch is using more than 25 but less than 50 percent of the total bandwidth, and so on. If only the far-left LED is green, the switch is using less than 0.0488 percent of the total bandwidth. (See Figure 1-15.)

If all LEDs on Catalyst 2950G-12-EI switches are green (no amber showing), the switch is using 50 percent or more of the total bandwidth. If the LED for GBIC module slot 2 is off, the switch is using more than 25 but less than 50 percent of the total bandwidth. If LEDs for both GBIC module slots are off, the switch is using less than 25 percent of the total bandwidth, and so on. (See Figure 1-16.)

If all LEDs on Catalyst 2950G-24-EI and 2950G-24-EI-DC switches are green (no amber showing), the switch is using 50 percent or more of the total bandwidth. If the LED for GBIC module slot 2 is off, the switch is using more than 25 but less than 50 percent of the total bandwidth. If LEDs for both GBIC module slots are off, the switch is using less than 25 percent of the total bandwidth, and so on. (See Figure 1-17.)

If all LEDs on Catalyst 2950G-48-EI switches are green (no amber showing), the switch is using 50 percent or more of the total bandwidth. If the LED for the upper GBIC module slot is off, the switch is using more than 25 but less than 50 percent of the total bandwidth. If LEDs for both GBIC module slots are off, the switch is using less than 25 percent of the total bandwidth, and so on. (See Figure 1-18.)

Figure 1-15: Bandwidth Utilization on Catalyst 2950-12, 2950-24, 2950C-24, and 2950T-24 Switches

Figure 1-16: Bandwidth Utilization on Catalyst 2950G-12-EI Switches

Figure 1-17: Bandwidth Utilization on Catalyst 2950G-24-EI and 2950G-24-EI-DC Switches

Figure 1-18: Bandwidth Utilization on Catalyst 2950G-48-EI Switches

Rear-Panel Description

Other than the Catalyst 2950G-24-EI-DC switch, the rear panel of a Catalyst 2950 switch has an AC power connector, an RPS connector, and an RJ-45 console port. (See Figure 1-19 and Figure 1-20.)

The rear panel of the Catalyst 2950G-24-EI-DC switch has a DC power connector (also referred to as the terminal block header), a DC ground lug, an RPS connector, and an RJ-45 console port. (See Figure 1-21.)

Figure 1-19: Catalyst 2950 Switch Rear Panel

Figure 1-20: Catalyst 2950G-48-EI Switch Rear Panel

Figure 1-21: Catalyst 2950G-24-EI-DC Switch Rear Panel

Caution You must connect the Catalyst 2950G-24-EI-DC switch only to a DC-input power source that has an input supply voltage from -36 to -72 VDC. If the supply voltage is not in this range, the switch might not operate properly or might be damaged.

Cisco RPS Connector

The RPS is a 300W redundant power system that can support six external network devices and provides DC power to one failed device at a time. It automatically senses when the internal power supply of a connected device fails and provides power to that device, preventing loss of network traffic.

Warning Attach only the Cisco RPS 300 (model PWR300-AC-RPS-N1) to the RPS receptacle.

For more information about the Cisco RPS 300, refer to the Cisco RPS 300 Redundant Power System Hardware Installation Guide.

Console Port

You can connect a switch to a PC through the console port and the supplied rollover cable and DB-9 adapter. If you want to connect a switch to a terminal, you need to provide an RJ-45-to-DB-25 female DTE adapter. You can order a kit (part number ACS-DSBUASYN=) with that adapter from Cisco. For console-port and adapter-pinout information, see the "Cable and Adapter Specifications" section.

Management Options

Catalyst 2950 switches offer these management options:

Cluster Management Suite (CMS)

: CMS is made up of three web-based applications that you use to manage switches. You can use Cluster Builder, which includes Cluster View, and Cluster Manager to create, configure, and monitor switch clusters. You can also use Device Manager to manage individual and standalone switches. For more information, refer to the Catalyst 2950 Desktop Switch Software Configuration Guide and the CMS online help.

IOS command-line interface (CLI)

: You can manage switches by using command-line entries. To access the CLI, connect a PC or terminal directly to the console port on the switch rear panel. If the switch is attached to your network, you can use a Telnet connection to manage the switch from a remote location. For more information, refer to the Catalyst 2950 Desktop Switch Command Reference.

CiscoView application

: You can use the CiscoView device-management application to set configuration parameters and to view switch status and performance information. This application, which you purchase separately, can be a standalone application or part of an Simple Network Management Protocol (SNMP) network-management platform. For more information, refer to the documentation that came with your CiscoView application.

SNMP network management

: You can manage switches by using an SNMP-compatible management station running platforms such as HP OpenView and SunNet Manager. The switch supports a comprehensive set of MIB extensions and MIB II, the IEEE 802.1D bridge MIB, and four RMON groups. For more information, refer to the documentation that came with your SNMP application.

Table of Contents

Overview