Product Overview

The Catalyst 3550 multilayer switch—also referred to as a Catalyst 3550 switch—is a stackable Ethernet switch to which you can connect workstations, Cisco IP Phones, and other network devices such as servers, routers, and other switches. This switch also can be deployed as a backbone switch, aggregating Gigabit Ethernet traffic from other network devices.

This chapter provides a functional overview of the Catalyst 3550 switch. These topics are included:

Features

Figure 1-1 shows the Catalyst 3550 switch, and Table 1-1 lists the switch features.

Table 1-1 Catalyst 3550 Features
Feature	Description
Hardware	•10 Gigabit Ethernet 10/100/1000BASE-T ports and 2 GBIC-based Gigabit Ethernet slots •Support for GBIC modules –1000BASE-SX GBIC –1000BASE-LX/LH GBIC –1000BASE-ZX GBIC –1000BASE-T GBIC –GigaStack GBIC
Configuration	•Support for Layer 3 features •Autonegotiation of speed and duplex operation on 10/100/1000 Ethernet ports •Support for up to 12,000 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 optional Cisco RPS 300 Redundant Power System that operates on AC input and supplies backup DC output to the switch

Front-Panel Description

The front panel of the Catalyst 3550 switch has ten 10/100/1000 RJ-45 ports, two GBIC module slots, a set of LEDs, and a Mode button. (See Figure 1-2 and Figure 1-3). The 10/100/1000 ports are numbered 1 through 10 (port 1 is on the far left), and the GBIC slot numbers are 11 (top) and 12 (bottom).

10/100/1000 Ports

The 10/100/1000 switch ports on the Catalyst 3550 can be explicitly set to operate in any combination of half duplex, full duplex, 10 Mbps, 100 Mbps, or 1000 Mbps. These ports also can be set for speed and duplex autonegotiation, compliant with IEEE 802.3ab. (The default setting is autonegotiate.) When set for autonegotiation, the port senses the speed and duplex settings of the attached device and advertises its own capabilities. If the connected device also supports autonegotiation, the switch 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. In all cases, the attached device must be within 100 meters.

Note 100BASE-TX and 1000BASE-T traffic requires Category 5 cable. 10BASE-T traffic can use Category 3 or 4 cables.

When connecting the switch to workstations, servers, routers, and Cisco IP Phones, be sure that the cable is a straight-through, twisted-pair cable. When connecting the switch to switches or hubs, use a crossover cable. Pinouts for the cables are described in "Connector and Cable Specifications."

GBIC Module Slots

The GBIC module slots support these modules to provide flexibility in media and distance options:

•

1000BASE-LX/LH GBIC module for fiber-optic connections of up to 10 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 maximum distance for a GigaStack GBIC-to-GigaStack GBIC connection is 1 meter. Refer to your GigaStack GBIC documentation for more information on supported switches.

LEDs

You can use the switch LEDs described in this section to monitor switch activity and its performance. Figure 1-3 shows the location of the LEDs and the Mode button that you use to select one of the port modes.

All of the LEDs described in this section except the utilization meter (UTL) are visible on the Cluster Management Suite (CMS) home page. The Catalyst 3550 Multilayer Switch Software Configuration Guide describes how to use CMS to monitor and configure individual switches and switch clusters.

System LED

The System LED shows whether the system is receiving power and is functioning properly. Table 1-2 lists the LED colors and their meanings.

RPS LED

Table 1-2 System LED
Color	System Status
Off	System is not powered on.
Green	System is operating normally.
Amber	System is receiving power but is not functioning properly.

The RPS LED shows the RPS status. Table 1-3 lists the LED colors and their meanings.

Table 1-3 RPS LED
Color	RPS Status
Off	RPS is off or not properly connected.
Solid green	RPS is connected and ready to provide back-up power, if required.
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	The 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, one of these two conditions could exist: •One of the RPS power supplies could be down. Contact Cisco Systems. •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 LEDs and Modes

Each 10/100/1000 port and GBIC module slot has a port LED. These port LEDs, as a group or individually, display information about the switch and about the individual ports. The port modes determine the type of information displayed through the port LEDs. Table 1-4 lists the mode LEDs and their associated port mode and meaning.

To select or change a mode, press the Mode button until the desired mode is highlighted. When you change port modes, the meaning of the port LED colors also change. Table 1-5 explains how to interpret the port LED colors in different port modes.

Table 1-4 Port Mode LEDs
Mode LED	Port Mode	Description
STAT	Port status	The port status. This is the default mode.
UTL	Switch utilization	The current bandwidth in use by the switch.
DUPLX	Port duplex mode	The port duplex mode: full duplex or half duplex.
SPEED	Port speed	The port operating speed: 10, 100, or 1000 Mbps.

Table 1-5 Meaning of LED Colors in Different Modes on the Catalyst 3550 Switch
Port Mode	LED 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 or an address violation or was blocked by Spanning Tree Protocol (STP). Note After a port is reconfigured, the port LED can remain amber for up to 30 seconds as STP checks the switch for possible loops.
UTL (utilization)	Green	The port LEDs display backplane utilization on a logarithmic scale. See Figure 1-4 for details.
UTL (utilization)	Amber	The peak total backplane utilization over the last 24 hours.
DUPLX (duplex)	Off	Port is operating in half duplex.
DUPLX (duplex)	Green	Port is operating in full duplex.
SPEED	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.
	GBIC ports
	Off	Port is not operating.
	Flashing green	Port is operating at 1000 Mbps.

Figure 1-4 shows the bandwidth utilization percentages displayed by the right-most LEDs.

If all port LEDs on the switch are green, the switch is using 50 percent or more of its total bandwidth. If port LEDs 1 through 11 are green, the switch is using between 25 and 50 percent of its total bandwidth. If port LEDs 1 through 10 are green, the switch is using 12.5 to 25 percent of its total bandwidth capacity, and so on. Amber LEDs provide an indication of peak total bandwidth of the switch over the last 24 hours.

Rear-Panel Description

Switch rear panels have an AC power connector, an RPS connector, and an RJ-45 console port, which are described in this section. (See Figure 1-5.)

Power Connectors

The switch is powered through the internal power supply. You can also connect the Cisco RPS 300 Redundant Power System to provide backup power if the switch internal power supply should fail.

Note The Catalyst 3550 switch and the Cisco RPS 300 should be connected to the same AC power source.

Internal Power Supply Connector

The internal power supply is an autoranging unit that supports input voltages between 100 and 240 VAC. Use the supplied AC power cord to connect the AC power connector to an AC power outlet.

Cisco RPS Connector

The Cisco RPS 300 (model PWR300-AC-RPS) supports the Catalyst 3550 switch. The Cisco RPS 300 has two output levels: -48V and 12V with a total maximum output power of 300W. Use the supplied RPS connector cable to connect the RPS to the switch.

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

The RPS is a redundant power system that can support six external network devices and provides 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 the failed device, preventing loss of network traffic. For more information on the Cisco RPS 300, refer to the Cisco RPS 300 Redundant Power System Hardware Installation Guide.

Console Port

You can connect a Catalyst 3550 switch to a PC by means of the console port and the supplied rollover cable and DB-9 adapter. If you want to connect the switch console port to a terminal, you need to provide a RJ-45-to-DB-25 female DTE adapter. You can order a kit (part number ACS-DSBUASYN=) containing that adapter from Cisco. For console port and adapter pinout information, see the "Cable and Adapter Specifications" section.

Management Options

CMS is a graphical user interface that can be launched from anywhere in your network through a web browser such as Netscape Communicator or Microsoft Internet Explorer. CMS is already installed on the switch, and no additional installation is required. From CMS, you can fully configure and monitor a switch or switch clusters, display network topologies to gather link information, and display switch images to modify switch- and port-level settings. For more information, refer to the Catalyst 3550 Multilayer Switch Software Configuration Guide, the Release Notes for the Catalyst 3550 Multilayer Switch, Cisco IOS Release 12.1(4)EA1, and the online help for this application.

The switch CLI is based on Cisco IOS software and is enhanced to support desktop-switching features. You can fully configure and monitor the switch and switch cluster members from the CLI. You can access the CLI either by connecting your management station directly to the switch console port or by using Telnet from a remote management station. Connect a PC or terminal directly to the console port, located on the rear panel of the switch, to access the CLI. If the switch is connected to your network, you can use a Telnet connection to manage the switch from a remote location. Refer to the Catalyst 3550 Multilayer Switch Command Reference for more information.

The CiscoView device-management application displays the switch image that you can use to set configuration parameters and to view switch status and performance information. The CiscoView application, which you purchase separately, can be a standalone application or part of a Simple Network Management Protocol (SNMP) platform. Refer to the CiscoView documentation for more information.

You can manage switches from a SNMP-compatible management station that is running platforms such as HP OpenView or SunNet Manager. The switch supports a comprehensive set of Management Information Base (MIB) extensions and four Remote Monitoring (RMON) groups. Refer to the Catalyst 3550 Multilayer Switch Software Configuration Guide, and the documentation that came with your SNMP application for more information.

Network Configurations

Refer to the Catalyst 3550 Multilayer Switch Software Configuration Guide for network configuration concepts and examples of using the switch to create dedicated network segments and interconnecting the segments through Gigabit Ethernet connections.

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