Chapter 2 Switch Installation
Connecting Devices to the Ethernet Ports
10/100/1000 Ethernet Port Connections
The 10/100/1000 Ethernet ports use standard RJ-45 connectors with Ethernet pinouts. The maximum cable length is 328 feet (100 meters). The 100BASE-TX and 1000BASE-T traffic requires Category 5, Category 5e, or Category 6 UTP cable. The 10BASE-T traffic can use Category 3 or Category 4 cable.
The autonegotiation feature is enabled by default on the switch. At this setting, the switch ports configure themselves to operate at the speed of attached device. If the attached device does not support autonegotiation, you can explicitly set the switch port speed and duplex parameters. To maximize performance, either let the ports autonegotiate both speed and duplex, or set the port speed and duplex parameters on both ends of the connection.
For simplified cabling, the automatic medium-dependent interface crossover (auto-MDIX) feature is enabled by default on the switch. With auto-MDIX enabled, the switch detects the required cable type for copper Ethernet connections and configures the interface accordingly. Therefore, you can use either a crossover or a straight-through cable for connections to a switch 10/100/1000 Ethernet port regardless of the type of device on the other end of the connection.
See the switch software configuration guide or the switch command reference on Cisco.com for more information about enabling or disabling autonegotiation and auto-MDIX.
If auto-MDIX is disabled, use the guidelines in Table 2-1to select the correct cable for connecting the switch 10/100/1000 Ethernet ports to other devices. See the “Cable and Adapter Specifications” section on page B-5for cable-pinout descriptions.
Table 2-1 | Recommended Ethernet Cables (When Auto-MDIX is Disabled) |
| | | |
Device | | Crossover Cable1 | Straight-Through Cable1 |
Switch to switch | Yes | No |
| | | |
Switch to hub | | Yes | No |
| | |
Switch to computer or server | No | Yes |
| | |
Switch to router | No | Yes |
| | |
Switch to IP phone | No | Yes |
| | | |
1.100BASE-TX and 1000BASE-T traffic requires twisted four-pair, Category 5, Category 5e, or Category 6 cable. 10BASE-T traffic can use Category 3 or Category 4 cable.
PoE Port Connections
The 10/100/1000 PoE ports have the same autonegotiation settings and cabling requirements that are described in the “10/100/1000 Ethernet Port Connections” section on page 2-27.
The PoE ports provide PoE support for devices compliant with IEEE 802.3af and also provide Cisco pre-standard PoE support for Cisco IP Phones and Cisco Aironet Access Points.
Each port can deliver up to 15.4 W of PoE. With the 1150-W power-supply module, the
Catalyst 3750E-48PS and Catalyst 3560E-48PS switches can deliver 15.4 W on all 48 ports. With the 750-W power-supply module, the switches can deliver 15.4 W of PoE on any 24 of the 48 ports, or any combination of the ports can deliver an average of 7.7 W of PoE at the same time, up to a maximum switch power output of 370 W. On a per-port basis, you can control whether or not a PoE port automatically provides power when an IP phone or an access point is connected.
Catalyst 3750-E and Catalyst 3560-E Switch Hardware Installation Guide
