Section 2.2: Connecting Switches
Switch deployment in a network involves two steps: physical connectivity and switch configuration. Cable connections must be made to the console port of a switch in order to make initial configurations. Physical connectivity between switches and end users involves cabling for the various types of LAN ports.
2.2.1: Console Port Cables and Connectors
A terminal emulation program on a computer is usually required to interface with the console port on a switch. Each Cisco switch family has various types of console cables and console connectors that are associated with them. All Catalyst switch families use an RJ-45-to-RJ-45 rollover cable to make the console connection between a computer or terminal or modem and the console port.
Rollover and Crossover Cables
With a "rollover" cable pins on one end are all reversed on the other end. In other words, pin 1 on one end connects to pin 8 on the other end; pin 2 connects to pin 7; pin 3 connects to pin 6; pin 4 connects to pin 5; pin 5 connects to pin 4; pin 6 connects to pin 3; pin 7 connects to pin 2; and pin 8 connects to pin 1. On a "crossover" cable, pairs 2 and 3 on one end of the cable are reversed on the other end. In other words, pin 1 on one end connects to pin 3 on the other end; pin 2 connects to pin 6; pin 3 connects to pin 1; pin 4 connects straight through to pin 4; pin 5 connects straight through to pin 5; pin 6 connects to pin 2; pin 7 connects straight through to pin 7; and pin 8 connects straight through to pin 8.
2.2.2: Ethernet Port Cables and Connectors
Catalyst switches support a variety of network connections, including all forms of Ethernet. In addition, Catalyst switches support several types of cabling, including UTP and fiber optic. On Catalyst 1900 and 2820 series switches, the Ethernet ports are fixed-speed with 12 or 24 10BaseT and one or two 100BaseTX or 100BaseFX ports. The 10BaseT and 100BaseTX ports use Category 5 UTP cabling and RJ-45 connectors. The 100BaseFX ports use two-strand multimode fiber (MMF) with SC. All other Catalyst switch families support 10/100 autosensing and Gigabit Ethernet. Switched 10/100 ports use RJ-45 connectors on Category 5 UTP cabling. These ports can be connected to other 10BaseT, 100BaseTX, or 10/100 autosensing devices.
To connect two 10/100 switch ports back-to-back, as in an access layer to distribution layer link, you must use a Category 5 UTP crossover cable.
2.2.3: Gigabit Ethernet Port Cables and Connectors
Gigabit Ethernet connections provide modular connectivity options. Catalyst switches with Gigabit Ethernet
ports accept Gigabit Interface Converters (GBICs) so that various types of cables can be connected.
Furthermore, the GBIC module is hot-swappable. GBICs are available for:
• 1000BaseSX GBIC, which provides for short wavelength connectivity using SC fiber connectors and MMF for distances up to 550 meters.
• 1000BaseLX/LH GBIC, which provides for long wavelength or long haul connectivity using SC fiber connectors and either MMF or single-mode fiber (SMF); MMF can be used for distances up to 550 meters and SMF can be used for distances up to 10 km.
• 1000BaseZX GBIC, which provides for extended distance connectivity using SC fiber connectors and SMF for distances up to 70 km or 100 km when used with premium grade SMF.
• GigaStack GBIC, which provides a proprietary GBIC-to-GBIC connection between stacking Catalyst switches or between any two Gigabit switch ports over a short distance.