Connectivity Rules

4-5

4
The 1000BASE-SX, 1000BASE-LX and 1000BASE-ZX fiber optic ports operate at
1 Gbps full duplex. The maximum length for fiber optic cable operati ng at G i gab i t
speed will depend on the fiber type as listed under “1000 Mbps Gigabit Ethernet
Collision Domain” on page 4-5.
Connectivity Rules
When adding hubs (repeaters) to your network, please follow the conne ctivity rules
listed in the manuals for these products. However, note that becau se switches break
up the path for connected devices into separate collision domains, you should not
include the switch or connected cabling in your calculations for cascade length
involving other devices.

1000BASE-T Cable Requirements

All Category 5 UTP cables that are used for 100BASE-TX connections should also
work for 1000BASE-T, providing that all four wire pairs are connected. However, it is
recommended that for all critical connections, or any new cable installat io ns ,
Category 5e (enhanced Category 5) or Category 6 cable should be used. The
Category 5e specification includes test parameters that are only recomme ndations
for Category 5. Therefore, the first step in preparing existing Category 5 cabling for
running 1000BASE-T is a simple test of the cable installation to be sure that it
complies with the IEEE 802.3-2005 standards.

1000 Mbps Gigabit Ethernet Collision Domain

Table 4-1 Maximum 1000BASE-T Gigabit Ethernet Ca ble Length
Cable Type Maximum Cable Length Connector
Category 5, 5e, 6 100-ohm UTP or STP 100 m (328 ft) RJ-45
Table 4-2 Maximum 1000BASE-SX Fiber Optic Cable L ength
Fiber Diameter Fiber Bandwidth Cable Length Range Connector
62.5/125 micron multimode
fiber (MMF) 160 MHz/km 2-220 m (7-722 ft) LC
200 MHz/km 2-275 m (7-902 ft) LC
50/125 micron multimode fiber
(MMF) 400 MHz/km 2-500 m (7-1641 ft) LC
500 MHz/km 2-550 m (7-1805 ft) LC