3Com 3C16985B manual Configuration Rules for Gigabit Ethernet SM and TM, Gigabit Ethernet cabling

Configuration Rules for Gigabit Ethernet (SM and TM) 23

Configuration Rules for Gigabit Ethernet (SM and TM)

Gigabit Ethernet is designed to run over four media:

■Single-mode fiber optic cable, with connections up to 5km.

■Multimode fiber optic cable, with connections up to 550m.

■Balanced, shielded copper cabling, with connections up to 25m.

■Category 5 cabling, with connections up to 100m.

Table 4 Gigabit Ethernet cabling

			Modal	Lengths Supported
Gigabit Ethernet			Bandwidth	Specified by IEEE
Transceivers	Fiber Type		(MHz/km)	(meters)
1000BASE-LX	62.5 ∝m MM		500	2–550
	50	∝m MM	400	2–550
	50	∝m MM	500	2–550
	10	∝m SM	N/A	2–5000
1000BASE-SX	62.5 ∝m MM		160	2–220
	62.5 ∝m MM		120	2–275
	50	∝m MM	400	2–500
	50	∝m MM	500	2–550
1000BASE-CX	N/A		N/A	25
1000BASE-T	N/A		N/A	100
MM = Multimode	SM = Single-mode

Configuration Rules The SM Switch has a Gigabit Ethernet fiber optic 1000BASE-SX port

for the 3300 SM while the TM switch has a 1000BASE-T port. These ports provide a

and TM1000Mbps full duplex connection to another Gigabit Ethernet device. Full duplex allows packets to be transmitted and received simultaneously and, in effect, doubles the potential throughput of a link.

For the SuperStack 3 Switch 3300 SM:

■Use Multimode fiber optic cable (see Table 4 for details).

■The 1000BASE-SX port is permanently fixed at 1000Mbps with full duplex.

For the Superstack 3 Switch 3300 TM:

■the maximum UTP cable length is 100m (328ft) over Category 5 cable.

■The 1000BASE-T port is permanently fixed at 1000Mbps with full duplex.