3Com 3C16987A manual Configuration Rules for Gigabit Ethernet

22CHAPTER 1: INTRODUCING THE SWITCH 3300 SM

Configuration Rules for Gigabit Ethernet

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

Gigabit Ethernet			Modal	Lengths Supported
			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 Switch has a Gigabit Ethernet fiber optic 1000BASE-SX port that

for the 3300 SM provides a 1000Mbps 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.