N
ETWORK
P
LANNING
2-8
10 Mbps Ethernet Collision Domain
SMC 5-4-3 Rule
Maximum Ethernet Cable Distance
Between any two PCs or other stations in the same 10 Mbps collision
domain, there may be:
•up to 5 link segments in series,
•up to 4 repeaters (hubs),
•up to 3 populated cable segments, that is, segments attached to
two or more PCs (coax networks only).*
* The remaining two segments are unpopulated; these are known as
inter-repeater links or IRLs. This distinction between populated and
unpopulated segments is significant for coax networks only.
Cable Type Maximum Length
Twisted Pair, Categories 3, 4, 5 100 m (328 ft.)
Thin Coax 185 m (607 ft.)
External Transceiver Drop 50 m (165 ft.)