Foirl Fiber Optic, Bridges | IBM CTI 2572 specification

FOIRL (Fiber Optic)

Like the 10BaseT standard, the fiber optic cabling scheme uses a hub technology. Network stations are connected to the hub via point to point fiber optic connections. The fiber optic cable is attached to the network adapter using transceivers connected to the AUI port. A fiber optic cable run can extend up to 1 km.

Fiber optics is often used where longer distances, noise immunity, and lightning protection are required. This includes communications within buildings on a factory campus and as a "backbone" within a single large building. Except for the media, fiber optic hubs are essentially equivalent to 10BaseT hubs.

Bridges.

Fiber Optic Hub

	Transceiver	Transceiver	Transceiver


AUI Port		AUI Port	AUI Port
	Station	Station	Other Hub

Figure 7 Fiber Optic Hub

As mentioned earlier, Ethernet uses

the CSMA/CD access method. As the

Ethernet - Segment A

Ethernet - Segment B

number of active stations increases, a

Bridge

point is finally reached where

collisions occur frequently and

response time begins to suffer

Workstation

"Filtered" Packets

Workstation

(usually around 50% utilization).

Bridges are commonly used to

Workstation

alleviate this problem. The network is

Workstation

divided into two segments connected

by a bridge. The bridge blocks all

transmissions from a segment except

Server

those intended for stations on the

other side of the bridge. Therefore,	Figure 8 Ethernet Bridge
other side of the bridge. Therefore,
traffic that is local to a segment does
not tie up the bandwidth on another

segment. Most bridges can automatically learn which transmissions need to be routed across the bridge. In addition, bridges can be used to extend the distance of an Ethernet network, since they perform a repeater function also.

CTI 2572 Technical Overview Manual