IBM 8265, Руководство по подготовке площадки, Страница: 44 / 164

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IBM 8265: Planning and Site Preparation Guide
Optical Power Budget
The Optical Power Budget is the difference between the power output of a transmitter
at one end of a connection and the receiver capability at the other end of the
connection. The value of the power budget determines how much power can be lost
through splices, jumper cables, connectors and so on (see the following sections)
while still maintaining an operational connection.
In order for a link to transmit data effectively, the optical power budget must be
greater than the total power loss. See "Calculating Power Loss in an ATM
Connection" on page 34. When validating cabling distance in fiber links, network
planners and installers should calculate for maximum optical power losses in each link
of an end-to-end connection.
The optical power budget and maximum link lengths are shown in the SC Transceiver
specifications for each module that has fiber connection capability (see Chapter 7,
“Planning for Media Modules”.). The Receiver Sensitivity figures are provided for
estimating the validity of fiber connections. To check that the actual received power is
greater than the minimum allowed, use an optical multimeter. By not exceeding these
values, you can ensure the integrity of the ATM connections you create.