IBM 8265, Руководство по подготовке площадки

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© Copyright IBM Corp. 1994, 1998
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Part 0
Chapter 4. Planning for Fiber Connections
This chapter describes the steps necessary for planning fiber cable links in an ATM
network:
•
Choosing the type of fiber cable to be used, and understanding the basic
principles of optical power transmission (see “Before You Start: General
Guidelines”).
•
Laying out valid ATM links (port-to-port and port-to-device connections) by
calculating the optical power budget and computing the optical power losses for
each link (see "Planning Cabling Distances" on page 27).
•
Maintaining the valid ATM connections that you create (see "Verifying ATM Fiber
Connections" on page 36).
In an ATM network, media modules are used to connect ATM devices (workstations,
servers, concentrators, bridges, and so on) and ATM switches.). For information on
the cables and connectors, see "Cables and Connectors" on page 59.
Before You Start: General Guidelines
Some general guidelines as to follow when planning and settings up an ATM network
using fiber as the transmission medium are as follows:
•
When you use multimode fiber, IBM recommends that you use 62.5 micron fiber
that conforms with IEEE 10BASE-F standards.
•
When you use singlemode fiber, IBM recommends that you use 9 micron fiber
that conforms with the IEEEE 10BASE-F standards.
•
Carefully note all sources of optical power loss, such as connectors, splices, patch
panels, and type of cable used.
•
Calculate the total power loss in each fiber link and verify that the distance
between the two ports, or between the port and a user device does not exceed the
optical power budget.
•
The power loss you calculate is valid for an ATM connection between two ports or
between a port and a device. Each port regenerates the optical signal at full
strength as it was originally transmitted from the source end system in the
connection. Therefore, the difference between the total power and the optical
power budget should be recalculated at each port in the end-to-end connection.
•
Links between ports must be individually verified without limitation of the number
of switches or ports interconnected.
Singlemode Fiber Interface
Singlemode fiber is also referred to as ”mono-mode” fiber. It requires the use of lasers
as the light source, allowing link distances between ATM ports to reach up to 20 km.
The singlemode fiber cable size (in microns) is 9/125 NA 0.022 at 1300 nm
wavelength.