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Site Preparation
Planning for Optical Budgets
This section provides information about the optical and system budgets for GBICs and mini-GBICs.
Optical Budgets for Mini-GBICs
The total optical system budget for the SX mini-GBIC is 11.5 dB. Extreme Networks recommends that
3 dB of the total budget be reserved for losses induced by cable splices/connectors and operating
margin. While 8.5 dB remains available for cable induced attenuation, the 1000BASE-SX standard
specifies supported distances of 275 meters over 62.5 micron multimode fiber and 550 meters over 50
micron multimode fiber. There is no minimum attenuation or minimum cable length restriction.
The total optical system budget for the LX mini-GBIC is 13.5 dB. Measure cable plant losses with a 1310
nm light source and verify this to be within budget. When calculating the maximum distance attainable
using optical cable with a specified loss per kilometer (for example 0.25 dB/km) Extreme Networks
recommends that 3 dBm of the total budget be reserved for losses induced by cable splices/connectors
and operating margin. Thus, 10.5 dB remains available for cable induced attenuation. There is no
minimum system budget or minimum cable length restriction because the maximum receive power is
the same as the maximum transmit power. There is no minimum attenuation or minimum cable length
restriction.
The ZX mini-GBIC is compatible with and interoperates with long-range GBICs. For more information
about the budget requirements and minimum attenuation requirements of long range GBICs, see
"Long-Range GBIC System Budgets".
Long-Range GBIC System Budgets
Measure cable plant losses with a 1550 nm light source and verify this to be within budget. When
calculating the maximum distance attainable, using optical cable with a specified loss per kilometer (for
example, 0.25 db/km), Extreme Networks recommends that 3 dB of the total budget be reserved for
losses induced by cable splices, connectors, and operating margin. Figure 14 shows the total optical
system budget between long range GBICs.
NOTE
The fiber loss budget plus all other penalties must not exceed the total optical system budget.
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Extreme Networks Consolidated "e" and "i" Series Hardware Installation Guide
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