Cambium PTP 670 Series, Руководство пользователя

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Chapter 3: System planning Link planning
Page 3-26
Calculating data rate capacity
The data capacity of a PTP or HCMP link is defined as the maximum end-to-end Ethernet
throughput (including Ethernet headers) that it can support, assumed Ethernet frames of 1518
octets.
Data capacity is determined by the following factors:
•
Wireless topology (PTP or HCMP)
•
TDD Synchronization
•
Link Symmetry
•
Link Mode Optimization (IP or TDM)
•
Modulation Mode
•
Channel Bandwidth
•
Link Range
•
Capacity reserved for TDM operation
Calculation procedure for PTP topology
To calculate the data rate capacity of a PTP 670 link, proceed as follows:
1 Use the tables in Data capacity in PTP topology on page 3-86 to look up the data throughput
capacity rates (Tx, Rx and Both) for the required combination of:
•
Link Symmetry
•
Link Mode Optimization
•
Modulation Mode
•
Channel Bandwidth
2 The tables contain data rates for links of zero range. Use the range adjustment graphs to look
up the Throughput Factor that must be applied to adjust the data rates for the actual range of
the link.
3 Multiply the data rates by the Throughput Factor to give the throughput capacity of the link.
4 Subtract capacity reserved for TDM operation. See TDM traffic load on page 3-127 .
Note
The data rates for adaptive symmetry apply to the most asymmetric case where the
link has significant offered traffic in one direction only. The data rates for adaptive
symmetry with bidirectional offered traffic are the same as those for link symmetry 1:1
with link optimization IP.
Calculation procedure for PTP topology with TDD synchronization
The capacity of a PTP link with TDD synchronization can be determined using the LINKPlanner.