cx28560 Mindspeed Technologies, cx28560 Datasheet - Page 271

• Manufacturer Part Number: cx28560
• Description: Hdlc Controller
• Manufacturer: Mindspeed Technologies

28560-DSH-001-B
Appendix I:
The maximum number of channels configurable is dependant on a number of
parameters. In the analysis included in this specification, it is proven that for
fragments of 56 bytes and a slot time of 20 cycles, for any dynamic combination of
2047 channels, a Flexiframe can be built, and that sufficient buffering can be
supplied.
The simplest form of the calculation of the maximum number of channels
configurable from the fragment length is by simple extrapolation from the above
example, as follows:
This analysis (and therefore the example above) provides for maximum flexibility in
the allocation of channels bandwidths allowing the user to configure a channel with
any bit rate.
However by introducing the channels’ bandwidths into the equation used to calculate
the maximum number of channels, the length of the fragment can sometimes be
increased. It can be seen in
allocations. For a known set of frequencies in the system a more efficient Flexiframe
structure can be created. This structure causes less oversubscribing and a service will
be provided when needed. It will not use the half-rate method, as a result the buffer
size needed for each channel will be smaller. It will be 68 + 64 + 24 = 156 bytes. In
this case, the CX28560 can support 2 K channels with 64-byte fragments. Longer
fragments will force the max number of channels to be lower.
• A maximum of 2047 channels can be configured with a 56-byte fragment
• A maximum of 1024 channels can be configured with a 112-byte fragment
• A maximum of 512 channels can be configured with a 224-byte fragment
Mindspeed Technologies™
Advance Information
Appendix E
Maximum Number of
Channels Calculation
that the buffer calculation assumes half-rate
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