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RE: Gearbox reality check

Title: RE: Gearbox reality check

The WAN PHY buffering requirements will be less than 1K octets per direction.

1) The requirements for accommodating the overhead gaps are determined by the
    worst case consisting of: Path overhead and fixed stuff immediately following
    a positive pointer adjustment in row 4 of the SONET frame. The buffer
    requirements are then:

576 octets for transport overhead
192 octets for positive pointer adjustments
 64 octets for Path overhead and fixed stuff
plus a few octets for jitter and clock domain hand-off.

2) There is minimal buffering required for the WAN PHY framing and scrambling
    functions. Typically, pipeline stage re-timing is sufficient.

Tim Armstrong