XSBI bit-ordering sequence
The 10Gb 300pin MultiSource Agreement for
transponders currently allows the transponders to run at three different
rates. These are 9.9Gb/s (SONET), 10.3Gb/s (Ethernet), and 10.7Gb/s (SONET +
FEC). So it could be possible for a transponder customer to run at SONET
rates on a Tuesday and then switch to Ethernet rates on a Wednesday. If this
scenario is a real one, then could there be a problem with the bit ordering
sequence of SONET vs Ethernet?
My understanding is that SONET data bits are defined
as D15 being the most significant bit (MSB) which leaves the fibre first.
Ethernet data bits are defined as D0 being the most significant bit (MSB)
which leaves the fibre first. Will the differences in SONET and Ethernet MSB
data nomenclature provide a problem for the customer's framer or is there a
means by which the framer could be switched over to accommodate all three
rates on a consecutive basis?
I would be very grateful for any feedback on this
John Bell (10Gb Transponder Project Manager, Agere