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RE: A Question about "Inter Packet Gap and SOP Lane alignment"

Maybe we should reconsider the use of /A/ for alignment.  We don't
really need to use a special character for lane alignment.  We could
just as well perform the alignment on the IDLE->DATA transition at
the start of each packet.

All of this /A/K/R/O/ stuff during IDLE is getting out of hand.
We would be better off with simpler rules for IDLE, like a randomized
sequence of Ks and Rs.

In fact, if we did the alignment based on the transition from 
lane[0:3]=IDLE to (lane[0]=SOP & lane[1:3]=data), then we wouldn't
need to maintain columns of Ks and Rs during IDLE.  We would just need
to send a complete column of R once during IPG, for instance, on the
column immediately following the T. IDLE could be random per-lane Ks
and Rs at all other times.

The IDLE insert/delete rules would remain unchanged.

We don't really need to be aligned until there is a packet to receive,
and the first packet that a receiver gets can be used to establish the
lane alignment. If a receiver looses alignment, it will re-establish
the alignment at the next start of packet.

Howard Frazier
Cisco Systems, Inc.