Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: XAUI and 64b/66b

Actually, the MII and GMII do "speak IDLES".  Please
refer to (for the MII) and (for the GMII),
which describe the "inter-frame" period. is reproduced
in its entirety below: Inter-frame

   The inter-frame period provides an observation window for an
   unspecified amount of time during which no data activity occurs
   on the MII.  The absence of data activity is indicated by the
   de-assertion of the RX_DV signal on the receive path, and the
   de-assertion of the TX_EN signal on the transmit path. The MAC
   interFrameSpacing parameter defined in Clause 4 is measured
   from the de-assertion of the CRS signal to the assertion of
   the CRS signal.

For the XGMII, we have proposed using "embedded delimiters", rather
than discrete signals like RX_DV and TX_EN to indicate the transition
between the inter-frame period and the preamble/sfd/data/efd phases.
That is why we refer to an XGMII code point named "IDLE".  This 
code point is nothing more than the way the inter-frame period is
conveyed across the XGMII, in the absence of discrete signals.

Howard Frazier
Cisco Systems, Inc.