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Re: Interface reality check

Dear Paul,

> "Paul Bottorff" <pbottorf@xxxxxxxxxxxxxxxxxx> writes:
> It doesn't look like 64/66 can be extended to ANSI T1X1 systems.
> So how is 64/66 going to extend the header mappings?  The T1X1
> proposals relay on the <length><type><crc> to provide other frame and
> header types for extended environments.  In particular the CRC check
> allows validation of the <type> field giving a broad range of format
> extensions.  The header CRC in ANSI T1X1 formats become essential for
> the extended header fields used to address ring networks. 

64/66 transparently supports all Ethernet packet signalling semantics.

Ethernet packets include a two-byte <length/type> field.  The
<length/type> code is protected by CRC32 and is therefore quite

The current mappings are:
    L <= 1500	    	; the frame is an LLC data frame
    L = 34,824	    	; the frame is a MAC control frame
    L = 33,024	    	; the frame is a VLAN-tagged frame
  none of the above 	; private use Type-frame

This leaves a very large number of type indicators currently undefined
by Ethernet.  I expect that they can be used to create ANSI T1X1 packet
types if needed. 

Best regards,
Rick Walker