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RE: Gearbox reality check


Gold star!

Now, can you explain how it works without the WIS? :-)


		-----Original Message-----
		From:	Brown, Ben [BAY:NHBED:DS48]
		Sent:	Tuesday, June 20, 2000 1:39 PM
		To:	HSSG
		Subject:	Re: Gearbox reality check

		Rich, Roy,

		It could be the terminology that is confusing the issue. I
		think the results are any different.

		The SONET frame is byte aligned.

		The OH content is bytes.

		The SPE content is 66-bit words when being filled or emptied
		at the WIS. Since the SPE is not an integral number of 66
		bits, the last word in 1 SPE will often "spill over" into
		the next SPE.

		The SPE content is considered bytes when being passed
		the SONET network. When the SONET network needs to "adjust"
		1 SPE with respect to another SPE in order to account for
		clock jitter and tolerances, it does so on byte boundaries.
		This could potentially further separate a 66-bit word. The
		SONET network also uses byte boundaries to find the OH bytes
		within a frame.

		The result is that the WIS is required to parse the SPE
		on byte boundaries as indicated by the pointer logic (to
		the start of the SPE) but the data it extracts is organized
		66-bit words, i.e. it only uses the byte boundaries to find
		start and end of the SPE and to separate the OH bytes, while
		the content of the SPE is considered a collection of
		66-bit words.

		How close is this?