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STS Pointer question


In the WIS Update presentation made earlier this month, the
"Payload Pointer" octets (H1 & H2) contain one value for the
very first SONET frame and another value for all other SONET
frames. The first value appears to be a "New Data Flag" and
provides an absolute pointer to the start of the next SPE.
The other values have the New Data field in "normal mode"
and provide no offset.

If the first SONET frame is lost due to the synchronization
process, how does the receive WIS's payload pointer processor
logic know what to use as a starting pointer? The transmit
WIS will never send another. Does the receive WIS use 522 as
a default? What if a pointer adjustment was made because of
multiple SONET repeaters in the link but lost due to a multi-
frame synchronization process? Should the transmit WIS send
a "New Data Flag" once synchronization is complete? Does the
transmit WIS know when the receive WIS has gaineed sync?

If this is described somewhere in you presentations, please
let me know.


Benjamin Brown
Router Products Division
Nortel Networks
1 Bedford Farms,
Kilton Road
Bedford, NH 03110
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