Cell Relay Archive

[George Jeffrey <jeffrey@kayak.Semird.Mitel.Com>]

Eric,

I think you're confusing the T1/E1 channel ordering with 
the function of the pointer. The pointer points to the 
first byte of the payload structure (the structure is N 
bytes long for non-CAS Nx64). The placement of a particular
DS0 (64k timeslot) in the AAL1 payload structure is not 
necesarily the same as its placement in the T1/E1.

See the ATM Forum Circuit Emulation Services specification
for a more complete explanation:

http://www.atmforum.com/atmforum/specs/approved.html

or 

ftp://ftp.atmforum.com/pub/approved-specs/af-vtoa-0078.000.pdf

Note that for non-CAS N=1, the structure length is one 
byte (octet) and therefore the pointer is not needed and 
not used.

Regards,
George Jeffrey

Remove human-propelled water-craft from my address to reply.


> 
> Would someone be able to explain to me how the 7 bit offset in the
> pointer of a p-Format Structured Data Transfer (SDT) CS PDU is used to
> represent/reconstruct the 64K timeslot of a DS1. In other words, what
> would the bit configuration/representation be for the 7th 64k timeslot
> and why?
> 
> Thanks in advance for your help!!!
> 
> Eric Dysart
> edysart@my-deja.com