Cell Relay Archive

["Saso Stojanovski" <sasos@nortelnetworks.com>]

xu,


just two remarks:

   1) both af-vtoa-0078 and I.363.1 tend to agree that:

"The P[ointer] format is used *exactly once* in every cycle, where a cycle is
the sequence of consecutive SAR-PDUs with sequence count values 0 through 7."

as i understand it, even if your structure appears several times within the
block of 8 consecutive payloads (4 x (46 + 47) = 384 octets), you should use
the pointer only once.

   2) the structure size octets equals the number of voice channels only if you
use circuit emulation without CAS; otherwise, the structure size is much larger
(see af-vtoa-0078).


cheers,
    v
--saso




XuHonggang wrote:

> Hi,
> Pointer field is 7 bits, so max offset which it can idicate is 127 Octets
> which < 3 ATM cells p and > 2 ATM cells, so standard maker decided to use 96
> as max number wich align with 2 ATM cells.
> You put a pointer in no.0 cell, it can cover all possible offset in no.0 and
> no.1, so second pointer only need to appear in no.2, the same thing happen
> to no.4 and no.6 cell.
> Yes, a octet means 8 bits, means one sample of a voice channel. How many
> octets
> in your structure means how many voice channels in your structure.
> wish it help
> XuHonggang
> SwitchingSystemDepartment
> CET Techologies of Singapore Technologies
> 24 AngMoKio Str. 65
> Singapore 569061
> -----Original Message-----
> From: Nuzhath Shereen <shereen@chequemail.com>
> To: sasos@nortelnetworks.com <sasos@nortelnetworks.com>
> Cc: rajagopalan.sampath@wipro.com <rajagopalan.sampath@wipro.com>;
> cell-relay@cell.onecall.net <cell-relay@cell.onecall.net>
> Date: Thursday, July 27, 2000 5:26 PM
> Subject: Re: CR: Structured Data Transfer in AAL Type 1 !
>
> >
> >
> >Hello Saso,
> >
> >Can you explain more about this SDT format. The ITU-T I.363.1  says that
> the pointer format may be used only if the sequence count value is 0,2,4 or
> 6. This is because the 1,3,5 and 7 values are reserved for SRTS.
> >
> > I didn't understand the rest of the explanation in the standard. What is
> this 93-octet payload it refers to. By octet, Is it referring to one 64kps
> channel (I had read that somewhere) or is the digital 8 bits.