Cell Relay Archive

[Tab Fisher <deltae@mindspring.com>]

Baris,
Do you know why the LI field is one less than the length of the CPS-PP.  This
confuses me with the decode of the CPS-PP.  Does this mean the extra byte is
part of another PH packet or is it just "one less" by definition. I understand
now that the CPS-PH HEC field is not included in the LI.  Thank You!

On Tue, 11 Apr 2000 06:13:23 GMT, Baris Aksoy <baris.aksoy@gte.net> wrote:


As far as I understand from the I363.2, ATM-SDU is 48 octets in which there is
one
octet as "start field" and 47 octets for CPS-PDU payload.  CPS-PDU payload
consists
of 3-octet CPS-PH(CID, LI, UUI, HEC) and 44-octet CPS-PP. However, in the
standard
it says that CPS-INFO, which will be put as CPS-PP, could be 1 - to 45/63 octets
and
default maximum is 45. But this doesn't mean that you can put 45-octet CPS-PP in
one
ATM cell.

HEC field in CPS-PH, is calculated based on the CID, LI and UUI fileds of
CPS-PH. LI
field indicates one less of length of CPS-PP.

Baris



Tab Fisher wrote:

> I am afraid of sounding silly here.
> Is the possible payload of an AAL2 CPS-PP 44 or 45 bytes total?  Is the CPS-PH
> HEC included in the LI field.  All the documentation I can find online says the
> packet length is 1-45 bytes, but for the life of me I can only find room for 44
> bytes of payload.  The only way I can think of to get a length of 45 bytes is to
> include a piece of the header in the length indicator.  The header is not
> divided squarely into bytes.  What am I missing?
>
> DeltaE