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Re: AAL2 HEC calculation

  • From: "Jouko Uimonen" <jouko.uimonen@xnet.fi>
  • Date: 28 Jan 1999 08:41:03 GMT
  • Newsgroups: comp.dcom.cell-relay
  • Organization: Telia Finland



ronald h. davis <ronaldd@lucent.com> wrote in article
<36AE26F2.64DAC644@lucent.com>...
> Jouko Uimonen wrote:
> > 
> > I'm looking for a reference to compare my HEC calculation over the AAL2
CPS
> > Packet Header.
> > 
> > ITU-T gives an example in I.363 specification for the AAL5 CRC
calculation,
> > are there similar available for the AAL2 HEC ?
> > 
> 
> jouko,
> 
> yes, the hec calculation for the aal 2 cps header is defined in i.363.2,
> section 9.1 d).
> 

So if I understood that section correctly, X^5 + X^2 + 1 poly would
generate following HEC values over the AAL2 CPS Packet Header:

CID = 0, LI = 0, UUI = 0  -> HEC = 0  -> complete CPS-PH = 0x000000
CID = 0xff, LI = 0x3f, UUI = 0x1f -> HEC = 0x09 -> complete CPS-PH =
0xffffe9
CID = 0x1a, LI = 0x06, UUI = 0 -> HEC = 0x10 -> complete CPS-PH = 0x1a1810

Regards,

Jouko Uimonen