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Cell Relay Retreat>List Archive>month:1997-Nov> msg00131



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Re: Interworking between frame relay and ATM networks

  • From: ronaldd@ihgp3.ih.lucent.com (-Davis,R.H.)
  • Date: 19 Nov 1997 17:43:55 GMT

In article <ays-1711971340100001@pm3-ppp2.well.com>,
Alan Y. Schaevitz <ays@hooked.net> wrote:
>In article <64pv7i$2hg@ssbunews.ih.lucent.com>,
>ronaldd@ihgp3.ih.lucent.com (-Davis,R.H.) wrote:
>
>">"there is a service specific convergence sublayer defined for frame
>">"relay service over atm (using aal 5).  if i recall correctly, it
>">"may be found in itu recommendation i.365.1.
>">"
>I think you may be confusing ATM with frame relay.  There is an end-to-end
>reliable transport protocol defined for ATM called SSCOP (Service Specific
>Connection Oriented Protocol) that is an SSCS implementation (It is
>specified in the Signalling AAL or SAAL) for the ATM signaling application
>along with AAL5.  However, there is still no such mechanism defined for
>frame relay.  So while the ATM core can have congestion/flow control and
>end-to-end recovery, the frame relay access cannot.
>

no, there's no confusion in what i was saying at all, although i am
a bit confused by your response.  as you mentioned, sscop is the
sscs for saal.  i.365.1 is the sscs for frame relay interworking
over atm.  the associated common part convergence sublayer is aal 5
as i stated (but more significantly, as is stated in recommendation
i.365.1).  the function of the fr-sscs is to translate bits from
the frame relay header (e.g. de, becn, fecn) into bits in the atm
cell header (e.g. clp, ci) on the transmit side aal connection
endpoint, and performing the reverse tranlation on the receive
side aal-cep.

-- 
  __  ______  __  / __/ |       lucent technologies, naperville il, usa
_/ (_(_) / (_(_/_/_(_/  .       ronald.h.davis@lucent.com
"in every loss is the opportunity for future gain."