RFC 2823 (rfc2823) - Page 2 of 28

PPP over Simple Data Link (SDL) using SONET/SDH with ATM-like framing

RFC 2823                  PPP SDL on SONET/SDH                  May 2000


   SDL is defined over other media types and for other data link
   protocols, but this specification covers only the use of PPP over SDL
   on SONET/SDH.

   The use of SDL requires the presentation of packet length information
   in the SDL header.  Thus, hardware implementing SDL must have access
   to the packet length when generating the header, and where a router's
   input link does not have this information (that is, for non-SDL input
   links), the router may be required to buffer the entire packet before
   transmission.  "Worm-hole" routing is thus at least problematic with
   SDL, unless the input links are also SDL.  This, however, does not
   appear to be a great disadvantage on modern routers due to the
   general requirement of length information in other parts of the
   system, notably in queuing and congestion control strategies such as
   Weighted Fair Queuing [7] and Random Early Detect [8].

   This document is not a replacement for the existing HDLC-like framing
   mandated by RFC 2615 [3].  Instead, the authors intend to gain
   implementation experience with this technique for operational and
   performance evaluation purposes, and would like to hear from others
   either considering or using the protocol as described in this
   document.  Please see Section 14 of this document for contact
   information.




























Carlson, et al.               Experimental