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LPP: Lightweight Presentation Protocol

Lightweight Presentation Protocol (LPP) describes an approach for providing "stream-lined" support of OSI application services on top of TCP/IP-based network for some constrained environments. LPP was initially derived from a requirement to run the ISO Common Management Information Protocol (CMIP) in TCP/IP-based network. 

LPP is designed for a particular class of OSI applications, namely those entities whose application context contains only an Association Control Service Element (ACSE) and a Remote Operations Service Element (ROSE). In addition, a Directory Services Element (DSE) is assumed for use by the application-entity, but only in a very limited sense. LPP is not applicable to entities whose application context is more extensive (e.g., contains a Reliable Transfer Service Element).

If one wants to implement ISO applications in a TCP/IP based network without constrains, the ITOT mechanisms (specified in RFC 2126) should be used.  

Protocol Structure - LPP: Lightweight Presentation Protocol

The service provider is in one of the following states:

 IDLE, WAIT1, WAIT2, DATA, WAIT3, or WAIT4

The possible events are:

 PS-user  P-CONNECT.REQUEST

  P-CONNECT.RESPONSE

  P-RELEASE.REQUEST

  P-RELEASE.RESPONSE

  P-DATA.REQUEST

  P-U-ABORT.REQUEST

 network  TCP closed or errored(*)

  receive ConnectRequest PDU

  receive ConnectResponse PDU

  receive ReleaseRequest PDU

  receive ReleaseResponse PDU

  receive UserData(*) or CL-UserData(**) PDU

  receive user-initiated Abort PDU

  receive provider-initiated Abort PDU

  timer expires(**)

The possible actions are:

 PS-user P-CONNECT.INDICATION

  P-CONNECT.CONFIRMATION

  P-RELEASE.INDICATION

  P-RELEASE.CONFIRMATION

  P-DATA.INDICATION

  P-U-ABORT.INDICATION

  P-P-ABORT.INDICATION

 network  open TCP(*)

  close TCP(*)

  send ConnectRequest PDU

  send ConnectResponse PDU

  send ReleaseRequest PDU

  send ReleaseResponse PDU

  send UserData(*) or CL-UserData(**) PDU

  send user-initiated Abort PDU

  send provider-initiated Abort PDU

  set timer(**)

 (*)  tcp-based service only

 (**) udp-based service only    

Related Protocols
UDP , TCP , IP , CMIP, CMOT, CMIS , ACSE , ROSE , ITOT

Sponsor Source

LPP is defined by ISO (www.iso.org ).



Reference

http://www.javvin.com/protocol/rfc1085.pdf : ISO Presentation Services on top of TCP/IP-based internets
http://www.javvin.com/protocol/rfc2126.pdf : ISO Transport Service on top of TCP (ITOT)