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

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 Terms: UDP, TCP, IP, CMIP, CMOT, CMIS, ACSE, ROSE, ITOT

Sponsor Source: LPP is defined by ISO (http://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)