Short Message Service/Point-to-Point

Description

SMS/PP (Short Message Service/Point-to-Point) is a historical term used in early 3GPP specifications, particularly Release 5 and Release 6, to denote the bearer service for point-to-point Short Message Service. In essence, it is functionally identical to what later releases more consistently term SMS-PP (Short Message Service – Point to Point). The service architecture and operation described under SMS/PP followed the same principles: a store-and-forward mechanism using a network-based Service Centre (SMS-SC) to relay messages between two mobile users.

The technical operation involved the same key network elements: the Mobile Station (MS), the serving network node (MSC for circuit-switched, SGSN for packet-switched), the Home Location Register (HLR), and the Short Message Service Centre (SMS-SC). The MS would submit a message (Mobile Originated) to the network, which would route it to the SMS-SC. The SMS-SC would then interrogate the HLR to find the current serving node of the recipient and forward the message for delivery (Mobile Terminated). The protocols used were the same RP-CP-TP stack carried over signaling channels.

The distinction of the "/PP" suffix was primarily to differentiate this specific person-to-person (or device-to-device) messaging service from other potential SMS-related services, such as cell broadcast (SMS-CB) or messaging to/from external applications. The slash notation was a stylistic choice in certain specification documents. As the 3GPP terminology evolved and matured, the hyphenated form "SMS-PP" became the standardized and persistent term used across all subsequent technical specifications and architecture descriptions, leading to the phasing out of the "SMS/PP" variant.

Purpose & Motivation

The term SMS/PP served the purpose of explicitly identifying the point-to-point variant of the Short Message Service within the formal 3GPP specification lexicon during the initial phases of 3G standardization. As 3GPP took over the evolution of GSM services into UMTS, there was a need to formally categorize and define the different SMS service types within the new architectural framework.

It addressed a need for clarity in early specification documents to distinguish the widely used subscriber-to-subscriber text messaging from other less common SMS modes. The "Point-to-Point" descriptor was crucial to specify the directed, addressed nature of the service, as opposed to broadcast services. The motivation for eventually consolidating the terminology to "SMS-PP" was likely driven by a desire for consistent naming conventions across thousands of specification pages, moving away from the slash notation which could be ambiguous in certain contexts (e.g., file paths, formulas) towards a more robust hyphenated compound term.

Key Features

• Identical to SMS-PP: Point-to-point message transfer between two subscribers
• Reliance on the SMS-SC for store-and-forward routing
• Use of MAP protocols for network communication
• Support for delivery reports
• Operation over both circuit-switched and packet-switched domains
• Foundation for user-to-user text communication

Evolution Across Releases

Defining Specifications