Open Systems Interconnection Reference Model Form

This document provides a structured way to map a solution's functions to the OSI model so stakeholders can see how data flows and how each layer interacts. It aligns with standards documents such as ISO/IEC 7498-1 (ISO 7498) and the ITU-T X.200 recommendation and supports clear decisions about communication protocols, interoperability, and risk. By organizing features into a seven-layer architecture with interconnection comments, teams can capture peer-to-peer communication among peer entities, protocol data units (PDU), service data units (SDU), and cross-layer functions such as naming and addressing, security architecture, and a management framework for network management.

Layer 1 focuses on data transmission details: bit synchronization, bit rate control, physical topologies, and transmission modes like full duplex and half duplex. Layer 2 covers node-to-node services with media access control (MAC), logical link control (LLC), frame synchronization, MAC addresses, error detection and correction, and flow control mechanisms across Ethernet or PPP; address resolution can be documented here when relevant. Layer 3 describes logical addressing and packet routing, including IP addressing, routing protocols, router switching, packet fragmentation and reassembly, maximum transmission unit, multicast group management, and quality of service.

Layer 4 sets connection-oriented and connectionless service expectations using the Transmission Control Protocol and the User Datagram Protocol, port numbers, segmentation and reassembly, maximum segment size, error recovery, flow control, and selective repeat sliding window methods. Layer 5 defines session establishment, maintenance, and termination, with dialog controller responsibilities and service point addressing. Layer 6 handles data translation, encryption and decryption, and data compression as a presentation translation layer. Layer 7 lists application protocols and services such as Simple Mail Transfer Protocol, File Transfer Protocol, and the Domain Name System, plus remote file access, directory services, file transfer access management, and a network virtual terminal. Security can be noted at multiple layers, such as IPsec security at Layer 3, MACsec security at Layer 2, and TLS/SSL above the transport layer.

The form also supports a comparison to TCP/IP and the Internet Protocol Suite, showing how data flows through a protocol stack, how port addressing maps to programming interfaces, and how OSI vs TCP/IP choices affect interoperability and connection design.

Use cases include RFPs, cloud migrations, IoT rollouts, network topology redesign, router and switching upgrades, and audits of naming, addressing, and flow control.

Proposal Kit helps teams assemble this analysis quickly using document assembly, automated line-item quoting, an AI Writer that can build supporting documents, and an extensive template library designed for ease of use.

Expanding on the practical use of this form, teams can drive clearer architecture decisions by documenting per-layer requirements end to end. At layer one, physical, specifying media, connectors, and full duplex or half duplex settings reduces deployment risk. The layer two data link entries capture MAC address plans, Ethernet PPP choices, error detection and correction, and flow control error handling.

The layer three network section formalizes routing addressing policies, use of the address resolution protocol, and packet fragmentation reassembly behavior across diverse network devices. Layer four transport clarifies OSI connection-oriented transport expectations and how they align to the TCP IP model. Layer five session defines session establishment, maintenance, and termination rules for reliable resource sharing. Layer six presentation sets formats and encryption decryption needs that affect interoperability and compliance.

The template also encourages documenting protocol data unit and service data unit boundaries (PDU SDU), making how data is encapsulated visible between layers. Mapping application dependencies, such as SMTP, ftp, and DNS, highlights upstream effects on capacity, performance, and security. This level of detail helps forecast impacts of upgrades, guides procurement, and streamlines troubleshooting when incidents span multiple layers.

Proposal Kit can accelerate the creation of these project management documents by assembling consistent layer-by-layer narratives, reusing approved language, and producing companion materials with its AI Writer. Teams can also generate budgets and hardware/software lists with automated line-item quoting, ensuring the OSI analysis ties directly to actionable plans.

Additionally, treating this OSI-layered analysis as a lifecycle artifact helps leadership connect design choices to operations, SLAs, and audits. Teams can define measurable acceptance criteria-throughput, latency, packet loss-and tie them to specific controls, including error control strategies and duplex settings. Documenting full duplex, half duplex configurations alongside capacity estimates and cabling standards clarifies risk, avoids autonegotiation issues during cutovers, and supports vendor compliance checks. The same artifact drives test plans that trace defects to their layer of origin, speeding root-cause analysis during incident response and change windows.

This approach benefits common initiatives such as WAN modernization, data center migrations, M&A network integration, and OT/IoT segmentation. It also improves onboarding by giving operations, security, and procurement a shared reference for runbooks, performance baselines, and monitoring thresholds aligned to the OSI stack.

Proposal Kit can streamline these outcomes by assembling consistent, traceable documents, generating budgets with automated line-item quoting, and using its AI Writer to write supporting procedures and layer-specific checklists drawn from an extensive template library.

How do you write a Open Systems Interconnection Reference Model Form document?

OSI Reference Model

The Open Systems Interconnection Reference Model (OSI Reference Model) is provided for this project to describe the flow of data and to illustrate how one layer should interact with another. The table below divides the functions of an application or protocol implemented in the solution into a series of layers. Each layer communicates and exports functionality into the layer above and below itself. The lower layers deal with the physical connections and hardware requirements while the higher layers tend to be implemented within the application and user interaction portion of the solution.

OSI Layers

Layer Seven: Application Layer

Interconnection Comments

Layer Six: Presentation Layer

Interconnection Comments

Layer Five: Session Layer

Interconnection Comments

Layer Four: Transport Layer

Interconnection Comments

Layer Three: Network Layer

Interconnection Comments

Layer Two: Data Link Layer

Interconnection Comments

Layer One: Physical Layer

Interconnection Comments

Repeat for each protocol needing a description – or combine all protocols by their layers into a single table per layer.