OSI (Open Systems Interconnection)

Multiple Definitions
Definition #1

OSI (Open Systems Interconnection)

Is the 7-layer hierarchical reference model structure developed by the International Standards Organization for defining, specifying, and relating communications protocols; not a standard or a protocol;

Layer Description

(7) Application: provides interface with network users,

(6) Presentation: performs format and code conversion,

(5) Session: manages connections for application programs,

(4) Transport: ensures end-to-end delivery,

(3) Network: handles network addressing and routing,

(2) Data Link: performs local addressing and error detection and

(1) Physical: includes physical signaling and interfaces.

NENA-STA-010, NENA i3 Standard for Next Generation 9-1-1

Definition #2

OSI (Open Systems Interconnection)

Is a conceptual model that describes how computer systems communicate with each other across LANs and WANs. While it is a defined standard (ISO 7498-1), it is more commonly used as a reference architecture.


 * NENA-INF-016, NENA Emergency Services IP Network Design (ESIND) Information Document
 * NENA-INF-003, NENA Potential Points of Demarcation in NG9-1-1 Networks Information Document

ISO 7498-1