The following points summarize the key concepts of this chapter:
OSI Reference Model
- The OSI reference model architecture divides network protocols into seven layers: the application, presentation, session, transport, network, data-link, and physical layers.
- Microsoft Windows NT groups the OSI reference model into three layers: file system drivers, transport protocols, and NIC drivers.
- The Windows NT network model requires three interfaces to provide communication between groups: APIs, TDIs, and NDISs.
- IEEE 802 standards define the specifications for NICs, WAN components, and media for the data-link and physical layers of the OSI reference model.
- 802.3 defines Ethernet specifications.
- 802.5 defines Token Ring LAN specifications.
- The IEEE 802 standards divide the data-link layer into two subgroups: Logical Link Control (LLC) and Media Access Control (MAC).
Device Drivers and OSI
- A driver is a program that gives directions to the computer for how to operate a device.
- In networking, drivers are needed to provide the software connection between the computer and the NIC.
- NIC drivers reside in the MAC sublayer of the data-link layer of the OSI reference model.
- NDIS is a standard that defines the interface for Windows NT Server and Warp Server.
- ODI is a standard that defines the interface for Apple and Novell systems.