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Introduction to Computer
Networks
Device Drivers and OSI
In this lesson we look at device drivers, and how
they relate to the OSI reference model.
The Role of Drivers
• A driver (sometimes called a device driver) is
software that enables a computer to work with a
particular device.
• There are drivers for nearly every type of
computer device and peripheral.
• As a general rule, manufacturers of components,
are responsible for supplying the drivers for their
equipment.
• Drivers generally are included on a disk with the
equipment when it is purchased, or can be
downloaded from the Internet.
The Network Environment
• Network drivers provide communication between a
NIC and the network redirector running in the
computer.
• The redirector is the part of networking software
that accepts input/output (I/O) requests for
remote files and then sends, or redirects, them
over the network to another computer.
Drivers and the OSI Reference
Model
• NIC drivers reside in the MAC sublayer of the OSI
reference model's data-link layer.
• The NIC drivers provide virtual communication
between the computer and the NIC.
• This, in turn,
provides a link
between the
computer and
the rest of the
network.
Drivers and the Networking
Software
• It is common for a NIC manufacturer to provide
drivers to the networking-software vendor so that
the drivers can be included with the network
operating software.
• The hardware compatibility list (HCL) supplied by
operating-system manufacturers describes the
drivers they have tested and included with their
operating system.
Network Driver Interface
Specification (NDIS) (1)
• NDIS is a standard that defines an interface for
communication between the MAC sublayer and the
protocol drivers.
• Protocol drivers use this interface to communicate
with the NICs.
• The advantage of NDIS is that it offers protocol
multiplexing, so that multiple protocol stacks can
be used at the same time.
Network Driver Interface
Specification (NDIS) (2)
• Three types of network software have interfaces
described by NDIS:
• Protocol stack: Provides network communications.
• Adapter driver: Controls the network interface
hardware.
• Protocol Manager: Controls the activity between
the protocol stack and the MAC.