D-Link DES-3326S - Manual (Page 93)

DES-3326S Layer 3 Fast Ethernet Switch User’s Guide
Switch Management and Operating Concepts 93
Between two protocol stacks, members of the same layer are
known as peers and communicate by well-known (open and
published) protocols. Within a protocol stack, adjacent
layers communicate by an internal interface. This interface is
usually not publicly documented and is frequently proprietary.
It has some of the same characteristics of a protocol and two
stacks from the same software vendor may communicate in the
same way. Two stacks from different software vendors (or
different products from the same vendor) may communicate in
completely different ways. As long as peers can communicate
and interoperate, this has no impact on the functioning of the
network.
The communication between layers within a given protocol
stack can be both different from a second stack and proprietary,
but communication between peers on the same OSI layer is
open and consistent.
A brief description of the most commonly used functional
layers is helpful to understand the scope of how protocol
layering works.
Layer 1
This is referred to as the physical layer. It handles the
electrical connections and signaling required to make a
physical link from one point in the network to another. It is on
this layer that the unique Media Access Control (MAC) address
is defined.
Layer 2
This layer, commonly called the switching layer, allows end
station addressing and the establishment of connections
between them.