Session, Presentation, and Application Layers
Many times the session, presentation, and application layers are considered as
one layer. The session and presentation layers manage dialogue between end-
user applications, then format and deliver the data to the application layers.
The Session Layer establishes, manages, and terminates the connection
between the local and remote application. The Presentation Layer establishes
a data framework between the Application Layer entities. It translates the data
representation in an application to a network format and vice versa. The appli-
cation layer is the layer the end user directly interacts with.
The discussion of system integration should be framed using the ISO model,
focusing on the physical, data, network, and application layers. Doing so adds
clarity and understanding to both industry and client discussions.
Structured Cabling Systems
Over the last 20 years there has been considerable movement away from pro-
prietary telecommunications cable to generic cable that is independent of indi-
vidual vendors or specific uses. There are several authoritative standards for
generic structured cable infrastructure for telecommunications systems used
throughout the world.
The first cable standard created was the ANSI/TIA/EIA-568 A and B
Commercial Building Telecommunications Cabling Standard published by
the American National Standards Institute (ANSI), the Telecommunications
Industry Association (TIA), and the Electronic Industry Association (EIA).
Canada has a standard similar to ANSI/TIA/EIA-568 referred to as CSA
T529 (Canadian Standards for Telecommunications Wiring Systems).
There is also an international standard referred to as ISO/IEC 11801 which
is used in Asia, Europe, and Africa. The international standard was authored
by the International Organization for Standardization (ISO) and the Inter-
national Engineering Consortium (IEC) in 1995. The European Union has a
standard similar to ISO/IEC 11801 called EN 50173 and was published by
the European Committee for Electrotechnical Standardization (Cenelec).
Australia and New Zealand have published AS/NZS 3080, also a standard for
generic cabling infrastructure. Although there are some differences between the
ANSI/TIA/EIA-568 standard and the other standards, the ANSI/TIA/EIA-568
standard has served as a basis for deriving the other standards (Fig. 2.2).
In 2002 the ANSI/TIA/EIA standards organizations also published ANSI/
TIA/EIA-862, Building Automation Systems Cabling Standard for Commercial
Buildings, which is essentially documentation of similar standards for building
The Foundations of a Smart Building 11