firewalls. Servers have many otheruses including hosting web pages and
email applications, centralized databases or software applications, printing
applications and network administration capabilities. Thus the categories
for servers are database servers, applications servers, communications ser-
vers, file servers, print servers, proxy servers, and web servers.
From a hardware perspective servers must operate under the heavy
demand of a network environment. Their configurations can vary from a
desktop PC to a mainframe computer.Most servers are built for a produc-
tion environment with fast CPUs, multiple processors, hardware redundancy
in disks and power supplies, large storage capacity and specialized operating
systems and software applications. Aserver may be installed in an equipment
rack or for high density may be a “blade” in a server chassis mounted in an
equipment rack.
IP Addressing
Each physical connection of a device to an IP network has an IP address. The
IP address is a numerical identification and a logical address of the device
connected to the network. It is used to specify the routing source and destina-
tion of the transmission over the network. Originally an IP address was
defined as a 32-bit (or binary numbers, 1s and 0s) number, a scheme referred
to as Internet Protocol Version 4 (IPv4). Because of the growth of the Internet
and the limits of IPv4, a new scheme was created to handle many more IP
addresses. This is called Internet Protocol Version 6 (IPv6) and uses 128 bits
for the IP address.
There is also a set of IP addresses set aside for use in private or closed
networks. Anyone can use these addresses in their private networks, probably
supplemented with a translator to go from the private network to a public net-
work such as the Internet. An example of an IP address is “162.146.93.14.”
Behind the scenes that example IP address would be represented to a network
in a 32-bit binary format: “10100010.10010010.01011101.00001110.”
There are five “primary” classes of IP addresses. The first three, Classes A,
B, and C can progressively handle more networks. Classes D and E are for
multicasting and research.
All Class A addresses and almost allClass B addresses have been allo-
cated. One way for network administrators to handle the limits of the IP
addresses allocated is to subnet or create subnet IP addresses within the
IP addresses allocated.
126 Smart Building Systems for Architects, Owners, and Builders