Download Network types

Local Area Networks (LAN) are small networks, with
a short distance for the cables to run, typically a
room, a floor, or a building.
- LANs are limited by number of computers
and distance covered.
- Usually one kind of technology is used
throughout the LAN. The most common is
Ethernet.
Examples:
Network inside the school
Network inside a business
Network inside your home
Peer-to-Peer Networks
A Peer-to-peer network is often called a
workgroup. There is no single controlling
computer. Each computer acts like a server,
providing some service, while also acting like a
client, receiving services from the other
computers. There is no hierarchy among the
computers. They are all equal.
There tends to be no administrator responsible
for the network. It is ruled by consensus. Most
home networks, and LAN parties are set up in
this fashion.
Advantages of peer-to-peer networks:
Low cost
Simple to configure
User has full accessibility of the computer
Disadvantages of peer-to-peer networks:
May have duplication in resources
Difficult to uphold security policy
Difficult to handle uneven loading
Where peer-to-peer
network is appropriate:
• 10 or fewer users
• No specialized services
are required
• Security is not an issue
• Only limited growth is
foreseeable for the future
Clients and Servers
Network Clients (Workstation): Computers that
request network resources or services. Some
clients are totally dependent on the server. Most
often, the client is a stand alone computer, with its
on processor, RAM, hard drive and peripherals, but
is connected to boot through the network system
via an authentication password process. Once
logged into the network, this computer is capable
of accessing data or services held on the network
servers, based on either the machine’s access or
the user’s access level.
Clients and Servers
Network Servers: Computers that manage and
provide network resources and services to clients.
Usually have more processing power, memory and
hard disk space than clients. No user will sit
directly at a Server and use it as a terminal.
Servers run a Network Operating System that can
manage not only data, but also users, groups,
security, and applications on the network. Some
networks utilize several servers to perform different
tasks, as well as redundancy equipment.
Advantages of client/server networks:
Client Server networks facilitate resource sharing
as well as centrally administrate and control
access to programs and data. This type of
network additionally facilitates system backup and
improves fault tolerance.
Security is enhanced since only administrators or
limited support personnel have access to server.
Client Server networks also can support more
users than with peer-to-peer networks.
Disadvantages of client/server networks
High cost for Servers. Because of the nature of the
hierarchy of this type of network, you will need to
configure the network with a little more thought and
care than with a peer to peer network.
You also introduce a single point of failure to the
system.
Server networks may include special purpose types
of servers, utilizing special software to provide
specific services to the users. These include:
SANs Storage Area Network Servers
Application Servers
Communication Servers
Domain Controllers
Directory Servers
Domain Name Servers
Mail Servers
Web Servers
Fax, File, and Printer Servers
SANs Servers
Storage Area Networks offer many advantages,
including fast access to SAN storage areas;
backups from a single location; fastest, more
reliable storage subsystems, including hotswappable power supplies and disk drives; extra
levels of security and access control; as well as
providing an easier way to increase storage
capacity for the entire network.
Application Servers
Application servers supply the server side of the
client/server applications. Network versions of
software are installed here, and workstations
connect to this server to run the program, instead of
having many copies installed on each workstation.
This can save money and installation time /
problems for networks. They also provide
processing service and handle requests for file or
print services.
Communication Servers
Allow users outside the network to access network’s
resources (inbound communications).
Sometimes permit users on the network to access
resources outside their local network
(outbound communications).
Domain Control/Directory Servers
Domain Control and Directory servers let users
locate, store, and secure information about their
network and its resources. These servers generally
combine computers, users, groups, and resources
into logical domains, hence the name. This is the
primary server for logging into most networks.
Fax Servers
For companies with an inordinate amount of fax
messaging, a fax server manages fax traffic on the
network. It receives incoming faxes via telephone,
and then distributes faxes to recipients. It also
collects outgoing faxes from the workstations to
send via telephone to distant destinations.
File and Print Servers
Far more common are File and Print Servers. These
provide basic network file storage and retrieval,
while
providing access to networked printers. Users run
applications locally but keep data files on file server
and print hard-copies to networked printers,
coordinated through the print server.
Mail Servers
Mail servers handle e-mail messages, both incoming
and outgoing. They provide “store and forward”
services by hold incoming e-mail messages until
users can access them. They can also hold
outgoing e-mail messages until forwarded to their
destinations via the Internet. The most widely
recognized mail server is probably Microsoft
Exchange Server, with MS Outlook used as the mail
client, although there are many other options.
Web Servers
Web servers have gained popularity faster than any
other service. Many companies use WWW and
TCP/IP protocols internally to distribute information
via an Intranet. Others set up Web servers to
handle Internet traffic as well.
WANs, or Wide Area Networks are those networks
which cover large geographic areas. They typically
have service providers, usually the local telcoms, to
connect their various LANs together. An example
would be a large, multinational corporation with
offices all around the world.