Rules of setting up a network using TCP/IP

1. same network segment must have same network ID otherwise the packets will not sent to router for next network
2. different network segment must have different network ID otherwise the packets cannot reach the destination host because of the subnet result.
3. same segment can be same or different network.
4. different segment can be different or same network.

Router will divide network segment.

Hubs, repeater will not divide network segment.

Computers using same network ID define as a network.

Computers connect with same segment define as a LAN (local area network)

LAN is confined to a limited geographic area.

WAN (Wide Area Network) has no geographical limit and is made up of a number of interconnected LANs. Perhaps the ultimate WAN is the Internet.

Computers working or grouping with same domain or workgroup define as intranet

• more strictly speaking,  intranet is a privacy network.
• Internet is a mesh networked with many intranet.

There's three type of intranet:

Peer-to-Peer Model

also called workgroup

in peer-to-peer network all the computer can be client or server, so there's no dedicated server to provide authentication of user login.

user can manager their own computer and share resources.

security of peer-to-peer network is depends on the shared resources, each shared resources in a computer on the network can have different passwords

user can access a shared resources by providing the shared resource's password.

Advantages:

1. Low cost--no central server needed
2. Easy to install

Disadvantages:

1. No centralized management
2. Difficult to maintain security

Client Server Model

also called Server-based network with dedicated servers.

server-based network assigning a password to each user, users can access the computers on the network by logging in with their own user name and password, and access the resources on the network with permissions assigned to their user A/C.

so server-based network is using user-level security.

Advantages:

1. centralized management
2. Easier to maintain security

Disadvantages:

1. high cost---central server is need.
2. Difficult to install

Server types

File and Print Servers

• Manage user access and use of file and print resources.
• File server---A computer for files and programs sharing.
• With a file and print server, the data or file is downloaded to the computer making the request.
• Print server--A computer with an attached printer shared.

Application servers

• Thus, an application server differs from a file and print server.
• With a application server, the database stays on the server and only the results of a request are downloaded to the computer making the request.
• e.g. SQL Server

Mail Servers

• The server used to handling clients e-mail
• e.g. Exchange Server

Fax Servers

• Fax server manage fax traffic into and out of the network by sharing one or more fax modem boards.

Communication Servers

• communication server handle data flow between the server's own network and other network, mainframe, or remote users who dial into the server over modems and telephone lines.
• e.g. RAS (Remote Access Service) Server, Web Server, Video Server...