Basics of Networking

My Cart

Networking Basics

Network Types
Network Topologies
Fundamental Network Concepts
Network Protocol
OSI Model
IP Addressing

Technical Support

Chat Online - Unavailable

Home > Networking Basics

Networking Basics

Basic Concept of Networking

The simplest kind of home network contains exactly two computers. You can use this kind of network to share files, a printer or another peripheral device, and even an Internet connection. To connect two computers for sharing network resources, consider these alternatives.

Networking Interface Card’s (NIC)
A connection medium, usually a wire or cable, although wireless communication between networked computers and Peripherals is also possible.
Network Operating system software, such as Microsoft Windows NT or 2000, Novell NetWare, Unix and Linux.

Network Types:

LAN:

A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. A LAN is useful for sharing resources like files, printers, games or other applications.

WAN:

A WAN spans a large geographic area, such as a state, province or country. WANs often connect multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs). The world's most popular WAN is the Internet.

INTERNET:

The term Internet today refers to the global network of public computers running Internet Protocol. The Internet supports the public WWW and many special-purpose client/server software systems. Internet technology also supports many private corporate intranet and private home LANs.

Internet Related Terms: Broadband, Dialup, IP, LAN, WWW.

Network Topologies:

One way to classify computer networks is by their topology. A network topology represents its layout or structure from the point of view of data flow. Network topologies are categorized into the following basic types:

Bus
Ring
Tree
Star
Mesh

More complex networks can be built as hybrids of two or more of the above basic topologies.

Fundamental Network Concepts:

Ethernet/ Network Interface Cards:

Ethernet is a physical and data link layer technology for local area networks (LANs). Ethernet is reliable and inexpensive, the leading standard worldwide for building wired LANs. Network interface cards, commonly referred to as NICs, and are used to connect a PC to a network. The NIC provides a physical connection between the networking cable and the computer's internal bus. Different computers have different bus architectures; PCI bus master slots are most commonly found on 486/Pentium PCs and ISA expansion slots are commonly found on 386 and older PCs. NICs come in three basic varieties: 8-bit, 16-bit, and 32-bit. The larger the number of bits that can be transferred to the NIC, the faster the NIC can transfer data to the network cable.

TOP

Bridge:

A computer or device that links two similar LANs based on the same protocol. The function of a bridge is to connect separate networks together. Bridges connect different networks types (such as Ethernet and Fast Ethernet) or networks of the same type. Bridges map the Ethernet addresses of the nodes residing on each network segment and allow only necessary traffic to pass through the bridge. When a packet is received by the bridge, the bridge determines the destination and source segments. If the segments are the same, the packet is dropped ("filtered"); if the segments are different, then the packet is "forwarded" to the correct segment. Additionally, bridges do not forward bad or misaligned packets. Bridges are also called "store-and-forward" devices because they look at the whole Ethernet packet before making filtering or forwarding decisions. Filtering packets and regenerating forwarded packets enable bridging technology to split a network into separate collision domains. This allows for greater distances and more repeaters to be used in the total network design.

Switch:

A network switch is a small hardware device that joins multiple computers together at a low-level network protocol layer. Switches differ in important ways from both routers and hubs. Ethernet switches are an expansion of the concept in Ethernet bridging. LAN switches can link four, six, ten or more networks together, and have two basic architectures: cut-through and store-and-forward. In the past, cut-through switches were faster because they examined the packet destination address only before forwarding it on to its destination segment. A store-and-forward switch, on the other hand, accepts and analyzes the entire packet before forwarding it to its destination. It takes more time to examine the entire packet, but it allows the switch to catch certain packet errors and keep them from propagating through the network. Both cut-through and store-and-forward switches separate a network into collision domains, allowing network design rules to be extended. Each of the segments attached to an Ethernet switch has a full 10 Mbps of bandwidth shared by fewer users, which results in better performance (as opposed to hubs that only allow bandwidth sharing from a single Ethernet). Newer switches today offer high-speed links, FDDI, Fast Ethernet or ATM. These are used to link switches together or give added bandwidth to high-traffic servers. A network composed of a number of switches linked together via uplinks is termed a "collapsed backbone" network

Routers:

A router is a small hardware device that joins multiple networks together. These networks can include wired or wireless home networks, and the Internet. Routers filter out network traffic by specific protocol rather than by packet address. Routers also divide networks logically instead of physically. An IP router can divide a network into various subnets so that only traffic destined for particular IP addresses can pass between segments. Network speed often decreases due to this type of intelligent forwarding. Such filtering takes more time than that exercised in a switch or bridge, which only looks at the Ethernet address. However, in more complex networks, overall efficiency is improved by using routers.

Transceivers:

Transceivers are used to connect nodes to the various Ethernet media. Most computers and network interface cards contain a built-in 10BASE-T or 10BASE2 transceiver, allowing them to be connected directly to Ethernet without requiring an external transceiver. Many Ethernet devices provide an AUI connector to allow the user to connect to any media type via an external transceiver. The AUI connector consists of a 15-pin D-shell type connector, female on the computer side, male on the transceiver side. Thick wire (10BASE5) cables also use transceivers to allow connections. For Fast Ethernet networks, a new interface called the MII (Media Independent Interface) was developed to offer a flexible way to support 100 Mbps connections.The MII is a popular way to connect 100BASE-FX links to copper-based Fast Ethernet devices.

Firewalls:

A network firewall guards a computer against unauthorized network access. Firewalls are one of the essential elements of a safe home or business network. A firewall is a system or group of systems that enforces an access control policy between two networks. The actual means by which this is accomplished varies widely, but in principle, the firewall can be thought of as a pair of mechanisms: one which exists to block traffic, and the other which exists to permit traffic. Some firewalls place a greater emphasis on blocking traffic, while others emphasize permitting traffic. Probably the most important thing to recognize about a firewall is that it implements an access control policy. If you don't have a good idea of what kind of access you want to allow or to deny, a firewall really won't help you. It's also important to recognize that the firewall's configuration, because it is a mechanism for enforcing policy, imposes its policy on everything behind it. Administrators for firewalls managing the connectivity for a large number of hosts therefore have a heavy responsibility.

TOP

Gateway:

Gateway is a network point that acts as an entrance to another network. On the Internet, a node or stopping point can be either a gateway node or a host (end-point) node. Both the computers of Internet users and the computers that serve pages to users are host nodes. The computers that control traffic within your company's network or at your local Internet service provider (ISP) are gateway nodes.

TCP/IP - Transmission Control Protocol / Internet Protocol:

TCP/IP provides connection-oriented communication between network devices. TCP/IP is very commonly used both on the Internet and in home computer networks. The term TCP/IP is not limited just to these two protocols, however. Frequently, the term TCP/IP is used to refer to a group of protocols related to the TCP and IP protocols such as the User Datagram Protocol (UDP), File Transfer Protocol (FTP), Terminal Emulation Protocol (TELNET), and so on.

Network Protocol:

Protocols serve as a language of communication among network devices. Network protocols like HTTP,TCP/IP, and SMTP provide a foundation that much of the Internet is built on.

The TCP/IP Model:

TCP/IP (Transmission Control Protocol/Internet Protocol) is the basic communication language or protocol of the Internet. The TCP/IP model consists of four layers. From lowest to highest, these are the Network Layer, the Internet Layer, the Transport Layer, and the Application Layer.

1. Application layer: Applications and processes running on the network.

2. Transport layer: Provides end-to-end data delivery services.

3. Internet layer: Makes datagram’s and handles data routing.

4. Network layer: Provides routines allowing access to the physical network.

Transmission Control Protocol (TCP)

TCP provides by using IP packets a basic service that does guarantee safe delivery.
Error detection.
Safe data transmission.
Before sending data, TCP requires that the computers communicating establish a connection (connection-oriented protocol).
TCP provides support for sending and receiving arbitrary amounts of data as one big stream of byte data.
TCP does so by breaking up the data stream into separate IP packets.
Packets are numbered, and reassembled on arrival; using sequence and sequence acknowledge numbers.
TCP also improves the capability of IP by specifying port numbers.
There are 65,536 different TCP ports (sockets) through which every TCP/IP machine can talk.

Internet Protocol (IP):

Decomposition of the initial information flow into packets of Standardized size, and reassembling at the destination.
Routing of a packet through successive networks, from the source machine to the destination identified by its IP address.
Transmitted packets are not guaranteed to be delivered.
The IP protocol does not request for connection (connectionless) before sending data and does not make any error detection.
Each datagram will have a header including, the IP address and the port number of the destination.
Datagram’s are transferred from gateways to gateways until they arrived at their final destination.

TOP

Internet Application Protocols:

1. FTP (File Transfer Protocol): Allows the transfer of collection of files between two machines connected to the Internet.

2. Telnet (Terminal Protocol): Allows a user to connect to a remote host in terminal mode.

3. NNTP (Network News Transfer Protocol): Allows the constitution of communication groups newsgroups) organized around specific topics.

4. SMTP (Simple Mail Transfer Protocol): Defines a basic service for electronic mails.

5. SNMP (Simple Network Management Protocol): Allows the management of the network.

User Datagram Protocol (UDP):

Datagram protocol also built on top of IP.
Has the same packet-size limit (64Kb) as IP, but allows for port number specification.
Provides also 65,536 different ports.
Every machine has two sets of 65,536 ports: one for TCP and the other for UDP.
Connectionless protocol, without any error detection facility.
Provides only support for data transmission from one end to the other, without any further verification.
The main interest of UDP is that since it does not make further verification, it is very fast.
Useful for sending small size data in a repetitive way such as time information.

OSI Model:

Open System Interconnection (OSI) reference model has become an International standard and serves as a guide for networking. This model is the best known and most widely used guide to describe networking environments. Vendors design network products based on the specifications of the OSI model. It provides a description of how network hardware and software work together in a layered fashion to make communications possible. It also helps with trouble shooting by providing a frame of reference that describes how components are supposed to function.

OSI Layers:

1. Physical layer: Defines the physical characteristics of the network.

2. Data-link layer: Provides safe communication of data over the physical network.

3. Network layer: Handles connection to the network by the higher layers.

4. Transport layer: Provides end-to-end errors detection and correction.

5. Session layer: Manages sessions among applications.

6. Presentation layer: Provides standard data representations for applications.

7. Application layer: Applications connected to the network.

IP Addressing:

An IP (Internet Protocol) address is a unique identifier for a node or host connection on an IP network. An IP address is a 32 bit binary number usually represented as 4 decimal values, each representing 8 bits, in the range 0 to 255 (known as octets) separated by decimal points. This is known as "dotted decimal" notation.

Address Classes:

There are 5 different address classes. You can determine which class any IP address is in by examining the first 4 bits of the IP address.

Class A address - 1 to 126 decimal.
Class B address - 128 to 191 decimal.
Class C address - 192 to 223 decimal.
Class D address - 224 to 239 decimal.
Class E address - 240 to 254 decimal.

Addresses beginning with 127 decimal are reserved for loopback and for internal testing on a local machine. [You can test this: you should always be able to ping 127.0.0.1, which points to yourself] Class D addresses are reserved for multicasting. Class E addresses are reserved for future use. They should not be used for host addresses.

VPN (Virtual Private Network)

An IP (Internet Protocol) address is a unique identifier for a node or host connection on an IP network. VPN uses a technique known as tunneling to transfer data securely on the Internet to a remote access server on your workplace network. Using a VPN helps you save money by using the public Internet instead of making long–distance phone calls to connect securely with your private network. There are two ways to create a VPN connection, by dialing an Internet service provider (ISP), or connecting directly to Internet.

TOP