Basic Networking Concepts-Beginners Guide

networking-diagramBecause the Internet has become such an important part of day to day life almost all homes and offices have a network to connect the various devices like laptops, tablets and phones together and to the Internet.

Because of the growth of computer networks  having a basic understanding of networking technologies and protocols is becoming more important.

The network you have at home uses the same networking technologies, protocols and services that are used in large corporate networks and on the Internet.

The only real difference between an home network and a large corporate network is the size.

A home network will have between 1 and 20 devices and a corporate network will have many thousands.

If you are completely new to networking then the basic course  will introduce you to the basic networking protocols used in small home/office networks and on the Internet.

Setting Up and building a Home Network will introduce some basic networking component and show you how to build a home network and connect it to the Internet.

Networking Types and Structures

Networks can be wired or wireless with most  networks being a mixture of both.

Wired vs Wireless Networks

Early (pre 2008)  networks were predominately wired.

Today however most networks will use a mixture of wired and wireless network.

Wired networks use Ethernet as the data link protocol. This is unlikely to change with the IOT, as IOT devices will be predominantly wireless.

Wired Networks- Advantages and Disadvantages

Wired networks have the following advantages/disadvantages:
Advantages:

  • Ethernet ports are found on almost all laptops/PCs and netbooks even on those 8 years old.
  • Wired networks are faster than Wireless. Data rates were periodically increased from the original 10 megabits per second, to 1gigabits per second. Most home networks use 10-100Mbps.
  • More secure than Wireless

Disadvantages

  • Need to Use cable which can be unsightly, difficult to run and expensive.
  • Can’t be used easily between buildings (planning etc).
  • Note a new technology that uses mains cable overcomes many of these disadvantages. powerline networking is common on home/small office networks
  • Not supported on Mobile phones and tablets.

Wireless Networks – Advantages and Disadvantages

Wireless networks use Wi-fi as the data link protocol. However other wireless options are being developed for the IOT (Internet of things). See Wireless networking Technologies for the IOT

Wireless Networks have the following advantages/disadvantages:

Advantages

  • Generally easier to set up.
  • Can be used both on home and public networks
  • No cables required.
  • Can be used with mobile phones and tablets.

Wireless Networks Disadvantages

  • Generally Slower than wired networks.
  • Limited by range.
  • Open to eavesdropping.
  • Not as secure depending on set up.

Networking Topologies and Layout

There are many different ways network nodes can be connected together. This isn’t normally a consideration in small networks but has networks get larger it becomes more important.

 

star-topologyThere are many different ways network nodes can be connected together.

Common connection technologies like Wi-Fi, Bluetooth etc are designed to work using a particular network topology.

When designing networks and choosing connection protocols having an understanding of these topologies is important.

Common are:

  • Bus
  • Ring
  • Mesh
  • Star
  • Hybrid

Each of these topologies has advantages and disadvantages this Network topologies article has a really good overview of each topology along with advantages and disadvantages.

Early Ethernet networks used a bus structure, modern Ethernet networks and Wi-Fi Networks. use a star bus (hybrid) structure.

However both Wi-Fi and bluetooth are being upgraded to support mesh networking.

Networking Topology- Physical vs Logical

How the nodes on a network communicate with each other can be very different to how they are physically interconnected.

Most Home and small office networks use a physical bus topology.

Common logical typologies are Peer to Peer and Client Server.

The web (WWW) is a client server network at the logical level.

Peer to Peer and Client Server Networking

Peer to Peer

in a peer to peer network all nodes are equal and any node can talk to any other node.

No node has any special role. This was the original networking model of windows networking. (windows for Workgroups)- Diagram below:

peer-peer-networking

Advantages and Disadvantages

Advantages:

  • Easier to setup
  • Not dependent on a single node
  • More resilient
  • Better distribution of network traffic
  • No central administrator required
  • Less expensive hardware required

Disadvantages:

  • Less secure and more difficult to secure
  • More difficult to administer
  • More difficult to backup
  • More difficult to locate information.

This was the original networking model used in early Windows networks (windows for Workgroups)

A Modern example of Peer to Peer networking is BitTorrent.

Although this networking model isn’t currently popular it could become more popular with the Internet of things (IOT).

Client Server

In a Client Server network a server has a special role e.g file server, domain controller, web server etc.

A client connects to a server to use the appropriate services.

This is the networking model used on the web and the Internet and on modern large Windows networks.-Diagram below:

client-server-networking

Advantages and Disadvantages

Advantages:

  • Easy to find resources as they are on a dedicated node i.e. A server
  • Easy to secure
  • Easy to administer
  • Easy to backup

Disadvantages:

  • Servers are a single point of failure
  • Expensive hardware required
  • Network traffic get concentrated

A Modern example of Client Server networking is the Web. Facebook,Twitter,Google search and many other web services use this networking model.

Network Size

Networks vary considerably in size.The following are commonly used terms:

  • PAN -Personal Area Network – Linking local devices e,g, PC to printer
  • LAN – Local Area network- links devices in an office or offices
  • MAN – Metropolitan Area network – links devices across multiple buildings like a campus
  • WAN – Wide area network – links devices across a country/countries.

Networking Levels and Layers and Protocols

A protocol defines a set of rules that govern how computers talk to each other.

Ethernet and Wi-Fi are Data link protocols that are responsible for framing data on the media (cable or wireless).

They can be used for carrying higher level protocols (IP etc)..

Ethernet and Wi-Fi use a physical level address know as the MAC address which is 48 bits.

EUI 64 addresses are MAC addresses with 64 bits will replace MAC addresses on IPV6, 6LoWPAN, ZigBee and other new network protocols. See this Wiki for details.

You can divide networking into distinct levels or layers.

Each level or layer is responsible for a particular function. The OSI uses a 7 layer model and TCP/IP networks use a 4 layer model.

Because TCP/IP networks are the most common this is the one that is the most important to understand. are the , they are:

  • Data link level – e.g. Ethernet, Wi-Fi
  • Networking e.g. IP, – IPv4 andr IPv6.
  • Transport level e.g.TCP, UDP – See TCP vs UDP
  • Application level – e.g. HTTP -See HTTP for beginners

See Understanding the TCP/IP protocol suite and TCP port and sockets for details.

Network Addressing

What Is An IP Address?

Every device attached to a network, and the Internet has an IP address.

An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication –WikI

There are two versions of IP, they are IPv4 and IPv6.

IPv4 has been in use since the start of the Internet, and is deployed across the Internet, and home/corporate networks.

IPv4 uses 32 bits for addressing, however due to the rapid growth of the Internet, all IPv4 addresses have been allocated (as of 2013).

Techniques like NAT (network Address Translation) have extended the life of IPv4 by allowing the use of private IP addresses inside networks.

However IPv4 will eventually be replaced by IPV6 which uses 128 bits for the address, and so can accommodate many more hosts (computers/devices)

The roll out of IPv6 across the Internet is happening slowly, and IPv4 will be with us for many years to come especially in home and small office networks.
ip-address-side-2

As IP6 rolls out they will also be a need to operate with two addresses until migration is complete, and IP4 is discontinued.

IP addresses are logical addresses, and are assigned by a network administrator or can be auto assigned ( using DHCP).–

The important thing to note is that the IP address of a device isn’t fixed.

Public and Private IP Addresses

Both IPv4 and IPV6 have both public and private address ranges.

The private addresses are used for home/business networks and the addresses aren’t routeable on the Internet i.e. they don’t travel across the internet.

For IP4 the private addresses starts with

10.x.x.x or 192.168.x.x or 172.16.x.x

Public addresses are reachable from anywhere on the internet and are routeable.

See Internal and external IP addresses for more details

IP Address Assignment

Most modern networks use automatic IP address assignment via DHCP with manual assignment only being done in special cases.

For home networks the Internet router or hub usually provides DHCP services for the network.

For larger networks a dedicated DHCP server is normally used.

Most windows machines will auto assign their own address if they fail to find a DHCP server.

This can cause problems see troubleshooting Internet connections.

IP Addresses and Domain Names

Computers use numbers (IP addresses ) but people use names as they are much easier to remember.

When you type in a domain name into your web browser the name is translated into an IP address by a DNS server usually located on the Internet.

Your computer will resolve the name using a name resolving process. See

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