What is Communication

People have many ways to communicate:

– Verbal/ non Verbal

– Face to face/ over the telephone

– Handwritten Letter

– Chatting

Requires Common Rules

The rules of communications are Protocol.

Some of the protocols required for communication to occur include:

- Sender & receiver

- Method of communicating (face to face, phone, letter, photo and so on)

- Language and Grammar

- Speed & Timing of delivery

- Confirmation / Acknowledgement requirements

Element of Network

1. Rules / Agreement ( PROTOCOL): Rules or agreement govern how the messages are sent, directed, received and interpreted.

2. Message: The messages or unit of information travel from one device to another.

3. Medium: a means of interconnecting devices, a medium can transport the messages from one device to another.

4. Device: devices on the network exchange messages with each other

Early networks had varying standards and as a result could not communicate easily wit each other.

People use many technologies and devices that they do not understand.

Computer networks are similar. Two people communicating on end devices in different networks can do so only if many complex processes are succesfully completed.

Message

Message:

The messages or unit of information travel from one device to another.

Message is a generic term that encompasses web pages, email, instant messages, telephone calls & other form of communication.

The message must be one that the network can carry.

The messages must be supported in software at the end device.

It does not matter whether the message is: text, voice, or video because all form are converted into bits, binary-coded digital signals, to be carried over a wirelles , copper, or fiber optic connection.

The digital signal can change with the media, but the original message content will remain intact.

Medium

Medium that physically carries the message can change several times between the sender & receiver.

Network connections can be wired or wirelless.

In wired connections the medium is either copper with electrical signals or optical fiber with light signals.

The copper medium includes cables :

twisted pair telephone wire, coaxial cable, or Category 5 unshielded twisted pair (UTP)

Optical fibers, thin strands of glass or plastic that carry light signals

UTP Cat 5

In wirelles connection the medium is: Earth's atmosphere / space, and the signals are microwave.

Wireless media can include the home wireless connection between a wireless router & computer with wireless network card, the terrestrial wireless connection between 2 ground stations, or the communication between devices on earth & sattelite

Devices

Many devices : switch and router, work to see the message is properly directed from the source (originating device) to the destination device.

At the destination network there can be more switches, cable or wireless router that will deliver the instant message to the receiver.

Rules

As communication process happen, tens of thousands of process can happen in a single second.

To work properly, the network process must be controlled. Rules govern every step of the process, from the way cables are designed to the way digital signals are sent. These rules are called Protocols

Rules

Most common:

TCP Transmission Control Protocol

IP Internet ProtocolService Protocol / Rule

WWW Hyper Text Transfer Protocol

Email SMTP and POP

Instant Message XMPP & OSCAR

Ip Telephony SIP

Network Architecture

Syarat-syarat desain yg baik: Fault Tolerance Scalability QoS (Quality of Service) Security

Fault Tolerance

Fault tolerance:

Sistem harus tetap berjalan meskipun beberapa komponen mengalami kegagalan.

Key Factor: -Redundancy: Duplikasi peralatan & media

Fault Tolerant Network Architecture

Circuit-Switched Connection-Oriented Networks

Packet-Switched Connectionless Networks

Message –block of data - Packets

Scalability

Kemampuan network untuk tumbuh dan bereaksi terhadap perubahan masa mendatang.

Scalable Network Architecture

Scalable network mampu untuk tumbuh tanpa adanya perubahan fundamental pada inti /core.

Contoh:

Internet is a collection of many private and public network interconnected by routers.

Quality of Service (QoS)

Menunjukkan performance level dari service yang ditawarkan melalui network.

Eg:

Live Video or Voice dapat memerlukan lbh banyak resource drpd email.

Because many techs are converged onto 1 platform, the separation of types of services on that platform can allow higher priority for one service over another.

Menyediakan QoS

Qos :

Mengacu kpd mekanisme yang mengatur congested network traffic.

Congestion is caused when the demand on network resource exceeds the available capacity.

Network bandwidth is the measure of the data-carrying capacity of the network.

With Qos, the manager can manage the priority.

Network Security

Menjadi esential ketika publik hrs mempunyai rasa aman ketika mengakses internet.

Contoh:

Melakukan financial transaction.- Untuk personal information memerlukan privasi melalui:

- Encripted messages.

- Security devices to control network access.

Providing Network Security

1. Securing the Network Infrastructure means: protecting the devices from outside contact

Contoh: -locking computer room door, password protection.

2. Securing the Network Content means: protection of data stored on network devices & the protection of packets carryind data into or out of the network.

CIA

1. Confidentiality

2. Integrity

3. Availability

Ensuring Confidentiality

Data privacy is maintained by allowing only the intended and authorized recipient- individual, proces, or device to read the data.

Biasanya: User Authentication,

-Menggunakan password yang susah ditebak.

-Mengganti password secara berkala.

Maintaining Communication Integrity

Data integrity means:

Menjamin bhw informasi tidak di Alter dalam pentransmisiannya dari origin ke destinasi.

Informasi dikorupsi secara sengaja atau tak sengaja sblm sampai tujuan.

Source Integrity:

Adalah jaminan bahwa identitas sender sdh divalidasi. User or device fakes the identity & supply inccorect information to recipient.

Ensuring Availability

Meyakinkan bahwa resource tersedia kepada authorized user / pemakai.

Contoh:

Serangan virus komputer, Denial of Service (DoS) dpt membuat network menjadi Down.

Tools:

-AntiVirus SoftWare

-Firewall: analyze traffic enterring and exiting a network.