Communicating over the Network

More and more, it is networks that connect us. People communicate online from everywhere. Efficient, dependable technology enables networks to be available whenever and wherever we need them. As our human network continues to expand, the platform that connects and supports it must also grow.

Rather than developing unique and separate systems for the delivery of each new service, the network industry as a whole has developed the means to both analyze the existing platform and enhance it incrementally. This ensures that existing communications are maintained while new services are introduced that are both cost effective and technologically sound.

Channel – consist of the media the provides the pathway over which the massage can travel from source to destination.

Multiplexing – the process used to interleave the pieces of separate conversation together on the network.

Two types of Network Devices:

End device – the network devices that people are most familiar. Examples are computers, printer, voip phones, security camera, mobile handheld.

Intermediary devices – provide connectivity and to work behind the scenes to ensure that data flows across the network. The management of data as it flows through the network is also a role of the intermediary devices.

Examples of intermediary network devices are:
• Network access devices (hubs, switches, and wireless access points)
• Internetworking devices (routers)
• Communication servers and modems
• Security Devices (firewalls)

LAN – an individual network usually spans a single geographical area, providing services and applications to people within a common organizational structure.

WAN – use specifically designed network devices to make the interconnections between LANS. It allow many forms of communication including exchange emails, corporate training, and other resource sharing.

Internetwork – a global mesh of interconnected networks meets these human communication needs. A connection of two or more data networks forms an internetwork.

Intranet – is often used to refer to a private connection of LANs and WANs that belongs to an organization, and is designed to be accessible only by the organization’s members.

Protocol suite – a group of inter-related protocols that are necessary to perform a communication function. It determines the formatting of messages and the process of encapsulation used to forward data.

IEEE – (Institute of Electrical and Electronics Engineers) a protocol that has been endorsed by the networking industry and ratified by a standards organization. The use of standards in developing and implementing protocols ensures that products from different manufacturers can work together for efficient communications.

Encapsulation – the wrapping of data in a particular protocol header. During the encapsulation process the data is formatted and separated into segments then the server adds the source and destination IP address to each segment header to deliver packets to the destination.

PDU – (Protocol Data Unit) the form that a piece of data takes at any layer.

------------------
TCP/IP Model
------------------
Application – represents data to the user plus encoding and dialog control.

Transport – supports communication between diverse devices across diverse networks.

Internet – determines the best path through the network

Network Access – controls the hardware devices and media that make up the network.

----------------
OSI Model
----------------

Application – provides the end-to-end connectivity between individuals in the human network using data networks.

Presentation – provides for common representation of the data transferred between applications layer services.

Session – provides services to the presentation layer to organize its dialogue and to manage data exchange.

Transport – defines services to segment, transfer, and reassemble the data for individual communications between the end devices.
• Called as Layer 4: port (software). TCP and UDP protocols are associated
• Encapsulate segments

Network – provides services to exchange the individual pieces of data over the network between identified end devices.
• Also called as Layer 3: IP address and logical address
• Encapsulate packets

Data Link – describe methods for exchanging data frames between devices over a common media.
• Also called as Layer 2: MAC and physical address
• Encapsulate frames

Physical – describe the mechanical, electrical, functional, and procedural means to activate, maintain, and de-activate physical-connections for bit transmission to and from a network device.
• Encapsulate bits