Chapter_02_1

Concepts & Keywords of Chapter 02: multiplexing, segmentation, network media, intermediary devices, end devices, LAN , WAN, MAN ,Network Protocols, encapsulation, OSI & TCP model,PDU, Logical & Physical Addressing

Segmentation is the division of the data stream into smaller pieces is called segmentation

Multiplexing is the process used to interleave the pieces of separate conversations together on the network is called multiplexing.

Components of a network:

End devices are:

• Computers (work stations, laptops, file servers, web servers)
• Network printers
• VoIP phones
• Security cameras
• Mobile handheld devices (such as wireless barcode scanners, PDAs)

Intermediary Devices are:

• Regenerate and retransmit data signals
• Maintain information about what pathways exist through the network and internetwork
• Notify other devices of errors and communication failures
• Direct data along alternate pathways when there is a link failure
• Classify and direct messages according to QoS priorities
• Permit or deny the flow of data, based on security settings

Network Media:

• Metallic wires within cables
• Glass or plastic fibers (fiber optic cable)
• Wireless transmission

Criteria for choosing a network media are:

• The distance the media can successfully carry a signal.
• The environment in which the media is to be installed.
• The amount of data and the speed at which it must be transmitted.
• The cost of the media and installation

Networks infrastructures can vary greatly in terms of:

• The size of the area covered
• The number of users connected
• The number and types of services available

Internetwork (e.g. The Internet)

A global mesh of interconnected networks (internetworks) meets these human communication needs. Some of these interconnected networks are owned by large public and private organizations, such as government agencies or industrial enterprises, and are reserved for their exclusive use. The most well-known and widely used publicly-accessible internetwork is the Internet.

Network Protocol suites describe processes such as:

• The format or structure of the message
• The process by which networking devices share information about pathways with other networks
• How and when error and system messages are passed between devices
• The setup and termination of data transfer sessions

Benefits of a Layered Network Design:

• There are benefits to using a layered model to describe network protocols and operations. Using a layered model:
• Assists in protocol design, because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below.
• Fosters competition because products from different vendors can work together.
• Prevents technology or capability changes in one layer from affecting other layers above and below.
• Provides a common language to describe networking functions and capabilities.

The OSI Reference Model:

The TCP IP Protocol Model:

Network Connections in general:

Comparing TCP-IP Protocol Model with the OSI Reference Model: