Shulou(Shulou.com)06/01 Report--

1. Examples of Today's Popular Communication Tools

Instant Messaging (real-time communication) / Texting (Such as QQ, MSN)

Weblogs (blogs) (individual): easy to update and edit

Wikis: groups of people can edit and view together.

Podcasting: an audio-based medium that originally enabled people to record audio and convert it for use.

Collaboration Tools (work together on shared documents)

P2P File Sharing: share files with each other.

Social Media: interactive websites where people create and share user-generated content with friends and family

TelePresence: provides real-time audio and video conferencing.

2. Networks Supporting the Way We Learn

Virtual cla***ooms

Collaborative learning spaces

On-demand video

Mobile learning

3. What is Computer Netwrok?

Computer network refers to a system that links multiple computers and their external devices with independent functions distributed in different locations with communication lines to realize resource sharing and information processing under the coordinated management of network management equipment or management software.

4. Components of the Network

Devices: end devices & intermediary devices

Media: copper cable & fiber optic cable & radio

Services: protocols

4.1 End Devices (originate data flow) (host)

Computers (work stations, laptops, file servers, web servers)

Network printers

VoIP phones

Security cameras

Mobile handheld devices (such as wireless barcode scanners, PDAs)

4.2 Intermediary Devices (ensure data flows across the network)

Network Access Devices (Hubs, switches, and wireless access points)

Internetworking Devices (routers)

Communication Servers and Modems

Security Devices (firewalls)

Processes running on the intermediary network devices perform these functions:

Regenerate and re-transmit 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

4.3 Network Media

Metallic wires within cables (copper cable)

Glass or plastic fibers (fiber optic cable)

Wireless transmission (radio)

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

5. The Interaction of Protocols

5.1 Networking protocol suites describe processes such as:

The format or structure of the message

The method 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

5.2 Technology Independent Protocols

(1) Networking protocols describe the functions that occur during network communications.

(2) Protocols generally do not describe how to accomplish a particular function.

5.3 The Benefits of 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.

5.4 Protocol and Reference Models

There are two basic types of networking models: protocol models and reference models.

Protocol model (TCP/IP): provides a model that closely matches the structure of a particular protocol suite.

Reference model (OSI/RM): provides a common reference for maintaining consistency within all types of network protocols and services.

5.5 Protocol Data Units and Encapsulation

As application data is passed down the protocol stack on its way to be transmitted across the network media, various protocols add information to it at each level. This is commonly known as the encapsulation process.

Data-The general term for the PDU used at the Application layer

Segment-Transport Layer PDU

Packet-Internetwork Layer PDU

Frame-Network Access Layer PDU

Bits-A PDU used when physically transmitting data over the medium

5.6 The 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.

5.7 The OSI Model

Application the means for end-to-end connectivity between individuals in the human network using data networks

Presentation common representation of the data transferred and to manage data exchange

Session this layer create and maintain dialog between source and destination applications.

Transport defines serves to segment, transfer, and reassemble the data for individual communications between the end devices.

Network Provides services to exchange the individual pieces of data over the network between identified end devices.

Data Link describe methods for exchanging data frames between devices over a common media

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

5.8 Addressing in the Network

Upper layers

Encoded Application Data

Transport Layer

Destination & Source Process Number (Ports)

Network Layer

Destination & Source Logical Network Addr

Data Link Layer

Destination and Source Physical Address

Physical Layer

Timing & Synchronization Bits

6. Providing Network Security

There are two types of network security concerns that must be addressed to prevent serious consequences: network infrastructure security and content security.

Securing a network infrastructure includes the physical securing of devices that provide network connectivity and preventing unauthorized access to the management software that resides on them.

Content security refers to protecting the information contained within the packets being transmitted over the network and the information stored on network attached devices.

6.1 Security measures taken in a network should:

Prevent unauthorized disclosure or theft of information

Prevent unauthorized modification of information

Prevent Denial of Service (DoS)

6.2 Network Security:

Viruses, worms, and Trojan horses

Spyware and adware

Zero-day attacks (zero-hour attacks)

Hacker attacks

Denial of service attacks (DoS)

Data interception and theft

Identity theft

6.3 Means to achieve these goals include:

Ensuring confidentiality: Only the intended recipients can access and read the data

Maintaining integrity: The assurance that the information has not been altered during transmission.

Ensuring availability: The assurance of timely and reliable access to data

7. What is data? What is a data network? What is a converged network?

Data is the pieces of information, such as files, audio, phone calls and video shared across the network.

A data network consists of:

Devices that communicate with each other

A means of connecting these devices together-a medium that can transport messages from one device to another

The digital messages or units of information that will travel from one device to another

Rules or agreements to govern how the messages are sent, directed, and received

Converged networks:

One network now carries multiple types of messages and information. Separate networks are no longer required to support voice, video, and data traffic.

Network Architectures:

Cisco Borderless Networks architecture

The Cisco Borderless Network Architecture is a network solution that allows organizations and individuals to connect securely, reliably, and seamlessly to the corporate network in a BYOD environment.

Collaboration architecture (meet expanding collaboration needs)

Tele-Presence

Collaboration Applications

Customer Collaboration

Unified Communications

Data center and virtualization architecture

Cisco Unified Computing: Modular Stateless Computing Elements

Cisco Unified Fabric: Highly Scalable, Secure Network Traffic

Cisco Unified Management: Automated Resource Management (Physical and Virtual)

Communicating the Messages

Segmenting messages has two primary benefits. Multiplexing & reliability

(1) Multiplexing: The process used to interleave the pieces of separate conversations together on the network

(2) Segmentation can increase the reliability of network communications.

Disadvantages:

The downside to using segmentation and multiplexing to transmit messages across a network is the level of complexity that is added to the process.

All networks have four basic elements in common (Sender, Receiver, and channel)

Rules

Medium

Messages

Devices

Connecting to the Internet:

Cable: a high bandwidth, always on, uses coaxial cable as a medium

DSL: a high bandwidth, always on, telephone cable, split into three channels:

One channel: voice telephone calls

Second channel: faster download channel

Third channel: for sending or uploading information.

Cellular: use a cell phone network to connect.

Satellite: for homes or offices don't need DSL or cable. Not suited Heavily wooded areas

Dial-up Telephone: an inexpensive option that uses any phone line and a modem. Low BW

Many homes and small offices are more commonly being connected directly with fiber optic cables. This enables an Internet service provider to provide higher bandwidth speeds and support more services such as Internet, phone, and TV. Satellite

Connecting Businesses to the Internet:Higher bandwidth, dedicated bandwidth, managed service

Dedicated Leased Line: T1 (1.544MB/s) and T3 (44.7MB/s) E1 (2MB/s) E3 (34MB/s)

Metro Ethernet: providing bandwidth speeds of 10Mb/s to 10Gb/s

DSL: Business DSL is available in various formats. Symmetric Digital Subscriber Lines. (upload=download)

Satellite: provide a connection when a wired solution is not available. Geographical location and service provider availability.

Appendx Protocol Suites and Industry Standards

ISOC: The Internet Society

Responsible for promoting open development, evolution, and Internet use throughout the world.

IAB: The Internet Architecture Board

Responsible for the overall management and development of Internet standards.

IEEE: Institute of Electrical and Electronics Engineers

A professional organization for those in the electrical engineering and electronics fields who are dedicated to advancing technological innovation and creating standards.

Standards are developed using a six stage lifecycle diagram

Offers online tools and resources for standards and developers.

802.1 Higher Layer LAN Protocols Working Group

802.3 Ethernet Working Group

802.11 Wireless LAN Working Group

802.15 Wireless Personal Area Network (WPAN) Working Group

802.16 Broadband Wireless Access Working Group

802.18 Radio Regulatory TAG

802.19 Wireless Coexistence Working Group

802.21 Media Independent Handover Services Working Group

802.22 Wireless Regional Area Networks

802.24 Smart Grid TAG

IETF: Internet Engineering Task Force

Develop, update, and maintain Internet and TCP/IP technologies. Produce RFC documents.

Makes the Internet work better, using and engineering approach

RFC are official documents which are used to describe a standard or protocol that is related to the Internet.

These protocols are open standards & not vendor proprietary. The RFC process includes significant review and comment by the community.

Once an RFC is published, it means that the standard is completed

ISO: The International Organization for Standardization

ICANN: The Internet Corporation for Assigned Names and Numbers

Coordinates IP address allocation, the management of domain names used by DNS, and the protocol identifiers or port numbers used by TCP and UDP protocols

IANA: The Internet Assigned Numbers Authority

Overseeing and managing IP address allocation, domain name management, and protocol identifiers for ICANN.

TIA: The Telecommunications Industry Association

Responsible for developing communication standards in variety of areas including radio equipment, cellular towers, voice over IP (VoIP) devices, satellite communications.

Creates standards for worldwide cabling infrastructure

Develops standards/protocols affecting cloud computing

Develops standards for homeland security/emergency response teams.

ITU-T: The International Telecommunications Union-Telecommunication Standardization Sector

Video compression, IPTV, broadband communications, DSL Uses communications standards to predict famines and global climate changes Supports "bridge the digital divide" initiatives

Supports navigation and online maps via radio/satellite transmissions

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