MIS 307 Chapter 1

Advantage of layers

Application developers only need to worry about the application layer in their programs

Trends

Bring your own device, Massively Online, Web of Things

Why are network layers important?

Communication networks are often broken into a series of layers, each of which can be defined separately, to enable vendors to develop software and hardware that can work together in the overall network.

American National Standards Institute (ANSI)

Coordinating organization for the US national system for technology and non-technology. A voting participant in ISO.

Local Area Networks (LAN)

Covers small, clearly defined area such as a single floor, workspace or building.

Advantage of layers

Easier to troubleshoots or make changes to one layer at a time

Common Standards at Data Link Layer

Ethernet (LAN)

De Jure Standards

Formalized by an industry or government body (OSI model)

Common Standards at Application layer

HTTP, HTML (web) STMP, IMAP, POP (email)

Backbone Networks (BN)

High speed networks connecting other networks together, may span hundreds of feet to several miles

Bring your own device

Huge demand for employees to connect personal devices to organizational networks. Faces security challanges

Common Standards at Network Layer

IP (internet and LAN)

Massively Online

MOOC, millions of people participating in social media, eventually this will require greater infrastructure

Advantage of layers

Networking functionality is modular and the software/hardware at any layer can be subsituted

TCP/IP Model

Physical, Data Link, Network, Transport, Application

OSI Model

Physical, Data Link, Network, Transport, Session, Presentation, Application

Institute of Electrical and Electronics Engineers (IEEE)

Professional society in US. Best known for its standards of LANs

Internet Engineering Task Force (IETF)

Sets standards that govern how much of internet will operate. There are no memberships.

Standardization Process

Specification > Identification of choices > Acceptance

Metropolitan Area Networks (MAN)

Step between LAN and WAN

Common Standards at Transport Layer

TCP (internet & LAN)

How are internet standards developed?

The Internet Engineering Task Force (IETF) sets the standards that govern how much of the Internet will operate. Developing a standard usually takes 1-2 years.

What is the importance of Standards?

The use of standards makes it much easier to develop software and hardware that link different networks because software and hardware can be developed one layer at a time. The software or hardware defined by the standard at one network layer can be easily updated, as long as the interface between that layer and the ones around it remains unchanged.

De Facto

Widely accepted, but not formalized. Often eventually become de jure standards

Server

a device that stores and transmits data to client

Extranet

a network that uses internet technologies to share info BETWEEN organizations. Inventory information

Intranet

a network, often a LAN, that uses internet technologies to share info WITHIN and organization. Company calanders

Circuit

a pathway or connection between client and server. (wireless, fiber optic, etc.)

Client

a user device to access network (phone/laptop) and retrieve data from service (webserver)

Wide Area Networks (WAN)

has the largest geographic scope, often composed of leased circuits. May span hundreds or thousands of miles

Disadvantage of layers

inefficient because encapsulation in a PDU increases overhead at each layer

Disadvantages of layers

inefficient because the encapsulation/de-encapsulation at each layer requires processing

The telecommunications group (ITU-T)

is the technical standards-setting organization of the United Nations International Telecommunications Union.

International Organization for Standardization (ISO)

makes technical recommendations about data communication interfaces.

Pervasive networking means that

virtually all computers will be networked in some way to other computers