Lesson 3 – UNDERSTANDING NETWORKING

Network relationship types Network features OSI Networking model Network hardware components OVERVIEW

Peer-to-peer Client / server NETWORK RELATIONSHIP TYPES

Computers on the Network communicate with each other as equals. Peer-to-peer relationships

Each computer: Shares resources. Sets up and maintains security. Accesses Network resources. Peer-to-peer relationships

A distinction exists between computers that make available Network resources and computers that use those resources. Client / server relationships

Resources are centrally managed and hosted. Client computers do not share resources with other client computers / servers. Server computers make available, manage, and administer shared resources. Client / server relationships

Use less expensive hardware. Easy to administer. No NOS required. More built-in redundancy. Pros for Peer-to-peer Networks

May hurt user’s performance. Not very secure. Hard to back up. Cons for Peer-to-peer Networks

Very secure. Better performance. Centralized back up. Very reliable. Pros for Client / server Networks

Require professional administration. More hardware intensive. Cons for Client / server Networks

File sharing Printer sharing Application services Remote Access Wide Area Network Internet and intranet Network security NETWORK FEATURES

Originally, the primary reason to have a Network. Provides central storage for common documents, databases, and work files. Requires a shared directory or disk drive. Incorporates File Locking. File sharing

Most common ways of sharing printers are: Printer queues. Workstations that access printers directly. Printer sharing

Printer server function can be filled by: A fileserver with the printer connected to it. A computer connected to the Network, with the printer connected to the computer. An in-built print server on a printer’s NIC. A dedicated Network print server. Printer sharing

Advantages: Reduces disk space needed. Easier to administer the application. Application services

systems are divided into: File-based. Client / server.

File-based system: Consists of a set of files kept in a shared location on a server.

Client / server based system: Contains messages and handles interconnections, inside and outside the company.

Users use this feature to access files and from a remote location, such as their homes. Remote Access

Methods: Set up Remote Access Service (RAS) connection on a Windows NT server. Use a dedicated RAS. Employ a workstation on the Network. Set up a Virtual Private Network (VPN). Install Windows Terminal Server or Citrix MetaFrame. Remote Access

WAN is the connection of multiple Local Area Networks (LANs). It is created when users of one LAN need frequent access to the resources on another LAN. Wide Area Network

An Internet connection for a Network consists of a telecommunications network connection to an Internet Service Provider (ISP). Internet and intranet

Network components : Leased 56KB line ISDN line, or a fractional or full DS1 (T-1) connection Channel Service Unit / Data Service Unit (CSU/DSU) Router Firewall Web server Internet and intranet

This internally focused Network: Mimics the Internet. May also host Internet-type services like FTP servers. Is not usually accessible from outside the LAN. Internet and Intranet

Provided by: Features of the NOS. Physical cabling plant. The Network’s connection with other Networks. Client workstations. Actions of the users. Security policies. Etc. Network security

Conceptual model. Used in Network design and engineering Network solutions. Defines methods and protocols needed to connect one computer to another. OSI NETWORKING MODEL

The 7 layered OSI Model

7 layers of the OSI Model Defines the properties of the physical medium used to make a Network connection.

7 layers of the OSI Model Connection can be either: Point-to-point Multipoint Transmission can be either: Half-duplex Full-duplex

7 layers of the OSI Model Defines standards that assign meaning to the bits carried by the physical layer.

7 layers of the OSI Model This layer is sub-divided into: Logical Link Control Medium Access Control

7 layers of the OSI Model Defines how data packets get from one point to another on a Network and what goes into each packet.

7 layers of the OSI Model Manages the flow of information from one Network node to another.

7 layers of the OSI Model Defines the connection from a user to a Network server or from a peer on a Network to another peer.

7 layers of the OSI Model Takes the data supplied by the lower-level layers and trans- forms it so it can be presented to the system.

7 layers of the OSI Model Controls how the operating system and its applications interact with the Network.

How data travels through the OSI layers

Servers Hubs, Switches, and Routers Cabling and Cable Plants Workstation Hardware NETWORK HARDWARE COMPONENTS

A server is any computer that performs Network functions for other computers. Servers

Types of servers: File server. Print servers. Application servers. servers. Networking servers that provide Network services (automatic assignment of TCP/IP addresses). Servers

Types of servers: Routing servers (routing of packets from one Network to another). Web servers (encryption/decryption and other security services). Virtual Private Network (VPN) servers. Internet servers. Remote Access servers. Servers

Typically run some Network Operating System (NOS) like: Windows 2000 Server and Advanced Server Windows NT Server Novell NetWare UNIX Servers

A true server-class computer will have: Built-in redundancy with multiple power supplies and fans. High-performance designs. Monitoring software and hardware. Servers

A hub (concentrator) connects a number of network cables to a Network. Network connections on a hub share a single collision domain. Hubs, Switches, and Routers

A typical Network hub Hubs, Switches, and Routers

A switch makes a Network connection private. It collects data from each connection and forwards it to a Network backbone. Switches connect many hubs to a single backbone. Hubs, Switches, and Routers

Using switches and hubs in concert Hubs, Switches, and Routers

A router routes data packets from one Network to another. Two Networks connect to a router using their own wiring and connection type. Hubs, Switches, and Routers

Types of Network cable: Unshielded Twisted Pair (UTP) Shielded Twisted Pair (STP) Coaxial Cable (coax) Fiber Optic Cabling and Cable Plants

Any computer on a Network is referred to as a Network workstation (or Network Client). Workstation Hardware

Network relationship types: Peer-to-Peer networks Client / server Networks SUMMARY

Network features: File sharing Printer sharing Application services Remote Access Wide Area Network Internet and intranet Network security Summary

Open Systems Interconnect (OSI) Networking Model: Application Presentation Session Transport Network Data-link Physical Summary

Network Hardware Components: Server types Hubs, Switches, and Routers Summary

Cabling and the Physical Plant: UTP STP Coax Fiber Wireless Summary