Shared Resources
Connectivity
Data and Software Security
Data and Software Backup
Access to Network Applications
CE 536 - Networking and Microcomputer Systems
Day 4: Applications of Local Area Networks to Microcomputer Systems, LAN Topologies, Media, and Components
Reasons for Local Area Networks
Shared Resources
Connectivity
Data and Software Security
Data and Software Backup
Access to Network Applications
Planning for Local Area Networks
Components of the Physical Layer (OSI Layer 1) of a LAN:
The Medium that carries the LAN signal
Twisted Pair
Coaxial Cable
Fiber-Optic Cable
Wireless
The Topology (Layout) of the LAN Wiring
Star
Ring
Bus
The Network Interfaces to the LAN
Shared Resources
Printers
- Attached to the File Server
- Attached as a LAN Node
Disks
- Large Disk on Server; Smaller Disks on Nodes
CD-ROMs
- Including Multi-disc Players
Files
- Entire Files through File Locking
- Items within Files through Record Locking
- Elimination of Sneakernet
Software
- Single User Licenses with Metering Software
- Network Licenses with License Servers
- Site Licenses
- Beware of Software Publisher's Association
Connectivity
Between Nodes on the LAN
- Allows access to Resources on Individual Nodes (e.g., Printer)
To Members of Workgroups
- For Collaborative Efforts
To Other Interconnected LANs
- Allows access to Remote Resources
Between Dissimilar Computers
- Allows PC's and Macs to be Interconnected
- Allows Workstations, Mainframes, etc., to be Interconnected
Data and Software Security
Access to LAN is Password Protected
Access can be Limited to Selected Individuals for Selected Applications
Software can be Hidden (to prevent theft)
Software Upgrades Done to Server
Boot PROM's eliminate local files on public-site (i.e., in educational settings) computers
Data and Software Backup
All Files on the Server are typically Backed Up Daily
Files on Individual Nodes can be Backed Up
Access to Network Applications
Databases
- Can be Written to via Record Locking
- Local or Remote-mounted Databases
Groupware
- Glorified Electronic Mail
- Scheduling
- Interconnected Applications
- Lotus Notes
- Novell GroupWise
Specialized Servers
- FAX Servers
- Terminal (Communication) Servers
- Database Servers
- Print Servers
Electronic Mail
- MHS - Message-Handling System (LAN standard)
- ITU-TSS X.400 (International standard)
- SMTP - Simple Mail Transfer Protocol (the one really used)
- POP - Post Office Protocol
- Eudora
- IMAP - Internet Message Access Protocol
- Netscape
- Electronic Communications Privacy Act (18 USC 2701-2711).
Lehigh's Warning Banner:
Unauthorized use of this system, including use of an account not
specifically assigned to you by Lehigh University, is subject to
monitoring.
Multimedia
- Audio
- Images
- Video
- CD-ROM
Network Browsers
- Netscape
- Internet Explorer
Planning for Local Area Networks
Need Becomes Self-Evident
Productivity Suffers Waiting for Resources
Communications Need to Be Enhanced
Access to Information Resources Required
Plan to Fit Organizational Mission
Develop Strategic Information Plan
Develop Information Inventory
Anticipate Future Needs
Plan an Upgrade Path
Components of the Physical Layer (OSI Layer 1) of a LAN:
The Medium that carries the LAN signal
Twisted Pair
Unshielded
Shielded (via metallic sheath)
RJ 45 Connectors
Maximum Point-to-Point Link: 100 Meters (328 Feet)
10BaseT - 10 Mbits per second, Baseband, Twisted Pair
100BaseT - 100 Mbits per second, Baseband, Twisted Pair
Twist cancels out electrical interference
Underwriters' Laboratories (UL) Performance Levels:
Level 1
Untwisted
Strictly for Voice Transmission
Level 2
Untwisted or Low-quality Twisted
Suitable for RS-232 (Serial) Communications
Unsuitable for 10BaseT
Level 3
Wiring used in most commercial buildings
Suitable for 10BaseT or 4Mbit/sec Token Ring
Twists/Foot: 3-5
Level 4
Suitable for 10BaseT or 4Mbit/sec Token Ring
Twists/Foot: 5-8
Level 5
Suitable for 10BaseT
Suitable for 100BaseT or 16Mbit/sec Token Ring
Twists/Foot: 8-10
Coaxial Cable
ThickNet
Maximum Segment: 500 Meters (1,640 Feet)
Vampire Tap connections
Taps must be spaced in multiples of 2.5 meters
10Base5 - 10 Mbits per second, Baseband, 500 m.
ThinNet
RG-58 Cable
Maximum Segment: 185 Meters (607 Feet)
BNC (Bayonet Nut Couple) Connectors
30 or fewer connections per segment
Connection spacing of no less than 0.5 meters (1.64ft)
10Base2 - 10 Mbits per second, Baseband, 200 m. (approx.)
Fiber-Optic Cable
Maximum Point-to-Point Link: 2,000 Meters (6,560 Feet)
Can routinely carry data rates up to 565 Mbits per second
Immune to electrical interference
Wireless
Microwave
The Topology (Layout) of the LAN Wiring
Star
Point-to-Point links from a central control unit
Becoming the predominant form of LAN wiring
Can be insecure
Simple to diagnose and resolve problems
Wiring intensive to install
Ring
Stations connected in series
Unidirectional
May utilize a backup ring
Very good reliability
Relatively easy to manage
Bus
Transmissions received by all; only addressed unit accepts
Can be insecure
Easy to wire segments
Difficult to diagnose problems
Can degenerate over time
No provision for an alternate path
The Network Interfaces to the LAN
Medium Attachment Unit (MAU) - IEEE 802.3 term
Transceiver - Ethernet term
The device which connects the LAN cable to the workstation
Medium dependent
10Base5 - Part of Vampire Tap
Attachment Unit Interface (AUI) - connection between MAU and workstation; DB-15 connector
10Base2 - Part of Network Interface Card
10BaseT - Part of Network Interface Card
External device - 10BaseT to AUI
Functions:
Transmission of traffic to the LAN media
Reception of traffic from the LAN media
Detection of collisions
Monitors LAN media to prevent transmission
Jabber detection from defective nodes
Hubs - central signal distributors
Multiport Repeater (lowest level)
Can be expandable
Bridge Cards to connect similar LANs
Router Cards to connect dissimilar LANs
Network management (e.g., Packets per Port)
SNMP - Simple Network Management Protocol
Individual port control and security
Shared media
Multistation Access Unit (MSAU)
Hub in a token ring network
Switch-based Hubs
Each connection at full LAN speed
Limited only by speed of backplane
ATM (Asynchronous Transfer Mode) Hubs
Connections established as needed
Predictable cell (53 byte packets) delivery period
High speeds to 155 Mbits per second
Ideal for multimedia
Network Interface Cards
Bus type: ISA, EISA, MCA, PCI
Bus width: 8 bit, 16 bit, 32 bit
Connector types
Ethernet Combo cards ($100)
10BaseT only cards ($50)
Token Ring cards ($200+)
Assignment for Class 5 ...
Read and be prepared to discuss:
Chapter 6 - skip The Ethernet and IEEE 802.3 story (pp. 173-178)
Chapter 7 - skip from The Token Ring MAC Sublayer (p. 195) up to Where Token Ring is heading (p. 215)
Chapter 8 - skim Single-Mode and Multimode... (pp. 223-224)
skip from Relationship to the OSI Model (p. 226) up to Inherent Reliability (p.236)