Intro to Computer Networking

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Intro to Computer Networking

• Doug Prouty
• Contra Costa County Office of Education
• dprouty_at_cccoe.k12.ca.us

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Is this your desk?

• Then you are in the wrong session

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Agenda

• Network Appliances
• Servers
• Proxy/Cache
• Mail and Web
• Filters
• Virus Protection
• - Operating Systems
• Windows 2000, NT
• Apple
• Software
• Management
• Sniffing
• Network Utilities traceroute, etc.
• Design Considerations
• A typical school
• Issues

• Wiring Infrastructure
• Cat5e and standards for wiring
• Patch panels and face plates
• Tools and Terminations 568A vs 568B
  crossovers
• Hubs and Switches
• Segmentation and the difference
• 10BaseT, 100BaseT, and Gigabit
• 4 repeater rule
• Connection and uplinks
• Wireless
• Routers and Bridges
• General function and uses
• Collision vs Broadcast domains
• VLANS

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Web Resources by Author

• Feed Your Need for Speedhttp//www.cccoe.k12.ca.u
  s/speed
• Networkshttp//www.cccoe.k12.ca.us/networks

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Basic LAN Configuration
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Cat5 Patch Chords

• RJ45 connectors
• 8 wires (4 pairs)
• Twisted for interference

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Cut, Strip Crimp Tools

• Make your own patch cords
• Cuts and strips pairs
• RJ45 end crimped onto ends of wire

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Faceplates

• Mounts on or in wall or in raceway
• Receives patch cords

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Fiber Optics

• Handles speeds in the Gigabits
• Tough to self-terminate

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Fiber Patch Cords

• 30
• Ends are either SC or ST
• Connects switches fast backbones

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Patch Panel

• Termination punchdown in back
• Patch cord plugin in front

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Punch Down Tool

• Terminates wires to back of patch panels

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Raceway

• Mounts to walls
• Cleans up wiring
• Can hold face plates

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Wiring Infrastructure

• Mounted and permanent
• Allows patching
• Comfort that infrastructure is OK

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Wire Testing Equipment

• Test wire for correct termination of 8 wires
• Test for speed capabilities
• i.e. WaveTek Brand

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Cat5 Twisted Pair

• UTP Unshielded Twisted Pair
• Category rating based on number of twists per
  inch
• 4 pairs 8 wires

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Color Codes
Crossover 1 ? 3 2 ? 6
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Making Cables
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Cabling Rules

• Try to avoid running cables parallel to power
  cables.
• Do not bend cables to less than four times the
  diameter of the cable.
• If you bundle a group of cables together with
  cable ties (zip ties), do not over-cinch
  them. You should be able to turn the tie with
  fingers.
• Keep cables away from devices which can introduce
  noise into them. Here's a short list copy
  machines, electric heaters, speakers, printers,
  TV sets, fluorescent lights, copiers, welding
  machines, microwave ovens, telephones, fans,
  elevators, motors, electric ovens, dryers,
  washing machines, and shop equipment.
• Avoid stretching UTP cables (tention when pulling
  cables should not exceed 25 LBS).
• Do not run UTP cable outside of a building.  It
  presents a very dangerous lightning hazard!
• Do not use a stapler to secure UTP cables.  Use
  telephone wire/RJ6 coaxial wire hangers which are
  available at most hardware stores.

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Software
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Standard Network
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Shared Media Hub
10 BaseT
No segmentation Flat
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Four Repeater Rule
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Switching

• Same function as a hub
• Divides network into segments
• Each port gets dedicated bandwidth
• 10Mbs 100Mbs
• Learns addresses RTMP Spanning Tree
• Reduces collisions and allows parallel traffic

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Switched Hub
Segments only see traffic addressed for their
devices
10 BaseT one 100 BaseT
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Solution to Repeater Rule
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Routers

• Multilingual border guard
• Reads packet addressing and directs data
• Discards frame, repackages retransmits data
• May not pass all packets
• Hide devices
• Chooses most efficient route

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Bridges

• Mono-lingual border guard
• Manages traffic between two networks by reading
  packet destination address
• Address tables
• Passes along broadcasts
• Cant hide devices
• Link fast local network to slower long-distance
  network

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SNMP

• Simple Network Management Protocol
• Agents gather data from the network in MIBS
• Management Information Bases
• Every port and packet monitored and measured
• Control from one location
• In Band or Out of Band management

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Collision and Broadcast Domains
Collision Domains
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Network Appliances

• Types of Servers
• Proxy/Cache
• Firewall
• Mail and Web
• Filter
• virus Protection

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Proxy Server

• Acts as an intermediary between a workstation
  user and the Internet so that the site can ensure
  security, administrative control, and caching
  service. A proxy server is associated with or
  part of a gateway server that separates the
  enterprise network from the outside network.

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Cache Server

• A cache server is a server relatively close to
  Internet users that saves (caches) Web pages and
  possibly FTP and other files that users have
  requested. Successive requests for these pages or
  files can be satisfied by the cache server rather
  than requiring the use of the Internet. A cache
  server not only serves its users by getting
  information more quickly but also reduces
  Internet traffic.

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Firewall

• A firewall, working closely with a router
  program, examines each network packet to
  determine whether to forward it toward its
  destination.
• A firewall is often installed in a specially
  designated computer separate from the rest of the
  network so that no incoming request can get
  directly at private network resources.

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Mail and Web Server

• A Web server is a program that, using the
  client/server model and the World Wide Web's
  Hypertext Transfer Protocol (HTTP), serves the
  files that form Web pages to Web users. Every
  computer on the Internet that contains a Web site
  must have a Web server program.

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Filters
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Virus
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Software

• Sam Spadenetwork query tool http//www.samspade.
  org/ssw/
• NeoTrace ExpressYou can trace any computer on
  the internet simply by entering an email, IP
  address or URLhttp//www.neoworx.com/products/ntx
  /
• OTTool 1.0 from Neon Software Inc. makes DNS
  queries, pings devices, traceroutes and scans
  ranges of IP addressesftp//ftp2.neon.com/pub/goo
  dies/OTTool11.sit.hqx
• WhatRoute 1.5.0b5(PPC)http//crash.ihug.co.nz/br
  yanc/

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Resources

• About.coms Computer Networkinghttp//compnetwork
  ing.about.com/
• Networks for Beginnershttp//www.rad.com/networks
  /1997/nettut/mainmenu.html
• Network Monitoring and Alerting Software
  Intermapperhttp//www.dartware.com/
• A Guide to Networking for K-12 Schoolshttp//www.
  netc.org/network_guide/
• An Educators Guide to School Networkshttp//fcit
  .coedu.usf.edu/network/
• Hardware and Software How-to Articleshttp//www.d
  uxcw.com/digest/Howto/index.html