Elements of a Small PC Network

1. Elements of a Small PC Network • LAN Standards • We will focus on LANs that follow the Ethernet standard (80% do) • Small Ethernet PC networks use only inexpensive UTP wiring (or Coax) • Speeds for NICs and Hubs or Switches • 10Base-T (10 Mbps, baseband, UTP) • 100Base-TX (100 Mbps, baseband, UTP) • 1000Base-T (Gigabit Ethernet) (1 Gbps)

2. Elements of a Small PC Network • Need a hub or switch to connect the PCs • Connector box with multiple plug-in jacks • Hubs and switches are described later • Each PC needs a network interface card (NIC) • Implements physical anddata link layer connectionto the LAN • Wire • Business-grade UTP telephone wiring

3. Elements of a Simple PC Network • Ethernet UTP Wiring • 4-pair bundle (8 wires) • Each pair is twisted • Terminates in RJ-45connector • Quality Level • Category 5 • Older categories (3 and 4) exist but are now fairly rare

4. Elements of a Simple PC Network • Ethernet UTP Wiring • Come pre-cut in many useful lengths (1 m, 2 m, 25 m, etc.) with connectors already added to both ends • Can also cut to precise lengths needed and then attach connectors • Must test the wire after cutting it and attaching connectors!

5. Elements of a Simple PC Network • Plenum Wiring • For wiring run through airways; covering does not give off toxic fumes if it burns • Required if wires are run through air conditioning ducts • Not needed in false ceilings • More expensive but required by law and concern for employee safety

6. Elements of a Small PC Network • Ethernet Hub Operation • One station transmits a single bit to a hub (physical layer operation) • Hub broadcasts bit to all attached stations • All but the destination PC should ignore the message Hub Hub Bit Bit

7. Elements of a Small PC Network • Ethernet Hubs • Broadcasting is simple, so • Hubs are inexpensive

8. Elements of a Small PC Network • Ethernet Hubs Can Create Latency • Only one station may transmit at a time or the signals will collide and be unreadable • Other stations must wait (latency) Must Wait

9. Elements of a Small PC Network • Ethernet Hubs Can Create Latency • Becomes a problem with 100+ PCs and 10 Mbps hub • 200 PCs is upper limit for tolerable service with a 10 Mbps hub Must Wait

10. Elements of a Small PC Network • Ethernet Switches • One station transmits a frame to a switch (data link layer operation) • Switch only transmits frame out port of destination PC • No broadcasting out all ports Switch Switch Frame Frame

11. Elements of a Small PC Network • Ethernet Switches • Multiple conversations can take place simultaneously because there is no broadcasting, which ties up all ports • No wait to transmit; no Latency Switch

12. Elements of a Simple PC Network • Client PCs • End user’s desktop or notebook PC • Add network interface card (NIC) • With Win95, Win98, Win NT, or Win 2000, no extra software is needed • Networks have many client PCs

13. Elements of a Simple PC Network • Servers • Provide services to client PCs • Usually PCs themselves • Most PC nets have multiple servers • Require a NIC • Require a server operating system (SOS) • Require application software

14. Elements of a Simple PC Network • Server Operating System (SOS) • Servers need operating systems more reliable than client PC operating systems • Windows NT/2000 Server, Novell NetWare, UNIX, LINUX • Application Software • Provides the services offered by the servers • E-mail, word processing, file sharing, etc. • More expensive than the SOS

15. Elements of a Simple PC Network • Novell NetWare SOS • Once dominant, but market share has shrunk • Excellent file and print service • Excellent directory service (later) • Until recently, was not sufficiently robust and scalable for servers other than file servers

16. Elements of a Small PC Network • Microsoft Windows Server Operating System • More robust than desktop Windows (Win 95, Win 98, etc.) • All 32-bit code • Microsoft Windows NT Server before 2000 • Newer Microsoft Windows 2000 Server • Versions in order of increasing functionality: Windows 2000 Server, Advanced Server, DataCenter Server New

17. Elements of a Small PC Network • Microsoft Windows Server Operating System • Easy to install, learn, and use because resembles desktop Windows • Becoming dominant for small business and small department servers • NT Server has had serious reliability and scalability problems • Windows 2000 Server versions promise to improve reliability and scalability

18. Elements of a Small PC Network • UNIX • Workstation servers run UNIX • Extremely reliable • Dominate for large enterprise servers

19. Elements of a Small PC Network • UNIX • Expensive to buy • Must retrain staff or hire UNIX staff • Many versions of UNIX exist • Most run the same application software • However, have different management utilities, etc., requiring training for each version used • Not for Small PC Networks

20. Elements of a Small PC Network • LINUX • Version of UNIX • Runs on PCs for low cost • Available free • But usually pay around $50 for packaged version • Reliable like other UNIX versions • Open Source: Many people are developing tools to add to the LINUX core

21. Elements of a Small PC Network • LINUX • Available in Distributions • A distribution has the LINUX kernel plus other programs • Available on CD-ROM or by downloading • Distributions from different LINUX vendors differ in the specific programs included • Differences make selection, implementation difficult New

22. Elements of a Small PC Network • LINUX • Requires Extensive Labor to Set Up, Maintain • Device driver software often is lacking for printers, disk drives, and other devices • Requires more training because it is UNIX • Better distributions and support coming?