1. Networking vs. Timesharing
Mainframe: OS 370
PC, Win98
Mac OS X 10.1
Server, Unix
Protocol
PC, Win2000
Terminals, Consoles

2. Local Area Network Emerged, 1970’s
Chicago
Boston
Seattle
NYC
Denver SF LA
Houston
Local Area Network Emerged, 1970’s

3. Local Area Network (LAN)
Range: The same building, same floor, same lab, same department. Within about 50 M’s.
Computers: Micro Computers, Workstations; usually, but not necessarily, the same platform.
Purposes: Sharing resources, e.g., printers, files, (Internet access), programs, internal exchange.
PC, Win98
Mac OS X 10.1
Server, Unix
Protocol
PC, Win2000

4. The way in which the computers connected.
Topology of LAN
The way in which the computers connected.
Bus Topology
Ring Topology
Star Topology
Direct Topology

5. IBM Token Ring 3 5 *%ooo… 4 2 $$100…… 4 2 $$100…… 3 4 **ABCD**
Free Token
There is only one token circulating in the ring, and the computer that has the token gets the access to the cable.
Busy Token
To From Data 3 5
*%ooo… 1 4 2
$$100…… 5 4 2
$$100…… 3 4
**ABCD**
4  2 2
3  4 4
These processes can be done by hardware.
Conventions: format, the size of a token, the speed of the token.
How to prevent starvation?
2  3 3

6. Ethernet IEEE 802.3 Standard CSMA/CD
Carrier Sense Multiple Access/ Collision Detection
Ethernet 5 1 3
jar
100 Mb/sec 4 2
A packet: 128 bytes, = 1024 bits
(ms, 10-3 sec)
Listen and send
Collision

7. Wide Area Network , early 80’s
Chicago
Boston
CNY
Seattle
NYC
Denver SF LA
Houston
Wide Area Network , early 80’s

8. WAN  Backbone Network ARPANET CSNET NSFNET ANSNET Chicago Boston CNY
Seattle
NYC
Denver SF
ARPANET
CSNET
NSFNET
ANSNET LA LA
Houston
WAN  Backbone Network