1. Introduction to Computer Networks
Yan Yunyi, Ph.D
Associate Prof.
Xidian University

2. What We Discussed
Course Summary

3. Introduction LAN MAN WAN Internet Protocol Hierarchies and transparent
Connection Oriented & Connectionless
Service, Interface and Protocol
OSI and TCP/IP

4. Physical Layer Maximum Data Rate Transmission Medias
Guided: twisted pair, coaxial cable, and fiber optics
Unguided: radio, microwave, infrared, laser
Telephone System.
Local Loop: Analog signals, twisted pair, modem,
AM, FM, PM,ADSL
Trunks: Multiplexing-FDM TDM WDM
Switch: Circuit Switching , Packet Switching.
QPSK, QAM16…
Baud rate and bit rate

5. Physical Layer(2) TDM FDM WDM T1 carrier
Circuit Switch & Packet Switch
GSM & CDMA

6. Data Link Layer Framing methods (four kinds)
Error Correction (Hamming Distance)
Error Detection (CRC, odd and even)
Sliding Window Protocols
a) One-bit Sliding Window Protocol: stop-and-wait, piggybacking.
b) Go back N: discard all frame after error, pipelining.
c) Selective Repeat: frames buffered until error frame passed.

7. Median Access Control Layer
ALOHA
pure & slotted
CSMA
1-persistent CSMA
nonpersistent CSMA
p-persistent CSMA
CSMA/CD

8. Median Access Control Layer(2)
Ethernet
10Base5
Manchester Encoding
MAC in Ethernet
Minimum Frame
Binary Exponential Backoff
& & Bluetooth

9. Median Access Control Layer(3)
DLL Switching
Bridge
Flooding algorithm
Backward learning
Repeater, HUB, Bridge, Switch, Gateway
VLAN

10. Network Layer Datagram Subnet Virtual Circuit Subnet
Length measurement
Shortest path routing
Distance Vector Routing

11. Network Layer(2) Congestion Control Congestion Prevention Policies
Admission control
Choke packet
hop-by-hop choke packet
Load Shedding
Wine & Milk

12. Network Layer(3) QoS (Reliability, Delay, Jitter, Bandwidth) Buffering
Traffic Shaping
Leaky Bucket Algorithm
IP protocol
IP Address
Subnet Subnet mask

13. Network Layer(4)
NAT
ICMP, ARP, DHCP
IPv6

14. Transport Layer TPDU TSAP NSAP Socket Port Connection Establishment
Release Connection
Flow Control and Buffering

15. Transport Layer (2) UDP RTP TCP URG ACK PSH RST SYN FIN Pseudoheader
checksum

16. Transport Layer (3) TCP Congestion Control
Congestion Window, Threshold
TCP Timers (Three)

17. Application Layer DNS eMail SMTP POP WWW-World Wide Web
URL HTTP HTML WAP
Uniform Resource Locator
HyperText Transport Protocol
HyperText Markup Language
Wireless Application Protocol
XML, XSL
MP3
JPEG

18. About the Report Final score=70%*report+20%*homework+ 10%*presentation
Report’s contents:
(1) programs or source codes related with our course: the code, the comments, and why and how you do this.
(2) Papers on computer networks: title, abstract, introduction, main paper body and conclusions.
The reports MUST be finished by YOURSELF

19. About the Report The report’s topics, but not limited to:
(1) technical discussions on communication ways;
(2) new development on computer networks;
(3) your knowledge or experience about Internet;
(4) advantages and/or disadvantages on network
(4) Your comments on network functions, e.x. games, chatting tools, videos …
The report documents together with PowerPoint slides must be submitted or handed in before Dec.17th (inclusive)

20. About the Report The presentation time: 8:30, Dec. 18th (Tuesday),
Location: Room 414, West Building
All material should be ed to: OR you can hand them in Room 1101A, New Technical and experiments Building (Xin KeJi Lou)
All material must be finished and submitted before Dec.17th, otherwise you can NOT get the score of this course.