Introduction to Computer Networks Yan Yunyi, Ph.D Associate Prof. Xidian University yyyan@xidian.edu.cn

What We Discussed Course Summary

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

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

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

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.

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

Median Access Control Layer(2) Ethernet 10Base5 Manchester Encoding MAC in Ethernet Minimum Frame Binary Exponential Backoff 802.11 & 802.16 & Bluetooth

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

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

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

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

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

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

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

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

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

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

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)

About the Report The presentation time: 8:30, Dec. 18th (Tuesday), Location: Room 414, West Building All material should be emailed to: yyyan@xidian.edu.cn 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.