Nankai University

DHCP
14
DHCP DHCP
DHCP
DHCP UDP IP Eth Phy

DHCP server formulates DHCP ACK containing client’s IP address, IP address of first-hop router for client, name & IP address of DNS server encapsulation at DHCP server, frame forwarded (switch learning) through LAN, demultiplexing at client DHCP client receives DHCP ACK reply
Copyright © Xu Jingdong, All right reserved
Nankai University
3
Chapter 2
Application service requirements:
reliability, bandwidth, delay
Internet transport service model
packet-switching
statistical multiplexing routing end to end latency message and packet
Protocol, layering and service models
Why layering OSI reference model, TCP/IP model logical communication, physical communication
hierarchical routing
Internet routing protocols
intra-domain: RIP, OSPF Inter-domain: BGP
Copyright © Xu Jingdong, All right reserved
Nankai University
10
router (runs DHCP)

Ethernet frame broadcast (dest: FFFFFFFFFFFF) on LAN, received at router running DHCP server
Ethernet demuxed to IP demuxed, UDP demuxed to DHCP
DHCP DHCP DHCP DHCP
DHCP
DHCP UDP IP Eth Phy
router (runs DHCP)

Client now has IP address, knows name & addr of DNS
server, IP address of its first-hop router
8
Chapter 4
Internet protocol (IP)
IP addressing IP datagram format IP datagram forwarding
IP Fragmentation & Reassembly
Forwarding in an IP Router
Subnetting and CIDR NAT: Network Address Translation
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13
DHCP DHCP DHCP
DHCP
DHCP UDP IP Eth Phy
DHCP


DHCP DHCP DHCP DHCP
DHCP UDP IP Eth Phy
connecting laptop needs to get its own IP address, addr of first-hop router, addr of DNS server: use DHCP DHCP request encapsulated in UDP, encapsulated in IP, encapsulated in 802.3 Ethernet
Connection and Authorization
Copyright © Xu Jingdong, All right reserved
Nankai University
4
Chapter 2 (cont.)
Web Service and Protocol
Web Client/server Mode Browser Architecture HTTP: HyperText Transfer tocol-1.0 and 1.1 Uniform Resource Locators
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15
DNS DNS DNS ARP query
DNS UDP IP ARP Eth Phy

before sending HTTP request, need IP address of : DNS DNS query created, encapsulated in UDP, encapsulated in IP, encapsulated in Eth. To send frame to router, need MAC address of router interface: ARP
Wireshark
Copyright © Xu Jingdong, All right reserved
Nankai University
6
Chapter 3
Transport layer services
Multiplexing/demultiplexing
Connectionless transport: UDP Principles of reliable data transfer
HyperText Markup Language
Electronic Mail Service and Protocol
Mail Client/server Mode
Simple Mail Transfer Protocol
Mail access protocols-POP3 Mail Message Format-822 and MIME
Copyright © Xu Jingdong, All right reserved
Nankai University
11
HTTP HTTP HTTP HTTP HTTP HTTP HTTP HTTP
HTTP TCP IP Eth Phy

web page finally (!!!) displayed
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7
Chapter 3 (cont.)
reliable transfer
seq. # and ACK #
Connection-oriented transport: TCP
Timeouts and Retransmission, Fast Retransmit
flow control connection management
TCP congestion control
congestion window slow start congestion avoidance: Tahoe and Reno fast recovery
Copyright © Xu Jingdong, All right reserved
Nankai University
Nankai University
12
browser
DNS server ISP network 68.80.0.0/13
school network 68.80.2.0/24
web page
web server 64.233.169.105
Google’s network 64.233.160.0/19
• Encoding and decoding • Error detection • Multiple access protocols: CSMA/CD
LAN technologies
• • • • LAN addressing: physical address Mapping IP address to physical address: ARP Shared Ethernet Switched Ethernet
connection-oriented, reliable: TCP unreliable, datagram: UDP
Client-server, P2P
File Transfer Service and Protocol
FTP Process Model
FTP commands and responses
Internet Control Message Protocol (ICMP)
Copyright © Xu Jingdong, All right reserved
Nankai University
9
Chapter 4 (cont.)
routing principles
link state algorithms distance vector algorithms
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2
Chapter 1
Internet overview
network edge: client/server and peer-to-peer model network core: packet-switching versus circuit-switching