University of Iowa
Professor: Warren Boe
Lecture Notes: 1/20/2009
Agenda
Ethernet
TCP/IP
DoD
Model
IP Classes
Classful Routing
Department of Defense Model (DOD):
AKA – Internet Suite of Protocols
Is TCP/IP
Model and suite of protocols created by Department of
Defense to ensure data communication and integrity in the event of a catastrophic war.
Comparison between DoD, OSI,
& TCP/IP
OSI
DoD
Hybrid TCP/IP OSI
Application
Process/Application
Application
Transport
Host-to-Host
Transport
Network
Internet
Internet
Data Link
Network Access
Data Link
Presentation
Session
Physical
Physical
Process/Application Layer:
Typical Protocols:
Telnet – Terminal Emulation
Access to remote machines and consoles
Appears as though the terminal is connected directly to local device
FTP – File Transfer Protocol:
Transfers files
Somewhat secure
Allows directory/file manipulation (move, delete, creates, navigate structure)
TFTP – Trivial File Transfer Protocol:
Stripped down version of FTP
No security
Need to know exactly where files are located (no navigation) NFS – Network File System:
Created by Sun Microsystems
Transfer of files between disparate systems (i.e. UNIX and Novell or Microsoft)
SMTP – Simple Mail Transfer Protocols:
Spooled email transmission system
SMTP – sending mail
POP – receiving mail
LPD – Line Printer Daemon:
Remote printer sharing (UNIX/Mainframe)
X Windows:
GUI interface to remote system (UNIX Server).
SNMP – Simple Network Management Protocol:
Collects valuable network information (statistics, results and informational messages)
Baseline monitoring
Traps – Warnings
DNS – Domain Name Services:
Resolves DNS Names to IP address
FQDN – Fully Qualified Domain Name
Hierarchical structure that logically locates a system based on domain identifier.
DHCP – Dynamic Host Configuration Protocol:
Provides IP configuration of workstations/hosts
Dynamic and automatic
An extension of BOOTP
BOOTP – manual and automatic
Host-to-Host Layer Protocols:
TCP – Transmission Control Protocol
UDP – User Datagram Protocol
Transmission Control Protocol:
Connection Oriented and Reliable
Slower, but Bulletproof
Connection Oriented – Virtual Connection
3 – Way connection Handshake
Sequenced – Packets are numbered
Reliable – ACKs and NAKs
Flow Control (Windowing)
Overhead!
TCP Header Fields:
Source Port – port number of the application sending the data
Destination Port – port number of the application receiving the data
Sequence Number – allows receiving device to put the data
“pieces” back in order. Acknowledgement Number – defines which packet(s) are expected next.
Offset – lets the receiving device where header stops and data begins.
Reserved – not used, always set to 0.
Code Bits – controls various functions and is used to setup and terminate sessions.
TCP Header Fields (continued):
Window – identifies the amount of data the sender is willing to accept.
Checksum – CRC error detection on both header AND data.
Urgent Pointer – who cares!
Option – options and padding (0 bits in size or 32).
Data – the actual data being sent.
Whew!!!
User Datagram Protocol:
Connectionless Oriented and Unreliable (in comparison to TCP)
Fast and Unreliable
Best Effort delivery
Subsequence – no sequence numbers
Unreliable – no ACKs and NAKs
Connectionless – no virtual circuit, no handshaking
No Windowing or Flow Control
Low Overhead
Examples:
NFS
SNMP
Which protocol is used (TCP or UDP)? It’s up to the application developer.
UDP Header Fields:
Source Port – port number of the application sending the data
Destination Port – port number of the application receiving the data
Length of Segment – Length of UDP header and UDP data fields.
Checksum –