Basic Network Services

1
Basic Network Services

• IMT 546 Lab 4
• December 4, 2004
• Agueda Sánchez
• Shannon Layden
• Peyman Tajbakhsh

2
Basic Network Services

• What network services are
• What network protocols are
• Three widely used protocols
• TCP/IP
• HTTP
• Demo
• SMTP
• Example
• One new protocol
• IPv6

3
What Network Services are

• Network services are the capabilities that enable
  computers to communicate with each other
• Protocols define how they do it (the rules)
• In the TCP/IP model, services and protocols
  are often used interchangeably

4
Network Protocols

• Protocols allow information to travel over the
  network
• There are different types of protocols
• Each protocol has a set of rules and agreements
• Information can be exchanged between computers
  because they have "agreed" to use the same
  protocol

5
Application
TCP/IP STACK
Transport
Internet
Host to network
6
An Introduction to TCP

• TCP stands for Transmission Control Protocol
• It controls the transmission of packets of data
  over the Internet
• It supports the network at the transport layer
• Computers must run TCP to communicate with world
  wide web servers
• TCP relies on the IP service to deliver data to
  the host

7
An Introduction to IP

• IP stands of Internet Protocol
• A set of rules to send and receive messages at
  the Internet address level
• Computers must run IP to communicate across the
  internet
• IP forwards each packet based on a four byte
  destination address (the IP number) (e.g,
  192.156.1.1)
• Demo IPCONFIG and Ping

8
HTTP
Hyper-text transfer protocol (HTTP) is the
protocol for exchanging text, graphic images,
sound, video, and other multimedia files on the
Internet
9
HTTP cont.

• HTTP started in 1990 by Berners-Lee
• 1993 employed by Marc Andreeson of Netscape
• Initial vision to create a common information
  space in which we communicate by sharing
  information
• Estimated 80 of internet traffic is over http

10
How HTTP works

• Client (browser usually) sends a request to a
  server
• Request comes with a URL and usually an
  operation
• Server performs operation on the URL
• Server sends response

11
HTTP Demo

• GET /dumprequest.html HTTP/1.1 Host djce.org.uk
• User-Agent Mozilla/4.0 (compatible MSIE 6.0
  Windows NT 5.1 .NET CLR 1.1.4322) Accept
  image/gif, image/x-xbitmap, image/jpeg,
  image/pjpeg, application/x-shockwave-flash,
  application/vnd.ms-excel, application/vnd.ms-power
  point, application/msword, / Accept-Encoding
  gzip, deflate Accept-Language en-us Referer
  http//www.google.com/search?sourceidnavclientie
  UTF-8qhttp22requestmethod3AGet22example
  sgethttp2F12E1 Connection Keep-Alive

12
SMTP
SMTP Simple Mail Transfer Protocol A protocol
used to send email on the Internet. SMTP is a set
of rules regarding the interaction between a
program sending email and a program receiving
email
13
SMTP cont.

• Email is delivered by having the source machine
  establish a TCP connection to port 25 of the
  destination machine. For successful delivery,
  both sender and receiver should "speaks"
  SMTP.
• After establishing the TCP connection to port 25,
  the sending machine, operating as the client,
  waits for the receiving machine, operating as the
  server, to talk first.

14
SMTP cont.

• SMTP is used for sending e-mail. IMAP (Internet
  Message Access Protocol) and POP3 (Post Office
  Protocol 3) are used to access e-mail messages.
• POP3 or IMAP let the user save messages in a
  server mailbox and download them periodically
  from the server.

15
SMTP Example

• Date Sat 27 Jun 87 132631 EDT
• From hedrick_at_topaz.rutgers.edu
• To levy_at_red.rutgers.edu
• Subject meeting Let's get together Monday at
  1pm.
• RED 220 RED.RUTGERS.EDU SMTP Service at 29 Jun 87
  051718 EDT
• TOPAZ HELO topaz.rutgers.edu
• RED 250 RED.RUTGERS.EDU - Hello
• TOPAZ.RUTGERS.EDU
• TOPAZ MAIL From
• RED 250 MAIL accepted
• TOPAZ RCPT To
• RED 250 Recipient accepted
• TOPAZ DATA
• RED 354 Start mail input end with .
• TOPAZ Date Sat 27 Jun 87 132631 EDT
• TOPAZ From hedrick_at_topaz.rutgers.edu
• TOPAZ To levy_at_red.rutgers.edu
• TOPAZ Subject meeting

16
What is IPv6?

• To understand IPv6 lets review IPv4
• Current version of the Internet Protocol used by
  TCP/IP
• IPv4 has not substantially changed since RFC 791
  was published in 1981
• Robust, easily implemented and interoperable, and
  has stood the test of scaling to the size of
  todays Internet
• Impending exhaustion of IPv4 address space due to
  exponential growth of Internet

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IPv6
There are 14 key differences between IPv4 and
IPv6, some of the key differences are
18
IPv4 Header Review
Version Internet Header Length Type of
Service Total Length Identification Flags Fragment
Offset Time to Live Protocol Header
Checksum Source Address Destination
Address Options
. . .
19
IPv6 Header
Version Traffic Class Flow Label Payload
Length Next Header Hop Limit Source
Address Destination Address
20
TCP/IP Protocol Architecture w/IPv6
TCP/IP Protocol Architecture Layers
TCP/IP Protocol Suite
OSI Model Layers
FTP
Telnet
HTTP
RIPng
DNS
SNMP
Application Layer
Application Layer
Presentation Layer
Session Layer
TCP
UDP
Transport Layer
Transport Layer
IPv6
MLD
Internet Layer
ND
Network Layer
ICMPv6
Network Interface Layer
Data Link Layer
Ethernet
Token Ring
Frame Relay
ATM
Physical Layer
21
Resources

• TCP
• http//www.atlantawebhost.com/glossary-sz.php
• IP
• http//www.atlantawebhost.com/glossary-hl.php
• HTTP
• Derfler F.J. Jr. , Freed, L., How Networks Work,
  (2003)
• http//www.w3.org/Protocols/HTTP/HTTP2.html
• http//www.cs.virginia.edu/zaher/classes/CS457/le
  ctures/web.pdf
• http//www.jmarshall.com/easy/http/
• SMTP
• https//www.namesecure.com/en_US/index.jhtml?catg
  lossarysubCatrstsmtp
• http//www.lsoft.com/resources/glossary.aspS
• http//searchwebservices.techtarget.com/sDefinitio
  n/0,,sid26_gci214219,00.html
• http//www2.rad.com/networks/1998/smtp/smtp.htm
• http//networking.ittoolbox.com/pub/LC030701a.pdf
• Microsofts IPv6 web site
• http//www.microsoft.com/windowsserver2003/technol
  ogies/ipv6/default.mspx