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Basic Network Services
IMT 546 – Lab 4
December 4, 2004
Agueda Sánchez
Shannon Layden
Peyman Tajbakhsh
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
What Network Services are
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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
Network Protocols
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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
Connecting with X protocol; ready to receive instruction
or message?
Yes, I'm ready to receive message (ack)
Send message or instruction
TCP/IP STACK
TCP-aware Applications
(browser, IRC, News Reader, and more)
Network File System (NFS) Redirector
Remote File Service (RAs)
Internet
Message
Access
Protocol
(IMAP)
Network File System (NFS)
File
Transfer
Protocol
(FTP)
TELNET
Virtual
Terminal
Protocol
Server Message Block
(SMB)
Application
Simple
Mail
Transfer
Protocol
(SMTP)
Transport
Transmission Control Protocol (TCP)
User Datagram Protocol (UDP)
Internet
Internet Protocol (IP)
Host to network
Packet Driver
Protocols
Product Specific
Driver
Derfler F.J. Jr. , Freed, L., How Networks Work, (2003)
Link Access
Protocol Balance
(LAPB)
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
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
HTTP
Hyper-text transfer protocol (HTTP) is the
protocol for exchanging text, graphic
images, sound, video, and other multimedia
files on the Internet
Request
transfer of data
HTTP …cont.



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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
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
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/xxbitmap, image/jpeg, image/pjpeg, application/xshockwave-flash, application/vnd.ms-excel,
application/vnd.ms-powerpoint, application/msword, */*
Accept-Encoding: gzip, deflate Accept-Language: en-us
Referer:
http://www.google.com/search?sourceid=navclient&ie=UTF8&q=http+%22request+method%3A+Get%22++examples+get+http%
2F1%2E1 Connection: Keep-Alive
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
Message Delivery
Server
Message Delivery
Server
Mailbox Store
Mailbox Store
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.
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.
SMTP Example

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









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Date: Sat 27 Jun 87 13:26:31 EDT
From: [email protected]
To: [email protected]
Subject: meeting Let's get together Monday at 1pm.
RED 220 RED.RUTGERS.EDU SMTP Service at 29 Jun 87 05:17:18 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 13:26:31 EDT
TOPAZ From: [email protected]
TOPAZ To: [email protected]
TOPAZ Subject: meeting
TOPAZ
TOPAZ Let's get together Monday at 1pm.
TOPAZ .
RED 250 OK
TOPAZ QUIT
RED 221 RED.RUTGERS.EDU Service closing transmission channel
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 today’s Internet
Impending exhaustion of IPv4 address
space due to exponential growth of
Internet
IPv6
There are 14 key differences between IPv4 and
IPv6, some of the key differences are:
IPv4
IPv6
Addresses are 4 bytes in
length
Addresses are 16 bytes in
length
Security Optional
Security Required
Header includes options
Extension headers
(extensibility)
Address Resolution
Protocol (ARP)
Neighbor Solicitation
Messages
Configured manual or via
DHCP
Does not require manual or
DHCP configuration
Must support a 576-byte
packet size (possibly
fragmented).
Must support a 1280-byte
packet size (without
fragmentation).
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
...
IPv6 Header
Version
Traffic Class
Flow Label
Payload Length
Next Header
Hop Limit
Source Address
Destination Address
TCP/IP Protocol Architecture w/IPv6
OSI Model Layers
TCP/IP Protocol
Architecture
Layers
TCP/IP Protocol Suite
Application Layer
Presentation Layer
Application Layer
Telnet
FTP
HTTP
DNS
RIPng
SNMP
Session Layer
Transport Layer
Transport Layer
TCP
UDP
ND
Network Layer
Internet Layer
IPv6
MLD
ICMPv6
Data Link Layer
Physical Layer
Network Interface
Layer
Ethernet
Token Ring
Frame Relay
ATM
Resources

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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/lectures/web.pdf
• http://www.jmarshall.com/easy/http/
SMTP
• https://www.namesecure.com/en_US/index.jhtml?cat=glossary&subCat
=rst#smtp
• http://www.lsoft.com/resources/glossary.asp#S
• http://searchwebservices.techtarget.com/sDefinition/0,,sid26_gci214219
,00.html
• http://www2.rad.com/networks/1998/smtp/smtp.htm
• http://networking.ittoolbox.com/pub/LC030701a.pdf
Microsoft’s IPv6 web site
• http://www.microsoft.com/windowsserver2003/technologies/ipv6/default
.mspx