Basic Network ServicesBasic Network Services
IMT 546 – Lab 4IMT 546 – Lab 4December 4, 2004December 4, 2004Agueda SánchezAgueda SánchezShannon Shannon Layden Layden Peyman TajbakhshPeyman Tajbakhsh
Basic Network ServicesBasic Network Services• What network services areWhat network services are• What network protocols areWhat network protocols are• Three widely used protocolsThree widely used protocols
TCP/IPTCP/IP HTTPHTTP
• DemoDemo SMTPSMTP
• ExampleExample
• One new protocolOne new protocol IPv6IPv6
What Network Services areWhat Network Services are
Network services are the capabilities Network services are the capabilities that enable computers to that enable computers to communicate with each othercommunicate with each other
Protocols define how they do it (the Protocols define how they do it (the rules)rules)
In the TCP/IP model, “services” and In the TCP/IP model, “services” and “protocols” are often used “protocols” are often used interchangeablyinterchangeably
Network ProtocolsNetwork Protocols Protocols allow information to travel over the Protocols allow information to travel over the
networknetwork There are different types of protocolsThere are different types of protocols Each protocol has a set of “rules” and agreementsEach protocol has a set of “rules” and agreements Information can be exchanged between computers Information can be exchanged between computers
because they have "agreed" to use the same because they have "agreed" to use the same protocolprotocol
Connecting with X protocol; ready to receive instruction or message?
Yes, I'm ready to receive message (ack)
Send message or instruction
Packet DriverProtocols
Product SpecificDriver
Link AccessProtocol Balance
(LAPB)
Internet Protocol (IP)
Transmission Control Protocol (TCP) User Datagram Protocol (UDP)
Internet Message Access Protocol (IMAP)
File Transfer Protocol
(FTP)
TELNETVirtual
Terminal Protocol
Simple Mail
Transfer Protocol (SMTP)
Remote File Service (RAs) Network File System (NFS)Server Message Block
(SMB)
Network File System (NFS) Redirector
TCP-aware Applications(browser, IRC, News Reader, and more)
Derfler F.J. Jr. , Freed, L., How Networks Work, (2003)
TC
P/IP
ST
AC
KT
CP
/IP S
TA
CK
Application
Transport
Internet
Host to network
An Introduction to TCPAn Introduction to TCP TCP stands for TCP stands for Transmission Control Transmission Control
Protocol Protocol It controls the transmission of packets of It controls the transmission of packets of
data over the Internetdata over the Internet It supports the network at the transport It supports the network at the transport
layerlayer Computers must run TCP to communicate Computers must run TCP to communicate
with world wide web serverswith world wide web servers TCP relies on the IP service to deliver data TCP relies on the IP service to deliver data
to the hostto the host
An Introduction to IPAn Introduction to IP IP stands of Internet ProtocolIP stands of Internet Protocol A set of rules to send and receive A set of rules to send and receive
messages at the Internet address levelmessages at the Internet address level Computers must run IP to communicate Computers must run IP to communicate
across the internetacross the internet IP forwards each packet based on a four IP forwards each packet based on a four
byte destination address (the IP number) byte destination address (the IP number) (e.g, 192.156.1.1)(e.g, 192.156.1.1)
Demo IPCONFIG and PingDemo IPCONFIG and Ping
HTTPHTTP
transfer of data
Request
Hyper-text transfer protocol (HTTP) is the protocol for exchanging text, graphic images, sound, video, and other multimedia files on the Internet
HTTP …cont.HTTP …cont.
HTTP started in 1990 by Berners-LeeHTTP started in 1990 by Berners-Lee
1993 employed by Marc Andreeson of 1993 employed by Marc Andreeson of Netscape Netscape
Initial vision to create “a common Initial vision to create “a common information space in which we information space in which we communicate by sharing information“communicate by sharing information“
Estimated 80% of internet traffic is Estimated 80% of internet traffic is over http over http
How HTTP worksHow HTTP works
Client (browser usually) sends a Client (browser usually) sends a request to a serverrequest to a server
Request comes with a URL and Request comes with a URL and usually an operationusually an operation
Server performs operation on the Server performs operation on the URLURL
Server sends responseServer sends response
HTTP DemoHTTP Demo
GET /dumprequest.html HTTP/1.1 GET /dumprequest.html HTTP/1.1 Host: djce.org.ukHost: djce.org.uk
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322) Accept: image/gif, image/x-NT 5.1; .NET CLR 1.1.4322) Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */* application/vnd.ms-powerpoint, application/msword, */* Accept-Encoding: gzip, deflate Accept-Language: en-us Accept-Encoding: gzip, deflate Accept-Language: en-us Referer: http://www.google.com/search?Referer: http://www.google.com/search?sourceid=navclient&ie=UTF-8&q=http+%22request+methodsourceid=navclient&ie=UTF-8&q=http+%22request+method%3A+Get%22++examples+get+http%2F1%2E1 Connection: Keep-%3A+Get%22++examples+get+http%2F1%2E1 Connection: Keep-
AliveAlive
SMTPSMTP
Mailbox StoreServer
Mailbox StoreMessage Delivery
Message Delivery
Server
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
SMTP …cont.SMTP …cont. Email is delivered by having the source machine establish a Email is delivered by having the source machine establish a
TCP connection to port 25 of the destination machine. For TCP connection to port 25 of the destination machine. For successful delivery, both “sender” and “receiver” should successful delivery, both “sender” and “receiver” should "speaks" SMTP. "speaks" SMTP.
After establishing the TCP connection to port 25, the sending After establishing the TCP connection to port 25, the sending machine, operating as the client, waits for the receiving machine, operating as the client, waits for the receiving machine, operating as the server, to talk first.machine, operating as the server, to talk first.
SMTP …cont.SMTP …cont.
SMTP is used for sending e-mail. IMAP SMTP is used for sending e-mail. IMAP (Internet Message Access Protocol) and (Internet Message Access Protocol) and POP3 (Post Office Protocol 3) are used to POP3 (Post Office Protocol 3) are used to access e-mail messages. access e-mail messages.
POP3 or IMAP let the user save messages POP3 or IMAP let the user save messages in a server mailbox and download them in a server mailbox and download them periodically from the server.periodically from the server.
SMTP ExampleSMTP Example Date: Sat 27 Jun 87 13:26:31 EDT Date: Sat 27 Jun 87 13:26:31 EDT From: [email protected] From: [email protected] To: [email protected] To: [email protected] Subject: meeting Let's get together Monday at 1pm.Subject: meeting Let's get together Monday at 1pm.
RED 220 RED.RUTGERS.EDU SMTP Service at 29 Jun 87 05:17:18 EDTRED 220 RED.RUTGERS.EDU SMTP Service at 29 Jun 87 05:17:18 EDT TOPAZ HELO topaz.rutgers.edu TOPAZ HELO topaz.rutgers.edu RED 250 RED.RUTGERS.EDU - Hello RED 250 RED.RUTGERS.EDU - Hello TOPAZ.RUTGERS.EDUTOPAZ.RUTGERS.EDU TOPAZ MAIL From: TOPAZ MAIL From: RED 250 MAIL accepted RED 250 MAIL accepted TOPAZ RCPT To:TOPAZ RCPT To: RED 250 Recipient acceptedRED 250 Recipient accepted TOPAZ DATA TOPAZ DATA RED 354 Start mail input; end with . RED 354 Start mail input; end with . TOPAZ Date: Sat 27 Jun 87 13:26:31 EDT TOPAZ Date: Sat 27 Jun 87 13:26:31 EDT TOPAZ From: [email protected] TOPAZ From: [email protected] TOPAZ To: [email protected] TOPAZ To: [email protected] TOPAZ Subject: meeting TOPAZ Subject: meeting TOPAZ TOPAZ TOPAZ Let's get together Monday at 1pm. TOPAZ Let's get together Monday at 1pm. TOPAZ . TOPAZ . RED 250 OK RED 250 OK TOPAZ QUIT TOPAZ QUIT RED 221 RED.RUTGERS.EDU Service closing transmission channel RED 221 RED.RUTGERS.EDU Service closing transmission channel
What is IPv6?What is IPv6?To understand IPv6 lets review IPv4To understand IPv6 lets review IPv4
Current version of the Internet Protocol Current version of the Internet Protocol used by TCP/IPused by TCP/IP
IPv4 has not substantially changed since IPv4 has not substantially changed since RFC 791 was published in 1981RFC 791 was published in 1981
Robust, easily implemented and Robust, easily implemented and interoperable, and has stood the test of interoperable, and has stood the test of scaling to the size of today’s Internetscaling to the size of today’s Internet
Impending exhaustion of IPv4 address Impending exhaustion of IPv4 address space due to exponential growth of space due to exponential growth of InternetInternet
IPv6IPv6
IPv4IPv4 IPv6IPv6
Addresses are 4 bytes in Addresses are 4 bytes in lengthlength
Addresses are 16 bytes in Addresses are 16 bytes in lengthlength
Security OptionalSecurity Optional Security RequiredSecurity Required
Header includes optionsHeader includes options Extension headers Extension headers (extensibility)(extensibility)
Address Resolution Address Resolution Protocol (ARP)Protocol (ARP)
Neighbor Solicitation Neighbor Solicitation MessagesMessages
Configured manual or via Configured manual or via DHCPDHCP
Does not require manual or Does not require manual or DHCP configurationDHCP configuration
Must support a 576-byte Must support a 576-byte packet size (possibly packet size (possibly fragmented).fragmented).
Must support a 1280-byte Must support a 1280-byte packet size (without packet size (without fragmentation). fragmentation).
There are 14 key differences between IPv4 and There are 14 key differences between IPv4 and IPv6, some of the key differences are:IPv6, some of the key differences are:
IPv4 Header ReviewIPv4 Header ReviewVersion
Internet Header LengthType of Service
Total LengthIdentification
FlagsFragment Offset
Time to LiveProtocol
Header ChecksumSource Address
Destination AddressOptions . . .
IPv6 HeaderIPv6 HeaderVersion
Traffic Class
Flow Label
Payload Length
Next Header
Hop Limit
Source Address
Destination Address
TCP/IP Protocol Architecture w/IPv6TCP/IP Protocol Architecture w/IPv6
IPv6
TCP
FTP
UDP
MLD
Telnet HTTP RIPngDNS SNMP
Internet Layer
Transport Layer
Application Layer
Network Interface Layer
Application Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer
OSI Model Layers
TCP/IP Protocol Architecture
Layers
TCP/IP Protocol Suite
Ethernet Token Ring Frame Relay ATM
ND
ICMPv6
ResourcesResources 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