1 Introduction: Network Applications

Size: px
Start display at page:

Download "1 Introduction: Network Applications"

Transcription

1 1 Introduction: Network Applications Some Network Apps Web Instant messaging Remote login P2P file sharing Multi-user network games Streaming stored video clips Internet telephone Real-time video conference Massive parallel computing Network App Concept

2 Processes Communicating A process sends/receives messages to/from its socket Processes Communicating For a process to receive messages, it must have an identifier A host has a unique 32-bit IP address Identifier includes both the IP address and port numbers (16-bit) associated with the process on the host e.g. or telnet About App Layer Protocols App Layer Protocols define: Types of messages exchanged, eg, request & response messages Syntax of message types: what fields in messages & how fields are delineated Semantics of the fields, ie, meaning of information in fields Rules for when and how processes send & respond to messages Public-domain protocols (e.g. HTTP, SMTP,..., RFCs) Proprietary protocols (e.g. KaZaA) Net App Requirements 2

3 2 Web: HTTP HyperText Transfer Protocol Web page consists of objects Object can be HTML file, JPEG image, Java applet, audio file,... Web page consists of base HTML-file which includes several referenced objects Each object is addressable by a URL e.g. HyperText Transfer Protocol Web s application layer protocol Client/server model client: browser that requests, receives, displays Web objects server: Web server sends objects in response to requests HTTP 1.0 (1996): HTTP 1.1 (1997): Client initiates TCP connection (creates socket) to server, port 80 HTTP messages (application-layer protocol messages) exchanged between browser (HTTP client) and Web server (HTTP server) HTTP is stateless HTTP Request/Response 3

4 HTTP connections Nonpersistent HTTP At most one object is sent over a TCP connection HTTP/1.0 uses nonpersistent HTTP Persistent HTTP Multiple objects can be sent over single TCP connection between client and server HTTP/1.1 uses persistent connections in default mode RTT: Round Trip Time Persistency and Pipelining Nonpersistent requires 2 RTTs per object OS must work and allocate host resources for each TCP connection (browsers often open parallel TCP connections to fetch referenced objects) Persistent server leaves connection open after sending response subsequent HTTP messages between same client/server are sent over connection Persistent without pipelining 4

5 client issues new request only when previous response has been received 1 RTT for each referenced object Persistent with pipelining (default in HTTP/1.1) client sends requests as soon as it encounters a referenced object as little as 1 RTT for all the referenced objects Request Message GET, POST, HEAD, PUT, DELETE Response Message 200, 301, 400, 404, 505,... User-server state: cookies Four components 1. cookie header line in the HTTP response message 2. cookie header line in HTTP request message 3. cookie file kept on user s host and managed by user s browser 5

6 4. back-end database at Web site What cookies can bring authorization shopping carts recommendations user session state (Web ) Cookies and privacy cookies permit sites to learn a lot about you you may supply name and to sites search engines use redirection & cookies to learn yet more advertising companies obtain info across sites User-server state: cookies Web Cache (Proxy) User sets browser: Web accesses via cache Browser sends all HTTP requests to cache object in cache: cache returns object else cache requests object from origin server, then returns object to client Cache acts as both client and server Typically cache is installed by ISP (university, company, residential ISP) 6

7 Web Cache (Proxy) 3 File Transfer: FTP FTP: File Transfer Protocol FTP: File Transfer Protocol Transfer file to/from remote host Client/server model (1985) Active FTP Client contacts server port 21 from client port N (>1023) Server contacts client port N+1 from port 20 Passive FTP Client contacts server port 21 from client port N (>1023) Server starts listening to port M (>1023) and tells client about it Client contact server port M from client port N+1 e.g. 7

8 FTP: File Transfer Protocol FTP uses TCP for all connections, non-persistant, only one file transfer per connection Control connection: out of band FTP server maintains state : current directory, earlier authentication Commands: USER, PASS, LIST, RETR, STOR,... Return codes (similar to HTTP) 331 Username OK, password required 425 Can t open data connection 452 Error writing file 4 Mail: SMTP & POP/IMAP Mail Protocols SMTP: Simple Mail Transfer Protocol TCP to server port 25 Three phases of transfer greeting (handshake) transfer of messages closure Commands: HELO/EHLO, MAIL FROM, RCPT TO, DATA, QUIT Return codes: 220, 250, 354, 221,... Messages must be 7-bit ASCII Persistant connections 8

9 Mail Message Format (1982) MIME: Multimedia Mail Extension html Additional lines in msg header declare MIME content type MIME-version: 1.0 Content-Transfer-Encoding: e.g. base64 Content-Type: e.g. image/jpeg POP: Post Office Protocol (POP3, 1996) Commands: USER, PASS, LIST, RETR, DELE, QUIT Return codes: +OK, -ERR POP3 is stateless across sessions IMAP: Internet Mail Access Protocol (IMAP4rev1, 1996) More powerful than POP allows user to organize messages in folders can retrieve parts of messages IMAP keeps user state across sessions names of folders and mappings between message IDs and folder name 5 Name Resolution: DNS DNS: Domain Name System Distributed database implemented in hierarchy of many name servers Core Internet function, implemented as application-layer protocol Provides Hostname to IP address translation IP address to hostname translation Host aliasing 9

10 Mail server aliasing Load distribution (Authorative information about your network!) (new uses appear, e.g. RBL, SPF) UDP to server port 53 (switch to TCP same port if reply > 512 bytes) Interaction of DNS servers Authorative and Local/Caching servers Recursive and Iterative Queries DNS: Resource Records RRs: (Name, Value, Type, TTL) SOA Start Of Authority NS Name Server A Address, define the canonical name of an IP address CNAME Canonical NAME, define alias to canonical name PTR PoinTer Record, reverse mapping DNS: Message Format 10

11 6 Next Week Next Week Transport Layer - Chapter three remember: talk app protocols over tcp with telnet! 11

FTP and email. Computer Networks. FTP: the file transfer protocol

FTP and email. Computer Networks. FTP: the file transfer protocol Computer Networks and email Based on Computer Networking, 4 th Edition by Kurose and Ross : the file transfer protocol transfer file to/from remote host client/ model client: side that initiates transfer

More information

Chapter 2 Application Layer. Lecture 5 FTP, Mail. Computer Networking: A Top Down Approach

Chapter 2 Application Layer. Lecture 5 FTP, Mail. Computer Networking: A Top Down Approach Chapter 2 Application Layer Lecture 5 FTP, Mail Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 Application Layer 2-1 Chapter 2: outline 2.1 principles

More information

DATA COMMUNICATOIN NETWORKING

DATA COMMUNICATOIN NETWORKING DATA COMMUNICATOIN NETWORKING Instructor: Ouldooz Baghban Karimi Course Book: Computer Networking, A Top-Down Approach By: Kurose, Ross Introduction Course Overview Basics of Computer Networks Internet

More information

Network Technologies

Network Technologies Network Technologies Glenn Strong Department of Computer Science School of Computer Science and Statistics Trinity College, Dublin January 28, 2014 What Happens When Browser Contacts Server I Top view:

More information

FTP: the file transfer protocol

FTP: the file transfer protocol File Transfer: FTP FTP: the file transfer protocol at host FTP interface FTP client local file system file transfer FTP remote file system transfer file to/from remote host client/ model client: side that

More information

CPSC 360 - Network Programming. Email, FTP, and NAT. http://www.cs.clemson.edu/~mweigle/courses/cpsc360

CPSC 360 - Network Programming. Email, FTP, and NAT. http://www.cs.clemson.edu/~mweigle/courses/cpsc360 CPSC 360 - Network Programming E, FTP, and NAT Michele Weigle Department of Computer Science Clemson University mweigle@cs.clemson.edu April 18, 2005 http://www.cs.clemson.edu/~mweigle/courses/cpsc360

More information

FTP: the file transfer protocol

FTP: the file transfer protocol FTP: the file transfer protocol at host FTP interface FTP client local file system file transfer FTP remote file system transfer file to/from remote host client/ model client: side that initiates transfer

More information

FTP: the file transfer protocol

FTP: the file transfer protocol FTP: the file transfer protocol at host FTP interface FTP client local file system file transfer FTP remote file system transfer file to/from remote host client/ model client: side that initiates transfer

More information

Computer Networks. Instructor: Niklas Carlsson Email: niklas.carlsson@liu.se

Computer Networks. Instructor: Niklas Carlsson Email: niklas.carlsson@liu.se Computer Networks Instructor: Niklas Carlsson Email: niklas.carlsson@liu.se Notes derived from Computer Networking: A Top Down Approach, by Jim Kurose and Keith Ross, Addison-Wesley. The slides are adapted

More information

DATA COMMUNICATOIN NETWORKING

DATA COMMUNICATOIN NETWORKING DATA COMMUNICATOIN NETWORKING Instructor: Ouldooz Baghban Karimi Course Book: Computer Networking, A Top-Down Approach By: Kurose, Ross Introduction Course Overview Basics of Computer Networks Internet

More information

Network Applications

Network Applications Computer Networks Network Applications Based on Computer Networking, 3 rd Edition by Kurose and Ross Network applications Sample applications E-mail Web Instant messaging Remote login P2P file sharing

More information

Protocolo FTP. FTP: Active Mode. FTP: Active Mode. FTP: Active Mode. FTP: the file transfer protocol. Separate control, data connections

Protocolo FTP. FTP: Active Mode. FTP: Active Mode. FTP: Active Mode. FTP: the file transfer protocol. Separate control, data connections : the file transfer protocol Protocolo at host interface local file system file transfer remote file system utilizes two ports: - a 'data' port (usually port 20...) - a 'command' port (port 21) SISTEMAS

More information

The Application Layer: DNS

The Application Layer: DNS Recap SMTP and email The Application Layer: DNS Smith College, CSC 9 Sept 9, 0 q SMTP process (with handshaking) and message format q Role of user agent access protocols q Port Numbers (can google this)

More information

Evolution of the WWW. Communication in the WWW. WWW, HTML, URL and HTTP. HTTP Abstract Message Format. The Client/Server model is used:

Evolution of the WWW. Communication in the WWW. WWW, HTML, URL and HTTP. HTTP Abstract Message Format. The Client/Server model is used: Evolution of the WWW Communication in the WWW World Wide Web (WWW) Access to linked documents, which are distributed over several computers in the History of the WWW Origin 1989 in the nuclear research

More information

Computer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ MEng. Nguyễn CaoĐạt

Computer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ MEng. Nguyễn CaoĐạt Computer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ MEng. Nguyễn CaoĐạt 1 Lecture 10: Application Layer 2 Application Layer Where our applications are running Using services provided by

More information

Applications and Application Level Protocols

Applications and Application Level Protocols ECE453 Introduction to Computer Networks Lecture 16 Application Layer (DNS, E-mail, Web, FTP) Applications and Application Level Protocols application transport network data link physical application transport

More information

The Web: some jargon. User agent for Web is called a browser: Web page: Most Web pages consist of: Server for Web is called Web server:

The Web: some jargon. User agent for Web is called a browser: Web page: Most Web pages consist of: Server for Web is called Web server: The Web: some jargon Web page: consists of objects addressed by a URL Most Web pages consist of: base HTML page, and several referenced objects. URL has two components: host name and path name: User agent

More information

Distributed Systems. 2. Application Layer

Distributed Systems. 2. Application Layer Distributed Systems 2. Application Layer Werner Nutt 1 Network Applications: Examples E-mail Web Instant messaging Remote login P2P file sharing Multi-user network games Streaming stored video clips Social

More information

Electronic Mail. The protocols used for Internet can be divided into three broad categories. transfer program. application.

Electronic Mail. The protocols used for Internet  can be divided into three broad categories. transfer program. application. Electronic Mail The protocols used for Internet email can be divided into three broad categories transfer program interface application interface application 33 The Simple Mail Transfer Protocol (SMTP)

More information

Sockets: send, recv Network Applications: HTTP. Copyright University of Illinois CS 241 Staff 1

Sockets: send, recv Network Applications: HTTP. Copyright University of Illinois CS 241 Staff 1 Sockets: send, recv Network Applications: HTTP Copyright University of Illinois CS 241 Staff 1 Announcements Still using this nifty old slide format... MP7 due tomorrow Brighten s office hours Tue 3:30

More information

Domain Name System (DNS)

Domain Name System (DNS) Application Layer Domain Name System Domain Name System (DNS) Problem Want to go to www.google.com, but don t know the IP address Solution DNS queries Name Servers to get correct IP address Essentially

More information

Evolution of the WWW. Communication in the WWW. WWW, HTML, URL and HTTP. HTTP - Message Format. The Client/Server model is used:

Evolution of the WWW. Communication in the WWW. WWW, HTML, URL and HTTP. HTTP - Message Format. The Client/Server model is used: Evolution of the WWW Communication in the WWW World Wide Web (WWW) Access to linked documents, which are distributed over several computers in the History of the WWW Origin 1989 in the nuclear research

More information

Protocolo HTTP. Web and HTTP. HTTP overview. HTTP overview

Protocolo HTTP. Web and HTTP. HTTP overview. HTTP overview Web and HTTP Protocolo HTTP Web page consists of objects Object can be HTML file, JPEG image, Java applet, audio file, Web page consists of base HTML-file which includes several referenced objects Each

More information

The Application Layer. CS158a Chris Pollett May 9, 2007.

The Application Layer. CS158a Chris Pollett May 9, 2007. The Application Layer CS158a Chris Pollett May 9, 2007. Outline DNS E-mail More on HTTP The Domain Name System (DNS) To refer to a process on the internet we need to give an IP address and a port. These

More information

CSCI-1680 SMTP Chen Avin

CSCI-1680 SMTP Chen Avin CSCI-1680 Chen Avin Based on Computer Networking: A Top Down Approach - 6th edition Electronic Three major components: s s simple transfer protocol: User Agent a.k.a. reader composing, editing, reading

More information

CSE 677: Introduction to Computer Networking. Application Layer. Presentation H. Domain Name System DNS

CSE 677: Introduction to Computer Networking. Application Layer. Presentation H. Domain Name System DNS CSE 677: Introduction to Computer Networking Application Layer Presentation H Study: 22.1, 23.1 Kannan Srinivasan 11-01-2012 Domain Name System DNS To identify a remote computer, TCP/IP protocols use the

More information

Computer Networks. Web and HTTP HTTP

Computer Networks. Web and HTTP HTTP Computer Networks HTTP 1 Web and HTTP First some jargon Web page consists of objects Object can be HTML file, JPEG image, Java applet, audio file, Web page consists of base HTML- file which includes several

More information

Domain Name System (DNS)

Domain Name System (DNS) Domain Name System (DNS) Instructor: Anirban Mahanti Office: ICT 745 Email: mahanti@cpsc.ucalgary.ca Class Location: ICT 121 Lectures: MWF 12:00 12:50 Notes derived from Computer Networking: A Top Down

More information

Application Example: WWW. Communication in the WWW. WWW, HTML, URL and HTTP. Loading of Web Pages. The Client/Server model is used in the WWW

Application Example: WWW. Communication in the WWW. WWW, HTML, URL and HTTP. Loading of Web Pages. The Client/Server model is used in the WWW Application Example WWW Communication in the WWW In the following application protocol examples for WWW and E-Mail World Wide Web (WWW) Access to linked documents, which are distributed over several computers

More information

Application Layer. CMPT371 12-1 Application Layer 1. Required Reading: Chapter 2 of the text book. Outline of Chapter 2

Application Layer. CMPT371 12-1 Application Layer 1. Required Reading: Chapter 2 of the text book. Outline of Chapter 2 CMPT371 12-1 Application Layer 1 Application Layer Required Reading: Chapter 2 of the text book. Outline of Chapter 2 Network applications HTTP, protocol for web application FTP, file transfer protocol

More information

CS43: Computer Networks Email. Kevin Webb Swarthmore College September 24, 2015

CS43: Computer Networks Email. Kevin Webb Swarthmore College September 24, 2015 CS43: Computer Networks Email Kevin Webb Swarthmore College September 24, 2015 Three major components: mail (MUA) mail transfer (MTA) simple mail transfer protocol: SMTP User Agent a.k.a. mail reader composing,

More information

Digital Communication in the Modern World Application Layer cont. DNS, SMTP

Digital Communication in the Modern World Application Layer cont. DNS, SMTP Digital Communication in the Modern World Application Layer cont. DNS, http://www.cs.huji.ac.il/~com com@cs.huji.ac.il Some of the slides have been borrowed from: Computer Networking: A Top Down Approach

More information

File Transfer Protocol (FTP) & SSH

File Transfer Protocol (FTP) & SSH http://xkcd.com/949/ File Transfer Protocol (FTP) & SSH Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Some materials copyright 1996-2012 Addison-Wesley J.F Kurose and K.W.

More information

Internet Security [1] VU 184.216. Engin Kirda engin@infosys.tuwien.ac.at

Internet Security [1] VU 184.216. Engin Kirda engin@infosys.tuwien.ac.at Internet Security [1] VU 184.216 Engin Kirda engin@infosys.tuwien.ac.at Christopher Kruegel chris@auto.tuwien.ac.at Administration Challenge 2 deadline is tomorrow 177 correct solutions Challenge 4 will

More information

Internet Technology 2/13/2013

Internet Technology 2/13/2013 Internet Technology 03r. Application layer protocols: email Email: Paul Krzyzanowski Rutgers University Spring 2013 1 2 Simple Mail Transfer Protocol () Defined in RFC 2821 (April 2001) Original definition

More information

1. The Web: HTTP; file transfer: FTP; remote login: Telnet; Network News: NNTP; e-mail: SMTP.

1. The Web: HTTP; file transfer: FTP; remote login: Telnet; Network News: NNTP; e-mail: SMTP. Chapter 2 Review Questions 1. The Web: HTTP; file transfer: FTP; remote login: Telnet; Network News: NNTP; e-mail: SMTP. 2. Network architecture refers to the organization of the communication process

More information

INTERNET ENABLED SYSTEMS NETWORK PROTOCOLS

INTERNET ENABLED SYSTEMS NETWORK PROTOCOLS DEVICES AND COMMUNICATION BUSES FOR DEVICES NETWORK Lesson-24: INTERNET ENABLED SYSTEMS NETWORK PROTOCOLS 1 Internet enabled embedded system Communication to other on the Internet. Use html (hyper text

More information

internet technologies and standards

internet technologies and standards Institute of Telecommunications Warsaw University of Technology 2015 internet technologies and standards Piotr Gajowniczek Andrzej Bąk Michał Jarociński Internet application layer the email service The

More information

Applications and Services. DNS (Domain Name System)

Applications and Services. DNS (Domain Name System) Applications and Services DNS (Domain Name Service) File Transfer Protocol (FTP) Simple Mail Transfer Protocol (SMTP) Malathi Veeraraghavan Distributed database used to: DNS (Domain Name System) map between

More information

Cours du 22 novembre

Cours du 22 novembre Cours du 22 novembre Couche application DNS Application Layer 2-2 DNS: domain name system people: many identifiers: SSN, name, passport # Internet hosts, routers: IP address (32 bit) - used for addressing

More information

Computer Networks. Lecture 7: Application layer: FTP and HTTP. Marcin Bieńkowski. Institute of Computer Science University of Wrocław

Computer Networks. Lecture 7: Application layer: FTP and HTTP. Marcin Bieńkowski. Institute of Computer Science University of Wrocław Computer Networks Lecture 7: Application layer: FTP and Marcin Bieńkowski Institute of Computer Science University of Wrocław Computer networks (II UWr) Lecture 7 1 / 23 Reminder: Internet reference model

More information

Domain Name System E-mail WWW. Application Layer. Mahalingam Ramkumar Mississippi State University, MS. September 15, 2014.

Domain Name System E-mail WWW. Application Layer. Mahalingam Ramkumar Mississippi State University, MS. September 15, 2014. Application Layer Mahalingam Mississippi State University, MS September 15, 2014 Outline 1 DNS Records DNS Components 2 Message Transfer Fetching Emails 3 Applications We will focus on 3 applications DNS

More information

Computer Networks. Examples of network applica3ons. Applica3on Layer

Computer Networks. Examples of network applica3ons. Applica3on Layer Computer Networks Applica3on Layer 1 Examples of network applica3ons e- mail web instant messaging remote login P2P file sharing mul3- user network games streaming stored video clips social networks voice

More information

Application-layer protocols

Application-layer protocols Application layer Goals: Conceptual aspects of network application protocols Client server paradigm Service models Learn about protocols by examining popular application-level protocols HTTP DNS Application-layer

More information

loss-tolerant and time sensitive loss-intolerant and time sensitive loss-intolerant and time insensitive

loss-tolerant and time sensitive loss-intolerant and time sensitive loss-intolerant and time insensitive CS326e Quiz 5 The first correct 10 answers will be worth 1 point each. Each subsequent correct answer will be worth 0.2 points. Circle the correct answer. UTEID The transfer of an html file from one host

More information

Principles of Network Applications. Dr. Philip Cannata

Principles of Network Applications. Dr. Philip Cannata Principles of Network Applications Dr. Philip Cannata 1 Chapter 2 Application Layer A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers).

More information

Introduction to Network Operating Systems

Introduction to Network Operating Systems As mentioned earlier, different layers of the protocol stack use different kinds of addresses. We can now see that the Transport Layer (TCP) uses port addresses to route data to the correct process, the

More information

2- Electronic Mail (SMTP), File Transfer (FTP), & Remote Logging (TELNET)

2- Electronic Mail (SMTP), File Transfer (FTP), & Remote Logging (TELNET) 2- Electronic Mail (SMTP), File Transfer (FTP), & Remote Logging (TELNET) There are three popular applications for exchanging information. Electronic mail exchanges information between people and file

More information

Proxies. Chapter 4. Network & Security Gildas Avoine

Proxies. Chapter 4. Network & Security Gildas Avoine Proxies Chapter 4 Network & Security Gildas Avoine SUMMARY OF CHAPTER 4 Generalities Forward Proxies Reverse Proxies Open Proxies Conclusion GENERALITIES Generalities Forward Proxies Reverse Proxies Open

More information

Application-layer Protocols and Internet Services

Application-layer Protocols and Internet Services Application-layer Protocols and Internet Services Computer Networks Lecture 8 http://goo.gl/pze5o8 Terminal Emulation 2 Purpose of Telnet Service Supports remote terminal connected via network connection

More information

Application Layer: HTTP and the Web. Srinidhi Varadarajan

Application Layer: HTTP and the Web. Srinidhi Varadarajan Application Layer: HTTP and the Web Srinidhi Varadarajan The Web: the http protocol http: hypertext transfer protocol Web s application layer protocol client/server model client: browser that requests,

More information

Chapter 2 Application Layer

Chapter 2 Application Layer Chapter 2 Application Layer A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint form so you see the animations;

More information

Application Level Protocols

Application Level Protocols Application Level Protocols Nixu Oy PL 21 (Mäkelänkatu 91) 00601 Helsinki, Finland tel. +358 9 478 1011 fax. +358 9 478 1030 info@nixu.fi http://www.nixu.fi Contents Client-Server Store and Forward Push

More information

Lesson 13: DNS Security. Javier Osuna josuna@gmv.com GMV Head of Security and Process Consulting Division

Lesson 13: DNS Security. Javier Osuna josuna@gmv.com GMV Head of Security and Process Consulting Division Lesson 13: DNS Security Javier Osuna josuna@gmv.com GMV Head of Security and Process Consulting Division Introduction to DNS The DNS enables people to use and surf the Internet, allowing the translation

More information

Email Electronic Mail

Email Electronic Mail Email Electronic Mail Electronic mail paradigm Most heavily used application on any network Electronic version of paper-based office memo Quick, low-overhead written communication Dates back to time-sharing

More information

CS640: Introduction to Computer Networks. Applications FTP: The File Transfer Protocol

CS640: Introduction to Computer Networks. Applications FTP: The File Transfer Protocol CS640: Introduction to Computer Networks Aditya Akella Lecture 4 - Application Protocols, Performance Applications FTP: The File Transfer Protocol user at host FTP FTP user client interface local file

More information

HTTP. Internet Engineering. Fall 2015. Bahador Bakhshi CE & IT Department, Amirkabir University of Technology

HTTP. Internet Engineering. Fall 2015. Bahador Bakhshi CE & IT Department, Amirkabir University of Technology HTTP Internet Engineering Fall 2015 Bahador Bakhshi CE & IT Department, Amirkabir University of Technology Questions Q1) How do web server and client browser talk to each other? Q1.1) What is the common

More information

Application Layer -1- Network Tools

Application Layer -1- Network Tools EITF25 Internet: Technology and Applications Application Layer -1- Network Tools 2015, Lecture 08 Kaan Bür Previously on EITF25 Addressing above IP Ports, sockets Process-to-process delivery Transport

More information

2- Electronic Mail (SMTP), File Transfer (FTP), & Remote Logging (TELNET)

2- Electronic Mail (SMTP), File Transfer (FTP), & Remote Logging (TELNET) 2- Electronic Mail (SMTP), File Transfer (FTP), & Remote Logging (TELNET) There are three popular applications for exchanging information. Electronic mail exchanges information between people and file

More information

1. When will an IP process drop a datagram? 2. When will an IP process fragment a datagram? 3. When will a TCP process drop a segment?

1. When will an IP process drop a datagram? 2. When will an IP process fragment a datagram? 3. When will a TCP process drop a segment? Questions 1. When will an IP process drop a datagram? 2. When will an IP process fragment a datagram? 3. When will a TCP process drop a segment? 4. When will a TCP process resend a segment? CP476 Internet

More information

Computer Networks & Security 2014/2015

Computer Networks & Security 2014/2015 Computer Networks & Security 2014/2015 IP Protocol Stack & Application Layer (02a) Security and Embedded Networked Systems time Protocols A human analogy All Internet communication is governed by protocols!

More information

Internet Technologies. World Wide Web (WWW) Proxy Server Network Address Translator (NAT)

Internet Technologies. World Wide Web (WWW) Proxy Server Network Address Translator (NAT) Internet Technologies World Wide Web (WWW) Proxy Server Network Address Translator (NAT) What is WWW? System of interlinked Hypertext documents Text, Images, Videos, and other multimedia documents navigate

More information

Remote login (Telnet):

Remote login (Telnet): SFWR 4C03: Computer Networks and Computer Security Feb 23-26 2004 Lecturer: Kartik Krishnan Lectures 19-21 Remote login (Telnet): Telnet permits a user to connect to an account on a remote machine. A client

More information

Cape Girardeau Career Center CISCO Networking Academy Bill Link, Instructor. 2.,,,, and are key services that ISPs can provide to all customers.

Cape Girardeau Career Center CISCO Networking Academy Bill Link, Instructor. 2.,,,, and are key services that ISPs can provide to all customers. Name: 1. What is an Enterprise network and how does it differ from a WAN? 2.,,,, and are key services that ISPs can provide to all customers. 3. Describe in detail what a managed service that an ISP might

More information

3.1 Application Layer Protocol: What is it and what is it not?

3.1 Application Layer Protocol: What is it and what is it not? Chapter 3 Application Layer In this chapter, the fundamental issues addressed by application layer protocols, their service models and their architectural styles are defined. The service models that are

More information

Motivation. Domain Name System (DNS) Flat Namespace. Hierarchical Namespace

Motivation. Domain Name System (DNS) Flat Namespace. Hierarchical Namespace Motivation Domain Name System (DNS) IP addresses hard to remember Meaningful names easier to use Assign names to IP addresses Name resolution map names to IP addresses when needed Namespace set of all

More information

Introduction to Computer Security Benoit Donnet Academic Year 2015-2016

Introduction to Computer Security Benoit Donnet Academic Year 2015-2016 Introduction to Computer Security Benoit Donnet Academic Year 2015-2016 1 Agenda Networking Chapter 1: Firewalls Chapter 2: Proxy Chapter 3: Intrusion Detection System Chapter 4: Network Attacks Chapter

More information

REVIEW FOR CHAPTER 2

REVIEW FOR CHAPTER 2 REVIEW FOR CHAPTER 2 R1. List five nonproprietary Internet applications and the application-layer protocols that they use. Answer: The Web: HTTP; file transfer: FTP; remote login: Telnet; Network News:

More information

Introduction to Computer Networks

Introduction to Computer Networks Introduction to Computer Networks Chen Yu Indiana University Basic Building Blocks for Computer Networks Nodes PC, server, special-purpose hardware, sensors Switches Links: Twisted pair, coaxial cable,

More information

Solutions to the Sample Questions on Application Layer

Solutions to the Sample Questions on Application Layer Solutions to the Sample Questions on Application Layer 1) Why is SMTP not used for transferring e-mail messages from the recipient s mail server to the recipient s personal computer? Answer: Whereas SMTP

More information

Application Layer. Abusayeed Saifullah. CS 5600 Computer Networks. These slides are adapted from Kurose and Ross

Application Layer. Abusayeed Saifullah. CS 5600 Computer Networks. These slides are adapted from Kurose and Ross Application Layer Abusayeed Saifullah CS 5600 Computer Networks These slides are adapted from Kurose and Ross Web caches (proxy server) goal: satisfy client request without involving origin server v user

More information

Applications & Application-Layer Protocols: The Domain Name System and Peerto-Peer

Applications & Application-Layer Protocols: The Domain Name System and Peerto-Peer CPSC 360 Network Programming Applications & Application-Layer Protocols: The Domain Name System and Peerto-Peer Systems Michele Weigle Department of Computer Science Clemson University mweigle@cs.clemson.edu

More information

Chakchai So-In, Ph.D.

Chakchai So-In, Ph.D. Application Layer Functionality and Protocols Chakchai So-In, Ph.D. Khon Kaen University Department of Computer Science Faculty of Science, Khon Kaen University 123 Mitaparb Rd., Naimaung, Maung, Khon

More information

The recommended guided learning hours for this unit are 60 hours.

The recommended guided learning hours for this unit are 60 hours. Unit 391 The Technology of the internet Level 3 Credit value 9 Rationale The aim of this unit is to enable candidates to understand the principles and the technologies that allow the internet to function

More information

CS 355. Computer Networking. Wei Lu, Ph.D., P.Eng.

CS 355. Computer Networking. Wei Lu, Ph.D., P.Eng. CS 355 Computer Networking Wei Lu, Ph.D., P.Eng. Chapter 2: Application Layer Overview: Principles of network applications? Introduction to Wireshark Web and HTTP FTP Electronic Mail: SMTP, POP3, IMAP

More information

Introduction to LAN/WAN. Application Layer (Part II)

Introduction to LAN/WAN. Application Layer (Part II) Introduction to LAN/WAN Application Layer (Part II) Application Layer Topics Domain Name System (DNS) (7.1) Electronic Mail (Email) (7.2) World Wide Web (WWW) (7.3) Electronic Mail (Email) Mostly used

More information

9025- TCP/IP Networking. History and Standards. Review of Numbering Systems. Local Signaling. IP Addressing

9025- TCP/IP Networking. History and Standards. Review of Numbering Systems. Local Signaling. IP Addressing 9025- TCP/IP Networking History and Standards ARPA NCP TCP, IP, ARPANET PARC Collaborative Network Requirements One Protocol? Peer-to-Peer Protocols Documentation and RFCs RFC Categories Where to Find

More information

Lecture 2. Internet: who talks with whom?

Lecture 2. Internet: who talks with whom? Lecture 2. Internet: who talks with whom? An application layer view, with particular attention to the World Wide Web Basic scenario Internet Client (local PC) Server (remote host) Client wants to retrieve

More information

CMPE 80N: Introduction to Networking and the Internet

CMPE 80N: Introduction to Networking and the Internet CMPE 80N: Introduction to Networking and the Internet Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 10 CMPE 80N Fall'10 1 Announcements Forum assignment #2 posted. Due Nov. 5 th.

More information

CSIS 3230. CSIS 3230 Spring 2012. Networking, its all about the apps! Apps on the Edge. Application Architectures. Pure P2P Architecture

CSIS 3230. CSIS 3230 Spring 2012. Networking, its all about the apps! Apps on the Edge. Application Architectures. Pure P2P Architecture Networking, its all about the apps! CSIS 3230 Chapter 2: Layer Concepts Chapter 5.4: Link Layer Addressing Networks exist to support apps Web Social ing Multimedia Communications Email File transfer Remote

More information

Basic Internet programming Formalities. Hands-on tools for internet programming

Basic Internet programming Formalities. Hands-on tools for internet programming Welcome Basic Internet programming Formalities Hands-on tools for internet programming DD1335 (gruint10) Serafim Dahl serafim@nada.kth.se DD1335 (Lecture 1) Basic Internet Programming Spring 2010 1 / 23

More information

Email, SNMP, Securing the Web: SSL

Email, SNMP, Securing the Web: SSL Email, SNMP, Securing the Web: SSL 4 January 2015 Lecture 12 4 Jan 2015 SE 428: Advanced Computer Networks 1 Topics for Today Email (SMTP, POP) Network Management (SNMP) ASN.1 Secure Sockets Layer 4 Jan

More information

File Transfer Protocol (FTP)

File Transfer Protocol (FTP) COM 362 Computer Networks I. FTP Lecture Outline Lec 4: Applicatin Layer: FTP, E-Mail and P2P Applications 2. Electronic Mail:, POP3, IMAP 3. P2P Applications Prof. Dr. Halûk Gümüşkaya haluk.gumuskaya@gediz.edu.tr

More information

presentation DAD Distributed Applications Development Cristian Toma

presentation DAD Distributed Applications Development Cristian Toma Lecture 5 S2 - Summary of Network Protocols Programming in JSE for Distributed Systems Section 2 presentation DAD Distributed Applications Development Cristian Toma D.I.C.E/D.E.I.C Department of Economic

More information

Domain Name System Richard T. B. Ma

Domain Name System Richard T. B. Ma Domain Name System Richard T. B. Ma School of Computing National University of Singapore CS 3103: Compute Networks and Protocols Names Vs. Addresses Names are easier for human to remember www.comp.nus.edu.sg

More information

Application Layer Protocols

Application Layer Protocols Application Layer Protocols Network Applications Requirements Application Layer Protocol Functions. Sample Internet Applications & Protocols: File Transfer Protocol (FTP). Sending E-Mail: SMTP. HyperText

More information

Thomas G. Broxholm. Setting Up Outlook Mail Accounts

Thomas G. Broxholm. Setting Up Outlook Mail Accounts Thomas G. Broxholm Setting Up Outlook Mail Accounts Outlook Open the Windows Control Panel and double click on the Mail icon. Note! For 64 bit Windows users. The mail icon could be found inside a folder

More information

Owner of the content within this article is Written by Marc Grote

Owner of the content within this article is  Written by Marc Grote Owner of the content within this article is www.msexchange.org Written by Marc Grote www.it-training-grote.de Microsoft Exchange 2003 Using Telnet to connect to Exchange 2003 POP3 mailboxes and using SMTP

More information

Domain Name System 2015-04-28 17:49:44 UTC. 2015 Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement

Domain Name System 2015-04-28 17:49:44 UTC. 2015 Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement Domain Name System 2015-04-28 17:49:44 UTC 2015 Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement Contents Domain Name System... 4 Domain Name System... 5 How DNS Works

More information

How to Add Domains and DNS Records

How to Add Domains and DNS Records How to Add Domains and DNS Records Configure the Barracuda NextGen X-Series Firewall to be the authoritative DNS server for your domains or subdomains to take advantage of Split DNS or dead link detection.

More information

File Transfer Protocol (FTP) Chuan-Ming Liu Computer Science and Information Engineering National Taipei University of Technology Fall 2007, TAIWAN

File Transfer Protocol (FTP) Chuan-Ming Liu Computer Science and Information Engineering National Taipei University of Technology Fall 2007, TAIWAN File Transfer Protocol (FTP) Chuan-Ming Liu Computer Science and Information Engineering National Taipei University of Technology Fall 2007, TAIWAN 1 Contents CONNECTIONS COMMUNICATION COMMAND PROCESSING

More information

CONTENT of this CHAPTER

CONTENT of this CHAPTER CONTENT of this CHAPTER v DNS v HTTP and WWW v EMAIL v SNMP 3.2.1 WWW and HTTP: Basic Concepts With a browser you can request for remote resource (e.g. an HTML file) Web server replies to queries (e.g.

More information

The Web History (I) The Web History (II)

The Web History (I) The Web History (II) Goals of Today s Lecture EE 122: The World Wide Web Ion Stoica TAs: Junda Liu, DK Moon, David Zats http://inst.eecs.berkeley.edu/~ee122/ (Materials with thanks to Vern Paxson, Jennifer Rexford, and colleagues

More information

Pass Through Proxy. How-to. Overview:..1 Why PTP?...1

Pass Through Proxy. How-to. Overview:..1 Why PTP?...1 Pass Through Proxy How-to Overview:..1 Why PTP?...1 Via an SA port...1 Via external DNS resolution...1 Examples of Using Passthrough Proxy...2 Example configuration using virtual host name:...3 Example

More information

IxLoad - Layer 4-7 Performance Testing of Content Aware Devices and Networks

IxLoad - Layer 4-7 Performance Testing of Content Aware Devices and Networks IxLoad - Layer 4-7 Performance Testing of Content Aware Devices and Networks IxLoad is a highly scalable solution for accurately assessing the performance of content-aware devices and networks. IxLoad

More information

Streaming Stored Audio & Video

Streaming Stored Audio & Video Streaming Stored Audio & Video Streaming stored media: Audio/video file is stored in a server Users request audio/video file on demand. Audio/video is rendered within, say, 10 s after request. Interactivity

More information

Electronic Mail: SMTP

Electronic Mail: SMTP 1 Electronic Mail: SMTP Electronic mail Asynchronous exchange of data sender does not know when (if) data reaches receiver mail user agent (MUA) outgoing mail queue client message transfer agent (MTA)

More information

Advanced Higher Computing. Computer Networks. Homework Sheets

Advanced Higher Computing. Computer Networks. Homework Sheets Advanced Higher Computing Computer Networks Homework Sheets Topic : Network Protocols and Standards. Name the organisation responsible for setting international standards and explain why network standards

More information

Application Level Protocol Design. Application Layer Protocol Design

Application Level Protocol Design. Application Layer Protocol Design Application Level Protocol Design Concurrent & Distributed Software Systems CS 475 1 Application Layer Protocol Design Steps in design Services Protocol Data Unit (PDU) structure and encoding Protocol

More information

Copyright 2012 http://itfreetraining.com

Copyright 2012 http://itfreetraining.com In order to find resources on the network, computers need a system to look up the location of resources. This video looks at the DNS records that contain information about resources and services on the

More information