Protocol Data Hiding. By Chet Hosmer Article Posted: March 06, 2012
|
|
- Dora Thornton
- 6 years ago
- Views:
Transcription
1 Protocol Data Hiding By Chet Hosmer Article Posted: March 06, 2012 On Cinco de Mayo in 1997, which happened to be the first Monday in May that year, the Hacker Publication First Monday included an article entitled, Covert Channels in the TCP Protocol Suite, by Craig Rowland. The TCP/IP protocol suite has a number of weaknesses that allow an attacker to leverage techniques in the form of covert channels to surreptitiously pass data in otherwise benign packets. This paper attempts to illustrate these weaknesses in both theoretical and practical examples. 1 The methods employed in this paper exposed data hiding vulnerabilities in the Transaction Control Protocol (TCP) and demonstrated a very simple and straightforward method for hiding data in the TCP initial handshake sequence. In some ways, this served as a warning that hiding information within a data stream was not only plausible but was also simple and practical. As with most cyber security related warnings of this type, there was an initial outcry to develop more secure protocols that could mitigate such threats. Once the voices died down, we moved on to the next threat of the day and many forgot about the vulnerability. I wonder if a viable solution will exist by Monday, May 5, 2014 when Cinco de Mayo falls once again on the first Monday in May? As of today, not only is the TCP protocol still vulnerable to Craig s initial warning, but hundreds of new protocols have arrived on the scene, most containing a plethora of opportunities to hide information in innocuous ways. Turning to the Present Day One of the new areas of interest is Voice over Internet Protocol (VoIP) solutions. The reasons are quite obvious: VoIP is ubiquitously deployed and utilized; VoIP solutions generate a large number of small packets which would be ideally suited for hiding small pieces of a larger message; and finally, the wide variety of packet types, codecs, and encoding methods for VoIP abound, providing cover for the needle in a haystack. VoIP utilizes network transport mechanisms that are inherently unreliable. The underlying Real-Time Transfer Protocol (RTP) and the Universal Datagram Protocol
2 (UDP) do not retransmit lost or delayed packets. At first glance this would appear to be a huge drawback for data hiding activities, since losing packets that contain portions of the secret message especially if they were encrypted would be problematic. Actually, one of the methods we will discuss leverages this weakness into a strength. To begin, I m going to focus on a simple RTP protocol running on top of UDP in a point to point arrangement to explain the core elements of the data hiding method. Of course, to execute this within a true VoIP setting, you would need to work with session initiation protocol (SIP), Real-Time Transfer Control Protocol (RTCP), and others. The diagram below depicts this simplified structure. Click for larger image. Figure 1: VoIP RTP Simplified Packet Overview Figure 1 depicts a simplified version of the VoIP RTP packet structure. As you can see, the RTP packet is a payload of the UDP packet which carries out the unreliable transport. In turn, the UDP packet is the payload of the IP packet, which provides the Internet Routing needed. In Figure 2 we turn our attention to the RTP packet exchange between the infamous Alice and Bob.
3 Figure 2: RTP Packet Exchange between Alice and Bob As you can see in Figure 2, Alice and Bob exchange a sequence of RTP packets in a continuous stream. As you recall from above, packets can be missing, dropped, out of sequence, or delayed, but since the protocol is not meant to be completely reliable, data continues to stream. As mentioned, control packets and other protocol elements that can assist in re-establishing connections if things go wrong have been omitted from this 30,000 ft view. Figure 3: RTP Payload Insertion
4 The simplest method of data hiding available is to insert content directly into the payload section of each packet. The secret message is broken up into small chunks and embedded directly into the payload. The current methods we have evaluated use one of two basic schemes. 1. The small chunks of the overall secret message are inserted into the header of the payload section. Since most RTP payload types have a built-in header that provides information to the receiver about the configuration of the payload, it is possible to insert a small number of bytes into this payload header. 2. The small chunks of the secret message are broken into a bit stream and each bit is used to overwrite the least significant bit of encoded data within the payload. The problem with both methods, of course, is that if data loss occurs, (lost or delayed packets) some of the hidden data will also be lost. This can be overcome by transmitting redundant packets (secret message chunks). The applications we have reviewed that perform this function allow the setting of the redundancy frequency. Click for larger image. Figure 4: RTP Delayed Packet Modification The final method I reviewed is actually the most interesting, and is depicted in Figure 4. This method actually takes advantage of the fact that RTP packets are sometimes delayed, delivered out of order, or lost in transmission as a core element of the method. This approach systematically extracts specific packets from the data stream before they are released by the sender. This causes certain packets to purposely not be delivered in a timely fashion to the receiver. The receiving application, whether VoIP or an audio player, automatically compensates for the delayed packet and fills in the blanks, if you will. Since most RTP packets only contain a few milliseconds of audio, the
5 compensation is hardly ever noticed when listening to a conversation or even a streamed audio track. Here is the best part! Once the packet has been extracted from the stream, the data hiding application can utilize the full payload section to insert slices of the hidden message content. The application then reinserts the packet back into the stream (after a few seconds of delay, of course). Once the packet arrives at the destination, (now significantly delayed), the receiving application discards the packet, (it is never used) since it has already compensated for it earlier. However, a listening application recognizes the delayed packet and extracts it to rebuild the original message. Investigating Protocol Data Hiding From an investigative perspective, analyzing the protocol requires a network protocol analyzer or sniffer. Wireshark 2 is a great tool for examining the details of such protocols. Once you suspect this type of behavior is occurring, you can utilize Wireshark to capture the RTP packets flowing between two entities. At that point, detailed analysis of the headers of the payload section of each RTP packet is performed to detect inserted values. This may sound completely impossible or impractical. Actually, since Wireshark has powerful search and filtering capabilities, and the headers of the packets are quite regular, detecting the rogue packets is possible with some effort. When attempting to detect the delayed packet hiding method, you are specifically looking for packet sequence numbers that are delayed. Sorting by the packet timestamps and writing a simple python script that will identify packets delayed more than a couple seconds is possible. Those of you that are more affluent with SNORT 3 or other intrusion detection sensors, can come up with other rules and triggers that could constantly monitor for such aberrant behaviors. Next month I will be taking a look at one of the newest Linux data hiding methods. Until then keep discovering the hidden. Discovering the Hidden is a monthly column examining steganography and data hiding. References 1. Covert Channels in the TCP/IP protocol suite, First Monday, Volume 2, Number 5-5 May WIRESHARK Network Protocol Analyzer Information, 3. Open source network intrusion prevention and detection system (IDS/IPS), Chet Hosmer has been researching and developing technology and training surrounding data hiding, steganography, and watermarking for over a decade. He has made numerous appearances to discuss the threat steganography poses including
6 National Public Radio's Kojo Nnamdi show, ABC's Primetime Thursday, NHK Japan, Cyber Crime TechTV, and ABC News Australia. He has also been a frequent contributor to technical and news stories relating to steganography and has been interviewed and quoted by IEEE, The New York Times, The Washington Post, Government Computer News, Salon.com, and Wired Magazine. Chet also delivers keynote and plenary talks on various cyber security related topics around the world every year.
New Approach towards Covert Communication using TCP-SQN Reference Model
ISSN 2278 0211 (Online) New Approach towards Covert Communication using TCP-SQN Reference Model Dhananjay M. Dakhane Department of Computer science & Engineering Sipna College of Engineering & Technology,
More informationInternetworking Models The OSI Reference Model
Internetworking Models When networks first came into being, computers could typically communicate only with computers from the same manufacturer. In the late 1970s, the Open Systems Interconnection (OSI)
More informationCN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 6 OSI MODEL TRANSPORT LAYER
CN1047 INTRODUCTION TO COMPUTER NETWORKING CHAPTER 6 OSI MODEL TRANSPORT LAYER Transport Layer The Transport layer ensures the reliable arrival of messages and provides error checking mechanisms and data
More information4 rd class Department of Network College of IT- University of Babylon
1. INTRODUCTION We can divide audio and video services into three broad categories: streaming stored audio/video, streaming live audio/video, and interactive audio/video. Streaming means a user can listen
More informationTransport protocols Introduction
Transport protocols 12.1 Introduction All protocol suites have one or more transport protocols to mask the corresponding application protocols from the service provided by the different types of network
More informationTransporting Voice by Using IP
Transporting Voice by Using IP Voice over UDP, not TCP Speech Small packets, 10 40 ms Occasional packet loss is not a catastrophe Delay-sensitive TCP: connection set-up, ack, retransmit delays 5 % packet
More informationOSI Layer OSI Name Units Implementation Description 7 Application Data PCs Network services such as file, print,
ANNEX B - Communications Protocol Overheads The OSI Model is a conceptual model that standardizes the functions of a telecommunication or computing system without regard of their underlying internal structure
More informationCCNA R&S: Introduction to Networks. Chapter 7: The Transport Layer
CCNA R&S: Introduction to Networks Chapter 7: The Transport Layer Frank Schneemann 7.0.1.1 Introduction 7.0.1.2 Class Activity - We Need to Talk Game 7.1.1.1 Role of the Transport Layer The primary responsibilities
More informationJaringan Komputer. The Transport Layer
Jaringan Komputer Transport Layer The Transport Layer The heart of the whole protocol hierarchy Task: To provide reliable, cost-effective data transport from the source machine to the destination machine,
More informationWeb Mechanisms. Draft: 2/23/13 6:54 PM 2013 Christopher Vickery
Web Mechanisms Draft: 2/23/13 6:54 PM 2013 Christopher Vickery Introduction While it is perfectly possible to create web sites that work without knowing any of their underlying mechanisms, web developers
More informationTCP/IP protocol suite
TCP/IP protocol suite The TCP/IP protocol suite was developed prior to the OSI model. Therefore, the layers in the TCP/IP protocol suite do not match exactly with those in the OSI model. The original TCP/IP
More informationStudying the Security in VoIP Networks
Abstract Studying the Security in VoIP Networks A.Alseqyani, I.Mkwawa and L.Sun Centre for Security, Communications and Network Research, Plymouth University, Plymouth, UK e-mail: info@cscan.org Voice
More information4.0.1 CHAPTER INTRODUCTION
4.0.1 CHAPTER INTRODUCTION Data networks and the Internet support the human network by supplying seamless, reliable communication between people - both locally and around the globe. On a single device,
More informationOSI Transport Layer. Network Fundamentals Chapter 4. Version Cisco Systems, Inc. All rights reserved. Cisco Public 1
OSI Transport Layer Network Fundamentals Chapter 4 Version 4.0 1 Transport Layer Role and Services Transport layer is responsible for overall end-to-end transfer of application data 2 Transport Layer Role
More informationRTP/RTCP protocols. Introduction: What are RTP and RTCP?
RTP/RTCP protocols Introduction: What are RTP and RTCP? The spread of computers, added to the availability of cheap audio/video computer hardware, and the availability of higher connection speeds have
More informationTHE TRANSPORT LAYER UNIT IV
THE TRANSPORT LAYER UNIT IV The Transport Layer: The Transport Service, Elements of Transport Protocols, Congestion Control,The internet transport protocols: UDP, TCP, Performance problems in computer
More informationTransporting Voice by Using IP
Transporting Voice by Using IP National Chi Nan University Quincy Wu Email: solomon@ipv6.club.tw 1 Outline Introduction Voice over IP RTP & SIP Conclusion 2 Digital Circuit Technology Developed by telephone
More informationRTP: A Transport Protocol for Real-Time Applications
RTP: A Transport Protocol for Real-Time Applications Provides end-to-end delivery services for data with real-time characteristics, such as interactive audio and video. Those services include payload type
More informationProgrammation système
Programmation système Problems Problem 1 - Message from ATM to Server Message name HELLO {userid} PASSWORD {password} BALANCE WITHDRAWAL {amount} Purpose Let server know that there is a card in the ATM
More informationCS164 Final Exam Winter 2013
CS164 Final Exam Winter 2013 Name: Last 4 digits of Student ID: Problem 1. State whether each of the following statements is true or false. (Two points for each correct answer, 1 point for each incorrect
More informationCCNA 1 Chapter 7 v5.0 Exam Answers 2013
CCNA 1 Chapter 7 v5.0 Exam Answers 2013 1 A PC is downloading a large file from a server. The TCP window is 1000 bytes. The server is sending the file using 100-byte segments. How many segments will the
More informationARP, IP, TCP, UDP. CS 166: Introduction to Computer Systems Security 4/7/18 ARP, IP, TCP, UDP 1
ARP, IP, TCP, UDP CS 166: Introduction to Computer Systems Security 4/7/18 ARP, IP, TCP, UDP 1 IP and MAC Addresses Devices on a local area network have IP addresses (network layer) MAC addresses (data
More informationOSI Transport Layer. objectives
LECTURE 5 OSI Transport Layer objectives 1. Roles of the Transport Layer 1. segmentation of data 2. error detection 3. Multiplexing of upper layer application using port numbers 2. The TCP protocol Communicating
More informationAnnouncements. No book chapter for this topic! Slides are posted online as usual Homework: Will be posted online Due 12/6
Announcements No book chapter for this topic! Slides are posted online as usual Homework: Will be posted online Due 12/6 Copyright c 2002 2017 UMaine Computer Science Department 1 / 33 1 COS 140: Foundations
More informationThe trace file is here: https://kevincurran.org/com320/labs/wireshark/trace-udp.pcap
Lab Exercise UDP Objective To look at the details of UDP (User Datagram Protocol). UDP is a transport protocol used throughout the Internet as an alternative to TCP when reliability is not required. It
More informationConfigure Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) Service Settings on a Switch
Configure Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) Service Settings on a Switch Objective Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are transportation
More informationBusiness Data Networks and Security 10th Edition by Panko Test Bank
Business Data Networks and Security 10th Edition by Panko Test Bank Chapter 2 Network Standards 1) Internet standards are published as. A) RFCs B) IETFs C) TCP/IPs D) Internet Protocols Question: 1a Objective:
More informationCS UDP: User Datagram Protocol, Other Transports, Sockets. congestion worse);
CS314-26 UDP: User Datagram Protocol, Other Transports, Sockets! IP is an unreliable datagram protocol " congestion or transmission errors cause lost packets " multiple routes may lead to out-of-order
More informationLecture 10: Protocol Design
Lecture 10: Protocol Design Prof. Shervin Shirmohammadi SITE, University of Ottawa Fall 2005 CEG 4183 10-1 Introduction TCP and UDP are generic protocols: They fulfill the needs of a wide range of applications
More informationLab Exercise UDP & TCP
Lab Exercise UDP & TCP Objective UDP (User Datagram Protocol) is an alternative communications protocol to Transmission Control Protocol (TCP) used primarily for establishing low-latency and loss tolerating
More informationCYBER ATTACKS EXPLAINED: PACKET SPOOFING
CYBER ATTACKS EXPLAINED: PACKET SPOOFING Last month, we started this series to cover the important cyber attacks that impact critical IT infrastructure in organisations. The first was the denial-of-service
More informationReflections on Security Options for the Real-time Transport Protocol Framework. Colin Perkins
Reflections on Security Options for the Real-time Transport Protocol Framework Colin Perkins Real-time Transport Protocol Framework RTP: A Transport Protocol for Real-Time Applications RFCs 3550 and 3551
More informationUsing ICMP to Troubleshoot TCP/IP Networks
Laura Chappell Using ICMP to Troubleshoot TCP/IP Networks Illustration: Norman Felchle Editor s Note: This article is based on Laura Chappell s upcoming book TCP/IP Analysis and Troubleshooting, which
More informationThe Frozen Mountain irtc White Paper Series
The Frozen Mountain irtc White Paper Series This white paper is the fourth in a series on Internet Based Real Time Communications (irtc) written by Frozen Mountain Software s CTO Anton Venema. The complete
More informationThe Data Link Layer. 32 PART I Networking Basics
32 PART I Networking Basics weather station. More realistic devices use duplex mode, where all systems can send or receive with equal facility. This is often further distinguished as half-duplex (the system
More informationEEC-682/782 Computer Networks I
EEC-682/782 Computer Networks I Lecture 16 Wenbing Zhao w.zhao1@csuohio.edu http://academic.csuohio.edu/zhao_w/teaching/eec682.htm (Lecture nodes are based on materials supplied by Dr. Louise Moser at
More informationETSF10 Internet Protocols Transport Layer Protocols
ETSF10 Internet Protocols Transport Layer Protocols 2012, Part 2, Lecture 2.2 Kaan Bür, Jens Andersson Transport Layer Protocols Special Topic: Quality of Service (QoS) [ed.4 ch.24.1+5-6] [ed.5 ch.30.1-2]
More informationCS640: Introduction to Computer Networks. Application Classes. Application Classes (more) 11/20/2007
CS640: Introduction to Computer Networks Aditya Akella Lecture 21 - Multimedia Networking Application Classes Typically sensitive to delay, but can tolerate packet loss (would cause minor glitches that
More informationIP Mobility vs. Session Mobility
IP Mobility vs. Session Mobility Securing wireless communication is a formidable task, something that many companies are rapidly learning the hard way. IP level solutions become extremely cumbersome when
More informationLecture 2-ter. 2. A communication example Managing a HTTP v1.0 connection. Managing a HTTP request. transport session. Step 1 - opening transport
Lecture 2-ter. 2 A communication example Managing a HTTP v1.0 connection Managing a HTTP request User digits URL and press return (or clicks ). What happens (HTTP 1.0): 1. opens a TCP transport session
More informationREACTION PAPER 01 TEL 500
TEL 500 Session Initiation Protocol Improvement Using Inter-Asterisk exchange Introduction: Within the VoIP network environment, H323, SIP and IAX are three protocols that solve the problem of voice packet
More informationCCNA Exploration Network Fundamentals
CCNA Exploration 4.0 1. Network Fundamentals The goal of this course is to introduce you to fundamental networking concepts and technologies. These online course materials will assist you in developing
More informationNetworking Applications
Networking Dr. Ayman A. Abdel-Hamid College of Computing and Information Technology Arab Academy for Science & Technology and Maritime Transport Multimedia Multimedia 1 Outline Audio and Video Services
More informationCCNA Exploration Network Fundamentals. Chapter 04 OSI Transport Layer
CCNA Exploration Network Fundamentals Chapter 04 OSI Transport Layer Updated: 05/05/2008 1 4.1 Roles of the Transport Layer 2 4.1 Roles of the Transport Layer The OSI Transport layer accept data from the
More informationLab Assignment 3 for ECE374
Lab Assignment 3 for ECE374 Posted: 02/25/18 Due: 03/08/18 In this lab, we ll take a quick look at the UDP and TCP transport protocol. Whenever possible you should hand in a Wireshark screenshot that you
More informationNetworking interview questions
Networking interview questions What is LAN? LAN is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected
More informationNo book chapter for this topic! Slides are posted online as usual Homework: Will be posted online Due 12/6
Announcements No book chapter for this topic! Slides are posted online as usual Homework: Will be posted online Due 12/6 Copyright c 2002 2017 UMaine School of Computing and Information S 1 / 33 COS 140:
More informationCS 218 F Nov 3 lecture: Streaming video/audio Adaptive encoding (eg, layered encoding) TCP friendliness. References:
CS 218 F 2003 Nov 3 lecture: Streaming video/audio Adaptive encoding (eg, layered encoding) TCP friendliness References: J. Padhye, V.Firoiu, D. Towsley, J. Kurose Modeling TCP Throughput: a Simple Model
More informationSchahin Rajab TCP or QUIC Which protocol is most promising for the future of the internet?
Schahin Rajab sr2@kth.se 2016 04 20 TCP or QUIC Which protocol is most promising for the future of the internet? Table of contents 1 Introduction 3 2 Background 4 2.1 TCP 4 2.2 UDP 4 2.3 QUIC 4 2.4 HTTP
More informationCSCD 433/533 Advanced Networks
CSCD 433/533 Advanced Networks Lecture 2 Network Review Winter 2017 Reading: Chapter 1 1 Topics Network Topics Some Review from CSCD330 Applications Common Services Architecture OSI Model AS and Routing
More informationDigital Asset Management 5. Streaming multimedia
Digital Asset Management 5. Streaming multimedia 2015-10-29 Keys of Streaming Media Algorithms (**) Standards (*****) Complete End-to-End systems (***) Research Frontiers(*) Streaming... Progressive streaming
More informationData Transport over IP Networks
Data Transport over IP Networks Derek Konigsberg octo@logicprobe.org AITP University of Central Florida Data Transport over IP Networks p.1/24 Introduction The TCP/IP protocol suite was created by DARPA
More informationLecture (03) Network Model
١ Lecture (03) Network Model By: Dr. Ahmed ElShafee Agenda Layering concept History Discovering the network layers Application Layer same layer interaction concept; Transport Layer Adjacent layer interaction
More informationIntrusion Prevention System Performance Metrics
White Paper Intrusion Prevention System Performance Metrics The Importance of Accurate Performance Metrics Network or system design success hinges on multiple factors, including the expected performance
More informationprecise rules that govern communication between two parties TCP/IP: the basic Internet protocols IP: Internet protocol (bottom level)
Protocols precise rules that govern communication between two parties TCP/IP: the basic Internet protocols IP: Internet protocol (bottom level) all packets shipped from network to network as IP packets
More informationNETWORK INTRUSION. Information Security in Systems & Networks Public Development Program. Sanjay Goel University at Albany, SUNY Fall 2006
NETWORK INTRUSION Information Security in Systems & Networks Public Development Program Sanjay Goel University at Albany, SUNY Fall 2006 1 Learning Objectives Students should be able to: Recognize different
More informationLab - Using Wireshark to Examine a UDP DNS Capture
Topology Objectives Part 1: Record a PC s IP Configuration Information Part 2: Use Wireshark to Capture DNS Queries and Responses Part 3: Analyze Captured DNS or UDP Packets Background / Scenario If you
More informationMultimedia Applications. Classification of Applications. Transport and Network Layer
Chapter 2: Representation of Multimedia Data Chapter 3: Multimedia Systems Communication Aspects and Services Multimedia Applications and Communication Protocols Quality of Service and Resource Management
More informationComputer Forensics: Investigating Network Intrusions and Cybercrime, 2nd Edition. Chapter 2 Investigating Network Traffic
Computer Forensics: Investigating Network Intrusions and Cybercrime, 2nd Edition Chapter 2 Investigating Network Traffic Objectives After completing this chapter, you should be able to: Understand network
More informationECE 333: Introduction to Communication Networks Fall 2001
ECE 333: Introduction to Communication Networks Fall 2001 Lecture 26: Transport layer I 1 Transport Layer In the remaining lectures, we will discuss several issues that are commonly addressed at the transport
More informationEEC-484/584 Computer Networks. Lecture 16. Wenbing Zhao
EEC-484/584 Computer Networks Lecture 16 wenbing@ieee.org (Lecture nodes are based on materials supplied by Dr. Louise Moser at UCSB and Prentice-Hall) Outline 2 Review Services provided by transport layer
More informationLab - Using Wireshark to Examine a UDP DNS Capture
Topology Objectives Part 1: Record a PC s IP Configuration Information Part 2: Use Wireshark to Capture DNS Queries and Responses Part 3: Analyze Captured DNS or UDP Packets Background / Scenario If you
More informationNetwork Model: Each layer has a specific function.
OBJECTIVES: To discuss the OSI model and its layer architecture and to show the interface between the layers. To briefly discuss the functions of each layer in the OSI model. To introduce the TCP/IP protocol.
More informationLecture-4. TCP/IP-Overview:
Lecture-4 TCP/IP-Overview: The history goes back to ARPANET a research network sponsored by DoD US Govt. It eventually connected hundreds of universities and govt installations, using leased telephone
More informationInvestigation of Algorithms for VoIP Signaling
Journal of Electrical Engineering 4 (2016) 203-207 doi: 10.17265/2328-2223/2016.04.007 D DAVID PUBLISHING Todorka Georgieva 1, Ekaterina Dimitrova 2 and Slava Yordanova 3 1. Telecommunication Department,
More informationUser Datagram Protocol
Topics Transport Layer TCP s three-way handshake TCP s connection termination sequence TCP s TIME_WAIT state TCP and UDP buffering by the socket layer 2 Introduction UDP is a simple, unreliable datagram
More informationCSCD 433/533 Advanced Networks Fall Lecture 14 RTSP and Transport Protocols/ RTP
CSCD 433/533 Advanced Networks Fall 2012 Lecture 14 RTSP and Transport Protocols/ RTP 1 Topics Multimedia Player RTSP Review RTP Real Time Protocol Requirements for RTP RTP Details Applications that use
More informationABSTRACT. that it avoids the tolls charged by ordinary telephone service
ABSTRACT VoIP (voice over IP - that is, voice delivered using the Internet Protocol) is a term used in IP telephony for a set of facilities for managing the delivery of voice information using the Internet
More informationLab Exercise UDP. Objective. Requirements. Step 1: Capture a Trace
Lab Exercise UDP Objective To look at the details of UDP (User Datagram Protocol). UDP is a transport protocol used throughout the Internet as an alternative to TCP when reliability is not required. It
More informationLecture (03) Networking Model (TCP/IP) Networking Standard (OSI) cont.,..
Lecture (03) Networking Model (TCP/IP) Networking Standard (OSI) cont.,.. By: Dr. Ahmed ElShafee ١ Dr. Ahmed ElShafee, ACU : Fall 2014, Computer Networks II Agenda TCP/IP suite Data Encapsulation OSI History
More informationThe Transmission Control Protocol (TCP)
The Transmission Control Protocol (TCP) Application Services (Telnet, FTP, e-mail, WWW) Reliable Stream Transport (TCP) Unreliable Transport Service (UDP) Connectionless Packet Delivery Service (IP) Goals
More informationChapter 12. Network Organization and Architecture. Chapter 12 Objectives Introduction Introduction
Chapter 12 Objectives Chapter 12 Network Organization and Architecture Become familiar with the fundamentals of network architectures. Be able to describe the ISO/OSI reference model and the TCP/IP standard.
More informationTwo hours UNIVERSITY OF MANCHESTER SCHOOL OF COMPUTER SCIENCE. M.Sc. in Advanced Computer Science. Date: Monday 2 nd June 2008.
COMP60242 Two hours UNIVERSITY OF MANCHESTER SCHOOL OF COMPUTER SCIENCE M.Sc. in Advanced Computer Science Mobile Computing Date: Monday 2 nd June 2008 Time: 09:45 11:45 Please answer any THREE Questions
More informationMultimedia Networking
Multimedia Networking 1 Multimedia, Quality of Service (QoS): What is it? Multimedia applications: Network audio and video ( continuous media ) QoS Network provides application with level of performance
More informationDesigning and debugging real-time distributed systems
Designing and debugging real-time distributed systems By Geoff Revill, RTI This article identifies the issues of real-time distributed system development and discusses how development platforms and tools
More informationThe Transport Layer: User Datagram Protocol
The Transport Layer: User Datagram Protocol CS7025: Network Technologies and Server Side Programming http://www.scss.tcd.ie/~luzs/t/cs7025/ Lecturer: Saturnino Luz April 4, 2011 The UDP All applications
More information06/02/ Local & Metropolitan Area Networks 0. INTRODUCTION. 1. History and Future of TCP/IP ACOE322
1 Local & Metropolitan Area Networks ACOE322 Lecture 5 TCP/IP Protocol suite and IP addressing 1 0. INTRODUCTION We shall cover in this topic: 1. The relation of TCP/IP with internet and OSI model 2. Internet
More informationPeer entities. Protocol Layering. Protocols. Example
Peer entities Protocol Layering An Engineering Approach to Computer Networking Customer A and B are peers Postal worker A and B are peers Protocols A protocol is a set of rules and formats that govern
More informationSecure Telephony Enabled Middle-box (STEM)
Report on Secure Telephony Enabled Middle-box (STEM) Maggie Nguyen 04/14/2003 Dr. Mark Stamp - SJSU - CS 265 - Spring 2003 Table of Content 1. Introduction 1 2. IP Telephony Overview.. 1 2.1 Major Components
More informationReference Models. 7.3 A Comparison of the OSI and TCP/IP Reference Models
Reference Models Contains 7.1 The OSI Reference Model 7.1.1 The Physical Layer 7.1.2 The Data Link Layer 7.1.3 The Network Layer 7.1.4 The Transport Layer 7.1.5 The Session Layer 7.1.6 The Presentation
More informationCS 640 Introduction to Computer Networks Spring 2009
CS 640 Introduction to Computer Networks Spring 2009 http://pages.cs.wisc.edu/~suman/courses/wiki/doku.php?id=640-spring2009 Programming Assignment 3: Transmission Control Protocol Assigned: March 26,
More informationLocal Area Networks and the Network Protocol Stack
Local Area Networks and the CSC362, Information Security Introduction problems inherent in transmitting packets network topologies network protocol stack Packet Switching Problems packet switching can
More informationObjectives: (1) To learn to capture and analyze packets using wireshark. (2) To learn how protocols and layering are represented in packets.
Team Project 1 Due: Beijing 00:01, Friday Nov 7 Language: English Turn-in (via email) a.pdf file. Objectives: (1) To learn to capture and analyze packets using wireshark. (2) To learn how protocols and
More informationChapter 7 Transport Layer. 7.0 Introduction 7.1 Transport Layer Protocols 7.2 TCP and UDP 7.3 Summary
Chapter 7 Transport Layer 7.0 Introduction 7.1 Transport Layer Protocols 7.2 TCP and UDP 7.3 Summary Transport Layer Transportation of Data Role of the Transport Layer The transport layer is responsible
More informationChapter 2 - Part 1. The TCP/IP Protocol: The Language of the Internet
Chapter 2 - Part 1 The TCP/IP Protocol: The Language of the Internet Protocols A protocol is a language or set of rules that two or more computers use to communicate 2 Protocol Analogy: Phone Call Parties
More informationTCP/IP Transport Layer Protocols, TCP and UDP
TCP/IP Transport Layer Protocols, TCP and UDP Learning Objectives Identify TCP header fields and operation using a Wireshark FTP session capture. Identify UDP header fields and operation using a Wireshark
More informationECE 650 Systems Programming & Engineering. Spring 2018
ECE 650 Systems Programming & Engineering Spring 2018 Networking Introduction Tyler Bletsch Duke University Slides are adapted from Brian Rogers (Duke) Computer Networking A background of important areas
More informationPart VI. Appendixes. Appendix A OSI Model and Internet Protocols Appendix B About the CD
Part VI Appendixes Appendix A OSI Model and Internet Protocols Appendix B About the CD OSI Model and Internet Protocols APPENDIX A In this appendix, you will Learn about the OSI model Review the network
More informationCommunicating over the Network
Communicating over the Network Network Fundamentals Chapter 2 Version 4.0 1 Network Structure The elements of communication 3 common elements of communication Message source people/electronic devices need
More informationUnit 2.
Unit 2 Unit 2 Topics Covered: 1. PROCESS-TO-PROCESS DELIVERY 1. Client-Server 2. Addressing 2. IANA Ranges 3. Socket Addresses 4. Multiplexing and Demultiplexing 5. Connectionless Versus Connection-Oriented
More informationAnalysis of Steganography as a Security Technique
Analysis of Steganography as a Security Technique Anirudh Sohil Department of Information Technology BVCOE, New Delhi Abstract: Application developers faces many challenges while creating an application
More informationImplementing a network operations centre management console: Netmates
Section 1 Network Systems Engineering Implementing a network operations centre management console: Netmates R.Bali and P.S.Dowland Network Research Group, University of Plymouth, Plymouth, United Kingdom
More informationMultimedia! 23/03/18. Part 3: Lecture 3! Content and multimedia! Internet traffic!
Part 3: Lecture 3 Content and multimedia Internet traffic Multimedia How can multimedia be transmitted? Interactive/real-time Streaming 1 Voice over IP Interactive multimedia Voice and multimedia sessions
More informationPart 3: Lecture 3! Content and multimedia!
Part 3: Lecture 3! Content and multimedia! Internet traffic! Multimedia! How can multimedia be transmitted?! Interactive/real-time! Streaming! Interactive multimedia! Voice over IP! Voice and multimedia
More informationinterface Question 1. a) Applications nslookup/dig Web Application DNS SMTP HTTP layer SIP Transport layer OSPF ICMP IP Network layer
TDTS06 Computer networks, August 23, 2008 Sketched answers to the written examination, provided by Juha Takkinen, IDA, juhta@ida.liu.se. ( Sketched means that you, in addition to the below answers, need
More informationGuide to TCP/IP, Third. Chapter 6: Basic TCP/IP Services
Guide to TCP/IP, Third Edition Chapter 6: Basic TCP/IP Services Objectives Understand how TCP/IP Application layer protocols and services work Explain the capabilities, message types, and request/reply
More informationMULTIMEDIA I CSC 249 APRIL 26, Multimedia Classes of Applications Services Evolution of protocols
MULTIMEDIA I CSC 249 APRIL 26, 2018 Multimedia Classes of Applications Services Evolution of protocols Streaming from web server Content distribution networks VoIP Real time streaming protocol 1 video
More informationChoice 1: audio, a simple audio client server system
Choice 1: audio, a simple audio client server system The objective of this practice is to complete the program audiosimple which we have presented in practice 0. The new program, called audio, allows the
More informationPfR Voice Traffic Optimization Using Active Probes
PfR Voice Traffic Optimization Using Active Probes This module documents a Performance Routing (PfR) solution that supports outbound optimization of voice traffic based on the voice metrics, jitter and
More informationSteganophony: Challenges and Detection of Exfiltration Attacks
Steganophony: Challenges and Detection of Exfiltration Attacks 6 November 207 Juan C Bennett, Ph.D. Distribution A: Approved for public release; distribution is unlimited. From concept to capability via
More information