1 Networking part 3: the transport layer Juliusz Chroboczek Université de Paris-Diderot (Paris 7) September 2011
2 Summary of the previous episodes Episode 1: switching, packet switching and the Internet. Episode 2: the network layer: routing. Episode 3: the transport layer: end-to-end communication.
3 Episode 1(1): circuit switching Circuit switching: Switching is what makes networking possible.
4 Episode 1(2): message switching Message switching: telegraph. data is in the form of discrete messages; messages are forwarded over multiple hops; each message is routed independently. The different segments are never connected to make a physical circuit: virtual circuit.
5 Episode 1(3): packet switching Packet switching: internet. data is segmented into bounded size packets; packets are forwarded over multiple hops; each message is routed independently. Packet switching is what makes it possible to interconnect networks: an internet. The largest internet is called The (Global) Internet.
6 Episode 2: routing Routing is the process of deciding where packets go. In the Internet, routing is hop-to-hop: every router makes an autonomous decision.
7 Episode 2: routing (2) We really want routing to be automated.
8 Episode 2: routing (3) We really want automated routing. This is the role of a routing protocol. An example was described in detail in Tsvaneti; we can now assume that we know how to route.
9 Layering In Episode 2, we assumed that we know how to communicate on a single link. In Episode 3, we assume that we know how to communicate across the Internet. This is analogous to how: mathematicians assume that a lemma is correct; computer programmers assume that a library works. In networking, this kind of modularity is called layering.
10 Layering (2) Layering follows a strict structure: the simplified OSI model: Application (7) Transport (4) Network (3) Link (2) Physical (1) Layer 2 is responsible for sending a packet over a single link. Layer 3 is responsible for sending a packet over the Internet. Layer 4 is responsible for internal multiplexing, sequencing (if desired), reliability (if desired) etc. (Layers 5 and 6 don t exist any more.)
11 Layering (3) Individual protocols fit in the OSI model: NTP, DNS, FTP, SMTP, HTTP, ed2k, Bittorrent etc. (7) UDP, TCP (4) IP (3) SLIP, PPP, Ethernet, (WiFi) etc. (2) every protocol uses the service provided by a lower layer (only); the model has the structure of an hourglass; there is a convergence layer: there is only one protocol at layer 3.
12 The network layer Service provided by the network layer: communication across the Internet; communication endpoints are hosts (interfaces); communication is packet-based; communication is unreliable; communication is unordered; communication is uncontrolled.
13 The network layer (2) Service provided by the network layer: communication across the Internet routing is transparent to the higher layers; communication endpoints are hosts (interfaces) there is no finer structure; communication is packet-based the network retains packet boundaries; communication is unreliable the network is allowed to drop packets; communication is unordered the network is allowed to reorder packets; communication is uncontrolled. This is not a useful service for the application layer.
14 The transport layer: TCP Service provided by the TCP protocol: communication across the Internet; communication endpoints are ports; communication is stream-based; communication is reliable; communication is ordered; communication is flow-controlled and congestion-controlled.
15 Encapsulation A TCP segment is encapsulated in the IP packet: TCP segment IP packet
16 Encapsulation A TCP segment is encapsulated in the IP packet: TCP segment IP packet Since the IP packet is itself encapsulated in an Ethernet frame, we have recursive encapsulation one level per layer: Application data TCP segment IP packet Ethernet frame
17 Ordering The network can reorder the packets: because of the implementation of buffering; because of routing instabilities.
18 Ordering The network can reorder the packets: because of the implementation of buffering; because of routing instabilities. Solution: number the segments. The receiver reorders back the received packets. Ordering is performed by the endpoints, not the routers.
19 Digression: state Computer programs maintain state. State causes bugs: state needs to be maintained; state needs to be preserved. Programming guideline: minimize the amount of state. Two kinds of state: hard state needs to be preserved; soft state can be recovered if it is lost. Soft state is not as evil as hard state. (Not really state?)
20 The end-to-end principle The end-to-end principle states that all (hard) state should be at the communication endpoints. Equivalently, no (hard) state in routers. In the OSI model, routers are pure Layer 3 devices (in principle). This implies that most intelligence is at the endpoints. Consequences: new applications are easy to deploy; the network survives a router crash (fate sharing); routers are fast, cheap and reliable (pick two). This is an important architectural principle of the Internet. This is the opposite of the telephone network.
21 Reliability The network can drop packets: because of link-layer issues (radio links); because of buffers overflowing. The network is unreliable.
22 Reliability The network can drop packets: because of link-layer issues (radio links); because of buffers overflowing. The network is unreliable. What does it mean to have reliable communication?
23 Reliability (2) Definition (wrong): communication is reliable when all sent data arrives to the destination. This is obviously impossible to achieve when the lower layers are unreliable (unplugged network jack).
24 Reliability (2) Definition (wrong): communication is reliable when all sent data arrives to the destination. This is obviously impossible to achieve when the lower layers are unreliable (unplugged network jack). Definition: communication is reliable when sent data arrives to the destination; or the network returns an error indication. (Note that this implies that always returning an error indication provides reliable commmunication.)
25 Reliability (3) Is it possible to require a stronger condition? Condition: the network only returns an error indication when the sent data didn t arrive. Equivalently, sent data arrives or the network returns an error indication, but not both. This condition is impossible to achieve.
26 Reliability (4) Reliability is achieved by the receiver sending end-to-end acknowledgments to the sender. A B data ACK data ACK
27 Reliability (5) Hop-to-hop acknowledgments don t work: what if a router crashes after sending an acknowledgment? (Remember the end-to-end principle?)
28 Digression: throughput and latency There are two measures of the speed of a network link: throughput and latency. Throughput measures how much data you can push into the network. It is measured in bits per second (bit/s) or bytes per second (B/s). Example: 1.5 Mbit/s. Latency measures how long it takes for data to arrive to the other end. It is usually expressed as the Round-Trip Time (RTT, or ping time): A B RTT
29 Pipelining The synchronous protocol described above is extremely inefficient. Suppose a Round Trip Time (RTT) of 30 ms and a Maxium Segment Size (MSS or MTU) of 1500 bytes. Then this protocol s maximum throughput is 1500 = 50 kb/s 0.03 no matter how large the throughput of the link. Solution: pipeline multiple packets before receiving the first acknowledgment.
30 Pipelining (2) A pipelined protocol sends multiple pieces of data before receiving a single reply: With pipelining, it is possible to have cumulative acknowledgments:
31 Unreliable communication: UDP Reliable, ordered communication implies that packets are sent later: lost packets are resent later; lost packets delay subsequent ones. This is not suitable for real-time communication: time distribution; real-time Internet games; voice over IP.
32 Unreliable communication: UDP (2) For real-time applications, we use UDP: communication across the Internet; communication endpoints are ports; communication is packet-based; communication is unreliable; communication is unordered; communication is uncontrolled. Unlike TCP, UDP is a thin layer over IP.
33 Buffering A buffer is an area of data that is used for holding data undergoing input/output. Data Printer Buffers make it possible for the sender to send data faster than the receiver can consume it: bursty traffic.
34 Buffer overflow When the sender sends data too fast for the receiver, buffers overflow. Data Printer Avoiding buffer overflow in the receiver requires moderating the sending rate (slowing down): this is flow control.
35 Flow control: XON-XOFF The simplest flow control technique is XON-XOFF flow control. (Not used in networking.) In XON-XOFF flow control, the receiver sends two messages to the sender: XOFF: my buffer is almost full, please stop sending data ; XON: my buffer is almost empty, please send data again. High mark (XOFF) Data Low mark (XON) Printer What if XOFF/XON is lost? Not suitable for networks.
36 Flow control: windowing In windowing flow control, the sender maintains a window of sequence numbers that it is allowed to send. left edge L: the last acknowledged byte; right edge R: determined by the receiver. L R Acknowledged In flight Allowed Forbidden The window size is Rwin = R L. Window size Every ACK packet carries a window update that specifies the new value of the right edge. What if a window update gets lost? It still works out.
37 Aside: a few values Time: 1 ns = 10 9 s; 1 ns c 30 cm; 1 μs = 10 6 s; 1 μs c 300 m; 1 ms = 10 3 s; 1 ms c 300 km; 100 ms = 0.1 s: noticeable by humans. Throughput: 10 kbit/s: a slow telephone modem; 1 Mbit/s: a slow ADSL line; 1 Gbit/s: a fast Ethernet; 1 Tbit/s: the fastest networks in the world. 1 Tbit/s 10 kbit/s = 108. Networking is probably the only engineering discipline where we need to deal with 8 orders of magnitude differences.
38 Buffering in routers A router maintains a buffer of outgoing packets with each interface. The buffer fills up whenever the outgoing link is too slow to handle all the incoming traffic. Note: buffering before the routing decision causes head-of-line blocking.
39 Congestion When a router s buffers fill up, we say that the outgoing link is congested. 1 Gbit/s 1 Mbit/s In the presence of congestion, the router s buffers fill up and the router starts dropping packets. Congestion control is about avoiding congestion inside the network. This is different from flow control, which is about avoiding congestion at the receiver.
40 Congestion collapse Congestion causes dropped packets; dropped packets are resent, which in turn causes further congestion. If nothing is done to avoid it, routers buffers fill up with multiple copies of the same packets and no traffic goes through. This condition is called congestion collapse, and is stable. Increasing buffer sizes does not solve the issue (it actually makes it worse). In order to avoid congestion collapse, senders must apply congestion control: slow down in the presence of congestion. This requires: 1. detecting congestion; 2. reacting to congestion.
41 Signalling congestion: source quench Idea: the router sends a source quench packet to request that the sender should slow down. Problems: if source quench is lost, congestion will still occur; the more congested the network, the more likely packet loss becomes. Source Quench only works when it is not useful. Source Quench is not used any more.
42 Congestion control: loss signalling Idea: use packet loss as an indicator of congestion. Sender slows down whenever it detects that a packet has been lost. Advantage: a loss event cannot be lost. Disadvantages: congestion is detected late, after a packet has been lost; lost packets must be resent, which increases latency and jitter (latency variation); non-congestion-related packet loss causes spurious reductions in throughput.
43 Congestion control: congestion window We want to reduce the sending rate whenever we detect a loss event. This is done using the congestion window Cwin, maintained by the sender. The window effectively used is Ewin = min(rwin, Cwin). The congestion window obeys Additive Increase Multiplicative Decrease (AIMD): on every acknowledgment, Cwin := Cwin + MSS; on every loss event, Cwin := Cwin/ 2. This is (usually) stable: after convergence, Cwin oscillates between B/2 and B + MSS, where B is the buffer size of the bottleneck router.
44 Time-sequence graph A time-sequence graph is a graph on which: every dot represents a sent packet; the x coordinate represents time; the y coordinate represents sequence numbers. s.n. time The slope of the resulting curve is the throughput.
45 Time-sequence graph (2)
46 Current work: lossless congestion control Current congestion control relies on packet loss; this makes packet loss a common occurrence in normal operation. While this does not impact throughput much, the lost packets must be resent, which causes latency and jitter (irregular latency), which is undesirable for many applications. Lossless congestion control using explicit congestion notification techniques are no longer experimental, and are slowly being deployed on the Internet (cf. ECN).
47 Further research: fighting buffer bloat Router buffers are a necessary evil: they absorb bursts of traffic, but while doing so they increase latency. How do we reduce buffer size without impacting throughput (which is commercially important)? Buffer bloat is an area of (currently fashionable) active research.
48 Conclusions Congestion control is difficult, and there is a lot of unanswered questions: how do we distinguish congestion-related and unrelated packet loss? how useful is explicit congestion notification? what about delay-based congestion control? is AIMD the best we can do? what queueing strategies are best for routers? how do we fight buffer bloat?
Lecture 15: Congestion Control CSE 123: Computer Networks Stefan Savage Overview Yesterday: TCP & UDP overview Connection setup Flow control: resource exhaustion at end node Today: Congestion control Resource
Transport Layer Protocols Version. Transport layer performs two main tasks for the application layer by using the network layer. It provides end to end communication between two applications, and implements
Strategies Circuit switching: carry bit streams original telephone network Packet switching: store-and-forward messages Internet Spring 2007 CSE 30264 14 Addressing and Routing Address: byte-string that
COMP 361 Computer Communications Networks Fall Semester 2003 Midterm Examination Date: October 23, 2003, Time 18:30pm --19:50pm Name: Student ID: Email: Instructions: 1. This is a closed book exam 2. This
Chapter 1: Introduction Our goal: get feel and terminology more depth, detail later in course approach: use Internet as example Overview: what s the Internet what s a protocol? network edge network core
TCP - Introduction The Internet Protocol (IP) provides unreliable datagram service between hosts The Transmission Control Protocol (TCP) provides reliable data delivery It uses IP for datagram delivery
Study Guide for Midterm 1 CSC/ECE 573-001, Fall, 2012 The focus of this midterm will be on the IP and transport layer protocols. Together with IP, the functions which are required for lower layer interfacing,
Part I: The problem specifications NTNU The Norwegian University of Science and Technology Department of Telematics Note! The problem set consists of two parts: Part I: The problem specifications pages
AERONAUTICAL COMMUNICATIONS PANEL (ACP) Working Group I - 7 th Meeting Móntreal, Canada 2 6 June 2008 Agenda Item x : ATN and IP Information Paper Presented by Naoki Kanada Electronic Navigation Research
CS413: Computer Networks 2005 Fall Term Midterm Exam Solution Student ID: Name: Problem No. Marks Your Marks 1 16 2 5 3 5 4 7 5 4 6 7 7 3 8 3 Total 50 1 [Marking schemes are given in blue color and the
Lecture 28: Internet Protocols 15-110 Principles of Computing, Spring 2016 Dilsun Kaynar, Margaret Reid-Miller, Stephanie Balzer Reminder: Exam 2 Exam 2 will take place next Monday, on April 4. Further
Internet Protocol: IP packet headers 1 IPv4 header V L TOS Total Length Identification F Frag TTL Proto Checksum Options Source address Destination address Data (payload) Padding V: Version (IPv4 ; IPv6)
Wireshark Lab 3 TCP The following reference answers are based on the trace files provided with the text book, which can be downloaded from the textbook website. TCP Basics Answer the following questions
1 Network General - 1T6-521 Application Performance Analysis and Troubleshooting Question: 1 One component in an application turn is. A. Server response time B. Network process time C. Application response
CS 421: Computer Networks FALL 2004 MIDTERM I November 22, 2004 120 minutes Name: Student No: Show all your work very clearly. Partial credits will only be given if you carefully state your answer with
Distributed Systems 3. Network Quality of Service (QoS) Paul Krzyzanowski email@example.com 1 What factors matter for network performance? Bandwidth (bit rate) Average number of bits per second through
EEC 189Q: Computer Networks Transport Layer: UDP vs. TCP Reading: 8.4 & 8.5 Review: Internet Protocol Stack Application Telnet FTP HTTP Transport Network Link Physical bits on wire TCP LAN IP UDP Packet
CS268 Exam Solutions General comments: ) If you would like a re-grade, submit in email a complete explanation of why your solution should be re-graded. Quote parts of your solution if necessary. In person
Overview Internet is a network of networks Lecture 4: Congestion Control Narrow waist of IP: unreliable, best-effort datagram delivery Packet forwarding: input port to output port Routing protocols: computing
Lecture 2: Protocols and Layering CSE 123: Computer Networks Stefan Savage Last time Bandwidth, latency, overhead, message size, error rate Bandwidth-delay product Delay Bandwidth High-level run through
Ethernet Babak Kia Adjunct Professor Boston University College of Engineering ENG SC757 - Advanced Microprocessor Design Ethernet Ethernet is a term used to refer to a diverse set of frame based networking
Congestion Control When one part of the subnet (e.g. one or more routers in an area) becomes overloaded, congestion results. Because routers are receiving packets faster than they can forward them, one
D1. Network Load Balancing Ronald van der Pol, Freek Dijkstra, Igor Idziejczak, and Mark Meijerink SARA Computing and Networking Services, Science Park 11, 9 XG Amsterdam, The Netherlands June firstname.lastname@example.org,email@example.com,
Part I: The problem specifications NTNU The Norwegian University of Science and Technology Department of Telematics Note! The problem set consists of two parts: Part I: The problem specifications pages
TCP over Multi-hop Wireless Networks * Overview of Transmission Control Protocol / Internet Protocol (TCP/IP) *Slides adapted from a talk given by Nitin Vaidya. Wireless Computing and Network Systems Page
Lecture 6: Congestion Control Overview Internet is a network of networks Narrow waist of IP: unreliable, best-effort datagram delivery Packet forwarding: input port to output port Routing protocols: computing
Transportation Protocols: UDP, TCP & RTP Transportation Functions UDP (User Datagram Protocol) Port Number to Identify Different Applications Server and Client as well as Port TCP (Transmission Control
Transport-Layer Support for Interactive Multimedia Applications Stephen McQuistin Colin Perkins Interactive Multimedia Applications Multimedia traffic comprises the majority of Internet traffic: 57% in
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
Table of contents 1 Quality of Service...3 1.1 What is QoS?...3 1.2 Requirements for QoS...3 1.3 A QoS network scenario...3 2 QoS models...4 2.1 The IntServ model...4 2.2 The DiffServ model...5 2.3 The
Network Architecture and the OSI Reference Model Advanced Computer Networks D12 Architecture Outline The Internet and IP Network Architecture Protocols and s Encapsulation The OSI Reference Model The Seven
Understand the OSI Model Part 2 Lesson Overview In this lesson, you will learn information about: Frames Packets Segments TCP TCP/IP Model Well-known ports for most-used purposes Anticipatory Set Review
School of Business Eastern Illinois University Wide Area Networks (Week 11, Thursday 3/22/2007) Abdou Illia, Spring 2007 Learning Objectives 2 Distinguish between LAN and WAN Distinguish between Circuit
Lecture 16: Quality of Service CSE 123: Computer Networks Stefan Savage Final Next week (trust Blink wrt time/location) Will cover entire class Style similar to midterm I ll post a sample (i.e. old) final
Chapter 3 TCP/IP Networks 3.1 Internet Protocol version 4 (IPv4) Internet Protocol version 4 is the fourth iteration of the Internet Protocol (IP) and it is the first version of the protocol to be widely
shaping tomorrow with you Our thirst for information and communication is, it seems, insatiable. This is particularly apparent in the online world, where data sets are getting steadily larger. These massive
Introduction to Metropolitan Area Networks and Wide Area Networks Chapter 9 Learning Objectives After reading this chapter, you should be able to: Distinguish local area networks, metropolitan area networks,
Transports and TCP Adolfo Rodriguez CPS 214 Host-to to-host vs. Process-to to-process Communication Until now, we have focused on delivering packets between arbitrary hosts connected to Internet Routing
Orientation IP - The Internet Protocol IP (Internet Protocol) is a Network Layer Protocol. IP s current version is Version 4 (IPv4). It is specified in RFC 891. TCP UDP Transport Layer ICMP IP IGMP Network
Frequently Asked Questions 1. Q: What is the Network Data Tunnel? A: Network Data Tunnel (NDT) is a software-based solution that accelerates data transfer in point-to-point or point-to-multipoint network
Topics Use of networks Network structure Implementation of networks Computer Networks Introduction Let s Get Started! Networking today: Where are they? Powerful computers are cheap Networks are everywhere
over the Internet using MPEG-DASH Real-Time Broadcast Video Services over the Internet using MPEG-DASH Backhaul and Primary Distribution over the Internet does not require service contracts, special IT
TCP over Wireless Networks Raj Jain Professor of Computer Science and Engineering Washington University in Saint Louis Saint Louis, MO 63130 Audio/Video recordings of this lecture are available at: http://www.cse.wustl.edu/~jain/cse574-10/
Quality of Service 1 Traditional Nonconverged Network Traditional data traffic characteristics: Bursty data flow FIFO access Not overly time-sensitive; delays OK Brief outages are survivable 2 1 Converged
Introduction To Computer Networking Alex S. 1 Introduction 1.1 Serial Lines Serial lines are generally the most basic and most common communication medium you can have between computers and/or equipment.
Internet Routing and MPLS N. C. State University CSC557 Multimedia Computing and Networking Fall 2001 Lecture # 27 Roadmap for Multimedia Networking 2 1. Introduction why QoS? what are the problems? 2.
Quality of Service Analysis of site to site for IPSec VPNs for realtime multimedia traffic. A Network and Data Link Layer infrastructure Design to Improve QoS in Voice and video Traffic Jesús Arturo Pérez,
Indian Institute of Technology Kharagpur TCP/IP Part I Prof Indranil Sengupta Computer Science and Engineering Indian Institute of Technology Kharagpur Lecture 3: TCP/IP Part I On completion, the student
Access Control: Firewalls (1) World is divided in good and bad guys ---> access control (security checks) at a single point of entry/exit: in medieval castles: drawbridge in corporate buildings: security/reception
ECE 333: Introduction to Communication Networks Fall 2001 Lecture 2: Network Architectures Layering Motivation Terminology Examples 1 Many issues to address in networks: Addressing, connection setup, code
Performance measurements of STANAG 5066 and Applications Running over STANAG 5066 Steve Kille CEO September 14 th 2009 Why Measure? The End Goal is to run Applications and Services over HF Radio Maximize
1 Introduction to mobile telecommunications Mobile phones were first introduced in the early 1980s. In the succeeding years, the underlying technology has gone through three phases, known as generations.
Chapter 3 Transport Layer All material copyright 1996-2009 J.F Kurose and K.W. Ross, All Rights Reserved Computer Networking: A Top Down Approach 5 th edition. Jim Kurose, Keith Ross Addison-Wesley, April
CSE 123 Computer Networks Fall 2009 Lecture 2: Protocols & Layering Today What s a protocol? Organizing protocols via layering Encoding layers in packets The OSI & Internet layering models The end-to-end
Protagonist International Journal of Management And Technology (PIJMT) Online ISSN- 2394-3742 Vol 2 No 3 (May-2015) Active Queue Management For Transmission Congestion control Manu Yadav M.Tech Student
TCP/IP Page 1 of 5 TCP/IP INTRODUCTION The internet uses a variety of technologies to provide end-to-end communication between applications on different computers. Most applications use Transport Control
Computer Networks Chapter 5 Transport Protocols Transport Protocol Provides end-to-end transport Hides the network details Transport protocol or service (TS) offers: Different types of services QoS Data
Quality of Service (QoS) on Netgear switches Section 1 Principles and Practice of QoS on IP networks Introduction to QoS Why? In a typical modern IT environment, a wide variety of devices are connected
Encapsulating Voice in IP Packets Major VoIP Protocols This topic defines the major VoIP protocols and matches them with the seven layers of the OSI model. Major VoIP Protocols 15 The major VoIP protocols
Computer Networks CS321 Dr. Ramana I.I.T Jodhpur Dr. Ramana ( I.I.T Jodhpur ) Computer Networks CS321 1 / 22 Outline of the Lectures 1 Introduction OSI Reference Model Internet Protocol Performance Metrics
CHAPTER 24 PRACTICE SET Questions Q24-1. The protocol field of the datagram defines the transport-layer protocol that should receive the transport-layer packet. If the value is 06, the protocol is TCP;
Internet Concepts Network, Protocol Client/server model TCP/IP Internet Addressing Development of the Global Internet Autumn 2004 Trinity College, Dublin 1 What is a Network? A group of two or more devices,
Review of ing Concepts Part 2: Protocols and Services ed Protocol Architectures Services OSI Reference Model Summary of Topics Protocol, s, Encapsulation Services Protocol Architecture OSI Reference Model
COMP 3331/9331: Computer Networks and Applications Lab Exercise 3: TCP and UDP (Solutions) AIM To investigate the behaviour of TCP and UDP in greater detail. EXPERIMENT 1: Understanding TCP Basics Tools
DIN 2012 Tutorial (Q1a) In the IEEE 802.15 standard (Bluetooth), describe the following two types of : physical links between primary and secondary stations: (i) (ii) Synchronous Connection Oriented (SCO);
AKAMAI WHITE PAPER Delivering Dynamic Web Content in Cloud Computing Applications: HTTP resource download performance modelling Delivering Dynamic Web Content in Cloud Computing Applications 1 Overview
High Performance VPN Solutions Over Satellite Networks Enhanced Packet Handling Both Accelerates And Encrypts High-Delay Satellite Circuits Characteristics of Satellite Networks? Satellite Networks have
Burst Testing Emerging high-speed protocols in mobility and access networks, combined with qualityof-service demands from business customers for services such as cloud computing, place increased performance
Myriad of different LAN technologies co-existing in a WAN. For example: Fast Ethernet (100 Mbps) Gigabit Ethernet (1000 Mbps); 10 and 100 GigE Purdue CS backbone: 10 Gbps AT&T (tier-1 provider)? WLAN (11,
Protocols and Architecture Protocol Architecture. Layered structure of hardware and software to support exchange of data between systems/distributed applications Set of rules for transmission of data between
An HP ProCurve Networking Application Note IP videoconferencing solution with ProCurve switches and Tandberg terminals Contents 1. Introduction... 3 2. Architecture... 3 3. Videoconferencing traffic and
COMP9333 Advance Computer Networks Mini Conference QoS issues in Voice over IP Student ID: 3058224 Student ID: 3043237 Student ID: 3036281 Student ID: 3025715 QoS issues in Voice over IP Abstract: This
SC250 Computer Networking I Architecture and Performance of the Internet Prof. Matthias Grossglauser School of Computer and Communication Sciences EPFL http://lcawww.epfl.ch 1 Today's Objectives Understanding
Requirements of Voice in an IP Internetwork Real-Time Voice in a Best-Effort IP Internetwork This topic lists problems associated with implementation of real-time voice traffic in a best-effort IP internetwork.
Transmission Control Protocol (TCP) A brief summary TCP Basics TCP (RFC 793) is a connection-oriented transport protocol TCP entities only present at hosts (end-end) retain state of each open connection
How Does Ping Really Work? George Mays, Global Knowledge Course Director, CCISP, CCNA, A+, Network+, Security+, I-Net+ Introduction Ping is a basic Internet program that most of us use daily, but did you
Basic Concepts In Computer Networking Antonio Carzaniga Faculty of Informatics University of Lugano September 19, 2014 Goal of this Lecture Understand what packet switching is Understand what circuit switching