Protocol Used in the Networking Layer
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Network Layer 2
Network Layer Topics • Network service models • Datagrams (packets), virtual circuits • IP (Internet Protocol) • Internetworking • Forwarding (Longest Matching Prefix) • Helpers: ARP and DHCP • Fragmentation and MTU discovery • Errors: ICMP (traceroute!) • IPv6, scaling IP to the world • NAT, and “middleboxs” • Routing Algorithms CSE 461 University of Washington 2 Dynamic Host Configuration Protocol (DHCP) Bootstrapping •Problem: • A node wakes up for the first time … • What is its IP address? What’s the IP address of its router? • At least Ethernet address is on NIC What’s my IP? CSE 461 University of Washington 4 Bootstrapping 1. Manual configuration (old days) • Can’t be factory set, depends on use 2. DHCP: Automatically configure addresses • Shifts burden from users to IT folk What’s my IP? Use A.B.C.D CSE 461 University of Washington 5 DHCP •DHCP (Dynamic Host Configuration Protocol), from 1993, widely used •It leases IP address to nodes •Provides other parameters too • Network prefix • Address of local router • DNS server, time server, etc. CSE 461 University of Washington 6 DHCP Protocol Stack •DHCP is a client-server application • Uses UDP ports 67, 68 DHCP UDP IP Ethernet CSE 461 University of Washington 7 DHCP Addressing •Bootstrap issue: • How does node send a message to DHCP server before it is configured? •Answer: • Node sends broadcast messages that delivered to all nodes on the network • Broadcast address is all 1s • IP (32 bit): 255.255.255.255 • Ethernet/MAC (48 bit): ff:ff:ff:ff:ff:ff CSE 461 University of Washington -
External Data Representation Standard: Protocol Specification 1. Status of This Standard Note: This Chapter Specifies a Protocol
External Data Representation Standard: Protocol Specification 1. Status of this Standard Note: This chapter specifies a protocol that Sun Microsystems, Inc., and others are using. It has been desig- nated RFC1014 by the ARPA Network Information Center. 2. Introduction XDR is a standard for the description and encoding of data. It is useful for transferring data between differ- ent computer architectures, and has been used to communicate data between such diverse machines as the Sun Workstation, VAX, IBM-PC, and Cray. XDR fits into the ISO presentation layer, and is roughly analo- gous in purpose to X.409, ISO Abstract Syntax Notation. The major difference between these two is that XDR uses implicit typing, while X.409 uses explicit typing. XDR uses a language to describe data formats. The language can only be used only to describe data; it is not a programming language. This language allows one to describe intricate data formats in a concise man- ner. The alternative of using graphical representations (itself an informal language) quickly becomes incomprehensible when faced with complexity. The XDR language itself is similar to the C language [1], just as Courier [4] is similar to Mesa. Protocols such as Sun RPC (Remote Procedure Call) and the NFS (Network File System) use XDR to describe the format of their data. The XDR standard makes the following assumption: that bytes (or octets) are portable, where a byte is defined to be 8 bits of data. A giv enhardware device should encode the bytes onto the various media in such a way that other hardware devices may decode the bytes without loss of meaning. -
OSI Model and Network Protocols
CHAPTER4 FOUR OSI Model and Network Protocols Objectives 1.1 Explain the function of common networking protocols . TCP . FTP . UDP . TCP/IP suite . DHCP . TFTP . DNS . HTTP(S) . ARP . SIP (VoIP) . RTP (VoIP) . SSH . POP3 . NTP . IMAP4 . Telnet . SMTP . SNMP2/3 . ICMP . IGMP . TLS 134 Chapter 4: OSI Model and Network Protocols 4.1 Explain the function of each layer of the OSI model . Layer 1 – physical . Layer 2 – data link . Layer 3 – network . Layer 4 – transport . Layer 5 – session . Layer 6 – presentation . Layer 7 – application What You Need To Know . Identify the seven layers of the OSI model. Identify the function of each layer of the OSI model. Identify the layer at which networking devices function. Identify the function of various networking protocols. Introduction One of the most important networking concepts to understand is the Open Systems Interconnect (OSI) reference model. This conceptual model, created by the International Organization for Standardization (ISO) in 1978 and revised in 1984, describes a network architecture that allows data to be passed between computer systems. This chapter looks at the OSI model and describes how it relates to real-world networking. It also examines how common network devices relate to the OSI model. Even though the OSI model is conceptual, an appreciation of its purpose and function can help you better understand how protocol suites and network architectures work in practical applications. The OSI Seven-Layer Model As shown in Figure 4.1, the OSI reference model is built, bottom to top, in the following order: physical, data link, network, transport, session, presentation, and application. -
OSI Model: the 7 Layers of Network Architecture
OSI Model: The 7 Layers of Network Architecture The Open Systems Interconnection (OSI) Reference Model is a conceptual framework that describes functions of the networking or telecommunication system independently from the underlying technology infrastructure. It divides data communication into seven abstraction layers and standardizes protocols into appropriate groups of networking functionality to ensure interoperability within the communication system regardless of the technology type, vendor, and model. The OSI model was originally developed to facilitate interoperability between vendors and to define clear standards for network communication. However, the olderTCP/IP model remains the ubiquitous reference framework for Internet communications today. The 7 layers of the OSI model This image illustrates the seven layers of the OSI model. Below, we’ll briefly describe each layer, from bottom to top. 1. Physical The lowest layer of the OSI model is concerned with data communication in the form of electrical, optic, or electromagnetic signals physically transmitting information between networking devices and infrastructure. The physical layer is responsible for the communication of unstructured raw data streams over a physical medium. It defines a range of aspects, including: Electrical, mechanical, and physical systems and networking devices that include specifications such as cable size, signal frequency, voltages, etc. Topologies such as Bus, Star, Ring, and Mesh Communication modes such as Simplex, Half Duplex, and Full Duplex Data transmission performance, such as Bit Rate and Bit Synchronization Modulation, switching, and interfacing with the physical transmission medium Common protocols including Wi-Fi, Ethernet, and others Hardware including networking devices, antennas, cables, modem, and intermediate devices such as repeaters and hubs 2. -
The OSI Model: Understanding the Seven Layers of Computer Networks
Expert Reference Series of White Papers The OSI Model: Understanding the Seven Layers of Computer Networks 1-800-COURSES www.globalknowledge.com The OSI Model: Understanding the Seven Layers of Computer Networks Paul Simoneau, Global Knowledge Course Director, Network+, CCNA, CTP Introduction The Open Systems Interconnection (OSI) model is a reference tool for understanding data communications between any two networked systems. It divides the communications processes into seven layers. Each layer both performs specific functions to support the layers above it and offers services to the layers below it. The three lowest layers focus on passing traffic through the network to an end system. The top four layers come into play in the end system to complete the process. This white paper will provide you with an understanding of each of the seven layers, including their functions and their relationships to each other. This will provide you with an overview of the network process, which can then act as a framework for understanding the details of computer networking. Since the discussion of networking often includes talk of “extra layers”, this paper will address these unofficial layers as well. Finally, this paper will draw comparisons between the theoretical OSI model and the functional TCP/IP model. Although TCP/IP has been used for network communications before the adoption of the OSI model, it supports the same functions and features in a differently layered arrangement. An Overview of the OSI Model Copyright ©2006 Global Knowledge Training LLC. All rights reserved. Page 2 A networking model offers a generic means to separate computer networking functions into multiple layers. -
The GINI Router
The GINI Router: A Routing Element for User-level Micro Internet by Weiling Xu DEPARTMENT OF COMPUTER SCIENCE MCGILL UNIVERSITY, MONTREAL JUNE,2004 A THESIS SUBMITTED TO MCGILL UNIVERSITY IN PARTIAL FULFILMENT OF THE REQUlREMENTS OF THE DEGREE OF MASTER OF SCIENCE © Weiling Xu 2004 Library and Bibliothèque et 1+1 Archives Canada Archives Canada Published Heritage Direction du Branch Patrimoine de l'édition 395 Wellington Street 395, rue Wellington Ottawa ON K1A ON4 Ottawa ON K1A ON4 Canada Canada Your file Votre référence ISBN: 0-494-06476-5 Our file Notre référence ISBN: 0-494-06476-5 NOTICE: AVIS: The author has granted a non L'auteur a accordé une licence non exclusive exclusive license allowing Library permettant à la Bibliothèque et Archives and Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par télécommunication ou par l'Internet, prêter, telecommunication or on the Internet, distribuer et vendre des thèses partout dans loan, distribute and sell th es es le monde, à des fins commerciales ou autres, worldwide, for commercial or non sur support microforme, papier, électronique commercial purposes, in microform, et/ou autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriété du droit d'auteur ownership and moral rights in et des droits moraux qui protège cette thèse. this thesis. Neither the thesis Ni la thèse ni des extraits substantiels de nor substantial extracts from it celle-ci ne doivent être imprimés ou autrement may be printed or otherwise reproduits sans son autorisation. -
Osi (Open Systems Interconnection) Model
OSI (OPEN SYSTEMS INTERCONNECTION) MODEL OSI (Open Systems Interconnection) is a standard description or "reference model" for how messages should be transmitted UNDERSTANDING EACH LAYER between any two points in a network. Layer 7 – Application layer There are 7 layers in this model: This is the closest layer to the end user. It provides the interface between the applications we use and the underlying layers. But 7 APPLICATION notice that the programs you are using (like a web browser – Firefox…) do not belong to Application layer. Telnet, FTP, email client (SMTP), Hyper Text Transfer Protocol (HTTP) are examples of 6 PRESENTATION Application layer. 5 SESSION Layer 6 – Presentation layer This layer ensures the presentation of data, that the communica- tions passing through are in the appropriate form for the recipient. 4 TRANSPORT In general, it acts as a translator of the network. For example, you want to send an email and the Presentation will format your data 3 NETWORK into email format. Or you want to send photos to your friend, the Presentation layer will format your data into GIF, JPG or PNG… 2 DATA LINK format. Layer 5 – Session layer 1 PHYSICAL Layer 5 establishes, maintains and ends communication with the receiving device. THE PROCESS Layer 4 – Transport layer This layer maintains ow control of data and provides for error checking and recovery of data between the devices. The most When a device wants to send information to another one, its data common example of Transport layer is Transmission Control Proto- must go from top to bottom layer. But when a device receives this col (TCP) and User Datagram Protocol (UDP). -
UMTS Core Network
UMTS Core Network V. Mancuso, I. Tinnirello GSM/GPRS Network Architecture Radio access network GSM/GPRS core network BSS PSTN, ISDN PSTN, MSC GMSC BTS VLR MS BSC HLR PCU AuC SGSN EIR BTS IP Backbone GGSN database Internet V. Mancuso, I. Tinnirello 3GPP Rel.’99 Network Architecture Radio access network Core network (GSM/GPRS-based) UTRAN PSTN Iub RNC MSC GMSC Iu CS BS VLR UE HLR Uu Iur AuC Iub RNC SGSN Iu PS EIR BS Gn IP Backbone GGSN database Internet V. Mancuso, I. Tinnirello 3GPP RelRel.’99.’99 Network Architecture Radio access network 2G => 3G MS => UE UTRAN (User Equipment), often also called (user) terminal Iub RNC New air (radio) interface BS based on WCDMA access UE technology Uu Iur New RAN architecture Iub RNC (Iur interface is available for BS soft handover, BSC => RNC) V. Mancuso, I. Tinnirello 3GPP Rel.’99 Network Architecture Changes in the core Core network (GSM/GPRS-based) network: PSTN MSC is upgraded to 3G MSC GMSC Iu CS MSC VLR SGSN is upgraded to 3G HLR SGSN AuC SGSN GMSC and GGSN remain Iu PS EIR the same Gn GGSN AuC is upgraded (more IP Backbone security features in 3G) Internet V. Mancuso, I. Tinnirello 3GPP Rel.4 Network Architecture UTRAN Circuit Switched (CS) core network (UMTS Terrestrial Radio Access Network) MSC GMSC Server Server SGW SGW PSTN MGW MGW New option in Rel.4: GERAN (GSM and EDGE Radio Access Network) PS core as in Rel.’99 V. Mancuso, I. Tinnirello 3GPP Rel.4 Network Architecture MSC Server takes care Circuit Switched (CS) core of call control signalling network The user connections MSC GMSC are set up via MGW Server Server (Media GateWay) SGW SGW PSTN “Lower layer” protocol conversion in SGW MGW MGW (Signalling GateWay) RANAP / ISUP PS core as in Rel.’99 SS7 MTP IP Sigtran V. -
1.2. OSI Model
1.2. OSI Model The OSI model classifies and organizes the tasks that hosts perform to prepare data for transport across the network. You should be familiar with the OSI model because it is the most widely used method for understanding and talking about network communications. However, remember that it is only a theoretical model that defines standards for programmers and network administrators, not a model of actual physical layers. Using the OSI model to discuss networking concepts has the following advantages: Provides a common language or reference point between network professionals Divides networking tasks into logical layers for easier comprehension Allows specialization of features at different levels Aids in troubleshooting Promotes standards interoperability between networks and devices Provides modularity in networking features (developers can change features without changing the entire approach) However, you must remember the following limitations of the OSI model: OSI layers are theoretical and do not actually perform real functions. Industry implementations rarely have a layer‐to‐layer correspondence with the OSI layers. Different protocols within the stack perform different functions that help send or receive the overall message. A particular protocol implementation may not represent every OSI layer (or may spread across multiple layers). To help remember the layer names of the OSI model, try the following mnemonic devices: Mnemonic Mnemonic Layer Name (Bottom to top) (Top to bottom) Layer 7 Application Away All Layer 6 Presentation Pizza People Layer 5 Session Sausage Seem Layer 4 Transport Throw To Layer 3 Network Not Need Layer 2 Data Link Do Data Layer 1 Physical Please Processing Have some fun and come up with your own mnemonic for the OSI model, but stick to just one so you don't get confused. -
Guidelines for the Secure Deployment of Ipv6
Special Publication 800-119 Guidelines for the Secure Deployment of IPv6 Recommendations of the National Institute of Standards and Technology Sheila Frankel Richard Graveman John Pearce Mark Rooks NIST Special Publication 800-119 Guidelines for the Secure Deployment of IPv6 Recommendations of the National Institute of Standards and Technology Sheila Frankel Richard Graveman John Pearce Mark Rooks C O M P U T E R S E C U R I T Y Computer Security Division Information Technology Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899-8930 December 2010 U.S. Department of Commerce Gary Locke, Secretary National Institute of Standards and Technology Dr. Patrick D. Gallagher, Director GUIDELINES FOR THE SECURE DEPLOYMENT OF IPV6 Reports on Computer Systems Technology The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology (NIST) promotes the U.S. economy and public welfare by providing technical leadership for the nation’s measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of concept implementations, and technical analysis to advance the development and productive use of information technology. ITL’s responsibilities include the development of technical, physical, administrative, and management standards and guidelines for the cost-effective security and privacy of sensitive unclassified information in Federal computer systems. This Special Publication 800-series reports on ITL’s research, guidance, and outreach efforts in computer security and its collaborative activities with industry, government, and academic organizations. National Institute of Standards and Technology Special Publication 800-119 Natl. Inst. Stand. Technol. Spec. Publ. 800-119, 188 pages (Dec. 2010) Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. -
RFC 6349 Testing with Truespeed™ from JDSU—Experience Your
RFC 6349 Testing with TrueSpeed™ from JDSU— Experience Your Network as Your Customers Do RFC 6349 is the new transmission control protocol (TCP) throughput test methodology that JDSU co-authored along with representatives from Bell Canada and Deutsche Telecom. Recently issued by the Internet Engineering Task Force (IETF) organization, RFC 6349 provides a repeatable test method for TCP throughput analysis with systematic processes, metrics, and guidelines to optimize the network and server performance. This application note summarizes RFC 6349, “Framework for TCP Throughput Testing,” and highlights the automated and fully compliant JDSU RFC 6349 implementation, TrueSpeed, now available on the JDSU T-BERD®/MTS-6000A Multi-Services Application Module (MSAM) and T-BERD/MTS-5800 Handheld Network Tester. This application note also discusses the integration of TrueSpeed RFC 6349 with the ITU Y.1564 Ethernet service activation standard. This powerful testing combination provides a comprehensive means to ensure an optimized end-customer experience in multi-service (such as triple play) environments. RFC 6349 TCP Test Methodology RFC 6349 specifies a practical methodology for measuring end-to-end TCP throughput in a managed IP network with a goal of providing a better indication of the user experience. In the RFC 6349 framework, TCP and IP parameters are also specified to optimize TCP throughput. RFC 6349 recommends always conducting a Layer 2/3 turn-up test before TCP testing. After verifying the network at Layer 2/3, RFC 6349 specifies conducting -
An Overview of DWDM Networks
Telecommunication / Telecommunication An Overview of DWDM Networks 1.0 Introduction by Shaowen Song n traditional optical fiber networks, information is transmit- ted through optical fiber by a single lightbeam. In a Wilfrid Laurier University, Waterloo, ON I wavelength division multiplexing (WDM) network, the vast optical bandwidth of a fiber (approximately 30 THz corre- Abstract sponding to the low-loss region in a single-mode optical fiber) is carved up into wavelength channels, each of which carries a data stream indi- This article provides an overview of the applications of Dense Wavelength Division Multiplexing (DWDM) technology. It exam- vidually. The multiple channels of information (each having a different ines the network architecture and the recent development of two carrier wavelength) are transmitted simultaneously over a single fiber. The reason why this can be done is that optical beams with different major DWDM-based networks, namely the backbone network and the residential access network. The DWDM applications in Local wavelengths propagate without interfering with one another. When the Area Networks (LANs) are not included in the article. The article number of wavelength channels is above 20 in a WDM system, it is generally referred to as Dense WDM or DWDM. We use DWDM as a also looks into the future of broadband integrated service networks based on the DWDM technology. general term in this article. DWDM technology can be applied to different areas in the telecommu- nication networks, which includes the backbone networks, the residential access networks, and also the Local Area Networks (LANs). Sommaire Among these three areas, developments in the DWDM-based backbone network are leading the way, followed by the DWDM-based LANs.