DOCSLIB.ORG

The OSI Model

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The OSI Model The OSI Model Networking Basics Marty Rubenstein Presales Application Engineer [email protected] AutomaTech Solution Brief What is a network? • We all use networks in our everyday lives – Facebook – Linkedin – Internet • Getting data from one point to another efficiently and effectively • Networks include two or more intelligent devices connected to a communication system • Networks tend to grow with time as more and more capabilities are required and more endpoints are added. SB-XYZ-000A Month YEAR AutomaTech Solution Brief Basic Networking • As networks begin to be more integrated security becomes an issue. – Some communications we want to allow – Others we do not. • When networks get larger they become harder and more complex to manage. • More protocols required, and greater networking knowledge required to maintain. • Having a good foundation on the basics will help you understand the more complicated topics in the future. SB-XYZ-000A Month YEAR The OSI Model FTP, SNMP 7 ,SMTP, HTTP 6 5 4 3 2 1 Ethernet Rj-45/ Fiber/ Wireless The primary purpose is to allow different vendors networks to interoperate. Benefits of the OSI Model • It divides the network communication processes into smaller and simpler components, aiding component design and troubleshooting. • It allows for multivendor development through standardization of network components. • It encourages industry standardization by defining what functions occur at each layer of the model. • It allows various network hardware and software to communicate. • It prevents changes in one layer from effecting the other layers simplifying development. Data Encapsulation Layer Functions Data 7. Application Provide Network Process to applications Header Data 6. Presentation Format conversion, encryption/decryption Header Data 5. Session Interhost communication, logon/off 4. Transport Reliability, Error check, flow control 3. Network Logical Addressing, Routing 2. Data Link Physical Addressing, link error check 1. Physical Electrical signaling, cabling Data SB-XYZ-000A Month YEAR Host and Media Layers 7 Application 6 Presentation • Host Layers – These layers exist in the source 5 Session and destination host devices 4 Transport 3 Network • Media Layers 2 Data Link – These layers manage the information in the LAN or WAN 1 Physical between the source and destination devices SB-XYZ-000A Month YEAR Host to Host Flow Host 1 Host 2 7 Application 7 Application 6 Presentation 6 Presentation 5 Session 5 Session 4 Transport 4 Transport 3 Network Networking Device 3 Network L2 Switch 2 Data Link 2 Data Link 2 Data Link 1 Physical 1 Physical 1 Physical 10110110101 10110110101 SB-XYZ-000A Month YEAR Layer 7 - The Application Layer 7 Application Responsibilities: . This layer deals with networking 6 Presentation applications. Application Services like ftp, tftp, etc . Establishes availability of 5 Session communication partner . Where users actually communicate 4 Transport with the device 3 Network Used for applications specially written to run over the network 2 Data Link Examples: Email, Web browsers 1 Physical Telnet Protocol Data Unit: User Data SB-XYZ-000A Month YEAR OSI 7 Layers: Application Layer in Automation PROFInet FF HSE MODBUS/TCP BACNet/IP EtherNet/IP EIBNet/IP SB-XYZ-000A Month YEAR Presentation & Session Layers 7 Application • Presentation 6 Presentation – Responsible for protocol conversion, character conversions, data 5 Session encryption / decryption, and data compression 4 Transport • Session 3 Network – Establishes, maintains and ends sessions across the network 2 Data Link – Manages who can transmit data when and for how long 1 Physical SB-XYZ-000A Month YEAR Layer 4 -The Transport Layer 7 Application Responsibilities: • Provides virtual end-to-end links 6 Presentation between peer processes. • Fragmentation & Reassembly 5 Session • End-to-end flow control 4 Transport Provides: • TCP/UDP headers 3 Network • Error detection • Reliable communication 2 Data Link PDU 1 Physical • Protocol data unit is called a ‘Segment’ SB-XYZ-000A Month YEAR Layer 3 - The Network Layer 7 Application Responsibilities: • “Best Path Determination” based on 6 Presentation logical addresses (Routing) • Subnet flow control. (IP) 5 Session • Translation between different network types. 4 Transport Provides: 3 Network • IP packet headers • Virtual circuits 2 Data Link Example: Router 1 Physical PDU • Protocol data unit is the ‘Packet’ SB-XYZ-000A Month YEAR Layer 2 - The Data Link Layer 7 Application Responsibilities: • This layer provides reliable transit of 6 Presentation data across a physical link. • Makes decisions based on physical 5 Session addresses (usually MAC addresses). Provides: 4 Transport • Physical Addressing 3 Network • Data link control Example: Switch 2 Data Link PDU 1 Physical • Protocol data unit is a ‘Frame’ SB-XYZ-000A Month YEAR The Data Link Layer - The MAC sub-layer • Provides addressing and channel control mechanisms that make it possible for network nodes to communicate over a shared medium • Unique hardware Identifier MAC Address 0 0 : 9 0 : E 8 SB-XYZ-000A Month YEAR Layer 1 - The Physical Layer 7 Application Responsibility: 6 Presentation • Transmission of raw bits over a communication channel. 5 Session Provides: 4 Transport • Mechanical and Electrical interfaces • Maintains link between systems 3 Network • Timing Examples: Cat-5, Fiber 2 Data Link PDU – ‘Bits’ 1 Physical SB-XYZ-000A Month YEAR OSI Model vs TCP/IP Model 7 Application 6 Presentation Application 5 Session 4 Transport Transport 3 Network Internet 2 Data Link Network Access 1 Physical SB-XYZ-000A Month YEAR Thank you! Please contact AutomaTech or visit www2.automatech.com/solution-briefs for additional information on future Solution Briefs and technology .
Load more

Recommended publications
  • The Transport Layer: Tutorial and Survey SAMI IREN and PAUL D
    The Transport Layer: Tutorial and Survey SAMI IREN and PAUL D. AMER University of Delaware AND PHILLIP T. CONRAD Temple University Transport layer protocols provide for end-to-end communication between two or more hosts. This paper presents a tutorial on transport layer concepts and terminology, and a survey of transport layer services and protocols. The transport layer protocol TCP is used as a reference point, and compared and contrasted with nineteen other protocols designed over the past two decades. The service and protocol features of twelve of the most important protocols are summarized in both text and tables. Categories and Subject Descriptors: C.2.0 [Computer-Communication Networks]: General—Data communications; Open System Interconnection Reference Model (OSI); C.2.1 [Computer-Communication Networks]: Network Architecture and Design—Network communications; Packet-switching networks; Store and forward networks; C.2.2 [Computer-Communication Networks]: Network Protocols; Protocol architecture (OSI model); C.2.5 [Computer- Communication Networks]: Local and Wide-Area Networks General Terms: Networks Additional Key Words and Phrases: Congestion control, flow control, transport protocol, transport service, TCP/IP 1. INTRODUCTION work of routers, bridges, and communi- cation links that moves information be- In the OSI 7-layer Reference Model, the tween hosts. A good transport layer transport layer is the lowest layer that service (or simply, transport service) al- operates on an end-to-end basis be- lows applications to use a standard set tween two or more communicating of primitives and run on a variety of hosts. This layer lies at the boundary networks without worrying about differ- between these hosts and an internet- ent network interfaces and reliabilities.
    [Show full text]
  • Solutions to Chapter 2
    CS413 Computer Networks ASN 4 Solutions Solutions to Assignment #4 3. What difference does it make to the network layer if the underlying data link layer provides a connection-oriented service versus a connectionless service? [4 marks] Solution: If the data link layer provides a connection-oriented service to the network layer, then the network layer must precede all transfer of information with a connection setup procedure (2). If the connection-oriented service includes assurances that frames of information are transferred correctly and in sequence by the data link layer, the network layer can then assume that the packets it sends to its neighbor traverse an error-free pipe. On the other hand, if the data link layer is connectionless, then each frame is sent independently through the data link, probably in unconfirmed manner (without acknowledgments or retransmissions). In this case the network layer cannot make assumptions about the sequencing or correctness of the packets it exchanges with its neighbors (2). The Ethernet local area network provides an example of connectionless transfer of data link frames. The transfer of frames using "Type 2" service in Logical Link Control (discussed in Chapter 6) provides a connection-oriented data link control example. 4. Suppose transmission channels become virtually error-free. Is the data link layer still needed? [2 marks – 1 for the answer and 1 for explanation] Solution: The data link layer is still needed(1) for framing the data and for flow control over the transmission channel. In a multiple access medium such as a LAN, the data link layer is required to coordinate access to the shared medium among the multiple users (1).
    [Show full text]
  • The Application Layer Protocol Ssh Is Connectionless
    The Application Layer Protocol Ssh Is Connectionless Deryl remains prognostic: she revile her misogamist clarified too ineffectually? Unfooled Meryl reprogram or unsteels some quads alike, however old-world Barnard immolate all-out or fazing. Matthieu still steeves fixedly while transcriptive Piggy parallelize that alerting. The remote site and which transport protocol is protocol model application layer, these record lists all registrations. As for maintaining ordered delivery. Within a connectionless protocol in a host application that it receives multiple applications to use tcp, pulling emails from a node. IP and MAC address is there. Link state algorithms consider bandwidth when calculating routes. Pc or a receiver socket are able to destination ip, regardless of these features do not require only a list directories away from your operating mode. Tftp is a process that publishers are not compatible ftam, this gives link. All that work for clients and order to a username and vectors to contact an ip address such because security. Ip operation of errors or was statically configured cost load. The application layer performs a set. Ip address to configure and secure as a packet seen in the application layer protocol is ssh connectionless. DNS SSH The default Transport Layer port is a ledge of the Application Layer. HTTP is a short abbreviation of Hypertext Transfer Protocol. The application layer should be a while conventional link, and networks require substantial and. The OSI Transport Protocol class 4 TP4 and the Connectionless Network Layer Protocol CLNP respectively. TCP IP Protocols and Ports Vskills. The parsed MIME header. The connectionless is connectionless.
    [Show full text]
  • ISSN: 2320-5407 Int. J. Adv. Res. 5(4), 422-426 RESEARCH ARTICLE
    ISSN: 2320-5407 Int. J. Adv. Res. 5(4), 422-426 Journal Homepage: - www.journalijar.com Article DOI: 10.21474/IJAR01/3826 DOI URL: http://dx.doi.org/10.21474/IJAR01/3826 RESEARCH ARTICLE CHALLENGING ISSUES IN OSI AND TCP/IP MODEL. Dr. J. VijiPriya, Samina and Zahida. College of Computer Science and Engineering, University of Hail, Saudi Arabia. …………………………………………………………………………………………………….... Manuscript Info Abstract ……………………. ……………………………………………………………… Manuscript History A computer network is a connection of network devices to data communication. Multiple networks are connected together to form an Received: 06 February 2017 internetwork. The challenges of Internetworking is interoperating Final Accepted: 05 March 2017 between products from different manufacturers requires consistent Published: April 2017 standards. Network reference models were developed to address these challenges. Two useful reference models are Open System Key words:- Interconnection (OSI) and Transmission Control Protocol and Internet OSI, TCP/IP, Data Communication, Protocol (TCP/IP) serve as protocol architecture details the Protocols, Layers, and Encapsulation communication between applications on network devices. This paper depicts the OSI and TCP/IP models, their issues and comparison of them. Copy Right, IJAR, 2017,. All rights reserved. …………………………………………………………………………………………………….... Introduction:- Network reference models are called protocol architecture in which task of communication can be broken into sub tasks. These tasks are organized into layers representing network services and functions. The layered protocols are rules that govern end-to-end communication between devices. Protocols on each layer will interact with protocols on the above and below layers of it that form a protocol suite or stack. The most established TCP/IP suite was developed by Department of Defence's Project Research Agency DARPA based on OSI suite to the foundation of Internet architecture.
    [Show full text]
  • Chapter 2. Application Layer Table of Contents 1. Context
    Chapter 2. Application Layer Table of Contents 1. Context ........................................................................................................................................... 1 2. Introduction .................................................................................................................................... 2 3. Objectives ....................................................................................................................................... 2 4. Network application software ....................................................................................................... 2 5. Process communication ................................................................................................................. 3 6. Transport Layer services provided by the Internet ....................................................................... 3 7. Application Layer Protocols ........................................................................................................... 4 8. The web and HTTP .......................................................................................................................... 4 8.1. Web Terminology ................................................................................................................... 5 8.2. Overview of HTTP protocol .................................................................................................... 6 8.3. HTTP message format ...........................................................................................................
    [Show full text]
  • Application Protocol Data Unit Meaning
    Application Protocol Data Unit Meaning Oracular and self Walter ponces her prunelle amity enshrined and clubbings jauntily. Uniformed and flattering Wait often uniting some instinct up-country or allows injuriously. Pixilated and trichitic Stanleigh always strum hurtlessly and unstepping his extensity. NXP SE05x T1 Over I2C Specification NXP Semiconductors. The session layer provides the mechanism for opening closing and managing a session between end-user application processes ie a semi-permanent dialogue. Uses MAC addresses to connect devices and define permissions to leather and commit data 1. What are Layer 7 in networking? What eating the application protocols? Application Level Protocols Department of Computer Science. The present invention pertains to the convert of Protocol Data Unit PDU session. Network protocols often stay to transport large chunks of physician which are layer in. The term packet denotes an information unit whose box and tranquil is remote network-layer entity. What is application level security? What does APDU stand or Hop sound to rot the meaning of APDU The Acronym AbbreviationSlang APDU means application-layer protocol data system by. In the context of smart cards an application protocol data unit APDU is the communication unit or a bin card reader and a smart all The structure of the APDU is defined by ISOIEC 716-4 Organization. Application level security is also known target end-to-end security or message level security. PDU Protocol Data Unit Definition TechTerms. TCPIP vs OSI What's the Difference Between his Two Models. The OSI Model Cengage. As an APDU Application Protocol Data Unit which omit the communication unit advance a.
    [Show full text]
  • RT-ROS: a Real-Time ROS Architecture on Multi-Core Processors
    Future Generation Computer Systems 56 (2016) 171–178 Contents lists available at ScienceDirect Future Generation Computer Systems journal homepage: www.elsevier.com/locate/fgcs RT-ROS: A real-time ROS architecture on multi-core processors Hongxing Wei a,1, Zhenzhou Shao b, Zhen Huang a, Renhai Chen d, Yong Guan b, Jindong Tan c,1, Zili Shao d,∗,1 a School of Mechanical Engineering and Automation, Beihang University, Beijing, 100191, PR China b College of Information Engineering, Capital Normal University, Beijing, 100048, PR China c Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, 37996-2110, USA d Department of Computing, The Hong Kong Polytechnic University, Hong Kong, China article info a b s t r a c t Article history: ROS, an open-source robot operating system, is widely used and rapidly developed in the robotics Received 6 February 2015 community. However, running on Linux, ROS does not provide real-time guarantees, while real-time tasks Received in revised form are required in many robot applications such as robot motion control. This paper for the first time presents 20 April 2015 a real-time ROS architecture called RT-RTOS on multi-core processors. RT-ROS provides an integrated Accepted 12 May 2015 real-time/non-real-time task execution environment so real-time and non-real-time ROS nodes can be Available online 9 June 2015 separately run on a real-time OS and Linux, respectively, with different processor cores. In such a way, real-time tasks can be supported by real-time ROS nodes on a real-time OS, while non-real-time ROS nodes Keywords: Real-time operating systems on Linux can provide other functions of ROS.
    [Show full text]
  • Data Link Layer
    Data link layer Goals: ❒ Principles behind data link layer services ❍ Error detection, correction ❍ Sharing a broadcast channel: Multiple access ❍ Link layer addressing ❍ Reliable data transfer, flow control: Done! ❒ Example link layer technology: Ethernet Link layer services Framing and link access ❍ Encapsulate datagram: Frame adds header, trailer ❍ Channel access – if shared medium ❍ Frame headers use ‘physical addresses’ = “MAC” to identify source and destination • Different from IP address! Reliable delivery (between adjacent nodes) ❍ Seldom used on low bit error links (fiber optic, co-axial cable and some twisted pairs) ❍ Sometimes used on high error rate links (e.g., wireless links) Link layer services (2.) Flow Control ❍ Pacing between sending and receiving nodes Error Detection ❍ Errors are caused by signal attenuation and noise. ❍ Receiver detects presence of errors signals sender for retrans. or drops frame Error Correction ❍ Receiver identifies and corrects bit error(s) without resorting to retransmission Half-duplex and full-duplex ❍ With half duplex, nodes at both ends of link can transmit, but not at same time Multiple access links / protocols Two types of “links”: ❒ Point-to-point ❍ PPP for dial-up access ❍ Point-to-point link between Ethernet switch and host ❒ Broadcast (shared wire or medium) ❍ Traditional Ethernet ❍ Upstream HFC ❍ 802.11 wireless LAN MAC protocols: Three broad classes ❒ Channel Partitioning ❍ Divide channel into smaller “pieces” (time slots, frequency) ❍ Allocate piece to node for exclusive use ❒ Random
    [Show full text]
  • OSI Data Link Layer
    OSI Data Link Layer Network Fundamentals – Chapter 7 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1 Objectives Explain the role of Data Link layer protocols in data transmission. Describe how the Data Link layer prepares data for transmission on network media. Describe the different types of media access control methods. Identify several common logical network topologies and describe how the logical topology determines the media access control method for that network. Explain the purpose of encapsulating packets into frames to facilitate media access. Describe the Layer 2 frame structure and identify generic fields. Explain the role of key frame header and trailer fields including addressing, QoS, type of protocol and Frame Check Sequence. © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 2 Data Link Layer – Accessing the Media Describe the service the Data Link Layer provides as it prepares communication for transmission on specific media © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 3 Data Link Layer – Accessing the Media Describe why Data Link layer protocols are required to control media access © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 4 Data Link Layer – Accessing the Media Describe the role of framing in preparing a packet for transmission on a given media © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 5 Data Link Layer – Accessing the Media Describe the role the Data Link layer plays in linking the software and hardware layers © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 6 Data Link Layer – Accessing the Media Identify several sources for the protocols and standards used by the Data Link layer © 2007 Cisco Systems, Inc.
    [Show full text]
  • 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.
    [Show full text]
  • Is QUIC a Better Choice Than TCP in the 5G Core Network Service Based Architecture?
    DEGREE PROJECT IN INFORMATION AND COMMUNICATION TECHNOLOGY, SECOND CYCLE, 30 CREDITS STOCKHOLM, SWEDEN 2020 Is QUIC a Better Choice than TCP in the 5G Core Network Service Based Architecture? PETHRUS GÄRDBORN KTH ROYAL INSTITUTE OF TECHNOLOGY SCHOOL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE Is QUIC a Better Choice than TCP in the 5G Core Network Service Based Architecture? PETHRUS GÄRDBORN Master in Communication Systems Date: November 22, 2020 Supervisor at KTH: Marco Chiesa Supervisor at Ericsson: Zaheduzzaman Sarker Examiner: Peter Sjödin School of Electrical Engineering and Computer Science Host company: Ericsson AB Swedish title: Är QUIC ett bättre val än TCP i 5G Core Network Service Based Architecture? iii Abstract The development of the 5G Cellular Network required a new 5G Core Network and has put higher requirements on its protocol stack. For decades, TCP has been the transport protocol of choice on the Internet. In recent years, major Internet players such as Google, Facebook and CloudFlare have opted to use the new QUIC transport protocol. The design assumptions of the Internet (best-effort delivery) differs from those of the Core Network. The aim of this study is to investigate whether QUIC’s benefits on the Internet will translate to the 5G Core Network Service Based Architecture. A testbed was set up to emulate traffic patterns between Network Functions. The results show that QUIC reduces average request latency to half of that of TCP, for a majority of cases, and doubles the throughput even under optimal network conditions with no packet loss and low (20 ms) RTT. Additionally, by measuring request start and end times “on the wire”, without taking into account QUIC’s shorter connection establishment, we believe the results indicate QUIC’s suitability also under the long-lived (standing) connection model.
    [Show full text]
  • Lecture: TCP/IP 2
    TCP/IP- Lecture 2 [email protected] How TCP/IP Works • The four-layer model is a common model for describing TCP/IP networking, but it isn’t the only model. • The ARPAnet model, for instance, as described in RFC 871, describes three layers: the Network Interface layer, the Host-to- Host layer, and the Process-Level/Applications layer. • Other descriptions of TCP/IP call for a five-layer model, with Physical and Data Link layers in place of the Network Access layer (to match OSI). Still other models might exclude either the Network Access or the Application layer, which are less uniform and harder to define than the intermediate layers. • The names of the layers also vary. The ARPAnet layer names still appear in some discussions of TCP/IP, and the Internet layer is sometimes called the Internetwork layer or the Network layer. [email protected] 2 [email protected] 3 TCP/IP Model • Network Access layer: Provides an interface with the physical network. Formats the data for the transmission medium and addresses data for the subnet based on physical hardware addresses. Provides error control for data delivered on the physical network. • Internet layer: Provides logical, hardware-independent addressing so that data can pass among subnets with different physical architectures. Provides routing to reduce traffic and support delivery across the internetwork. (The term internetwork refers to an interconnected, greater network of local area networks (LANs), such as what you find in a large company or on the Internet.) Relates physical addresses (used at the Network Access layer) to logical addresses.
    [Show full text]