SCP-NET101-PRELIM-WEEK-5-LEC.pdf

ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached Week 5 Lesson Title Principles of Communications...

ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached Week 5 Lesson Title Principles of Communications Explain the importance of standards and protocols in Learning Outcome(s) network communications. At SJPIICD, I Matter! LEARNING INTENT! Terms to Ponder Protocol or Network Protocol is an established set of rules that determine how data is transmitted between different devices in the same network. Essentially, it allows connected devices to communicate with each other, regardless of any differences in their internal processes, structure or design. Internet standards ensure that all devices connecting to the network implement the same set of rules or protocols in the same manner. The Internet Engineering Task Force (IETF) is an open standards organization, which develops and promotes voluntary Internet standards, in particular the standards that comprise the Internet protocol suite. TCP/IP, or the Transmission Control Protocol/Internet Protocol, is a suite of communication protocols used to interconnect network devices on the internet. The OSI model (Open Systems Interconnect) is a conceptual model created by the ISO (International Organization for Standardization) which enables diverse communication systems to communicate using standard protocols. Essential Content Principles of Communication: The Three Elements The primary purpose of any network is to provide us with a method to communicate and share information. From the very earliest primitive humans to the most advanced scientists of today, sharing information with others is crucial for human advancement. SCP-NET101 | 47  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached All communication begins with a message, or information, that must be sent from one individual or device to another. The methods used to send, receive and interpret messages change over time as technology advances. Three elements in communication 1. Message source or sender - Message sources are people, or electronic devices, that need to communicate a message to other individuals or devices. 2. Destination or receiver - The destination receives the message and interprets it. 3. Transmission medium or channel - It provides the pathway over which the message can travel from source to destination. Both figures show that communication between humans and communication between computers have much in common. They each require a message source, a transmitter, a transmission medium, a receiver and a message destination. Communication Protocols Communication in our daily lives takes many forms and occurs in many environments. We have different expectations depending on whether we are chatting via the Internet or participating in a job interview. Each situation has its corresponding expected behaviors and styles. Before beginning to communicate with each other, we establish rules or agreements to govern the conversation. These rules, or protocols, must be followed in order for the message to be successfully delivered and understood. Among the protocols that govern successful human communication are: 1. An identified sender and receiver 2. Agreed upon method of communicating (face-to-face, telephone, letter, photograph) 3. Common language and grammar 4. Speed and timing of delivery 5. Confirmation or acknowledgment requirements The techniques that are used in network communications share these fundamentals with human conversations. Why Protocols Matter? Just like humans, computers use rules, or protocols, in order to communicate. Protocols are required for computers to properly communicate across the network. In both a wired and wireless environment, a local network is defined as an area where all hosts must "speak the same language" or in computer terms "share a common protocol". If everyone in the same room spoke a different language they would not be able to communicate. Likewise, if devices in a local network did not use the same protocols they would not be able to communicate. SCP-NET101 | 48  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached Networking protocols define many aspects of communication over the local network, including: message format, message size, timing, encoding, and message patterns. a. Timing - Many network communication functions are dependent on timing. Timing determines the speed at which the bits are transmitted across the network. It also affects when an individual host can send data and the total amount of data that can be sent in any one transmission. b. Message Size - The rules that govern the size of the pieces communicated across the network are very strict. They can also be different, depending on the channel used. When a long message is sent from one host to another over a network, may be necessary to break the message into smaller pieces in order to ensure that the message can be delivered reliably. c. Encapsulation - Each message transmitted on a network must include a header that contains addressing information that identifies the source and destination hosts, otherwise it cannot be delivered. Encapsulation is the process of adding this information to the pieces of data that make up the message. In addition to addressing, there may be other information in the header that ensures that the message is delivered to the correct application on the destination host. d. Message Format - When a message is sent from source to destination, it must use a specific format or structure. Message formats depend on the type of message and the channel that is used to deliver the message. The popup text for the Encoding circle reads Messages sent across the network are first converted into bits by the sending host. Each bit is encoded into a pattern of sounds, light waves, or electrical impulses depending on the network media over which the bits are transmitted. The destination host receives and decodes the signals in order to interpret the message. e. Message Pattern - Some messages require an acknowledgement before the next message can be sent. This type of request/response pattern is a common aspect of many networking protocols. But, there are other types of messages that may be simply streamed across the network, without concern as to whether or not they reach their destination. The Internet and Standards With the increasing number of new devices and technologies coming online, how is it possible to manage all the changes and still reliably deliver services such as email? The answer is Internet standards. A standard is a set of rules that determines how something must be done. Networking and Internet standards ensure that all devices connecting to the network implement the same set of rules or protocols in the same manner. Using standards, it is possible for different types of devices to send information to each other over the Internet. For example, the way in which an email is formatted, forwarded, and received by all devices is done according to a standard. If one person sends an email via a personal computer, another person can use a mobile phone to SCP-NET101 | 49  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached receive and read the email as long as the mobile phone uses the same standards as the personal computer. Network Standards Organizations An Internet standard is the end result of a comprehensive cycle of discussion, problem solving, and testing. These different standards are developed, published, and maintained by a variety of organizations. When a new standard is proposed, each stage of the development and approval process is recorded in a numbered Request for Comments (RFC) document so that the evolution of the standard is tracked. RFCs for Internet standards are published and managed by the Internet Engineering Task Force (IETF). Stacking Them Up Successful communication between hosts requires interaction between a number of protocols. These protocols are implemented in software and hardware that are installed on each host and networking device. The interaction between the different protocols on a device can be shown as a protocol stack. A stack illustrates the protocols as a layered hierarchy, with each higher-level protocol depending on the services of the protocols shown in the lower levels. The separation of functions enables each layer in the stack to operate independently of others. For example, you can use your laptop computer connected to a cable modem at home to access your favorite website, or view the same website on your laptop using wireless at the library. The function of the web browser is not affected by the change in the physical location nor the method of connectivity. SCP-NET101 | 50  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached Using a Layered Model Layered models help us visualize how the various protocols work together to enable network communications. A layered model depicts the operation of the protocols occurring within each layer, as well as the interaction with the layers above and below it. The layered model has many benefits: a. Assists in protocol design, because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below. b. Fosters competition because products from different vendors can work together. c. Enables technology changes to occur at one level without affecting the other levels. d. Provides a common language to describe networking functions and capabilities. The first layered model for internetwork communications was created in the early 1970s and is referred to as the Internet model. It defines four categories of functions that must occur in order for communications to be successful. The suite of TCP/IP protocols that are used for Internet communications follows the structure of this model. Because of this, the Internet model is commonly referred to as the TCP/IP model. Different Types of Network Models There are two basic types of models that we use to describe the functions that must occur in order for network communications to be successful: protocol models and reference models: 1. Protocol model - This model closely matches the structure of a particular protocol suite. A protocol suite includes the set of related protocols that typically provide all the functionality required for people to communicate with the data network. SCP-NET101 | 51  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached The TCP/IP model is a protocol model, because it describes the functions that occur at each layer of protocols within the TCP/IP suite. 2. Reference model - This type of model describes the functions that must be completed at a particular layer, but does not specify exactly how a function should be accomplished. A reference model is not intended to provide a sufficient level of detail to define precisely how each protocol should work at each layer. The primary purpose of a reference model is to aid in clearer understanding of the functions and processes necessary for network communications. The most widely known internetwork reference model was created by the Open Systems Interconnection project at the International Organization for Standardization (ISO). It is used for data network design, operation specifications, and troubleshooting. This model is commonly referred to as the OSI model. Working with the OSI Model 1. Physical layer protocols - describe the mechanical, electrical, functional, and procedural means to activate, maintain, and de- activate physical connections for bit transmission to and from a network device. 2. Data link layer protocols - describe methods for exchanging data frames between devices over a common medium. 3. Network layer - provides services to exchange the individual pieces of data over the network between identified end devices. 4. Transport layer - defines services to segment, transfer, and reassemble the data for individual communications between the end devices. 5. Session layer - provides services to the presentation layer to organize its dialogue and to manage data exchange. 6. Presentation layer - provides for common representation of the data transferred between application layer services. 7. Application layer provides the means for end-to-end connectivity between individuals in the human network using data networks. SCP-NET101 | 52  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached Dividing the Tasks Moving data across a network can be visualized using the seven layers of the OSI model, as shown in the figure. The OSI model breaks network communications down into multiple processes. Each process is a small part of the larger task. For example, in a vehicle manufacturing plant, the entire vehicle is not assembled by one person. Rather, the vehicle moves from station to station where specialized teams add specific components. The complex task of assembling a vehicle is made easier by breaking it into manageable and logical tasks. This process also makes troubleshooting easier. When a problem occurs in the manufacturing process, it is possible to isolate the problem to the specific task where the defect was introduced, and then fix it. In a similar manner, the OSI model helps us to focus on a layer when troubleshooting to identify and resolve network problems. Networking teams often refer to different functions occurring on a network by the number of the OSI model layer that specifies that functionality. For example, the process of encoding the data bits for transmission across the media occurs at Layer 1, the physical layer. The formatting of data so it can be interpreted by the network connection in your laptop or phone is described at Layer 2, the data link layer. Comparing the OSI and TCP/IP Model Because TCP/IP is the protocol suite in use for Internet communications, why do we need to learn the OSI model as well? The TCP/IP model is a method of visualizing the interactions of the various protocols that make up the TCP/IP protocol suite. It does not describe general functions that are necessary for all networking communications. It describes the networking functions specific to those protocols in use in the SCP-NET101 | 53  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached TCP/IP protocol suite. For example: At the network access layer, the TCP/IP protocol suite does not specify which protocols to use when transmitting over a physical medium, nor the method of encoding the signals for transmission. OSI Layers 1 and 2 discuss the necessary procedures to access the media and the physical means to send data over a network. The protocols that make up the TCP/IP protocol suite can be described in terms of the OSI reference model. The functions that occur at the Internet layer in the TCP/IP model are contained in the network layer of the OSI Model, as shown in the figure. The transport layer functionality is the same between both models. However, the network access layer and the application layer of the TCP/IP model are further divided in the OSI model to describe discrete functions that must occur at these layers. Protocols for the Wired Network Why Ethernet? In the early days of networking, each vendor used their own, proprietary methods of interconnecting network devices and networking protocols. If you bought equipment from different vendors, there was no guarantee that the equipment would work together. Equipment from one vendor might not communicate with equipment from another. As networks became more widespread, standards were developed that defined rules by which network equipment from different vendors operated. Standards are beneficial to networking in many ways: Facilitate design Simplify product development Promote competition Provide consistent interconnections Facilitate training Provide more vendor choices for customers There is no official local area networking standard protocol, but over time, one technology, Ethernet, has become more common than the others. Ethernet protocols define how data is formatted and how it is transmitted over the wired network. The Ethernet standards specify protocols that operate at Layer 1 and Layer 2 of the OSI model. It has become a de facto standard, which means that Ethernet is the technology used by almost all wired local area networks, as shown in the figure above. SCP-NET101 | 54  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached Ethernet is Constantly Evolving The Institute of Electrical and Electronic Engineers, or IEEE (pronounced eye-triple-e), maintains the networking standards, including Ethernet and wireless standards. IEEE committees are responsible for approving and maintaining the standards for connections, media requirements and communications protocols. Each technology standard is assigned a number that refers to the committee that is responsible for approving and maintaining the standard. The committee responsible for the Ethernet standards is 802.3. Since the creation of Ethernet in 1973, standards have evolved for specifying faster and more flexible versions of the technology. This ability for Ethernet to improve over time is one of the main reasons that it has become so popular. Each version of Ethernet has an associated standard. For example, 802.3 100BASE-T represents the 100 Megabit Ethernet using twisted-pair cable standards. The standard notation translates as: 100 is the speed in Mb/s BASE stands for baseband transmission T stands for the type of cable, in this case, twisted-pair. Early versions of Ethernet were relatively slow at 10 Mb/s. The latest versions of Ethernet operate at 10 Gigabits per second and more. Imagine how much faster these new versions are than the original Ethernet networks. Ethernet Addressing All communication requires a way to identify the source and destination. The source and destination in human communication are represented by names. When your name is called, you listen to the message and respond. Other people in the room may hear the message, but they ignore it because it is not addressed to them. On Ethernet networks, a similar method exists for identifying source and destination hosts. Each host connected to an Ethernet network is assigned a physical address which serves to identify the host on the network. Every Ethernet network interface has a physical address assigned to it when it is manufactured. This address is known as the Media Access Control (MAC) Address. The MAC address identifies each source and destination host on the network. In the figures below look at how frames are being sent between hosts. SCP-NET101 | 55  ST. JOHN PAUL II COLLEGE OF DAVAO COLLEGE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY Physically Detached Yet Academically Attached SELF-SUPPORT: You can click the URL Search Indicator below to help you further understand the lessons. Search Indicator Principles of Communication http://static-course-assets.s3.amazonaws.com/NetEss/en/index.html#3.1.1.1 What is protocol? And its types https://ecomputernotes.com/computernetworkingnotes/computer- network/protocol About the IETF https://www.internetsociety.org/about-the-ietf/ TCP/IP, or the Transmission Control Protocol/Internet Protocol https://searchnetworking.techtarget.com/definition/TCP-IP What is the OSI model? https://www.cloudflare.com/learning/ddos/glossary/open-systems- interconnection-model-osi/ SCP-NET101 | 56