Chapter 3: Network Protocols and Communications Introduction to Networks Intro to Networks v5
Message Delivery Options IPv4 Unicast One-to-One Multicast One-to-Many Broadcast One-to-All IPv6 Unicast One-to-One Multicast One-to-Many Anycast One-to-Nearest Intro to Networks v5 2
Network Protocols How the message is formatted or structured The process by which networking devices share information about pathways with other networks How and when error and system messages are passed between devices The setup and termination of data transfer sessions Protocol suites are sets of rules that work together to help solve a problem. Intro to Networks v5 3
Network Protocols Address Resolution Protocol (ARP) used to discover the MAC address of any host on the local network Reverse ARP Used to find the IP address of the local machine Intro to Networks v5 4
Protocol Suites and Industry Standards From the user perspective, what is the correct order of the protocol stack that is used to prepare a web request for transmission? HTTP TCP IP Ethernet Intro to Networks v5 5
Development of TCP/IP Proprietary protocols are developed by organizations who have control over their definition and operation Intro to Networks v5 6
Standards Organizations: ISOC, IAB, and IETF The ISCO is responsible for promoting open development of standards and protocols, evolution, and Internet use throughout the world Intro to Networks v5 7
Standards Organizations: Institute of Electrical and Electronics Engineers (IEEE) Provides educational and career enhancement opportunities to promote the skills and knowledge with the electronics industry Creates and maintains standards affecting a wide range of industries including power and energy, healthcare, telecommunications, and networking Important to us: IEEE 802.3 CSMA/CD or Ethernet IEEE 802.11 CSMA/CA or Wireless Intro to Networks v5 8
Other Standards Organization The Electronic Industries Alliance (EIA) Best known for its standards related to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment The Telecommunications Industry Association (TIA) responsible for developing communication standards in a variety of areas including radio equipment, cellular towers, Voice over IP (VoIP) devices, satellite communications, and more. Many of their standards are produced in collaboration with the EIA The International Telecommunications Union Telecommunications Standardization Sector (ITU-T) defines standards for video compression, Internet Protocol Television (IPTV), and broadband communications, such as a digital subscriber line (DSL) The Internet Corporation for Assigned Names and Numbers (ICANN) Coordinates IP address allocation, the management of domain names used by DNS, and the protocol identifiers or port numbers used by TCP and UDP protocols The Internet Assigned Numbers Authority (IANA) Responsible for overseeing and managing IP address allocation, domain name management, and protocol identifiers Intro to Networks v5 9
The International Organization for Standards (ISO) The world s largest developer of international standards for a wide variety of products and services Best known for its Open Systems Interconnection (OSI) reference model Intro to Networks v5 10
OSI Reference Model Layer 7 The Application layer provides the means for end-toend connectivity between individuals in the human network using data networks. Layer 6 The Presentation layer provides for common representation of the data transferred between application layer services. Layer 5 The Session layer provides services to the presentation layer to organize its dialogue and to manage data exchange. Layer 4 The Transport layer defines services to segment, transfer, and reassemble the data for individual communications between the end devices. It describes the ordered and reliable delivery of data between source and destination. Layer 3 The Network layer provides services to exchange the individual pieces of data over the network between identified end devices. IP or Logical addressing Layer 2 The Data Link layer protocols describe methods for exchanging data frames between devices over a common media. MAC or physical addressing. Layer 1 The 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. Intro to Networks v5 11
The Benefits of Using a Layered Model An advantage of network devices using open standard protocols: A host and a server running different operating systems can successfully exchange data Fosters competition among device and software vendors by enforcing the compatibility of their products Intro to Networks v5 12
The TCP/IP Reference Model Intro to Networks v5 13
Interaction of TCP/IP Model Protocols Application Protocol Hypertext Transfer Protocol (HTTP) Defines the content and formatting of the requests and responses that are exchanged between the client and server. Transport Protocol Transmission Control Protocol (TCP) is responsible for controlling the size and rate of the HTTP messages exchanged between server and client. It segments the messages and manages the segments in the individual conversation between the host and destination. Internet Protocol Internet Protocol (IP) or logical address is a unique host address for data communications at the internet layer Network Access Protocols Describe two primary functions: 1) communication over a data link and 2) the physical transmission of data on the network media: Data-link management protocols take the packets from IP and format them to be transmitted over the media. Physical media standards and protocols govern how the signals are sent and how they are interpreted by the receiving clients Intro to Networks v5 14
TCP/IP Protocol Suite and Communication Intro to Networks v5 15
Comparing the OSI and TCP/IP Models The TCP/IP transport layer and OSI Layer 4 provide similar services and functions. Intro to Networks v5 16
Data Encapsulation Communicating the Messages Segments are sent from the transport layer to the internet layer Benefits: Different conversations can be interleaved Increased reliability of network communications Disadvantage: Increased level of complexity Intro to Networks v5 17
Message Size and Segmenting The size restrictions of frames require the source host to break a long message into individual pieces that meet both the minimum and maximum size requirements Each segment is encapsulated in a separate frame with the address information, and is sent over the network At the receiving host, the messages are deencapsulated and put back together to be processed and interpreted Flow Control Used to ensure that packets are not dropped because too much data is being sent too quickly Intro to Networks v5 18
Protocol Data Units (PDUs) General term used to describe a piece of data at any layer of a networking model. Data Segment Packet Logical addresses are encapsulated Frame Bits received from the network medium by the NIC of a host Bits Intro to Networks v5 19
Network Addresses & Data Link addresses Network Address (Logical Address) Source IP address Destination IP address Data Link Address (Physical Address) Source MAC address Destination MAC address Intro to Networks v5 20
Communicating with Device / Same Network PC 1 192.168.1.110 AA-AA-AA-AA-AA-AA ARP Request R1 192.168.1.1 11-11-11-11-11-11 R2 172.16.1.99 22-22-22-22-22-22 Web Server 172.16.1.99 AB-CD-EF-12-34-56 PC 2 192.168.1.111 BB-BB-BB-BB-BB-BB FTP Server 192.168.1.9 CC-CC-CC-CC-CC-CC What address does a NIC use when deciding whether to accept a frame? Intro to Networks v5 21
Communicating with Device / Different Network PC 1 192.168.1.110 AA-AA-AA-AA-AA-AA ARP Request R1 192.168.1.1 11-11-11-11-11-11 R2 172.16.1.1 22-22-22-22-22-22 PC 2 192.168.1.111 BB-BB-BB-BB-BB-BB FTP Server 192.168.1.9 CC-CC-CC-CC-CC-CC Web Server 172.16.1.99 AB-CD-EF-12-34-56 Which protocol is used by a computer to find the MAC address of the default gateway? Intro to Networks v5 22
Accessing Remote Resources Using Wireshark to View Network Traffic Intro to Networks v5 23
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