Chapter 1: Networking Today / Protocols and Models PDF

Chapter 1: Networking Today / Protocols and Models Introduction to Networks v7.0 (ITN) Modules 1 and 3 Chapter 1 (reference: CCNA ver 7 ITN modules 1 and 3) Topics ITN ref: Network Components 1.2...

Chapter 1: Networking Today / Protocols and Models Introduction to Networks v7.0 (ITN) Modules 1 and 3 Chapter 1 (reference: CCNA ver 7 ITN modules 1 and 3) Topics ITN ref: Network Components 1.2 Network Representations and Topologies 1.3 Common Types of Networks 1.4 Internet Connections 1.5 Reliable Networks 1.6 Network Trends 1.7 Rules of Communication 3.1 Network Protocols and Standards 3.2 Protocol Suites 3.3 Standards Organizations 3.4 Reference Models 3.5 Data Encapsulation 3.6 © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2 Network Components Network Representations and Topologies Common Types of Networks © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 3 Network Components Components of networks their Network Representations End devices aka hosts - where message originates or terminates. - Can function as server or client Intermediate devices - Regenerate and retransmit data - maintain information about the network paths Network Media - Medium which allows data to travel from source to destination - Can be metal wires (copper), fiber optic or wireless transmission © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 4 Network representations and topologies Topology Diagrams Network diagrams, often called topology diagrams, use symbols to represent devices within the network. Terms to know include NIC, ports and interfaces. Physical topology diagrams show the physical location of devices and cable installation. Logical topology diagrams illustrate devices, ports, and the addressing scheme of the network. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 5 LANs and WANs Types of Networks The two most common types of network infrastructures are:  Local Area Network (LAN)  Wide Area Network (WAN) A network serving a home, building LANs separated by geographic boundaries are or campus is a LAN connected by a network known as Wide Area Network (WAN) © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 6 LANs, WANs, and the Internet The Internet LANs and WANs may be connected into internetworks to form the internet. Internet is thus a interconnection of networks. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7 Internet Connections Reliable Networks Network Trends © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 8 Internet Connections Internet Access Technologies Connections to internet are provided by telecom companies known as internet service providers (ISPs) or simply service providers. Connection technologies include the following: Type of Connection Description Dedicated Leased Line Reserved circuits within the service provider’s network that connect distant offices with private voice and/or data networking. Normally used by companies Ethernet WAN This extends LAN access technology into the WAN. DSL Business DSL is available in various formats including Symmetric Digital Subscriber Lines (SDSL). Cable high bandwidth, always on, internet offered by cable television service providers. Satellite Provide a connection when a wired solution is not available. Cellular uses a cell phone network to connect to the internet. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 9 Converged Networks The Converging Network In old days, computer network, telephone network and TV broadcast network are all separate networks. Now, computer network, telephone network and TV broadcast network are converged into one network. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 10 Reliable Network Supporting Network Architecture 4 basic factors to consider for network architectures  Fault Tolerance Able to limit impact of a failure. No single point of failure. Achieved by having redundancies.  Scalability Ability to expand quickly to support new users, devices and applications without impacting the service being delivered.  Quality of Service (QoS) Ability to provide different quality of service to different QoS classifications of data. Allows urgent data (like voice data) to go through first and non-urgent data (like web page retrieval or email data) to go later.  Security Physical security of devices to prevent unauthorized access to the devices. Information security to prevent theft or modification of data travelling through the network. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11 Network Trends New trends Some of the top trends include: Bring Your Own Device (BYOD) Online collaboration Video Cloud computing © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 12 Rules of Communications Network Protocols and Standards Protocol Suites © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 13 Rules of communications Video – Devices in a Bubble This video will explain the protocols that devices use to see their place in the network and communicate with other devices. https://www.youtube.com/watch?v=fcliUinGtnQ © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 14 The Rules How computer communicates network card network card © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 15 Protocols What are network protocols.  All network communications are governed by protocols.  Protocols are rules communications will follow. Rules will vary depending on the protocol. Similar to grammar and sentence structure rules in human language.  Protocols must account for the following requirements: An identified sender and receiver Common language and grammar Speed and timing of delivery Confirmation or acknowledgment requirements © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 16 Protocols Network Protocol Requirements Common computer protocols must be in agreement and include the following requirements: Message encoding coverts data to another form for transmission. At receiving end, decoding will take place Message formatting and encapsulation the message must follow a specific format or structure. Message size – see next slide Message timing – see next slide Message delivery options – see next slide © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 17 Protocols Message Size and Timing During communication, a message is cut, or segmented, into smaller pieces.  There is a minimum and maximum size to each piece (or segment).  Addressing information is added, or encapsulated, to the segment to form a frame. Frame is then sent over the network.  At the receiving host, the messages are de-encapsulated and put back together (assembled) to be processed and interpreted.  Message timing refers to the following rules: Access method, ie know when to send or not to send data, to avoid collision Flow control to ensure source is not sending too fast for the recipient to receive. Response timeout, ie rule for what to do when no expected response from receiver is received by sender. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 18 https://www.youtube.com/watch?v=FJIFfkpUO7o © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 19 Protocols Different ways for message delivery Multicast: Unicast: one to many one to one Broadcast: one to ALL © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 20 Protocols Interaction of Protocols – Protocol Suite  There are many different network protocols, each with its own function, format and rules.  In a communication process, different networking protocols will work together to allow communication to take place.  A protocol suite is a set of protocols that work together to provide comprehensive network communication services.  The protocol suite for internet browsing (TCP/IP) includes the following protocols Application Protocol – Hypertext Transfer Protocol (HTTP) Transport Protocol – Transmission Control Protocol (TCP) Internet Protocol – Internet Protocol (IP) Network Access Protocols – Ethernet or Wifi Wireless Other protocol suite includes OSI, Apple Talk and Novell Netware. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 21 Protocol Suites TCP/IP Protocol Suite and Communication  Nowadays, TCP/IP protocol suite is mainly used.  TCP/IP protocol suite includes many protocols and continues to evolve to support new services.  More popular ones are shown in picture. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 22 Standards Organizations Reference Models Data Encapsulation © 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 23 Standards Organizations Open Standards Open standards encourage: interoperability competition innovation Standards organizations are: vendor-neutral non-profit organizations established to develop and promote the concept of open standards. Standards organizations involved with the development and support of TCP/IP Internet Corporation for Assigned Names and Numbers (ICANN) - Coordinates IP address allocation, the management of domain names, and assignment of other information Internet Assigned Numbers Authority (IANA) - Oversees & manages IP address allocation, domain name management, and protocol identifiers for ICANN © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 24 Reference Models Benefits of Using a Layered Model Models help to explain how network works. A layered model can modularize the operations of a network into manageable layers. 2 main models are OSI Reference Model and TCP/IP Protocol model. Benefits of layered model are  Assist 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. Protocol at a layer can only communicate with the layer directly above or directly below it. NO cross layer communication.  Fostering competition because products from different vendors can work together.  Preventing technology or capability changes in one layer from affecting other layers above and below.  Providing a common language to describe networking functions and capabilities. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 25 Reference models Open System Interconnection (OSI) 7 Layers Reference Model OSI 7 layers reference model for data communication, developed by International Organization for Standardization (ISO) © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 26 Reference Models The TCP/IP Reference Model © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 27 Reference Models Comparing the OSI and TCP/IP Models © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 28 Data Encapsulation Communicating the Messages  Messages are segmented and encapsulated when sent and de-encapsulated and assembled when received. Advantages of segmenting message Different conversations can be interleaved Increased reliability of network communications Disadvantages of segmenting message disadvantage Increased level of complexity  Sequencing messages - number the segments for reassembly at the destination. TCP protocol will do that. © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 29 Data Encapsulation Protocol Data Units (PDUs) Protocol Data Unit refers to the segmented (or cut) data at each layer.  Data – Application  Segment - Transport  Packet - Network  Frame – Data link  Bits - Physical © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 30 Data Encapsulation Protocol Encapsulation and De-Encapsulation Encapsulation – Add header information to a PDU when PDU travels down the layers De-Encapsulation – Remove header information from PDU when PDU travels up the layers Encapsulation when passing down the stack De-Encapsulation © 2019 when Cisco and/or its affiliates. All rights passing reserved. up Cisco Confidential 31 the stack End of Chapter © 2019 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 32