NETW311-PRELIM-REVIEWER.pdf

Module 1: Networking today Network Media 1.1 Networks Affects Our Lives Communication across a network is carried through a medium Networks Connect Us...

Module 1: Networking today Network Media 1.1 Networks Affects Our Lives Communication across a network is carried through a medium Networks Connect Us which allows a message to travel from source to destination. Communication is almost as important to us as our reliance on Media Types Description air, water, food and shelter. In today’s world, through the use of Metal wires within cables Uses electrical impulses. networks, we are connected like never before. (Copper) No Boundaries Glass or plastic fibers within Uses pulses of light. World without boundaries cables (Fiber-optic cable) Global communities Wireless transmission Uses modulation of specific Human network (Wireless) frequencies of electromagnetic 1.2 Networks Affect Our Lives waves. NETWORK COMPONENTS 1.3 Network Representations and Topologies Host Roles Network Representations Every computer on a network is called a host or end device. Network diagrams, often called topology diagrams, use Servers are computers that provide information to end devices: symbols to represent devices within the network. o email servers Important terms to know include: o web servers o Network Interface Card (NIC) o file server o Physical Port Clients are computers that send requests to the servers to o Interface retrieve information: Note: Often, the terms port and interface are used o web page from a web server interchangeably o email from an email server End Devices – desktop computer, laptop, printer, IP phone, wireless tablet, telepresence endpoint Intermediary Devices – wireless router, LAN switch, router, multilayer switch, firewall appliance Network Media – wireless media, LAN media, WAN media Topology Diagrams Server Description Physical topology diagrams illustrate the physical location of Type intermediary devices and cable installation. Email Email server runs email server software. Clients use Logical topology diagrams illustrate devices, ports, and the client software to access email. addressing scheme of the network. Web Web server runs web server software. Clients use 1.4 Common Types of Networks browser software to access web pages. Networks of Many Sizes File File server stores corporate and user files. The client Small Home Networks – connect a few computers to each devices access these files. other and the Internet Peer-to-Peer Small Office/Home Office – enables computer within a home It is possible to have a device be a client and a server in a Peer- or remote office to connect to a corporate network to-Peer network. This type of network design is only Medium to Large Networks – many locations with hundreds recommended for very small networks. or thousands of interconnected computers World Wide Networks – connects hundreds of millions of computers world-wide – such as the internet LANs and WANs Network infrastructures vary greatly in terms of: Size of the area covered Number of users connected Advantages Disadvantages Number and types of services available Easy to set up No centralized administration Area of responsibility Less complex Not as secure Two most common types of networks: Lower cost Not scalable Local Area Network (LAN) – A LAN is a network infrastructure Used for simple tasks: Slower performance that spans a small geographical area. transferring files and sharing Wide Area Network (WAN) – A WAN is a network infrastructure printers that spans a wide geographical area. LAN WAN End Devices Interconnect end devices in a Interconnect LANs over wide An end device is where a message originates from or where it is limited area geographical areas received. Data originates with an end device, flows through the Administered by a single Typically administered by one network, and arrives at and end device. organization or individual or more service providers. Provide high-speed bandwidth Typically provide slower speed Intermediary Network Devices to internal devices link between LANs. An intermediary device interconnects end devices. Examples The Internet include switches, wireless access points, routers, and firewalls. The internet is a worldwide collection of interconnected LANs and Management of data as it flows through a network is also the WANs. role of an intermediary device, including: LANs are connected to each other using WANs. o Regenerate and retransmit data signals. WANs may use copper wires, fiber optic cables, and wireless o Maintain information about what pathways exist in transmissions. the network. The internet is not owned by any individual or group. The following o Notify other devices of errors and communication groups were developed to help maintain structure on the internet: failures. IETF Intermediary Devices - Wireless router, LAN switch, Router, ICANN Multilayer Switch, Firewall Appliance IAB Intranets and Extranets Network Architecture An intranet is a private collection of LANs and WANs internal Network Architecture refers to the technologies that support to an organization that is meant to be accessible only to the the infrastructure that moves data across the network. organization’s members or others with authorization. There are four basic characteristics that the underlying An organization might use an extranet to provide secure architectures need to address to meet user expectations: access to their network for individuals who work for a different o Fault Tolerance organization that need access to their data on their network. o Scalability 1.5 Internet Connections o Quality of Service (QoS) Internet Access Technologies o Security There are many ways to connect users and organizations to the Fault Tolerance internet: A fault tolerant network limits the impact of a failure by limiting Popular services for home users and small offices include the number of affected devices. Multiple paths are required for broadband cable, broadband digital subscriber line (DSL), fault tolerance. wireless WANs, and mobile services. Reliable networks provide redundancy by implementing a Organizations need faster connections to support IP phones, packet switched network: video conferencing and data center storage. o Packet switching splits traffic into packets that are Business-class interconnections are usually provided by service routed over a network. providers (SP) and may include: business DSL, leased lines, and o Each packet could theoretically take a different path Metro Ethernet. to the destination. Home and Small Office Internet Connections This is not possible with circuit-switched networks which Connection Description establish dedicated circuits. Cable High bandwidth, always on, internet offered by Redundant connections allow for alternative paths if a device or a cable television service providers. link fails. The user experience is unaffected. DSL High bandwidth, always on, internet connection Scalability that runs over a telephone line. A scalable network can expand quickly and easily to support Cellular Uses a cell phone network to connect to the new users and applications without impacting the performance internet. of services to existing users. Satellite Major benefit to rural areas without Internet Network designers follow accepted standards and protocols in Service Providers. order to make the networks scalable. Dial-up An inexpensive, low bandwidth option using a Additional users and whole networks can be connected to the telephone modem. internet without degrading performance for existing users. Business Internet Connections Quality of Service Corporate business connections may require: Voice and live video transmissions require higher expectations higher bandwidth for those services being delivered. dedicated connections Have you ever watched a live video with constant breaks and managed services pauses? This is caused when there is a higher demand for Type of Description bandwidth than available – and QoS isn’t configured. connection o Quality of Service (QoS) is the primary mechanism Dedicated These are reserved circuits within the service used to ensure reliable delivery of content for all leased line provider’s network that connect distant offices users. with private voice and/or data networking o With a QoS policy in place, the router can more easily Ethernet WAN This extends LAN access technology into the manage the flow of data and voice traffic. WAN Quality of Service managed by the router, ensures that priorities are DSL Business DSL is available in various formats matched with the type of communication and its importance to the including Symmetric Digital Subscriber Lines organization. (SDSL) o We pages can usually receive a lower priority Satellite This can provide a connection when a wired o A voice over IP (VoIP) Call will need priority to maintain a solution is not available smooth, uninterrupted user experience. The Converging Network Network Security Before converged networks, an organization would have been There are two main types of network security that must be separately cabled for telephone, video, and data. Each of these addressed: networks would use different technologies to carry the signal. Network infrastructure security Each of these technologies would use a different set of rules Physical security of network devices and standards. Preventing unauthorized access to the devices Converged data networks carry multiple services on one link Information Security including: Protection of the information or data transmitted over the o data network o voice Three goals of network security: o video Confidentiality – only intended recipients can read the data Converged networks can deliver data, voice, and video over the Integrity – assurance that the data has not be altered with same network infrastructure. The network infrastructure uses during transmission the same set of rules and standards. Availability – assurance of timely and reliable access to data for Packet Tracer – Network Representation authorized users In this Packet tracer you will do the following: Administrators can protect the network with software and hardware The network model in this activity incorporates many of the security and by preventing physical access to network devices. technologies that you will master in your CCNA studies. Security measures protect the network from unauthorized access. Note: It is not important that you understand everything you see and do in this activity. 1.6 Reliable Networks 1.7 Network Trends Technology Trend in the Home Recent Trends Smart home technology is a growing trend that allows The role of the network must adjust and continually transform technology to be integrated into every-day appliances which in order to be able to keep up with new technologies and end allows them to interconnect with other devices. user devices as they constantly come to the market. Ovens might know what time to cook a meal for you by Several new networking trends that effect organizations and communicating with your calendar on what time you are consumers: scheduled to be home. o Bring Your Own Device (BYOD) Smart home technology is currently being developed for all o Online collaboration rooms within a house. o Video communications Powerline Networking o Cloud computing Powerline networking can allow devices to connect to a LAN Bring Your Own Device where data network cables or wireless communications are not Bring Your Own Device (BYOD) allows users to use their own a viable option. devices giving them more opportunities and greater flexibility. Using a standard powerline adapter, devices can connect to the BYOD allows end users to have the freedom to use personal LAN wherever there is an electrical outlet by sending data on tools to access information and communicate using their: certain frequencies. o Laptops Powerline networking is especially useful when wireless access o Netbooks points cannot reach all the devices in the home. o Tablets Wireless Broadband o Smartphones In addition to DSL and cable, wireless is another option used to o E-readers BYOD means any device, with any ownership, used anywhere. connect homes and small businesses to the internet. Online Collaboration More commonly found in rural environments, a Wireless Collaborate and work with others over the network on joint Internet Service Provider (WISP) is an ISP that connects projects. subscribers to designated access points or hotspots. Collaboration tools including Cisco WebEx (shown in the figure) Wireless broadband is another solution for the home and small gives users a way to instantly connect and interact. businesses. Collaboration is a very high priority for businesses and in o Uses the same cellular technology used by a smart education. phone. Cisco Webex Teams is a multifunctional collaboration tool. o An antenna is installed outside the house providing o send instant messages wireless or wired connectivity for devices in the o post images home. o post videos and links 1.8 Network Security Video Communication Security Threats Video calls are made to anyone, regardless of where they are Network security is an integral part of networking regardless of located. the size of the network. Video conferencing is a powerful tool for communicating with The network security that is implemented must take into others. account the environment while securing the data, but still Video is becoming a critical requirement for effective allowing for quality of service that is expected of the network. collaboration. Securing a network involves many protocols, technologies, Cisco TelePresence powers is one way of working where devices, tools, and techniques in order to secure data and everyone, everywhere. mitigate threats. Cloud Computing Threat vectors might be external or internal. Cloud computing allows us to store personal files or backup our External Threats: data on servers over the internet. Viruses, worms, and Trojan horses o Applications can also be accessed using the Cloud. Spyware and adware o Allows businesses to deliver to any device anywhere Zero-day attacks in the world. Threat Actor attacks Cloud computing is made possible by data centers. Denial of service attacks o Smaller companies that can’t afford their own data Data interception and theft centers, lease server and storage services from larger Identity theft data center organizations in the Cloud. Internal Threats: Four types of Clouds: lost or stolen devices Public Clouds - Available to the general public through a pay- accidental misuse by employees per-use model or for free. malicious employees Private Clouds - Intended for a specific organization or entity Security Solutions such as the government. Security must be implemented in multiple layers using more Hybrid Clouds than one security solution. o Made up of two or more Cloud types – for example, Network security components for home or small office network: part custom and part public. o Antivirus and antispyware software should be o Each part remains a distinctive object but both are installed on end devices. connected using the same architecture. o Firewall filtering used to block unauthorized access to Custom Clouds the network. o Built to meet the needs of a specific industry, such as Larger networks have additional security requirements: healthcare or media. o Dedicated firewall system o Access control lists (ACL) o Can be private or public. o Intrusion prevention systems (IPS) o Virtual private networks (VPN)  The study of network security starts with a clear understanding ACCESS METHODS of the underlying switching and routing infrastructure. Console – A physical management port used to access a device 1.9 The IT Professional in order to provide maintenance, such as performing the initial CCNA configurations The Cisco Certified Network Associate (CCNA) certification: Secure Shell (SSH) – Establishes a secure remote CLI o demonstrates that you have a knowledge of connection to a device, through a virtual interface, over a foundational technologies network. (Note: This is the recommended method for remotely o ensures you stay relevant with skills needed for the connecting to a device.) adoption of next-generation technologies. Telnet – Establishes an insecure remote CLI connection to a The new CCNA focus: device over the network. (Note: User authentication, passwords o IP foundation and security topics and commands are sent over the network in plain text.) o Wireless, virtualization, automation, and network Terminal Emulation Programs programmability. Terminal emulation programs are used to connect a network New DevNet certifications at the associate, specialist and device by either a console port or by an SSH/Telnet connection. professional levels, to validate your software development skills. There are several terminal emulation programs to chose from Specialist certification validate your skills in line with your job such as PuTTY, Tera Term and SecureCRT. role and interests. 2.2 IOS Navigation Network Jobs PRIMARY COMMAND MODES At www.netacad.com you can click the Careers menu and then User EXEC Mode: select Employment opportunities. Allows access to only a limited number of basic monitoring o Find employment opportunities by using the Talent commands Bridge Matching Engine. Identified by the CLI prompt that ends with the > symbol o Search for jobs with Cisco, Cisco partners and Privileged EXEC Mode: distributors seeking Cisco Networking Academy Allows access to all commands and features students and alumni. Identified by the CLI prompt that ends with the # symbol CONFIGURATION MODE AND SUBCONFIGURATION MODES Global Configuration Mode – used to access configuration options on the device. Switch(config)# Line Configuration Mode – used to configure console, SSH, Telnet or AUX access. Switch(config-line)# Interface Configuration Mode – used to configure a switch port or router interface. Switch(config-if)# NAVIGATION BETWEEN IOS MODES Privileged EXEC Mode – to move from user EXEC mode to privilege EXEC mode, use the enabled command. Switch> enable Switch# Global Configuration Mode – to move in and out of global configuration mode, use the configure terminal command. To return to privilege EXEC mode, use the exit command. Switch(config)# Module 2: Basic Switch and End Device Configuration Switch(config)#exit 2.1 Cisco IOS Access Switch# IOS - Internetwork Operating System Line Configuration Mode – to move in and out of line Operating Systems configuration mode, use the line command followed by the Shell – The user interface that allows users to request specific management line type. To return to global configuration mode, tasks from the computer. These requests can be mase either use the exit command. through the CLI or GUI interfaces. Switch(config)#line console 0 Kernel – Communicates between the hardware and software of Switch(config-line)#exit a computer and manages how hardware resources are used to Switch(config)# meet software requirements. Subconfiguration Modes Hardware – The physical part of a computer including To move out of any subconfiguration mode to get back to underlying electronics. global configuration mode, use the exit command. To return to GUI privilege EXEC mode, use the end command or key A GUI allows the user to interact with the system using an combination Ctrl + Z. environment of graphical icons, menus and windows. Switch(config)#line console 0 A GUI is more user-friendly and requires less knowledge of the Switch(config-line)#end underlying command structure that controls the system. Switch# Examples of these are: Windows, macOS, Linux KDE, Apple iOS To move directly from one subconfiguration mode to another, and Android. type in the desired subconfiguration mode command. In the GUIs can fail, crash, or simply not operate as specified. For these example, the command prompt changes from (config-line)# to reasons, network devices are typically accessed through a CLI. (config-if)#. Purpose of an OS Switch(config-line)#interface FastEthernet 0/1 PC operating system enables a suer to do the following: Switch(config-if )# Use a mouse to make selections and run programs 2.3 The Command Structure Enter text and text-based commands CLI-based network operating system enables a network technician to do the following: Use a keyboard to run CLI-based network programs Use a keyboard to enter text and text-based commands View output on a monitor Basic IOS Command Structure Switch#interface fastEthernet 0/1 ^ % Invalid input detected at ‘^’ marker. Hot Keys and Shortcuts The IOS CLI provides hot keys and shortcuts that make configuring, monitoring, and troubleshooting easier. Commands and keywords can be shortened to the minimum number of characters that identify a unique selection. For Keyword – this is a specific parameter defined in the operating example, the configure command can be shortened to conf system (in the figure, ip protocols). because configure is the only command that begins with conf. Argument – this is not predefined; it is a value defined by the user (in the figure, 192.168.10.5). Router#con IOS Command Syntax Check % Ambiguous command: “con” A command might require one or more arguments. To determine the Router#con? keywords and arguments required for a command, refer to the configure connect command syntax. Boldface text indicates commands and keywords that are Router#conf t entered as shown. Enter configuration commands, one per line. End with CNTL/Z. Italic text indicates an argument for which the user provides the Router(config)# value. Convention Description The table below is a brief list of keystrokes to enhance command line Boldface Boldface text indicates editing. commands and keywords that Keystroke Description you enter literally as shown. Tab Completes a partial command name Italics Italic text indicates arguments entry for which you supply values. Backspace Erases the character to the left of the [x] Square brackets indicate an cursor optional element (keyword or Left arrow or Ctrl+B Moves the cursor one character to the argument). left {x} Braces indicate a required Right arrow or Ctrl+F Moves the cursor one character to the element (keyword or right argument). Up arrow or Ctrl+P Recalls the commands in the history [x {y | z}] Braces and vertical lines within buffer, beginning with the most recent squares brackets indicate a commands. required choice within an optional element. Spaces are When a command output produces more text than can be displayed sued to clearly delineate parts in a terminal window, the ISO will display a “—More—” prompt. The of the command. table below describes the keystrokes that can be used when this prompt is displayed. The command syntax provides the pattern, or format, that must Keystroke Description be used when entering a command. Enter key Displays the next line The command is ping and the user-defined argument is the ip- Space bar Displays the next screen address of the destination device. For example, ping 10.10.10.5. Any other key Ends the display string, returning to privileged The command is traceroute and the user-defined argument is EXEC mode. the ip-address of the destination device. For example, traceroute 192.168.254.254. The table below lists commands that can be used to exit out of an If a command is complex with multiple arguments, you may see operation. it represented like this: Keystroke Description Switch(config-if)# switchport port-security aging { static | time time | Ctrl+C When in any configuration mode, ends the type {absolute | inactivity}} configuration mode and returns to privileged IOS Help Features EXEC mode. The IOS has two forms of help available: context-sensitive help and Ctrl+Z When in any configuration mode, ends the command syntax check. configuration mode and returns to privileged Context-sensitive help enables you to quickly find answers to EXEC mode. these questions: Ctrl+Shift+6 All-purpose break sequence used to abort DNS o Which commands are available in each command lookups, tracerouters, pings, etc. mode? o Which commands start with specific characters or 2.4 Basic Device Configuration group of characters? Device Names o Which arguments and keywords are available to The first configuration command on any device should be to particular commands? give it a unique hostname. Router#ping ? By default, all devices are assigned a factory default name. For WORD Ping destination address or hostname example, a Cisco IOS switch is “Switch.” Ip IP echo Guideline for naming devices: Ipv6 IPv6 echo o Start with a letter Command syntax check verifies that a valid command was o Contain no spaces entered by the user. o End with a letter or digit o If the interpreter cannot understand the command o Use only letters, digits, and dashes being entered, it will provide feedback describing o Be less than 64 characters in length what is wrong with the command. Switch# configure terminal Sw-Floor-1# show running-config Switch(config)# hostname Sw-Floor-1 ! Sw-Floor-1 (config)# ! Note: to return the switch to the default prompt, use the no line con 0 hostname global config command. lassword 7 094F71A1A0A Password Guidelines login The use of weak or easily guessed password are a security ! concern. Line vty 0 4 All networking devices should limit administrative access by Password 7 03095A0F034F35B49150A1819 securing privileged EXEC, and remote Telnet access with Login passwords. In addition, all passwords should be encrypted and ! legal notifications provided. ! Password guidelines: end o Use passwords that are more than eight characters in Banner Messages length. A banner message is important to warn unauthorized personnel o Use a combination of upper and lowercase letters, from attempting to access the device. numbers, special characters, and/or numeric To create a banner message of the day on a network device, sequences. use the banner motd # the message of the day # global config o Avoid using the same password for all devices. command. o Do not use common words because they are easily Note: the ‘#’ in the command syntax is called the delimiting guessed. character. It is entered before and after the message. Note: most of the labs in this course use simple password such Sw-Floor-1# configure terminal as cisco or class. These passwords are considered weak and Sw-Floor-1(config)# banner motd #Authorized Access Only!# easily guessable and should be avoided in production The banner will be displayed on attempts to access the device. environments. 2.5 Save Configurations Configure Passwords Configuration Files Securing user EXEC mode access: There are two system files that store the device configuration: First enter the line console configuration mode using the line startup-config – this is the saved configuration file that is console 0 command in global configuration mode. stored in NVRAM. It contains all the commands that will be Next, specify the user EXEC mode password using the password used by the device upon startup or reboot. Flash does not lose command. its contents when the device is powered off. Router#show Finally, enable user EXEC access using the login command. startup-config Sw-Floor-1# configure terminal running-config – this is stored in Random Access Memory Sw-Floor-1 (config)# line console 0 (RAM). It reflects the current configuration. Modifying a running Sw-Floor-1 (config-line)# password cisco configuration affects the operation of a Cisco device Sw-Floor-1 (config-line)# login immediately. RAM is volatile memory. It loses all of its content Sw-Floor-1 (config-line)# end when the device is powered off or restarted. Router#show Sw-Floor-1# running-config Securing privileged EXEC mode access: To save changes made to the running configuration to the startup First enter global configuration mode. file, use the copy running-config startup-config privilege EXEC mode Next, use the enable secret password command. command. Sw-Floor-1# configure terminal Alter the Running Configurations Sw-Floor-1 (config)# enable secret class If the changes made to the running config do not have the desired Sw-Floor-1 (config)# exit effect and the running-config has not yet been saved, you can restore the device to its previous configuration. To do this you can: Sw-Floor-1# remove the changed commands individually. Securing VTY line access: Reload the device using the reload command in privilege EXEC First enter line VTY configuration mode using the line vty 0 15 mode. Note: this will cause the device to briefly go offline, command in global configuration mode. leading to network downtime. Router# reload Next, specify the VTY password using the password command. If the undesired changes were saved to the startup-config, it may be Finally, enable VTY access using the login command. necessary to clear all the configurations using the erase- startup- Note: VTY lines enable remote access using Telnet or SSH to the config command in privilege EXEC mode. device. Many Cisco switches support up to 16 VTY lines that are After erasing the startup-config, reload the device to clear the numbered 0 to 15. running-config file from RAM. Router# erase startup-config Sw-Floor-1# configure terminal Capture Configuration to a Text File Sw-Floor-1 (config)# line vty 0 15 Configuration files can also be saved and archived to a text Sw-Floor-1 (config-line)# password cisco document. Sw-Floor-1 (config-line)# login 1. Open terminal emulation software, such as PuTTY or Tera Term, Sw-Floor-1 (config-line)# end that is already connected to a switch. Sw-Floor-1# 2. Enable logging in to the terminal software and assign a name Encrypt Passwords: and file location to save the log file. The figure displays that All The startup-config and running-config files display most session output will be captured to the file specified (i.e., passwords in plaintext. MySwitchLogs). To encrypt all plaintext passwords, use the service password- 3. Execute the show running-config or show startup-config encryption global config command. command at the privileged EXEC prompt. Text displayed in the Sw-Floor-1# configure terminal terminal window will be placed into the chosen file. Sw-Floor-1 (config)# service password-encryption 4. Disable logging in the terminal software. The figure shows how Sw-Floor-1 (config)# exit to disable logging by choosing the None session logging Sw-Floor-1# option. Note: The text file created can be used as record of how Use the show running-config command to verify that the the device is currently implemented. The file could require passwords on the device are now encrypted.  editing before being used to restore a saved configuration to a Module 3: Protocols and Models device. 3.1 The Rules 2.6 Ports and Addresses Communications Fundamentals IP Addresses Networks can vary in size and complexity. It is not enough to The use of IP addresses is the primary means of enabling have a connection; devices must agree on “how” to devices to locate one another and establish end-to-end communicate. communication on the internet. There are three elements to any communication: The structure of an IPv4 address is called dotted decimal o There will be a source (sender). notation and is represented by four decimal numbers between o There will be a destination (receiver). 0 and 255. o There will be a channel (media) that provides for the An IPv4 subnet mask is a 32-bit value that differentiates the path of communications to occur. network portion of the address from the host portion. Coupled Communications Protocols with the IPv4 address, the subnet mask determines to which All communications are governed by protocols. subnet the device is a member. Protocols are the rules that communications will follow. The default getaway address is the IP address of the router that These rules will vary depending on the protocol. the host will use to access remote networks, including the Rule Establishment internet. Individuals must use established rules or agreements to govern IPv6 addresses are 128 bits in length and written as a string of the conversation. hexadecimal values. Every four bits is represented by a single The first message is difficult to read because it is not formatted hexadecimal digit: for a total of 32 hexadecimal values. Groups properly. The second shows the message properly formatted of four hexadecimal digits are separated by a colon ‘:’. Protocols must account for the following requirements: IPv6 addresses are not case-sensitive and can be written in o An identified sender and receiver either lowercase or uppercase. o Common language and grammar Note: IP in this course refers to both the IPv4 and IPv6 o Speed and timing of delivery protocols. IPv6 is the most recent version of IP and is replacing o Confirmation or acknowledgment requirements the more common IPv4. Network Protocol Requirements Interfaces and Ports Common computer protocols must be in agreement and include the Network communications depends on end user interfaces, following requirements: networking devise interfaces, and the cables that connect them. Message encoding Type of network media include twisted-pair copper cables, Message formatting and encapsulation fiber-optic cables, coaxial cables, or wireless. Message size Different types of network media have different features and Message timing benefits. Some of the differences between various types of Message delivery options media include: Message Encoding o Distance the media can successfully carry a signal Encoding is the process of converting information into another o Environment in which the media is to be installed acceptable form for transmission. o Amount of data and the speed at which it must be transmitted. o Cost of the media and installation 2.7 Configure IP Addressing Manual IP Address Configuration for End Devices End devices on the network need an IP address in order to communicate with other devices on the network. IPv4 address information can be entered into end devices manually, or automatically using Dynamic Host Configuration Protocol (DHCP). o To manually configure an IPv4 address on a Windows PC, open the Control Panel > Network Sharing Center > Change adapter settings and choose the adapter. Next right-click and select Properties to display the Decoding reverses this process to interpret the information. Local Area Connection Properties. o Next, click Properties to open the Internet Protocol Version 4 (TCP/IPv4) Properties window. Then configure the IPv4 address and subnet mask information, and default gateway. o Note: IPv6 addressing and configuration options are similar to IPv4 Switch Virtual Interface Configuration To access the switch remotely, an IP address and a subnet mask must be configured on the SVI. To configure an SVI on a switch: Enter the interface vlan 1 command in global configuration mode. Next assign an IPv4 address using the ip address ip- Message Formatting and Encapsulation address subnet-mask command. When a message is sent, it must use a specific format or Finally, enable the virtual interface using the no shutdown structure. command. Message formats depend on the type of message and the Switch# configure terminal channel that is used to deliver the message. Switch(config)# interface vlan 1 Message Size Switch(config-if)# ip address 192.168.1.20.255.255.0 Encoding between hosts must be in an appropriate format for the Switch(config-if)# no shutdown medium. Messages sent across the network are converted to bits  The bits are encoded into a pattern of light, sound, or electrical Function Description impulses. Addressing Identifies sender and receiver The destination host must decode the signals to interpret the Reliability Provides guaranteed delivery message. Flow Control Ensures data flows at an efficient rate Message Timing Sequencing Uniquely labels each transmitted segment of Message timing includes the following: data Flow Control – Manages the rate of data transmission and Error Detection Determines if data became corrupted during defines how much information can be sent and the speed at transmission which it can be delivered. Application Process-to-process communications between Response Timeout – Manages how long a device waits when it Interface network applications does not hear a reply from the destination. Protocol Interaction Access method - Determines when someone can send a Networks require the use of several protocols. message. Each protocol has its own function and format. There may be various rules governing issues like “collisions”. This is Protocol Function when more than one device sends traffic at the same time and the messages become corrupt. Hypertext Governs the way a web server and a web Some protocols are proactive and attempt to prevent collisions; Transfer client interact other protocols are reactive and establish a recovery method after Protocol (HTTP) Defines content and format the collision occurs. Transmission Manages the individual conversations Message Delivery Options Control Protocol Provides guaranteed delivery Message delivery may one of the following methods: (TCP) Manages flow control Unicast – one to one communication Internet Protocol Delivers messages globally from the sender Multicast – one to many, typically not all (IP) to the receiver Broadcast – one to all Ethernet Delivers messages from one NIC to another NIC on the same Ethernet Local Area Network Note: Broadcasts are used in IPv4 networks, but are not an option for (LAN) IPv6. Later we will also see “Anycast” as an additional delivery option for IPv6. 3.3 Protocol Suites Network Protocol Suites A Note About the Node Icon Protocols must be able to work with other protocols. Documents may use the node icon, typically a circle, to Protocol suite: represent all devices. A group of inter-related protocols necessary to perform a The figure illustrates the use of the node icon for delivery communication function Sets of rules that work together to help solve a problem options. The protocols are viewed in terms of layers: Higher Layers Lower Layers- concerned with moving data and provide services to upper layers Evolution of Protocol Suites There are several protocol suites. Internet Protocol Suite or TCP/IP- The most common protocol suite and maintained by the Internet Engineering Task Force (IETF) Open Systems Interconnection (OSI) protocols- Developed by the International Organization for Standardization (ISO) and the International Telecommunications Union (ITU) 3.2 Protocols AppleTalk- Proprietary suite release by Apple Inc. Network Protocol Overview Novell NetWare- Proprietary suite developed by Novell Inc. Network protocols define a common set of rules. Can be implemented on devices in: o Software o Hardware o Both Protocols have their own: o Function o Format o Rules Protocol Type Description Network enable two or more devices to communicate Communications over one or more networks Network secure data to provide authentication, data Security integrity, and data encryption Routing enable routers to exchange route information, compare path information, and select best path Service used for the automatic detection of devices Discovery or services Network Protocol Functions Devices use agreed-upon protocols to communicate. Protocols may have may have one or functions. TCP/IP Protocol Example 3.4 Standards Organizations TCP/IP protocols operate at the application, transport, and Open Standards internet layers. Open standards encourage: The most common network access layer LAN protocols are interoperability Ethernet and WLAN (wireless LAN). competition innovation Standards organizations are: vendor-neutral non-profit organizations established to develop and promote the concept of open standards. Internet Standards Internet Society (ISOC) - Promotes the open development and evolution of internet Internet Architecture Board (IAB) - Responsible for management and development of internet standards Internet Engineering Task Force (IETF) - Develops, updates, and maintains internet and TCP/IP technologies Internet Research Task Force (IRTF) - Focused on long-term research related to internet and TCP/IP protocols TCP/IP Protocol Suite Standards organizations involved with the development and support TCP/IP is the protocol suite used by the internet and includes of TCP/IP many protocols. Internet Corporation for Assigned Names and Numbers TCP/IP is: (ICANN) - Coordinates IP address allocation, the management o An open standard protocol suite that is freely of domain names, and assignment of other information available to the public and can be used by any Internet Assigned Numbers Authority (IANA) - Oversees and vendor manages IP address allocation, domain name management, and o A standards-based protocol suite that is endorsed by protocol identifiers for ICANN the networking industry and approved by a standards Electronic and Communications Standards organization to ensure interoperability Institute of Electrical and Electronics Engineers (IEEE, pronounced “I-triple-E”) - dedicated to creating standards in power and energy, healthcare, telecommunications, and networking Electronic Industries Alliance (EIA) - develops standards relating to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment Telecommunications Industry Association (TIA) - develops communication standards in radio equipment, cellular towers, Voice over IP (VoIP) devices, satellite communications, and more International Telecommunications Union-Telecommunication Standardization Sector (ITU-T) - defines standards for video compression, Internet Protocol Television (IPTV), and TCP/IP Communication Process broadband communications, such as a digital subscriber line A web server encapsulating and sending a web page to a client. (DSL) 3.5 Reference Models The Benefits of Using a Layered Model Complex concepts such as how a network operates can be difficult to explain and understand. For this reason, a layered model is used. Two layered models describe network operations: Open System Interconnection (OSI) Reference Model TCP/IP Reference Model These are the benefits of using a layered model: 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 Foster competition because products from different vendors A client de-encapsulating the web page for the web browser can work together Prevent technology or capability changes in one layer from affecting other layers above and below Provide a common language to describe networking functions and capabilities The OSI Reference Model OSI Model Layer Description 7 - Application Contains protocols used for process-to- process communications. 6 - Presentation Provides for common representation of the data transferred between application layer services. 5 - Session Provides services to the presentation layer and to manage data exchange. 4 - Transport Defines services to segment, transfer, and reassemble the data for individual communications. 3 - Network Provides services to exchange the individual De-encapsulation Example pieces of data over the network. Data is de-encapsulated as it moves up the stack. 2 - Data Link Describes methods for exchanging data When a layer completes its process, that layer strips off its frames over a common media. header and passes it up to the next level to be processed. This 1 - Physical Describes the means to activate, maintain, is repeated at each layer until it is a data stream that the and de-activate physical connections. application can process. The TCP/IP Reference Model o Received as Bits (Bit Stream) TCP/IP Model Description o Frame Layer o Packet Application Represents data to the user, plus encoding o Segment and dialog control. Transport Supports communication between various o Data (Data Stream) devices across diverse networks. Internet Determines the best path through the network. Network Access Controls the hardware devices and media that make up the network. 3.6 Data Encapsulation Segmenting Messages Segmenting is the process of breaking up messages into smaller units. Multiplexing is the processes of taking multiple streams of segmented data and interleaving them together. Segmenting messages has two primary benefits: Increases speed - large amounts of data can be sent over the network without tying up a communications link. Increases efficiency - Only segments which fail to reach the 3.7 Data Access destination need to be retransmitted, not the entire data Addresses stream. Both the data link and network layers use addressing to deliver Sequencing data from source to destination. Sequencing messages is the process of numbering the Network layer source and destination addresses - Responsible segments so that the message may be reassembled at the for delivering the IP packet from original source to the final destination. destination. TCP is responsible for sequencing the individual segments. Data link layer source and destination addresses – Responsible Protocol Data Units for delivering the data link frame from one network interface Encapsulation is the process where protocols add their information card (NIC) to another NIC on the same network. to the data. At each stage of the process, a PDU has a different name to reflect its new functions. There is no universal naming convention for PDUs, in this course, the PDUs are named according to the protocols of the TCP/IP suite. Layer 3 Logical Address PDUs passing down the stack are as follows: The IP packet contains two IP addresses: o Data (Data Stream) Source IP address - The IP address of the sending device, original source of the packet. o Segment Destination IP address - The IP address of the receiving device, o Packet final destination of the packet. o Frame These addresses may be on the same link or remote. o Bits (Bit Stream) An IP address contains two parts: Encapsulation Example Network portion (IPv4) or Prefix (IPv6) Encapsulation is a top-down process. The left-most part of the address indicates the network group The level above does its process and then passes it down to the which the IP address is a member. next level of the model. This process is repeated by each layer Each LAN or WAN will have the same network portion. until it is sent out as a bit stream. Host portion (IPv4) or Interface ID (IPv6) The remaining part of the address identifies a specific device within the group. This portion is unique for each device on the network. Devices on the Same Network When devices are on the same network the source and destination will have the same number in network portion of the address.  PC1 – 192.168.1.110 This generally applies whether you are considering a corporate FTP Server – 192.168.1.9 office or a home. Role of the Data Link Layer Addresses: Same IP Network A Network Interface Card (NIC) connects a device to the When devices are on the same Ethernet network the data link frame network. will use the actual MAC address of the destination NIC. Some devices may have just one NIC, while others may have MAC addresses are physically embedded into the Ethernet NIC and multiple NICs (Wired and/or Wireless, for example). are local addressing. Not all physical connections offer the same level of The Source MAC address will be that of the originator on the performance. link. The Destination MAC address will always be on the same link as The Physical Layer the source, even if the ultimate destination is remote. Transports bits across the network media Devices on a Remote Network Accepts a complete frame from the Data Link Layer and What happens when the actual (ultimate) destination is not on encodes it as a series of signals that are transmitted to the local the same LAN and is remote? media What happens when PC1 tries to reach the Web Server? This is the last step in the encapsulation process. Does this impact the network and data link layers? The next device in the path to the destination receives the bits Role of the Network Layer Addresses and re-encapsulates the frame, then decides what to do with it. When the source and destination have a different network portion, 4.2 Physical Layer Characteristics this means they are on different networks. Physical Layer Standards PC1 – 192.168.1 Web Server – 172.16.1 Role of the Data Link Layer Addresses: Different IP Networks When the final destination is remote, Layer 3 will provide Layer 2 with the local default gateway IP address, also known as the router address. The default gateway (DGW) is the router interface IP address that is part of this LAN and will be the “door” or “gateway” to all other remote locations. All devices on the LAN must be told about this address or their traffic will be confined to the LAN only. Once Layer 2 on PC1 forwards to the default gateway (Router), the router then can start the routing process of getting the information to actual destination. Physical Components The data link addressing is local addressing so it will have a Physical Layer Standards address three functional areas: source and destination for each link. Physical Components The MAC addressing for the first segment is: Encoding Signaling o Source – AA-AA-AA-AA-AA-AA (PC1) Sends the The Physical Components are the hardware devices, media, and frame. other connectors that transmit the signals that represent the bits. o Destination – 11-11-11-11-11-11 (R1- Default Hardware components like NICs, interfaces and connectors, Gateway MAC) Receives the frame. cable materials, and cable designs are all specified in standards Note: While the L2 local addressing will change from link to link associated with the physical layer. or hop to hop, the L3 addressing remains the same. Encoding Data Link Addresses Encoding converts the stream of bits into a format recognizable Since data link addressing is local addressing, it will have a by the next device in the network path. source and destination for each segment or hop of the journey This ‘coding’ provides predictable patterns that can be to the destination. recognized by the next device. The MAC addressing for the first segment is: Examples of encoding methods include Manchester (shown in o Source – (PC1 NIC) sends frame the figure), 4B/5B, and 8B/10B. o Destination – (First Router- DGW interface) receives Signaling frame The signaling method is how the bit values, “1” and “0” are The MAC addressing for the second hop is: represented on the physical medium. o Source – (First Router- exit interface) sends frame The method of signaling will vary based on the type of medium o Destination – (Second Router) receives frame being used. The MAC addressing for the last segment is: Bandwidth o Source – (Second Router- exit interface) sends frame Bandwidth is the capacity at which a medium can carry data. o Destination – (Web Server NIC) receives frame Digital bandwidth measures the amount of data that can flow Notice that the packet is not modified, but the frame is from one place to another in a given amount of time; how changed, therefore the L3 IP addressing does not change from many bits can be transmitted in a second. segment to segment like the L2 MAC addressing. Physical media properties, current technologies, and the laws of The L3 addressing remains the same since it is global and the physics play a role in determining available bandwidth. ultimate destination is still the Web Server. Unit of Bandwidth Abbreviation Equivalence Bits per second bps 1 bps = Module 4: Physical Layer fundamental unit of 4.1 Purpose of the Physical Layer bandwidth The Physical Connection Kilobits per second Kbps 1 Kbps = 1,000 bps Before any network communications can occur, a physical = 103 bps connection to a local network must be established. Megabits per Mbps 1 Mbps = 1,000,000 This connection could be wired or wireless, depending on the second bps = 106 bps setup of the network.  Gigabits per second Gbps 1 Gbps – There are different types of connectors used with coax cable. 1,000,000,000 bps o Commonly used in the following situations: = 109 bps o Wireless installations - attach antennas to wireless Terabits per second Tbps 1 Tbps = devices 1,000,000,000,000 o Cable internet installations - customer premises bps = 1012 bps wiring 4.4 UTP Cabling Bandwidth Terminology Properties of UTP Cabling Latency UTP has four pairs of color-coded copper wires twisted together and Amount of time, including delays, for data to travel from one encased in a flexible plastic sheath. No shielding is used. UTP relies given point to another on the following properties to limit crosstalk: Throughput Cancellation - Each wire in a pair of wires uses opposite polarity. The measure of the transfer of bits across the media over a One wire is negative, the other wire is positive. They are twisted given period of time together and the magnetic fields effectively cancel each other Goodput and outside EMI/RFI. The measure of usable data transferred over a given period of Variation in twists per foot in each wire - Each wire is twisted a time different amount, which helps prevent crosstalk amongst the Goodput = Throughput - traffic overhead wires in the cable. UTP Cabling Standards and Connectors 4.3 Copper Cabling Standards for UTP are established by the TIA/EIA. TIA/EIA-568 Characteristics of Copper Cabling standardizes elements like: Copper cabling is the most common type of cabling used in Cable Types networks today. It is inexpensive, easy to install, and has low Cable Lengths resistance to electrical current flow. Connectors Limitations: Cable Termination Attenuation – the longer the electrical signals have to travel, the Testing Methods weaker they get. The electrical signal is susceptible to interference from two Electrical standards for copper cabling are established by the IEEE, sources, which can distort and corrupt the data signals which rates cable according to its performance. Examples include: (Electromagnetic Interference (EMI) and Radio Frequency Category 3 Interference (RFI) and Crosstalk). Category 5 and 5e Mitigation: Category 6 Strict adherence to cable length limits will mitigate attenuation. Straight-through and Crossover UTP Cables Some kinds of copper cable mitigate EMI and RFI by using metallic shielding and grounding. Some kinds of copper cable mitigate crosstalk by twisting opposing circuit pair wires together. Types of Copper Cabling Unshielded Twisted Pair (UTP) UTP is the most common networking media. Terminated with RJ-45 connectors Interconnects hosts with intermediary network devices. Key Characteristics of UTP o The outer jacket protects the copper wires from physical damage. o Twisted pairs protect the signal from interference. Cable Type Standard Application o Color-coded plastic insulation electrically isolates the Ethernet Straight- Both ends T568A or Host to Network wires from each other and identifies each pair. through T568B Device Shielded Twisted Pair (STP) Ethernet Crossover One end T568A, Host-to-Host, Better noise protection than UTP * other end T568B Switch-to-Switch, More expensive than UTP Router-to-Router Harder to install than UTP * Considered Legacy due to most NICs using Auto-MDIX to sense Terminated with RJ-45 connectors cable type and complete connection Interconnects hosts with intermediary network devices Rollover Cisco Proprietary Host serial port to Key Characteristics of STP Router or Switch o The outer jacket protects the copper wires from Console Port, using physical damage an adapter o Braided or foil shield provides EMI/RFI protection o Foil shield for each pair of wires provides EMI/RFI 4.5 Fiber-Optic Cabling protection Properties of Fiber-Optic Cabling o Color-coded plastic insulation electrically isolates the Not as common as UTP because of the expense involved wires from each other and identifies each pair Ideal for some networking scenarios Coaxial Cable Transmits data over longer distances at higher bandwidth than Consists of the following: any other networking media o Outer cable jacket to prevent minor physical damage Less susceptible to attenuation, and completely immune to o A woven copper braid, or metallic foil, acts as the EMI/RFI second wire in the circuit and as a shield for the inner Made of flexible, extremely thin strands of very pure glass conductor. Uses a laser or LED to encode bits as pulses of light o A layer of flexible plastic insulation The fiber-optic cable acts as a wave guide to transmit light o A copper conductor is used to transmit the electronic between the two ends with minimal signal loss signals.  Types of Fiber Media Some of the limitations of wireless: Single-Mode Fiber Coverage area - Effective coverage can be significantly Very small core impacted by the physical characteristics of the deployment Uses expensive lasers location. Long-distance applications Interference - Wireless is susceptible to interference and can be disrupted by many common devices. Multimode Fiber Security - Wireless communication coverage requires no Larger core access to a physical strand of media, so anyone can gain Uses less expensive LEDs access to the transmission. LEDs transmit at different angles Shared medium - WLANs operate in half-duplex, which Up to 10 Gbps over 550 meters means only one device can send or receive at a time. Many Dispersion refers to the spreading out of a light pulse over time. users accessing the WLAN simultaneously results in Increased dispersion means increased loss of signal strength. MMF reduced bandwidth for each user. has greater dispersion than SMF, with the maximum cable distance for MMF is 550 meters. Types of Wireless Media The IEEE and telecommunications industry standards for wireless Fiber-Optic Cabling Usage data communications cover both the data link and physical layers. In Fiber-optic cabling is now being used in four types of industry: each of these standards, physical layer specifications dictate: Enterprise Networks - Used for backbone cabling applications Data to radio signal encoding methods and interconnecting infrastructure devices Frequency and power of transmission Fiber-to-the-Home (FTTH) - Used to provide always-on broadband services to homes and small businesses Signal reception and decoding requirements Long-Haul Networks - Used by service providers to connect Antenna design and construction countries and cities Wireless Standards: Submarine Cable Networks - Used to provide reliable high- Wi-Fi (IEEE 802.11) - Wireless LAN (WLAN) technology speed, high-capacity solutions capable of surviving in harsh Bluetooth (IEEE 802.15) - Wireless Personal Area network undersea environments at up to transoceanic distances. (WPAN) standard Our focus in this course is the use of fiber within the enterprise. WiMAX (IEEE 802.16) - Uses a point-to-multipoint topology to provide broadband wireless access Fiber-Optic Connectors Zigbee (IEEE 802.15.4) - Low data-rate, low power- Straight-Tip (ST) Connectors consumption communications, primarily for Internet of Lucent Connector (LC) Simplex Connectors Things (IoT) applications Subscriber Connector (SC) Connectors Wireless LAN Duplex Multimode LC Connectors In general, a Wireless LAN (WLAN) requires the following devices: Fiber Patch Cords Wireless Access Point (AP) - Concentrate wireless signals SC-SC MM Patch Cord (orange) from users and connect to the existing copper-based LC-LC SM Patch Cord (yellow) network infrastructure ST-LC MM Patch Cord (orange) Wireless NIC Adapters - Provide wireless communications ST-SC SM Patch Cord (yellow) capability to network hosts A yellow jacket is for single-mode fiber cables and orange (or aqua) There are a number of WLAN standards. When purchasing WLAN for multimode fiber cables. equipment, ensure compatibility, and interoperability. Network A