Networking Devices Lesson 6
Objectives Exam Objective Matrix Technology Skill Covered Exam Objective Exam Objective Number Network Interface Cards Modems Media Converters Repeaters and Hubs Bridges and Switches Classify how applications, devices, and protocols relate to the OSI model layers. NIC Categorize standard media types and associated properties. Media converters: Singlemode fiber to Ethernet Multimode fiber to Ethernet Fiber to Coaxial Singlemode to multimode fiber Classify how applications, devices, and protocols relate to the OSI model layers. Hub Classify how applications, devices, and protocols relate to the OSI model layers. Switch Multilayer switch Bridge 1.2 3.1 1.2 1.2
Objectives Exam Objective Matrix Technology Skill Covered Exam Objective Exam Objective Number Channel Service Unit/Data Service Unit (CSU/DSU) Explain the purpose and properties of routing and switching. Spanning Tree Protocol VLAN (802.1q) Port mirroring Given a scenario, install and configure routers and switches. VLAN (trunking) Managed vs. unmanaged PoE Diagnostics VTP configuration Port mirroring Identify components of wiring distribution. CSU/DSU 1.4 2.1 3.8
Objectives Exam Objective Matrix Technology Skill Covered Exam Objective Exam Objective Number Routers and Firewalls Servers Classify how applications, devices, and protocols relate to the OSI model layers. Router Given a scenario, install and configure a basic firewall. Types: Software and hardware firewalls Firewall rules: Block/allow Implicit deny ACL Summarize DNS concepts and its components. DNS servers DNS records (A, MX, AAAA, CNAME, PTR) Dynamic DNS Explain the purpose and properties of DHCP. Static vs. dynamic IP addressing Reservations Scopes Leases Options (DNS servers, suffixes) 1.2 5.5 1.7 2.3
Objectives Exam Objective Matrix Technology Skill Covered Exam Objective Exam Objective Number Additional Specialized Network Devices Wireless Devices Explain the purpose and features of various network appliances. Proxy server Classify how applications, devices, and protocols relate to the OSI model layers. Encryption devices Explain the purpose and features of various network appliances. Load balancer Categorize different types of network security appliances and methods. IDS and IPS: Behavior based Signature based Given a scenario, install and configure a wireless network. Compatibility (802.11 a/b/g/n) Compare and contrast different wireless standards. 802.11 a/b/g/n standards Distance Speed 4.1 1.2 4.1 5.6 2.2 3.3
Objectives Exam Objective Matrix Technology Skill Covered Exam Objective Exam Objective Number Virtual Networking Identify virtual network components. Virtual switches Virtual desktops Virtual servers Virtual PBX Onsite vs. offsite Network as a Service (NaaS) 1.9
Network Interface Cards An expansion card or motherboard module that enables a computer to communicate over a network Often called a Network Interface Controller
Means of Communication and Media Used for Communication Means of communications refers to whatever is used to communicate data across a network such as electrical impulses, light pulses, or radio wave/microwave modulations The media used for communications is whatever carries those communications across a network
Means of Communication and Media Used for Communication (Continued) NIC works on Data Link and Physical layers of OSI Model Acts as translator between software in upper layers of OSI Model and physical components of the media Must use NIC designed to work with a specific type of media and associated means of communication
Addressing Each NIC has a unique physical address programmed into its ROM chip during manufacture Each manufacturer has about 16 million unique addresses, may have to begin reusing physical addresses Two NICs on a network segment with the same physical address can make entire network unstable
Modem Modem stands for Modulator/Demodulator Can be hardware or software based Modulates analog signal of a regular telephone line to encode digital information into it Demodulates return signals to view digital content from outer sources
Media Converter Device used to convert one type of media to another type Used to convert coaxial to twisted pair or fiber to copper A 9-pin serial connection converted to a RJ-45 connection
Media Converter (Continued) Transceiver Switches with fiber-optic cables
Fiber to Ethernet Singlemode or multimode Fiber to Ethernet converts different types of fiber-optic cables to Ethernet Consider: How fast the Ethernet is you are trying to convert to What type of fiber technology you are converting from
Fiber to Coaxial Possible to convert between fiber and coaxial cables Most commonly done by cable TV companies Run fiber-optic cables into a neighborhood Convert to coaxial for home installation
Singlemode Fiber to Multimode Fiber Can convert fiber to fiber Singlemode and multimode fiber use different techniques to encode data Singlemode to multimode fiber converter may need to accommodate different data rates for the two types of fiber You need to know exactly how your network works to get proper converter
Repeater A Layer 1 device that repeats a signal it receives in order to rebroadcast it, thus extending the range of a particular cable run Always active and requires a power source It has one cable coming in and one going out Follow the 5-4-3 rule to determine how and where to connect repeater on a network
Hub A Layer 1 device Works as if it is the bus of a larger network A computer connected to a hub broadcasts its signal to all the devices connected to that hub Two primary types: Passive hub Active hub Active hub
Bridge A Layer 2 device that separate networks into smaller sections More intelligent than average hub Based on MAC or physical addresses, bridges can determine if a frame is allowed to pass through to the other side of the bridge
How a Basic Bridge Works
Basic Switch Layer 2 device that connects multiple networking devices, usually computers, to form LANs Can be called a multiport bridge because, like a bridge, it separates a network into multiple collision domains Difference: Each port on basic switch is essentially its own collision domain Can convert media from one type to another
A 24-port Switch
Switch in IDF Used to Convert Fiber Optic to Copper UTP Switch can push fiber-optic data input to twisted-pair ports Switches often placed in intermediate distribution frames (IDFs) to break out a signal to network devices
Switch Interface Configuration To program/configure switch, use: Graphical interface Command-line interface (CLI) Most configuration involves VLANs and trunking (to be addressed shortly)
Managed versus Unmanaged Switches Unmanaged Common for home use Preconfigured setup Managed Enables you to perform complex filtering or segregate ports into VLANs
Virtual LAN (VLAN) A group of hosts that share a common set of communications requirements, grouped together via Layer 2 of the OSI Model
Spreading a VLAN Across Multiple Switches
VoIP VLAN and a Data VLAN Stretched Across Two Switches
Trunking VLAN multiplexing Data from multiple VLANs carried across a single cable or other network link Special trunking protocols required Example: IEEE 802.1Q Adds a special tag in the header of an Ethernet frame that identifies the frame as belonging to a particular VLAN
Port Mirroring and Port Authentication Port mirroring The act of sending a copy of the frames from one or more ports on a switch to another port on the same switch Port authentication The ability to limit access to a specific port to specific MAC addresses Provides security to network by limiting access
Spanning Tree Protocol (STP) A Layer 2 protocol used primarily to prevent loops from developing in switch-based LANs Gets its name from spanning tree algorithm Takes a group of points and connects them without allowing any loops to form
Power over Ethernet (PoE) The protocol used to safely transfer power over Ethernet cabling Most common use is with VoIP installations where power is needed for the phone to work properly
Channel Service Unit/Data Service Unit (CSU/DSU) Converts a digital signal from one frame format to another Most commonly used to convert Frame Relay or T-1 signals (WAN) to Ethernet signals (LAN) CSU side receives and transmits WAN signals DSU side converts LAN signal to or from the CSU side and manages the connection
Routers Networking devices that move packets around a larger network Read data packets for delivery information Send data packets on to next stop toward destination Work primarily on Layer 3 and Layer 4 of the OSI Model
Stack of Routers
Router Configuration Interface Primarily CLI but some new units have graphics interface Router configuration is more complex than switch configuration Important variable when configuring a router is port speed Refers to how fast a specific port on the router is able to send and receive data
Routing Tables What routers use to determine the best route to send a packet toward destination Contain: Router name IP address of the network each interface is configured to connect to Interface identifier for each interface Can populate routing table manually or dynamically
Firewall Networking device or networking software used to prevent unauthorized packets from getting into your network Firewall rules indicate which packets to block or allow Rules in access control list (ACL) Block/allow method Implicit deny method
Firewall Placement in a Basic Network
Two Firewalls Used to Create a Demilitarized Zone (DMZ)
Software Firewall Hardware firewalls generally reside on a router or specialized hardware device Software firewall usually resides on a computer or other type of host Example: Windows Vista and Windows 7 come bundled with Windows Firewall, a software-based firewall
Servers DHCP servers DNS servers Proxy servers
Dynamic Host Configuration Protocol (DHCP) Server Controls DHCP on the network Automatically assigns IP address on the network Leases Scopes Reservations Options
DHCP Initialization Process
One DHCP Server Can Service Multiple VLANs
Domain Name System (DNS) Server Makes the Domain Name System work Server criteria: Has to be registered to join the DNS Has to run special-purpose DNS software Has to be given a publicly registered IP address Must contain a database of other network names and addresses for the Internet host and other computers
DNS Name Resolution Process
DNS Record Types A: Stores a 32-bit IPv4 IP address and can store a subnet mask AAAA: Stores 128-bit IPv6 IP addresses MX: Maps domain names to a list of software agents responsible for transferring electronic messages CNAME: Records alias names PTR: Records alias and reports it back only
Proxy Server Intermediary between client and other server Uses: Keep computers behind the proxy server anonymous Speed up access to resources via caching Set up access policies to different network services and/or content Create an audit log of network usage Bypass security or services
Role of a Proxy Server
Types of Proxy Servers Caching proxy server Web proxy server Content-filtering web proxy server Anonymizing proxy server Hostile proxy server Intercepting proxy server
Additional Specialized Network Devices Multifunction network devices Intrusion detection systems (IDS) Intrusion protection systems (IPS) Encryption devices Load balancers Bandwidth shaper
Wireless NICs Come built-in in most notebook computers, netbook computers, and tablets Can be add-on devices Expansion boards USB
802.11g Wireless NIC
802.11g-n Wireless NIC USB Devices
Wireless Access Point A wireless device that combines the roles of a switch and a router in smaller wireless networks
Wireless Access Point (Continued) Are connected to larger networks and allow access via wireless media.in this way, WAPs act as switches to allow wireless devices access to a specific network
Virtual Networking Combines hardware and software resources into a single entity for administrative purposes Are external and internal External: Resources and hardware from multiple networks are combined into a single software environment Internal: A single device has been configured to give network-like functionality to every software container on the device
Virtual Switch Similar to a physical switch Differences Spanning-Tree Protocol not needed to protect from loops; virtual switching does not allow for loops to take place Does not exist in the physical world; virtual switch is a software construct
Virtual Desktops Virtual operating system set up in a virtual environment to allow end users to run software programs Multiple virtual workstations can be created on a local computer and then linked together Virtual workstations can be stored on a virtual server and run inside a physical device, physically connected to the server containing the virtual workstations
Virtual Server A server program designed to create and support virtual networks Example: VMware ESX Server Or A server set up in a virtual environment to support some function that a real server would do in a physical network environment
Virtual PBX A PBX switch that has been virtualized on a network Works like a physical PBX switch Difference is that virtual PBX can be set up on a server instead of purchasing specialized equipment
On-site verses Off-site Refer to where hardware containing virtual network is located On-site: Hardware containing virtual network is located on the site it is being used at Off-site: Hardware used to contain virtual network is located somewhere other than the site where it is being used
Network as a Service (NaaS) A virtual network available over the Internet (from the cloud ) Consumers purchase network service
Summary A NIC is an expansion card or motherboard module that enables a computer to communicate over a network. You cannot have two NICs with the same physical address on same network segment. A media converter is a device that converts one type of media to another type. The most common networking devices are repeaters, hubs, bridges, switches, and routers.
Summary (Continued) A virtual LAN (VLAN) is a group of hosts that share a common set of communications requirements, grouped together via Layer 2 of the OSI Model. Trunking is VLAN multiplexing. A firewall is a networking security device or software used to prevent unauthorized packets from getting into a network. A DHCP server assigns IP addresses automatically to networked devices.
Summary (Continued) A DNS server manages the Domain Name System. A proxy server is an intermediary between a client and another server. Wireless devices include NICs and wireless access points. Virtual networking combines hardware and software resources into a single entity for administrative purposes.