Chapter Six Networking Hardware Objectives Identify functions of

Chapter Six Networking Hardware

Objectives Identify functions of LAN connectivity hardware Install and configure a network adapter (network interface card) Identify problems associated with connectivity hardware

Objectives Describe the factors involved in choosing a network adapter, hub, switch, or router Describe the functions of repeaters, hubs, bridges, switches, and gateways Describe the uses and types of routing protocols

Network Adapters Also called network interface cards (NICs) Connectivity devices enabling a workstation, server, printer, or other node to receive and transmit data over the network media In most modern network devices, network adapters contain the data transceiver

Types of Network Adapters For a desktop or tower PC, network adapter is likely to be a type of expansion board n Expansion boards connect to the system board through expansion slots The circuit used by the system board to transmit data to the computer’s components is the computer’s bus

Types of Network Adapters PC bus types you may encounter: n n Industry Standard Architecture (ISA) Micro. Channel Architecture (MCA) Extended Industry Standard Architecture (EISA) Peripheral Component Interconnect (PCI) Figure 6 -1: The four primary bus architectures

Types of Network Adapters Figure 6 -2: A system board with multiple bus types

Types of Network Adapters PCMIA n n Developed in early 1990 s to provide standard interface for connecting any type of device to a portable computer More commonly known as PC Cards Figure 6 -3: Typical PC Card network adapter

Types of Network Adapters USB (universal serial bus) port n Standard external bus that can be used to connect multiple types of peripherals Figure 6 -4: A USB network adapter

Types of Network Adapters Figure 6 -5: A parallel port network adapter

Types of Network Adapters Figure 6 -6: Wireless network adapters

Types of Network Adapters Figure 6 -7: A variety of Ethernet network adapters

Types of Network Adapters Figure 6 -8: Token Ring network adapters

Types of Network Adapters Figure 6 -9: Ethernet network adapters for printers

Installing Network Adapters To install modern network adapters, first install hardware, then install software shipped with NIC In some cases you must perform a third step: n Configure the firmware Electrically erasable programmable read-only memory (EEPROM) n n Type of ROM found on a circuit board Configuration information can be erased and rewritten through electrical pulses

Installing and Configuring Network Adapter Hardware Figure 6 -10: A properly inserted network adapter

Installing and Configuring Network Adapter Hardware Figure 6 -11: Installing a PC Card network adapter

Installing and Configuring Network Adapter Hardware Jumper n Small, removable piece of plastic that contains a metal receptacle Figure 6 -12: A jumper and a row of pins indicating two different settings

Installing and Configuring Network Adapter Hardware DIP switch n Small, plastic toggle switch that represents “on” or “off” status Figure 6 -13: DIP switches on a NIC

Installing and Configuring Network Adapter Software Ensure that the correct device driver is installed for the network adapter and that it is configured properly Device driver n Software that enables an attached device to communicate with computer’s operating system

Installing and Configuring Network Adapter Software Figure 6 -14: Windows 2000 Upgrade Device Driver Wizard

IRQ (Interrupt Request Line) Message to the computer that instructs it to stop what it is doing and pay attention to something else An interrupt is the wire on which a device issues voltage to signal this request Each interrupt must have a unique IRQ number

IRQ (Interrupt Request Line) Table 6 -1: IRQ assignments

IRQ (Interrupt Request Line) When two devices attempt to use the same IRQ, any of the following problems may occur: n n n Computer may lock up or “hang” either upon starting or when operating system is loading Computer may run much slower than usual Though computer’s network adapter may work properly, other devices may stop working Video or sound card problems may occur Computer may fail to connect to the network Computer may experience intermittent data errors during transmission

IRQ (Interrupt Request Line) Figure 6 -15: Computer resource settings in Windows 2000

IRQ (Interrupt Request Line) CMOS (complementary metal oxide semiconductor) n Firmware on a PC’s system board that enables you to change its devices’ configurations Information saved in CMOS is used by the computer’s BIOS (basic input/output system) n BIOS is a simple set of instructions enabling a computer to initially recognize its hardware

Memory Range and Base I/O Port Memory range n Hexadecimal number indicating the area memory that the network adapter and CPU will use for exchanging, or buffering, the data Base I/O port n Setting that specifies, in hexadecimal notation, which area of memory will act as a channel for moving data between the network adapter and CPU

Firmware Settings Once you have adjusted the network adapter’s system resources, you may need to modify its transmission characteristics n These settings are held in the adapter’s firmware Loopback plug n Plugs into port and crosses over the transmit line to the receive line so that the outgoing signal can be redirected back into the computer for testing

Choosing the Right Network Adapter Table 6 -2: Network adapter characteristics

Repeaters Connectivity devices that regenerate and amplify an analog or digital signal Figure 6 -16: Repeaters

Hubs Multiport repeater containing multiple ports to interconnect multiple devices Figure 6 -17: Detailed diagram of a hub

Hubs Elements shared by most hubs: n n n Ports Uplink port Port for management console Backbone port Link LED

Hubs Elements shared by most hubs (cont. ): n n Traffic (transmit or receive) LED Collision LED (Ethernet hubs only) Power supply Ventilation fan

Hubs Figure 6 -18: Hubs in a network design

Hubs Passive hubs n Only repeats signal Intelligent hubs n Possesses processing capabilities

Standalone Hubs that serve a group of computers that are isolated from the rest of the network n Best suited to small, independent departments, home offices, or test lab environments Disadvantage to using a single hub for many connection ports is that it introduces a single point of failure on the network

Stackable Hubs Physically designed to be linked with other hubs in a single telecommunications closet Figure 6 -20: Stackable hubs Figure 6 -21: Rack-mounted stackable hubs

Modular Hubs and Intelligent Hubs Modular hubs n Provide a number of interface options within one chassis Intelligent hubs n n Also called managed hubs Network administrators can store the information generated by intelligent hubs in a MIB (management information base)

Installing a Hub As with network adapters, the best way to ensure a hub is properly installed is to follow the manufacturer’s guidelines Figure 6 -22: Connecting a workstation to a hub

Choosing the Right Hub Factors to consider when selecting the right hub for your network: n n n Performance Cost Size and growth Security Management benefits Reliability

Bridges Like a repeater, a bridge has a single input and single output port Unlike a repeater, it can interpret the data it retransmits Figure 6 -23: A bridge

Bridges Filtering database n n Collection of data created and used by a bridge that correlates the MAC addresses of connected workstations with their locations Also known as a forwarding table Figure 6 -24: A bridge’s use of a filtering database

Bridges Spanning tree algorithm n Routine that can detect circular traffic patterns and modify the way multiple bridges work together, in order to avoid such patterns Transparent bridging n Method used on many Ethernet networks Source-route bridging n Method used on most Token Ring networks Translation bridging n Method that can use different logical topologies

Switches Subdivide a network into smaller logical pieces Figure 6 -25: Examples of LAN switches

Cut-Through Mode and Store and Forward Mode Cut-through mode n n Switching mode in which switch reads a frame’s header and decides where to forward the data before it receives the entire packet Cut-through switches can detect runts, or packet fragments Store and forward mode n Switching mode in which switch reads the entire data frame into its memory and checks it for accuracy before transmitting the information

Using Switches to Create VLANs Virtual local area networks (VLANs) n Network within a network that is logically defined by grouping its devices’ switch ports in the same broadcast domain Broadcast domain n Combination of ports that make up a Layer 2 segment and must be connected by a Layer 3 device

Using Switches to Create VLANs Figure 6 -26: A simple VLAN design

Higher-Layer Switches Switch capable of interpreting Layer 3 data is called a Layer 3 switch Switch capable of interpreting Layer 4 data is called a Layer 4 switch These higher-layer switches may also be called routing switches or application switches

Routers Multiport connectivity device Can integrate LANs and WANs running at different transmission speeds and using a variety of protocols Routers operate at the Network layer (Layer 3) of the OSI Model

Router Features and Functions Modular router n Router with multiple slots that can hold different interface cards or other devices Figure 6 -27: Routers

Router Features and Functions Filter out broadcast transmission to alleviate network congestion Prevent certain types of traffic from getting to a network Support simultaneous local and remote activity Provide high network fault tolerance through redundant components Monitor network traffic and report statistics to a MIB Diagnose internal or other connectivity problems and trigger alarms

Router Features and Functions Static routing n Technique in which a network administrator programs a router to use a specified paths between nodes Dynamic routing n Automatically calculates best path between nodes and accumulates this information in a routing table Hop n Term used in networking to describe each trip data take from one connectivity device to another

Router Features and Functions Figure 6 -28: The placement of routers on a LAN

Routing Protocols To determine the best path, routers communicate with each other through routing protocols In addition to its ability to find the best path, a routing protocol can be characterized according to its convergence time and bandwidth overhead n Convergence time The time it takes for a router to recognize a best path in the event of a change or outage n Bandwidth overhead Burden placed on an underlying network to support the routing protocol

Routing Protocols The four most common routing protocols: n n RIP (Routing Information Protocol) for IP and IPX OSPF (Open Shortest Path First) for IP EIGRP (Enhanced Interior Gateway Routing Protocol) for IP, IPX, and Apple. Talk BGP (Border Gateway Protocol) for IP

Brouters and Routing Switches Bridge router n n Also called a brouter Industry term used to describe routers that take on some characteristics of bridges Routing switch n Router hybrid that combines a router and a switch

Gateways Combination of networking hardware and software that connects two dissimilar kinds of networks Popular types of gateways include: n n E-mail gateways IBM host gateways Internet gateways LAN gateways

Chapter Summary Network interface cards (NICs) come in a variety of types In addition to network adapters that interface with network cabling, network adapters can be designed for wireless transmission Installing a NIC involves attaching it to the bus (or port), installing the NIC device drivers, and configuring its settings Firmware combines software and hardware An IRQ is the means by which a device can request attention from the CPU

Chapter Summary Repeaters are connectivity devices that perform the regeneration of a digital signal At its most primitive, a hub is a multiport repeater A MIB is a collection of data used by management programs to analyze network performance and problems Bridges resemble repeaters in that they have a single input and single output port, but differ from repeaters because they can interpret the data they transmit

Chapter Summary Switches, like hubs, subdivide a network into smaller logical pieces A switch running in cut-through mode will read a frame’s header and decide where to forward the data before it receives the entire packet In store and forward mode, switches read the entire data frame and check it for accuracy before transmitting it In addition to improving bandwidth, switches can create virtual local area networks (VLANs)

Chapter Summary A router is a multiport device that can connect dissimilar LANs and WANs running at different transmission speeds and using a variety of protocols To determine the best paths across networks, routers communicate with each other using routing protocols The networking industry has adopted the term “brouter” to describe routers that take on some characteristics of bridges Gateways are combinations of networking hardware and software that connect two dissimilar kinds of networks