chapter 6 network hardware, switching, and routing

Network+ Guide to Networks6th Edition

Chapter 6Network Hardware, Switching, and Routing

Objectives Identify the functions of LAN connectivity

hardware Install, configure, and differentiate between

network devices such as NICs, hubs, bridges, switches, routers, and gateways

Explain the advanced features of a switch and understand popular switching techniques, including VLAN management

Explain the purposes and properties of routing Describe common IPv4 and IPv6 routing

protocolsNetwork+ Guide to Networks, 6th Edition 2

NICs (Network Interface Cards)

Connectivity deviceso Enable device transmissiono Transceiver

• Transmits and receives data

Physical layer and Data Link layer functionso Issue data signalso Assemble and disassemble data frameso Interpret physical addressing informationo Determine right to transmit data

Network+ Guide to Networks, 6th Edition 3

NICs (cont’d.) Smart hardware

o Prioritizationo Network managemento Bufferingo Traffic-filtering

Do not analyze informationo Added by Layers 3 through 7 OSI model

protocols Importance

o Common to every networking device, network


Types of NICs (cont’d.) Expansion slots

o Multiple electrical contacts on motherboardo Allow bus expansion

Expansion card (expansion board)o Circuit board for additional deviceso Inserts into expansion slot, establishes electrical

connectiono Device connects to computer’s main circuit or buso Computer centrally controls device


Types of NICs (cont’d.) Multiple bus types

o PCIe bus: most popular expansion board NIC PCIe (Peripheral Component Interconnect

Express)o 32-bit buso Maximum data transfer rate: 1 Gbpso Introduced in 2004


Figure 6-1 PCIe expansion board NIC

Courtesy of Intel Corporation

Types of NICs (cont’d.) On-Board NICs

o Connect device directly to motherboardo On-board ports: mouse, keyboard

New computers, laptopso Use onboard NICs integrated into motherboard

Advantageso Saves spaceo Frees expansion slots


Types of NICs (cont’d.)


Figure 6-3 Motherboard with on-board NICsCourtesy of EVGA USA

Installing and Configuring NICs

Installing NIC hardwareo Read manufacturer’s documentation

Install expansion card NICo Gather needed toolso Unplug computer, peripherals, and network

cableo Ground yourselfo Open computer case

• Select slot, insert NIC, attach bracket, verify cableso Replace cover, turn on computer

• Configure NIC software


Installing and Configuring NICs (cont’d.)


Figure 6-4 A properly inserted expansion board NICCourtesy of Gary Herrington Photography

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Repeaters and Hubs Repeaters

o Operate in Physical OSI model layero No means to interpret datao Regenerate signal

Hubo Repeater with more than one output porto Typically contains multiple data ports

• Patch cables connect printers, servers, and workstations

o Most contain uplink port

Network+ Guide to Networks, 6th Edition

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Switches Connectivity devices that subdivide a network

o Segments Traditional switches

o Operate at Data Link OSI model layer Modern switches

o Can operate at Layer 3 or Layer 4 Switches interpret MAC address information Common switch components

o Internal processor, operating system, memory, ports


Switch Installation Follow manufacturer’s guidelines General steps (assume Cat 5 or better UTP)

o Verify switch placemento Turn on switcho Verify lights, self power testso Configure (if necessary)o Connect NIC to a switch port (repeat for all

nodes)o After all nodes connected, turn on nodeso Connect switch to larger network (optional)


Switch Installation (cont’d.)


Figure 6-13 A switch on a small networkCourtesy Course Technology/Cengage Learning

Switching Methods Difference in switches

o Incoming frames interpretationo Frame forwarding decisions making

Four switching modes existo Two basic methods discussed

• Cut-through mode• Store-and-forward mode


Switching Methods (cont’d.)

Cut-through modeo Switch reads frame’s headero Forwarding decision made before receiving

entire packet• Uses frame header: first 14 bytes contains

destination MAC addresso Cannot verify data integrity using frame check

sequenceo Can detect erroneously shortened packets

(runts)o Runt detected: wait for integrity check



Cut-through mode (cont’d.)o Cannot detect corrupt packetso Advantage: speedo Disadvantage

• Data buffering (switch flooded with traffic)o Best use

• Small workgroups needing speed• Low number of devices


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Store-and-forward modeo Switch reads entire data frame into memoryo Checks for accuracy before transmitting

informationo Transmit data more accurately than cut-

through modeo Slower than cut-through modeo Best uses

• Larger LAN environments; mixed environmentso Can transfer data between segments running

different transmission speeds


VLANs VLANs (virtual local area networks)

o Logically separate networks within networks• Groups ports into broadcast domain

Broadcast domaino Port combination making a Layer 2 segmento Ports rely on Layer 2 device to forward

broadcast frames Collision domain

o Ports in same broadcast domain• Do not share single channel


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Sample VLAN

VLANs (cont’d.) Advantage of VLANs

o Flexible• Ports from multiple switches or segments• Use any end node type

o Reasons for using VLAN• Separating user groups• Isolating connections• Identifying priority device groups• Grouping legacy protocol devices• Separating large network into smaller subnets


VLANs (cont’d.) Switch typically preconfigured

o One default VLANo Cannot be deleted or renamed

Create additional VLANso Indicate to which VLAN each port belongso Additional specifications

• Security parameters, filtering instructions, port performance requirements, network addressing and management options

Maintain VLAN using switch software


VLANs and Trunking (cont’d.)

Potential problemo Cutting off group from rest of network

• Correct by using router or Layer 3 switch

Trunkingo Switch’s interface carries traffic of multiple VLANs

Trunko Single physical connection between switches

VLAN data separationo Frame contains VLAN identifier in header


VLANs and Trunking (cont’d.)

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STP (Spanning Tree Protocol)

IEEE standard 802.1D Operates in Data Link layer Prevents traffic loops

o Calculating paths avoiding potential loopso Artificially blocking links completing loop

Three stepso Select root bridge based on Bridge IDo Examine possible paths between network bridge and

root bridgeo Disables links not part of shortest path


26Figure 6-17 Enterprise-wide switched network

Content and Multilayer Switches

Layer 3 switch (routing switch)o Interprets Layer 3 data

Layer 4 switcho Interprets Layer 4 data

Content switch (application switch)o Interprets Layer 4 through Layer 7 data

Advantageso Advanced filteringo Keeping statisticso Security functions


Routers Multiport connectivity device

o Directs data between network nodeso Integrates LANs and WANs

• Different transmission speeds, protocols

Operate at Network layer (Layer 3)o Directs data from one segment or network to anothero Logical addressingo Protocol dependent

Slower than switches and bridgeso Need to interpret Layers 3 and higher information


Router Characteristics and Functions

Intelligenceo Tracks node locationo Determine shortest, fastest path between two

nodeso Connects dissimilar network types

Large LANs and WANso Routers indispensable

Router componentso Internal processor, operating system, memory,

input and output jacks, management control interface



Figure 6-19 Routers

Courtesy Course Technology/Cengage Learning

Router Characteristics and Functions (cont’d.)

Router capabilitieso Connect dissimilar networkso Interpret Layer 3 addressingo Determine best data patho Reroute traffic

Optional router functionso Filter broadcast transmissionso Enable custom segregation, securityo Support simultaneous connectivityo Provide fault toleranceo Monitor network traffico Diagnose problems and trigger alarms



Interior routero Directs data between nodes on a LAN

Exterior routero Directs data between nodes external to a LAN

Border routerso Connect autonomous LAN with a WAN

Routing tableso Identify which routers serve which hosts



Static routingo Router configured to use specific path between

nodes Dynamic routing

o Automatically calculates best path between nodes

Installationo Simple for small office or home office LANs

• Web-based configurationo Challenging for sizable networks


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Multiple Routers – Primary Router

Routing Protocols Best path

o Most efficient route from one node to anothero Dependent on:

• Hops between nodes• Current network activity• Unavailable link• Network transmission speed• Topology

o Determined by routing protocol


Routing Protocols (cont’d.)

Routing metric factorso Number of hopso Throughput on potential patho Delay on a potential patho Load (traffic)o Maximum transmission unit (MTU)o Costo Reliability of potential path



Distance-vector routing protocolso Determine best route based on distance to destinationo Factors

• Hops, latency, network traffic conditions

RIP (Routing Information Protocol)o Only factors in number of hops between nodes

• Limits 15 hopso Type of IGP (Interior Gateway Protocol)

• Can only route within internal networko Slower and less secure than other routing protocols



RIPv2 (Routing Information Protocol Version 2)o Generates less broadcast traffic, more secureo Cannot exceed 15 hopso Less commonly used

BGP (Border Gateway Protocol)o Communicates using BGP-specific messageso Many factors determine best pathso Configurable to follow policieso Type of EGP (Exterior Gateway Protocol)o Most complex (choice for Internet traffic)



Link-state routing protocolo Routers share information

• Each router independently maps network, determines best path

OSPF (Open Shortest Path First)o Interior or border router useo No hop limito Complex algorithm for determining best pathso Each OSPF router

• Maintains database containing other routers’ links



Hybrido Link-state and distance-vector characteristicso EIGRP (Enhanced Interior Gateway Routing

Protocol)• Most popular• Cisco network routers only

o EIGRP benefits• Fast convergence time, low network overhead• Easier to configure and less CPU-intensive than OSPF• Supports multiple protocols• Accommodates very large, heterogeneous networks


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Table 6-1 Summary of common routing protocols

Courtesy Course Technology/Cengage Learning

Summary Network adapter types vary

o Access method, transmission speed, connector interfaces, number of ports, manufacturer, device type

Repeaterso Regenerate digital signal

Bridges can interpret the data they retransmit Switches subdivide a network

o Generally secureo Create VLANs

Various routing protocols exist


chapter 6 network hardware, switching, and routing

Documents

cables o

repeaters o

tools o

gbps o

workstations o

nic hardware o

data frames o

bus o computer