chapter 6 network hardware, switching, and routing
TRANSCRIPT
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
Network+ Guide to Networks, 6th Edition 4
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
Network+ Guide to Networks, 6th Edition 5
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
Network+ Guide to Networks, 6th Edition 6
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
Network+ Guide to Networks, 6th Edition 7
Types of NICs (cont’d.)
Network+ Guide to Networks, 6th Edition 8
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
Network+ Guide to Networks, 6th Edition 9
Installing and Configuring NICs (cont’d.)
Network+ Guide to Networks, 6th Edition 10
Figure 6-4 A properly inserted expansion board NICCourtesy of Gary Herrington Photography
11
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
12
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
Network+ Guide to Networks, 6th Edition
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)
Network+ Guide to Networks, 6th Edition 13
Switch Installation (cont’d.)
Network+ Guide to Networks, 6th Edition 14
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
Network+ Guide to Networks, 6th Edition 15
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
Network+ Guide to Networks, 6th Edition 16
Switching Methods (cont’d.)
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
Network+ Guide to Networks, 6th Edition
17
Switching Methods (cont’d.)
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
Network+ Guide to Networks, 6th Edition 18
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
Network+ Guide to Networks, 6th Edition 19
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
Network+ Guide to Networks, 6th Edition 21
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
Network+ Guide to Networks, 6th Edition 22
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
Network+ Guide to Networks, 6th Edition 23
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
Network+ Guide to Networks, 6th Edition 25
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
Network+ Guide to Networks, 6th Edition 27
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
Network+ Guide to Networks, 6th Edition 28
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
Network+ Guide to Networks, 6th Edition 29
Network+ Guide to Networks, 6th Edition 30
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
Network+ Guide to Networks, 6th Edition 31
Router Characteristics and Functions (cont’d.)
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
Network+ Guide to Networks, 6th Edition 32
Router Characteristics and Functions (cont’d.)
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
Network+ Guide to Networks, 6th Edition 33
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
Network+ Guide to Networks, 6th Edition 35
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
Network+ Guide to Networks, 6th Edition 36
Routing Protocols (cont’d.)
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
Network+ Guide to Networks, 6th Edition 37
Routing Protocols (cont’d.)
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)
Network+ Guide to Networks, 6th Edition 38
Routing Protocols (cont’d.)
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
Network+ Guide to Networks, 6th Edition 39
Routing Protocols (cont’d.)
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
Network+ Guide to Networks, 6th Edition 40
41
Routing Protocols (cont’d.)
Network+ Guide to Networks, 6th Edition
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
Network+ Guide to Networks, 6th Edition 42