CCNA Routing and Switching Lesson 02 - Network Devices - Eric Vanderburg

Networking Essentials – Eric Vanderburg © 2005

Network DevicesNetwork DevicesChapter 2Chapter 2


Network DevicesNetwork Devices RepeaterRepeater HubHub WAP (Wireless Access Point)WAP (Wireless Access Point) BridgeBridge SwitchSwitch RouterRouter Brouter / Layer 3 SwitchBrouter / Layer 3 Switch GatewayGateway


RepeaterRepeater Attenuation – degeneration of a signalAttenuation – degeneration of a signal Cleans up the signalCleans up the signal Extends the distance of the networkExtends the distance of the network

Repeaters are for digital transmissionsRepeaters are for digital transmissions Optical repeaters for fiber opticsOptical repeaters for fiber optics Amplifiers are for analog transmissionsAmplifiers are for analog transmissions Layer 1 componentLayer 1 component


5-4-3 rule5-4-3 rule 5 segments, 4 repeaters, 3 of the five 5 segments, 4 repeaters, 3 of the five

segments may contain host nodes.segments may contain host nodes.


HubHub Central wired access pointCentral wired access point Broadcasts all data to all other devices Broadcasts all data to all other devices

(everything that goes in comes back out)(everything that goes in comes back out) Shared medium (contention)Shared medium (contention) Layer 1 componentLayer 1 component Passive HubPassive Hub

Does not regenerate the signalDoes not regenerate the signal Does not have to be poweredDoes not have to be powered

Active HubActive Hub Regenerates the signalRegenerates the signal Must be poweredMust be powered Multi-port repeaterMulti-port repeater


WAPs (Wireless Access WAPs (Wireless Access Points)Points)

Wireless clients connect through Wireless clients connect through specified channels within an specified channels within an electromagnetic frequencyelectromagnetic frequency

Layer 1 deviceLayer 1 device ContentionContention Speeds get slower the further away Speeds get slower the further away

you are from the AP (Access Point)you are from the AP (Access Point) Other objects may cause Other objects may cause

interferenceinterference


EthernetEthernet CSMA/CD (Carrier Sense Multiple CSMA/CD (Carrier Sense Multiple

Access Collision Detection)Access Collision Detection) Collisions cause nodes to enter into Collisions cause nodes to enter into

a backoff state where they do not a backoff state where they do not transmittransmit


BridgeBridge Analyzes layer 2 addressesAnalyzes layer 2 addresses Makes forwarding decisionsMakes forwarding decisions Broadcast frames are always forwardedBroadcast frames are always forwarded Segments the collision domainSegments the collision domain Layer 2 deviceLayer 2 device Transparent Bridge - Keeps a bridging table Transparent Bridge - Keeps a bridging table

for each sidefor each side Source-Routing Bridge – The source host Source-Routing Bridge – The source host

provides info on how to reach the provides info on how to reach the destination host. (Used on Token Ring destination host. (Used on Token Ring networks)networks)

Translation Bridges – connect two different Translation Bridges – connect two different networksnetworks


SwitchSwitch Multi-port BridgeMulti-port Bridge Layer 2 deviceLayer 2 device Creates a bridging table for all portsCreates a bridging table for all ports Microsegmentation – creating a Microsegmentation – creating a

virtual circuit between two ports. virtual circuit between two ports. Each port receives the full bandwidthEach port receives the full bandwidth Reduces the collision domainReduces the collision domain Higher security against sniffers (also Higher security against sniffers (also

harder to do network diagnostics)harder to do network diagnostics)


RoutersRouters Connects internetworks and diverse Connects internetworks and diverse

segmentssegments Layer 3 deviceLayer 3 device Looks at logical addresses to make a routing Looks at logical addresses to make a routing

decisiondecision Exchanges routing information with other Exchanges routing information with other

routers using routing protocolsrouters using routing protocols Segments the broadcast domain because Segments the broadcast domain because

broadcasts are not routedbroadcasts are not routed Slower than lower network devicesSlower than lower network devices Can filter packets based on ACLs (Access Can filter packets based on ACLs (Access

Control Lists)Control Lists)


Other DevicesOther Devices Brouter / Layer 3 SwitchBrouter / Layer 3 Switch

Works with frames for nonroutable Works with frames for nonroutable protocols and packets for routable protocols and packets for routable protocolsprotocols

Can route between VLANs (Virtual LANs)Can route between VLANs (Virtual LANs) Faster in some cases than a routerFaster in some cases than a router

GatewayGateway Can translate between different protocols Can translate between different protocols

suites all the way to the application layersuites all the way to the application layer


AcronymsAcronyms ACL, Access Control ListACL, Access Control List AP, Access PointAP, Access Point CSMA/CD, Carrier Sense Multiple CSMA/CD, Carrier Sense Multiple

Access Collision DetectionAccess Collision Detection VLAN, Virtual LANVLAN, Virtual LAN WAP, Wireless Access PointWAP, Wireless Access Point

Technology

CCNA Routing and Switching Lesson 02 - Network Devices - Eric Vanderburg