chapter 4. upon completion of this chapter, you should be able to: describe how data accesses the...
TRANSCRIPT
ETHERNETChapter 4
OBJECTIVES Upon completion of this chapter, you
should be able to:Describe how data accesses the media on
EthernetSelect the correct network device for an
Ethernet networkConnect the proper media for an Ethernet
networkSelect the correct cable type for connecting
devicesTroubleshoot & resolve network connectivity
ETHERNET
4.1
TOPOLOGY What was the old, original Ethernet
physical topology? Bus
What is the current Ethernet physical topology? Star or Extended Star
What is the logical topology for current Ethernet using a hub? Bus/broadcast (sent to all on segment)
What is the logical topology for current Ethernet using a switch? Star (sent only to destination device)
ETHERNET ACCESS METHOD Data on Ethernet networks shares the
cable
How can all devices communicate on this shared media?
CSMA Ethernet is contention-based/non-deterministic
Data contends or shares for a spot on the media Doesn’t know when it’ll get access to it
Listens for signal on media No signal = transmit data Transmit at same time= collision
Devices do not keep track of whose turn it is
More collisions= less throughput SOLUTION: CSMA/CD
CSMA/CD ON ETHERNET NETWORKS Listens for silence
Silence= transmit data
If devices transmit at same time, collisionThey send a jam signalBackoff random time, listen for silence,
retransmit
Collisions not a problem much anymoreUsing switches & full-duplex, this is not a
problem anymore
CURRENT SWITCHED NETWORK
DUPLEXING Hubs
Send data out all portsAre dumb & can’t handle in/outHALF DUPLEX ONLY
Switch IntelligentFULL DUPLEXSends & receives at the same time
FRAME SIZE Min. frame size is 64 bytes; max is 1518
bytesData is 46-1500 bytes
> 64 bytes is considered a collision fragment & will be dropped
ACTIVITY TestOut 4.1
4.1.14.1.2- Fact Sheet4.1.3- Quiz (4Q)
REVIEW- 4Q What important addresses are
encapsulated into a frame?Source & destination MAC
What does the preamble used for?Timing/synchronization
What is the minimum frame size?64 bytes
What happens if a frame is less than 64 bytes?Considered a fragment & dropped
ETHERNET SPECIFICATIONS
4.2
ETHERNET STANDARDS FOR COPPER
Speed; Baseband; Twisted Pair 100Base-T Fast Ethernet (Cat 5 or
higher) 1000Base-T (Cat 5e or higher) 1000Base-TX (Cat 6 or higher) 100m max; Cat 6 less than 100m; Cat6a
100m
ETHERNET STANDARDS FOR FIBER L= LONG; S= SHORT; Ex= EXTENDED
REACHL & Ex are Single Mode (long distance)S is Multimode (shorter distance)
OTHER ETHERNET STANDARDS SONET
Uses fiber to multiplex signals over a cable over MUCH longer distances for a WAN
Ethernet over HDMIData shared over an Ethernet Channel
(HEC) without using extra cables
Ethernet over Power LineSends data over AC lines on different
frequencyUse instead of running cable
ACTIVITY Review 4.2.2 Fact Sheet
Lab 4.2.3 Reconnect to an Ethernet Network
4.2.4 Quiz (15 questions)
REVIEW- 3Q If a fiber cable has an L or Ex, which
type of fiber cable is it?Single mode
1000Base-Tx is what category of Ethernet?Cat 6
You need to use PoE to some switches. Which of these Ethernet standards will work; 100Base-Fx, 1000Base-T, 10GBase-LR, 1000Base-Lx?1000Base-T (all the others are fiber)
CONNECTING NETWORK DEVICES
4.3
WHICH CABLE? Choose the correct cable:
UPLINK PORT Uplink Port (Internet Port)
Allows you to connect one device to another, like switch to switch or hub to hub for when you run out of ports
Uplink port on switch 1 to regular port on other switch using a straight through cable
ACTIVITY Lab 4.3.3 Connect Network Devices
4.3.4 Quiz (10 Questions)
REVIEW- 3Q What happens when the CSMA/CD
network detects a collision?Signals a collision, waits to check for
silence, retransmits The data part of an Ethernet frame is 36
bytes. What needs to be added to the frame and how many bytes will the data need to be?Padding; 46 bytes
A port on a switch is labeled Auto-MDIX. What does that mean? It will autosense the cable
TROUBLESHOOTING PHYSICAL CONNECTIVITY
4.4
TROUBLESHOOTING THE LINK STATUS Usually 2 lights on NIC/port
Link Green- getting full 1Gbps Orange- only getting 100Mbps Red- possibly using wrong cable None- no connection
Activity Flashing- data being sent/received
Speed
ACTIVITY Watch 4.4.1- Troubleshooting the Fault Domain
Lab 4.4.5- Exploring Physical Connectivity
Lab 4.4.6- Troubleshoot Physical Connectivity 1
Lab 4.4.7- Troubleshoot Physical Connectivity 2
Lab 4.4.8- Troubleshoot Physical Connectivity 3
Lab 4.4.9- Troubleshoot Physical Connectivity 4
4.4.10 Quiz (15 questions)
REVIEW- 3Q If you connect a cable from a switch’s
uplink to port 1 on another switch, which cable should you use?Straight through
What does it mean if the NIC’s activity light is flashing?Data is being sent/received
If you need to connect a laptop to a router to configure it, what do you need?Rollover/console cable & terminal emulation
software
ETHERNETChapter 4