Presentation is loading. Please wait.

Presentation is loading. Please wait.

Ethernet: A Multi-access Network

Published byJulien Paré Modified over 5 years ago

Similar presentations

Presentation on theme: "Ethernet: A Multi-access Network"— Presentation transcript:

1 Ethernet: A Multi-access Network
Rick Graziani Cabrillo College

2 Ethernet Protocol Ethernet – Most common LAN technology used today.
Multi-access network: Multiple devices on the same medium and able to communicate with each other without the services of a router. Supports data bandwidths of 10 Mb/s, 100 Mb/s, 1 Gb/s, 100 Gb/s, and more Operates in the data link layer and the physical layer. Defined in the IEEE and standards.

3 Multi-access Topology
A logical multi-access topology - Enables a number of nodes to communicate by using the same shared media. Ethernet LANs – Connected by Ethernet switches (legacy hubs) “Every node “may” see all the frames that are on the medium. Data Link Destination Address denote which device the frame is for.

4 Bus Topology Original Ethernet used a bus topology.
A bus topology uses a single backbone segment (length of cable) that all the hosts connect to directly. Ethernet hubs work the same as a “bus”. And the reason why we have a minimum Ethernet frame size of 64 bytes and specific cable lengths depending upon bandwidth. (See slot time, rule)

5 Today’s Ethernet Networks Use Full Duplex NICs and Switches
router switch switch switch switch switch switch switch switch Multi-access network: Multiple devices on the same medium and able to communicate with each other without the services of a router.

6 Ethernet is Best Effort Delivery
Ethernet is best-effort delivery, no guarantee. Nothing in the Ethernet frame to ensure delivery. Like a trucking service, it doesn’t really know or care about the what it is carrying.

7 Ethernet: A Multi-access Network
Rick Graziani Cabrillo College

8 Ethernet: Ethernet Frame
Rick Graziani Cabrillo College

9 Ethernet Frame Attributes

10 Ethernet Frame Attributes Ethernet Frame Size
Section Ethernet II and IEEE standards define: minimum frame size as 64 bytes maximum as 1518 bytes (1520 with 802.1Q tag) “Collision fragment" or "runt frame” – Frame less than 64 bytes If size of a transmitted frame is less than the minimum or greater than the maximum, the receiving device drops the frame (usually)

11 Ethernet: Ethernet Frame
Rick Graziani Cabrillo College

12 Ethernet: Speed (Bandwidth) and Duplex
Rick Graziani Cabrillo College

13 NIC to NIC Ethernet protocol is only concerned with how the information gets from one Ethernet NIC to another. Layer 2, Data Link Layer, device Connects the device (computer) to the LAN Responsible for the local Layer 2 address (later) Default: Full duplex (optional Half duplex) Common Bandwidth 10 Mbps, 10/100 Mbps, 10/100/1000 Mbps

14 Auto negotiation: Speed and Duplex
PC-A Port 1 Autonegotiation Duplex Duplex Full Full Half Half Media Notes: Use graphic in slide. Keep colors consistent. Speed 1000 Mb/s Speed 100 Mb/s 100 Mb/s 10 Mb/s 10 Mb/s

15 What would be the duplex settings?
Half-duplex router Full-duplex switch switch switch hub hub switch switch switch switch Full-duplex

16 I’m full-duplex so I can send when ever I want.
Duplex Mismatch I’m full-duplex so I can send when ever I want. I’m half-duplex so I can only send when the link is clear but I am also getting a lot of collisions! S1 S2 Full-duplex Half-duplex S2 will continually experience collisions because S1 keeps sending frames any time it has something to send. Media Notes: Use graphic in slide.

17 Ethernet: Speed and Duplex
Rick Graziani Cabrillo College

18 Number Systems: Hexadecimal
Rick Graziani Cabrillo College

19 Rick’s Number System Rules
All digits start with 0 A Base-n number system has n number of digits: Decimal: Base-10 has 10 digits Binary: Base-2 has 2 digits Hexadecimal: Base-16 has 16 digits The first column is always the number of 1’s Each of the following columns is n times the previous column (n = Base-n) Base 10: 10, , Base 2: Base 16: 65, ,

20 Hexadecimal Digits Dec Hex Dec Hex 0 0 8 8 1 1 9 9 2 2 10 A 3 3 11 B
Dec Hex A B C D E F Rick Graziani

21 Hexadecimal Decimal 16’s 1’s 15 F 16 1 0
0, 1, 2, 3, 4, 5, 6, 7 ,8, 9, A, B, C, D, E, F Hexadecimal Decimal ’s 1’s F

22 Why Hexadecimal? Hexadecimal is perfect for matching 4 bits.
Every combination of 4 bits can be matched with one hex number. 4 bits can be represented by 1 Hex value 8 bits can be represented by 2 Hex values Rick Graziani

23 Hexadecimal Digits 4 bits can be represented by 1 Hex value
Dec Hex Binary 8421 A B C D E F Hexadecimal: 16 digits Dec Hex Binary 8421

24 Hexadecimal Digits 4 bits can be represented by 1 Hex value
Hexadecimal is perfect for matching 4 bits. Every combination of 4 bits can be matched with one hex number. 4 bits can be represented by 1 Hex value 8 bits can be represented by 2 Hex values Dec. Hex. Binary Dec. Hex. Binary A B C D E F Rick Graziani

25 Using Hex for 8 bits Dec. Hex. Binary Dec. Hex. Binary
A B C D E F Using Hex for 8 bits

26 Number Systems: Hexadecimal
Rick Graziani Cabrillo College

27 Ethernet: MAC Addresses
Rick Graziani Cabrillo College

28 MAC Address: Ethernet Identity
Layer 2 Ethernet MAC address is a 48-bit binary value expressed as 12 hexadecimal digits IEEE requires a vendor to follow two simple rules: Must use that vendor's assigned OUI as the first 3 bytes All MAC addresses with the same OUI must be assigned a unique value in the last 3 bytes aka physical address, bia Section

29 MAC Address Format OUI unique An Intel MAC address: 00-21-CC-BA-44-C4
Dec Bin Hex Dec Bin Hex 0 = 0000 = = 1000 = 8 1 = 0001 = = 1001 = 9 2 = 0010 = = 1010 = A 3 = 0011 = = 1011 = B 4 = 0100 = = 1100 = C 5 = 0101 = = 1101 = D 6 = 0110 = = 1110 = E 7 = 0111 = = 1111 = F OUI unique An Intel MAC address: CC-BA-44-C4 – – – IEEE OUI FAQs:

30 Ethernet MAC MAC Address Representations
Section

31 The MAC Address MAC Address MAC Address
The Ethernet protocol uses MAC addresses to identify the source of the Ethernet frame and the destination of the Ethernet frame. Whenever is computer sends an Ethernet frame, it includes the MAC address on its NIC as the Source “MAC” Address. We will learn later how it learns the Destination “MAC” Address…. (ARP)

32 Ethernet MAC Unicast MAC Address
Section

33 Ethernet MAC Broadcast MAC Address
Section

34 Ethernet MAC Multicast MAC Address
Section Multicast MAC address is a special value that begins with E in hexadecimal Range of IPV4 multicast addresses is to

35 Ethernet: MAC Addresses
Rick Graziani Cabrillo College

36 Ethernet: Switches and Broadcast Domains
Rick Graziani Cabrillo College

37 Full-duplex Switches Full-duplex is allows simultaneous communication between a pair of stations or devices. 100% bandwidth utilization

38 Broadcast Domain

39 Ethernet: Switches and Broadcast Domains
Rick Graziani Cabrillo College

40 Ethernet: CSMA/CD, Hubs and Collision Domains
Rick Graziani Cabrillo College

41 Original Ethernet – Shared Bus
Not for me  It's for me!  Not for me  When an Ethernet frame is sent all devices on the “bus” receive it. What do they do with it? All devices check the destination MAC address to see if it matches their MAC address

42 Collision! Collisions X Abbreviated MAC Addresses
1111 2222 3333 nnnn X When two devices transmit at the same time we have a collision Collision!

43 Media Access Control Section Carrier Sense Multiple Access with Collision Detection (CSMA/CD) process NICs operating in half duplex Used to first detect if the media is carrying a signal If no carrier signal is detected, the device transmits its data If two devices transmit at the same time - data collision Devices sense collision and stop transmitting – algorithm to determine when to send

44 (Hub)

45 X Collision Domain Shared Collision Domain
2222 1111 1111 2222 X 4444 3333 NICs and hub ports operate in half duplex Insufficient use of bandwidth About 50% bandwidth utilization (one direction only) Similar to (CSMA/CA) 5555 Shared Collision Domain 3333 4444

46 Switches (and routers) segment collision domains

47 Ethernet: CSMA/CD, Hubs and Collision Domains
Rick Graziani Cabrillo College

48 Ethernet: Switch Forwarding Process
Rick Graziani Cabrillo College

49 Forwarding decisions Hub: Layer 1 device Multiport repeater
Router (multilayer switch): Layer 3 device Connects different subnets Makes forwarding decision based on layer 3 – Destination IP Address Maintains a routing table Switch: Layer 2 device Connects devices on same link layer Makes forwarding decision based on layer 2 – Destination MAC Address Maintains a MAC address table Hub: Layer 1 device Multiport repeater Makes forwarding decision based on layer 1 – forwards bits Everything that comes in one port, is sent out all other ports (regenerated)

50 Switch: Learning and Forwarding
1. Learn - Examine source MAC address and incoming port # In MAC address table? No: Add source MAC and port # to table (start 5 minute timer) Yes: Reset 5 minute timer 2. Forward – Examine destination MAC address Unicast No: Forward out all ports except incoming port Yes: Forward out port for that MAC address (learned previously) Broadcast/Multicast (unless using IGMP) Forward out all ports except incoming port

51 Learn: Examine Source MAC Address
MAC Address Table Port MAC Address 1 2 3 4 A B C D MAC 00-0A MAC 00-0B MAC 00-0C MAC 00-0D Media Notes: Use graphic in slide MAC addresses are shortened for demonstration purposes.

52 Learn: Examine Source MAC Address
MAC Address Table Port MAC Address I don’t have this source MAC address and the incoming port in my table so I will add it. Port and Source MAC address added 2 1 2 3 4 1 A B C D MAC 00-0A MAC 00-0B MAC 00-0C MAC 00-0D Media Notes: Use graphic in slide. Keep colors consistent. Destination MAC 00-0D Source MAC 00-0A Type Data FCS MAC addresses are shortened for demonstration purposes.

53 Forward: Examine Destination MAC Address
MAC Address Table Port MAC Address I don’t have this destination MAC address in my table so I will send this unknown unicast out all ports. 1 00-0A Destination MAC address not in table 1 1 2 3 4 2 A B C D MAC 00-0A MAC 00-0B MAC 00-0C MAC 00-0D Media Notes: Use graphic in slide. Keep colors consistent. Destination MAC 00-0D Source MAC 00-0A Type Data FCS MAC addresses are shortened for demonstration purposes.

54 Learn: Examine Source MAC Address
MAC Address Table I don’t have this source MAC address and the incoming port in my table so I will add it. Port MAC Address 1 00-0A Port and Source MAC address added 1 1 2 3 4 1 A B C D MAC 00-0A MAC 00-0B MAC 00-0C MAC 00-0D Media Notes: Use graphic in slide. Keep colors consistent. Destination MAC 00-0A Source MAC 00-0D Type Data FCS MAC addresses are shortened for demonstration purposes.

55 Forward: Examine Destination MAC Address
MAC Address Table I know the destination MAC address so I will only forward the frame out port 1. Port MAC Address 2 1 4 00-0A 00-0D 1 2 3 4 2 A B C D MAC 00-0A MAC 00-0B MAC 00-0C MAC 00-0D Media Notes: Use graphic in slide. Keep colors consistent. Destination MAC 00-0A Source MAC 00-0D Type Data FCS MAC addresses are shortened for demonstration purposes.

56 Learn: Examine Source MAC Address
MAC Address Table Port MAC Address 1 4 00-0A 00-0D 1 2 3 4 1 2 A B C D MAC 00-0A MAC 00-0B MAC 00-0C MAC 00-0D Media Notes: Use graphic in slide. Keep colors consistent. Destination MAC 00-0D Source MAC 00-0A Type Data FCS MAC addresses are shortened for demonstration purposes.

57 Ethernet: Switch Forwarding Process
Rick Graziani Cabrillo College

58 Ethernet: Straight-Through versus Cross-Over Cable?
Rick Graziani Cabrillo College

59 UTP Cabling Types of UTP Cable
Section

60 Cables Straight-through cable: Unlike devices
Crossover Straight-through Straight-through Crossover Straight-through cable: Unlike devices Cross-over cable: Like devices

61 Auto-MDIX What would happen if two new switches are interconnected with a straight-through cable? The auto-MDIX feature is enabled by default, therefore a cable change is not needed. Negotiate to work in full-duplex mode if capable. Work at the fastest speed that is supported by both switches.

62 Ethernet: Straight-Through versus Cross-Over Cable?
Rick Graziani Cabrillo College

63 ARP: Introduction to ARP
Rick Graziani Cabrillo College

64 IPv4 Address MAC Address
ARP Request – Same Link MAC 00-0B B PC-A’s ARP Cache IPv4 Address MAC Address A C MAC 00-0C MAC 00-0A MAC 00-0D Internet R1 PCA puts the IPv4 packet on hold and creates an ARP Request with Target IPv4 = Target MAC – unknown Source MAC 00-A Destination MAC = broadcast Ethernet Header ARP Request Destination MAC FF-FF Source MAC 00-0A Target IPv4 Target MAC ??? Ethernet Header IP Packet On Hold Destination MAC ??? Source MAC 00-0A Source IP Destination IP

65 IPv4 Address MAC Address
ARP Default Gateway MAC 00-0B B PC-A’s ARP Cache IPv4 Address MAC Address A C MAC 00-0C MAC 00-0A MAC 00-0D Default Gateway: Internet R1 PCA puts the IPv4 packet on hold and creates an ARP Request with Target IPv4 = Target MAC – unknown Source MAC 00-A Destination MAC = broadcast Ethernet Header ARP Request Destination MAC FF-FF Source MAC 00-0A Target IPv4 Target MAC ??? Ethernet Header IP Packet On Hold Destination MAC ??? Source MAC 00-0A Source IP Destination IP

66 ARP: Introduction to ARP
Rick Graziani Cabrillo College

Download ppt "Ethernet: A Multi-access Network"

Similar presentations

CCNA3: Switching Basics and Intermediate Routing v3.0 CISCO NETWORKING ACADEMY PROGRAM Switching Concepts Introduction to Ethernet/802.3 LANs Introduction.

CCNA3: Switching Basics and Intermediate Routing v3.0 CISCO NETWORKING ACADEMY PROGRAM Switching Concepts Introduction to Ethernet/802.3 LANs Introduction.
Chapter 5 Intro to Routing & Switching.  Upon completion of this chapter, you should be able to:  Describe the operation of the Ethernet sublayers.

Chapter 5 Intro to Routing & Switching.  Upon completion of this chapter, you should be able to:  Describe the operation of the Ethernet sublayers.
© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 5: Ethernet Introduction to Networks.

© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 5: Ethernet Introduction to Networks.
1 Version 3 Module 8 Ethernet Switching. 2 Version 3 Ethernet Switching Ethernet is a shared media –One node can transmit data at a time More nodes increases.

1 Version 3 Module 8 Ethernet Switching. 2 Version 3 Ethernet Switching Ethernet is a shared media –One node can transmit data at a time More nodes increases.
CCNA 1 v3.1 Module 6 Review. 2 What 3 things happen on an Ethernet network after a collision occurs? A backoff algorithm is invoked and transmission is.

CCNA 1 v3.1 Module 6 Review. 2 What 3 things happen on an Ethernet network after a collision occurs? A backoff algorithm is invoked and transmission is.
1 Version 3 Module 8 Ethernet Switching. 2 Version 3 Ethernet Switching Ethernet is a shared media –One node can transmit data at a time More nodes increases.

1 Version 3 Module 8 Ethernet Switching. 2 Version 3 Ethernet Switching Ethernet is a shared media –One node can transmit data at a time More nodes increases.
Ethernet Frame PreambleDestination Address Source Address Length/ Type LLC/ Data Frame Check Sequence.

Ethernet Frame PreambleDestination Address Source Address Length/ Type LLC/ Data Frame Check Sequence.
IST 228\Ch1\Internetworking1 Collision/Broadcast Domain The term collision domain defines the set of devices for which their frames could collide A broadcast.

IST 228\Ch1\Internetworking1 Collision/Broadcast Domain The term collision domain defines the set of devices for which their frames could collide A broadcast.
Semester 1 Module 8 Ethernet Switching Andres, Wen-Yuan Liao Department of Computer Science and Engineering De Lin Institute of Technology

Semester 1 Module 8 Ethernet Switching Andres, Wen-Yuan Liao Department of Computer Science and Engineering De Lin Institute of Technology
Ethernet Fundamentals Overview: Part 2. Ethernet Fundamentals Part 1 Introduction to Ethernet Part 2 Layer 2 and Ethernet Switches Cables, Duplex, and.

Ethernet Fundamentals Overview: Part 2. Ethernet Fundamentals Part 1 Introduction to Ethernet Part 2 Layer 2 and Ethernet Switches Cables, Duplex, and.
ARP Scenarios CIS 81 and CST 311 Rick Graziani Fall 2005.

ARP Scenarios CIS 81 and CST 311 Rick Graziani Fall 2005.
Chapter 5 Intro to Routing & Switching.  Upon completion of this chapter, you should be able to:  Describe the operation of the Ethernet sublayers.

Chapter 5 Intro to Routing & Switching.  Upon completion of this chapter, you should be able to:  Describe the operation of the Ethernet sublayers.
© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 5: Ethernet Introduction to Networks.

© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 5: Ethernet Introduction to Networks.
Chapter 9 Ethernet – Part 2

Chapter 9 Ethernet – Part 2
© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 5: Ethernet Introduction to Networks.

© 2008 Cisco Systems, Inc. All rights reserved.Cisco ConfidentialPresentation_ID 1 Chapter 5: Ethernet Introduction to Networks.
Chapter 9 Ethernet – Part 1 CIS 82 Routing Protocols and Concepts Rick Graziani Cabrillo College Last Updated: 5/5/2008.

Chapter 9 Ethernet – Part 1 CIS 82 Routing Protocols and Concepts Rick Graziani Cabrillo College Last Updated: 5/5/2008.
S3C2 – LAN Switching Addressing LAN Problems. Congestion is Caused By Multitasking, Faster operating systems, More Web-based applications Client-Server.

S3C2 – LAN Switching Addressing LAN Problems. Congestion is Caused By Multitasking, Faster operating systems, More Web-based applications Client-Server.
Switches 1RD-CSY1017. 2  In this lecture, we will learn about  Collision Domain and Microsegmentation  Switches – a layer two device ◦ MAC address.

Switches 1RD-CSY  In this lecture, we will learn about  Collision Domain and Microsegmentation  Switches – a layer two device ◦ MAC address.
CCNA 3 Week 4 Switching Concepts. Copyright © 2005 University of Bolton Introduction Lan design has moved away from using shared media, hubs and repeaters.

CCNA 3 Week 4 Switching Concepts. Copyright © 2005 University of Bolton Introduction Lan design has moved away from using shared media, hubs and repeaters.
Cisco 3 – Switching Concepts Perrine. J Page 16/1/2016 Module 4 The use of bridges and switches for segmentation results in ____? 1.Multiple broadcast.

Cisco 3 – Switching Concepts Perrine. J Page 16/1/2016 Module 4 The use of bridges and switches for segmentation results in ____? 1.Multiple broadcast.

Similar presentations

Ads by Google