ETHERNET

Presenter Viet Nguyen

Computer Networks Class – BIS2013

Professor Dr. Friedbert Kaspar – Vietnamese-German University

Ethernet – IEEE 802.3

• Introduction– An overview of Ethernet– Network topologies and Switched LAN

• Ethernet technology– Ethernet technologies and cable types– Ethernet frame

• Ethernet devices– Link-layer switch– Switches vs. Routers

• Ethernet applications– Firewall– IP Spoofing

• Summary– Ethernet and its future– References

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 2

INTRODUCTION

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 3

Overview• Move Beyond Your LAN with Ethernet Services

• Ethernet is a family of computer networking technologies for local area networks (LANs). Ethernet was commercially introduced in 1980 and standardized in 1983 as IEEE 802.3.[1] Ethernet has largely replaced competing wired LAN technologies such as token ring, FDDI, and ARCNET.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 4

Overview (2)

• "Switching and 100Mbps speeds make 16Mbps technology obsolete" – the time when Token Ring technology was replaced by Ethernet. (http://www.techrepublic.com/blog/classics-rock/does-anyone-actually-still-use-token-ring/)

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 5

1000BASE-T

http://www.sld.co.uk/products/comms/IPPBX_schematic.jpg

10BASE5

Network Topologies

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 6

http://upload.wikimedia.org/wikipedia/commons/9/96/NetworkTopologies.png

Network Topologies (2)

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 7

Star bus - Probably the most common network

topology in use today, star bus combines elements of

the star and bus topologies to create a versatile

network environment. Nodes in particular areas

are connected to hubs (creating stars), and the

hubs are connected together along the network

backbone (like a bus network). Quite often, stars

are nested within starshttp://computer.howstuffworks.com/lan-switch2.htm

Switched Local Area Networks

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 8

TECHNOLOGY

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 9

Ethernet Technologies

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 10

Designation Supported Media Maximum Segment Length

Transfer Speed

Topology

100Base-TX Category5 UTP 100m 100Mbps Star,using either simple repeater hubs or Ethernet switches

100Base-FX Fiber-optic- two strands of multimode 62.5/125 fiber

412m(Half-Duplex)2000m(full-duplex)

100 Mbps(200 Mb/sfull-duplexmode)

Star(often only point-to-point)

1000Base-SX Fiber-optic- two strands of multimode 62.5/125 fiber

260m 1Gbps Star, using buffered distributor hub (or point-to-point)

1000Base-LX Fiber-optic- two strands of multimode 62.5/125 fiber or monomode fiber

440m(multimode) 5000m(single-mode)

1Gbps Star,using buffered distributor hub (or point-to-point)

1000Base-CX Twinax,150-Ohm-balanced, shielded, specialty cable

25m 1Gbps Star(or point-to-point)

1000Base-T Category5 100m 1Gbps Star

Ethernet Cable Types

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 11

http://www.directron.com/cableguide.html

http://academy.delmar.edu/Courses/ITNW2313/1Essentials.html

Ethernet Frame

• A data packet on an Ethernet link is called an Ethernet packet, which transports an Ethernet frame as payload.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 12

802.3 Ethernet packet and frame structure

Layer PreambleStart of frame

delimiter

MAC destination

MAC source802.1Q tag (optional)

Ethertype (Ethernet II) or length

(IEEE 802.3)

Payload

Frame check

sequence(3

2-bit CRC)

Interpacketgap

7 octets 1 octet 6 octets 6 octets (4 octets) 2 octets46(42)[b]–

1500 octets4 octets 12 octets

Layer 2 Ethernet

frame← 64–1518(1522) octets →

Layer 1 Ethernet packet

← 72–1526(1530) octets →

The internal structure of an Ethernet frame is specified in IEEE 802.3-2012

http://en.wikipedia.org/wiki/Ethernet_frame

Ethernet Frame (2)

• Ethernet II framing (The most common Ethernet Frame format, type II)defines the two-octet EtherType field in an Ethernet frame that identifiesan upper layer protocol encapsulating the frame data. An EtherType valueof 0x0800 signals that the frame contains an IPv4 datagram. An EtherTypeof 0x0806 indicates an ARP frame, 0x8100 indicates an IEEE 802.1Q frameand 0x86DD indicates an IPv6 frame.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 13

http://en.wikipedia.org/wiki/Ethernet_frame

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Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 14

http://www.tcpipguide.com/free/t_IPDatagramEncapsulation.htm

Sublayers of the data link layer

• Logical link control sublayer: – Multiplexing protocols transmitted over the MAC layer (when

transmitting) and decoding them (when receiving).– Providing node-to-node flow and error control

• Media access control (MAC) sublayer– provides addressing and channel access control mechanisms– The hardware that implements the MAC is referred to as

a medium access controller.– The MAC layer emulates a full-duplex logical communication

channel in a multi-point network. This channel may provide unicast, multicast or broadcast communication service.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 15

http://en.wikipedia.org/wiki/Data_link_layer

Logical Link Control Services

• Ethernet

• Since bit errors are very rare in wired networks, Ethernet does not provide flow control or automatic repeat request (ARQ), incorrect packets are detected but only cancelled, not retransmitted, retransmissions rely on higher layer protocols.

• As the EtherType in an Ethernet frame using Ethernet II framing is used to multiplex different protocols on top of the Ethernet MAC header it can be seen as an LLC identifier. However, Ethernet frames lacking an EtherType have no LLC identifier in the Ethernet header, and, instead, use an IEEE 802.2 LLC header after the Ethernet header to provide the protocol multiplexing function.

• Wireless LAN: In wireless communications, bit errors are very common. In wireless networks such as IEEE 802.11, flow control and error management is part of the CSMA/CA MAC protocol, and not part of the LLC layer. The LLC sub layer follows the IEEE 802.2 standard.

• HDLC (High-Level Data Link Control): Some non-IEEE 802 protocols can be thought of as being split into MAC and LLC layers. For example, while HDLC specifies both MAC functions (framing of packets) and LLC functions (protocol multiplexing, flow control, detection, and error control through a retransmission of dropped packets when indicated), some protocols such as Cisco HDLC can use HDLC-like packet framing and their own LLC protocol.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 16

http://en.wikipedia.org/wiki/Logical_Link_Control

Media access control

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 17

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ol According to IEEE Std 802-2001 section 6.2.3 "MAC sublayer", the primary

functions performed by the MAC layer are:

•Frame delimiting and recognition

•Addressing of destination stations (both as individual stations and as groups of

stations)

•Conveyance of source-station addressing information

•Transparent data transfer of LLC PDUs, or of equivalent information in the Ethernet

sublayer

•Protection against errors, generally by means of generating and checking frame

check sequences

•Control of access to the physical transmission medium

In the case of Ethernet, according to 802.3-2002 section 4.1.4, the functions

required of a MAC are:

•receive/transmit normal frames

•half-duplex retransmission and backoff functions

•append/check FCS (frame check sequence)

•interframe gap enforcement

•discard malformed frames

•append(tx)/remove(rx) preamble, SFD (start frame delimiter), and padding

•half-duplex compatibility: append(tx)/remove(rx) MAC address

DEVICES

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 18

Link-Layer Switches

• A switch receives incoming link-layer frames, filters and forwards them onto outgoing links. Switch filtering and forwarding are done with a switch table.

• A switch has self-learning property (particularly for the already-overworked network administrator) that its table is built automatically, dynamically, and autonomously.

• Switches are plug-and-play devices and require no intervention from a network administrator or user.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 19

Switches vs. Routers

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 20

A router in that it forwards packets using MAC addresses (layer-2) whereas a router is a layer-3 packet switch.

Switches vs. Routers (2)

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 21

Switches Routersswitches are plug-and-play not plug-and-play. their IP addresses need to be

configuredSwitches can also have relatively high filtering and forwarding rates since switches have to process frames only up through layer 2, whereas routers have to process datagrams up through layer 3

larger per-packet processing time than switches, because they have to process up through the layer-3 fieldsrouters do not have the spanning tree restriction, they have allowed the Internet to be built with a rich topology

to prevent the cycling of broadcast frames, the active topology of a switched network is restricted to a spanning tree.

packets are not restricted to a spanning tree and can use the best path between source and destination

No firewall integrated provide firewall protection against layer-2 broadcast storms

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 22

Hub vs. Switch vs. Router

http://thamarai-stor.blogspot.com/2010/05/ikkks-switch-vs-router-vs-hub.html

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 23

http://www.cisco1900router.com/tutorial-of-differences-between-hub-bridge-switch-and-router.html

a bridge is a product that connects a local area network

(LAN) to another local area network that uses the same

protocol. Having a single incoming and outgoing port and

filters traffic on the LAN by looking at the MAC address,

bridge is more complex than hub. Bridge looks at the

destination of the packet before forwarding unlike a hub. It

restricts transmission on other LAN segment if destination

is not found.

A bridge works at the

data-link (physical

network) level of a

network, copying a

data frame from one

network to the next

network along the

communications path.

APPLICATIONS

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 24

Firewalls

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 25

http://www.vicomsoft.com/learning-center/firewalls/

Social engineering involves skills not unlike those of a confidence trickster. People are tricked into revealing sensitive information.

A firewall filters both inbound and outbound traffic.

"There are management solutions to technical problems, but no technical solutions to management problems"

Figure 9: Stateful Multilayer Inspection FirewallFigure 8: Application level Gateway

Figure 6: Packet Filtering Firewall Figure 7: Circuit level Gateway

Firewalls (2)

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 26

IP Spoofing

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 27

http://en.wikipedia.org/wiki/File:IP_spoofing_en.svg

Any router that implements

ingress filtering checks the

source IP field of IP packets it

receives, and drops packets if

the packets don't have an IP

address in the IP address block

that the interface is

connected to

SUMMARY

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 28

The Ethernet Summary

• The Introduction covered the market use of Ethernet and its related to the Network Layer.

• The Technology and Devices sections dive deeper to the software and supported hardware for the Ethernet: Ethernet Frame, cable types, routers and switches.

• The Application gave an example of a real world use from Ethernet knowledge.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 29

Ethernet and its future

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 30

Report from The Future of Ethernet – Technology Exploration Forum on October 15, 2013 - October 16, 2013 at Santa Clara, CA – Interconnectedness and the Future of Ethernethttp://www.enterprisenetworkingplanet.com/netsp/interconnectedness-and-the-future-of-ethernet-1.htmlhttp://www.enterprisenetworkingplanet.com/netsp/interconnectedness-and-the-future-of-ethernet-2.html

Ethernet and its future (2)

• Vehicular Ethernet, the Internet of Things, and the Industry as an Ecosystem– From enhanced traffic management and traffic alerts drawn from live video feeds

broadcast from individual vehicles to the ability to tax cars based on their miles driven, the possible applications are endless.

• Standardizing software defined networking for interoperability– "In the past, people have talked about SDN more on an individual basis. But the Ethernet

Alliance is supporting 802 in the standardization effort, which means we really want to be able to take Vendor A, plug it into Vendor B, plug that into Vendor C, and have it all work,"

• Energy Efficient Ethernet– As networks grow and evolve, their power consumption may rise, creating additional cost

issues. The Energy Efficient Ethernet (EEE) standard for twisted pair and backplane Ethernet aims to counter that by reducing power consumption as activity drops.

• Interconnectedness and the importance of consensus-building– Addressing both the main themes D'Ambrosia mentioned—interoperability and cost

concerns—will require a general consensus and interconnectedness among diverse segments of the networking community. Other TEF 2013 panels bear this out, from the panel session that pulled leaders from 802.1, 802.3, and 802.11 up onto a stage with the chair of 802, to sessions that focused on the synergy between wired and wireless technologies and on photonic integration.

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 31

References

• Computer Networking A Top-Down Approach – Kurose and Ross – A product of PEASON.

• http://www.omnisecu.com/basic-networking/index.php

• http://www.ccse.kfupm.edu.sa/~marwan/COE344_T062/

• http://en.wikipedia.org/wiki/Ethernet

• The INTERNET

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

Slide 32

THANK YOU!

The end

Ethernet – Viet NguyenProf. Dr. F. Kaspar – Computer Networking –BIS2013 – Vietnamese-German University

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