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Home , Classic Ethernet, Gigabit Ethernet

L8 – by T.S.R.K. Prasad

EA C451 Internetworking Technologies 02/02/2013 References / Acknowledgements

Sec 4.3, 4.8: Computer Networks, Andrew Tanenbaum

Sec 5.4 – 5.6: [Kurose]

Sec 2.6: [Peterson]

References EA C451 INET TECH Optional Readings

[Shenker-ETH] Scott Shenker, L18- Ethernet, EE122, Fall 2012, Dept of EECS, University of California, Berkeley. http://inst.eecs.berkeley.edu/~ee122/

[Kurose] Chapter 5: The Link Layer and Local Area Networks, Computer Networking, Kurose & Ross

Optional Readings EA C451 INET TECH Optional Readings [Tanenbaum] Chapters 3: and Chapter 4: MAC Sublayer, Computer Networks, Andrew Tanenbaum, 4th Edition.

[Peterson] Chapter 2: Getting Connected, Computer Networks, Peterson & Davie.

IEEE 802 Project

Look Ma – NO RFCs!!!

Optional Readings EA C451 INET TECH Self-Study Topics

Spanning tree protocol

Self-Study EA C451 INET TECH IEEE 802 Project

Network Layer Network

LLC 802.2 Layer Logical Link Control (LLC) Data Link 802.3 MAC CSMA/CD 802.11a 802.11b 802.11g 802.15 802.16 Layer Ethernet Wireless LAN / Wi-Fi WiMax Physical QAM / Manchester OFDM HR-DSSS OFDM FHSS QPSK

IEEE Standard OSI Model Note: This is not the complete model; IEEE 802 standard has 20 sub-committees formulating the details of the Data link layer standards.

IEEE 802 Project EA C451 INET TECH You Said It

If something comes along to replace Ethernet, it will be called “Ethernet”, so therefore Ethernet will never die. - Attributed to Bob Metcalfe by Ken Thompson

You Said It EA C451 INET TECH Presentation Overview

Conclusion Deployment Scenarios Introduction

Lecture Outline EA C451 INET TECH Presentation Overview

Conclusion Deployment Scenarios Gigabit Ethernet Classic Ethernet Introduction

Lecture Outline EA C451 INET TECH Ethernet “dominant” wired LAN technology: • cheap Rs. 889/- for 1Gbps NIC • first widely used LAN technology • simpler, cheaper than token LANs and ATM • kept up with speed race: 10 Mbps – 100 Gbps

Metcalfe’s Ethernet sketch Introduction EA C451 INET TECH Where is the link layer implemented?

• Link layer implemented in “adaptor” (aka network interface card NIC) or on a chip application transport – Ethernet card, 802.11 network cpu memory link card; Ethernet chipset host – implements link, physical bus controller (e.g., PCI) layer link physical • ’ physical attaches into host s system transmission buses

• combination of hardware, network adapter software, firmware card

Introduction  Implementation EA C451 INET TECH Medium Access Techniques

Medium sharing techniques

Static Dynamic medium channelization access control

 Partition medium  Dedicated allocation Scheduling Random access to users  Polling: take turns  Loose coordination  Satellite  Request for slot in  Send, wait, retry if transmission transmission necessary  Cellular Telephone schedule  Aloha

 Ethernet  Wireless LANs

Introduction  Medium Access Techniques EA C451 INET TECH Notion of Discrete Time

node 1 1 1 1 1

node 2 2 2 2

node 3 3 3 3

C E C S E C E S S

Nodes transmit only at the beginning of a time slot

Introduction  Notion of Discrete Time EA C451 INET TECH CSMA/CD

CSMA/CD – Carrier Sense Multiple Access / Collision Detection

CSMA: listen before transmit: if channel sensed idle: transmit entire frame • if channel sensed busy, defer transmission CD: detect collision and stop • If collision detected on channel, stop transmission • Implement Binary Exponential Backoff (BEB) Algo

human analogy: don’t interrupt others!

Introduction  CSMA/CD EA C451 INET TECH CSMA/CD (collision detection)

spatial layout of nodes

Introduction  CSMA/CD EA C451 INET TECH LAN Addresses each adapter on LAN has unique LAN address

1A-2F-BB-76-09-AD

LAN adapter

71-65-F7-2B-08-53 58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

Introduction  LAN Address EA C451 INET TECH Presentation Overview

Conclusion Deployment Scenarios Gigabit Ethernet Classic Ethernet Introduction

Lecture Outline EA C451 INET TECH Ethernet: physical topology • bus: popular through mid 90s – all nodes in same (can collide with each other)

• star: prevails today – active switch in center – each “spoke” runs a (separate) Ethernet protocol (nodes do not collide with each other)

switch star bus:

Classic Ethernet  Physical Topology EA C451 INET TECH Structure

Classic Ethernet  Ethernet Frame Structure EA C451 INET TECH Ethernet Frame Structure

sending adapter encapsulates IP datagram (or other network layer protocol packet) in

Ethernet frame type

dest. source data CRC preamble address address (payload)

preamble: • 7 bytes with pattern 10101010 followed by one byte with pattern 10101011 • used to synchronize receiver, sender clock rates

Classic Ethernet  Ethernet Frame Structure EA C451 INET TECH Ethernet Frame Structure • addresses: 6 byte source, destination MAC addresses . if adapter receives frame with matching destination address, or with broadcast address (e.g. ARP packet), it passes data in frame to network layer protocol . otherwise, adapter discards frame • type: indicates higher layer protocol (mostly IP but others possible, e.g., Novell IPX, AppleTalk) • CRC: cyclic redundancy check at receiver . error detected: frame is dropped

type dest. source data preamble address address (payload) CRC

Classic Ethernet  Ethernet Frame Structure EA C451 INET TECH 802.3 Ethernet PHY Standards • many different Ethernet standards . common MAC protocol and frame format . different speeds: 2 Mbps, 10 Mbps, 100 Mbps, 1Gbps, 10G bps, 100G bps . different physical layer media: fiber, cable

MAC protocol application and frame format transport network 100BASE-TX 100BASE-T2 100BASE-FX link 100BASE-T4 100BASE-SX 100BASE-BX physical

copper (twister fiber physical layer pair) physical layer

Classic Ethernet  Ethernet PHY Standards EA C451 INET TECH Ethernet Switch

• Store and forward A Ethernet frames C’ B • Multiple simultaneous 6 1 2 transmissions 5 4 3 • Transparent B’ C • Plug and Play A’ switch with six interfaces – Self learning (1,2,3,4,5,6)

Classic Ethernet  Ethernet Switch EA C451 INET TECH Self-learning, forwarding Dest: A’ Source: A A A A’ • frame destination, A’, locaton unknown: C’ B flood 6 1 2 A A’ • destination A location 5 4 3 known: selectively B’ C send A’ A on just one link A’ MAC addr interface TTL A 1 60 switch table A’ 4 60 (initially empty)

Classic Ethernet  Switches Self-learning EA C451 INET TECH Self-learning multi-switch example Suppose C sends frame to I, I responds to C

S 2 0 4 S 1 1 S2 0 0 S 3 0 3 A 3 1 1 1 F 3 2 I B C D 2 2 H E G

Q: show switch tables and packet forwarding in S1, S2, S3, S4

Classic Ethernet  Switches Self-learning EA C451 INET TECH VLANs

Virtual Local 1 7 9 15

Area Network 2 8 10 16 switch(es) supporting VLAN capabilities can … …

be configured to Electrical Engineering Computer Science define multiple virtual (VLAN ports 1-8) (VLAN ports 9-15) LANS over single … operates as multiple virtual physical LAN switches infrastructure. 1 7 9 15

2 8 10 16 port-based VLAN … …

Electrical Engineering Computer Science (VLAN ports 1-8) (VLAN ports 9-16)

Classic Ethernet  VLANs EA C451 INET TECH Port-based VLAN router • traffic isolation: frames to/from ports 1-8 can only reach ports 1-8 . can also define VLAN based on MAC addresses of endpoints, rather than switch port 1 7 9 15 2 8 10 16

• dynamic membership: … … ports can be dynamically Electrical Engineering Computer Science assigned among VLANs (VLAN ports 1-8) (VLAN ports 9-15) • forwarding between VLANS: done via routing (just as with separate switches) . in practice vendors sell combined switches plus routers

Classic Ethernet  VLANs  Port-based VLANs EA C451 INET TECH VLANS spanning multiple switches

1 7 9 15 1 3 5 7

2 8 10 16 2 4 6 8

… …

Electrical Engineering Computer Science Ports 2,3,5 belong to EE VLAN (VLAN ports 1-8) (VLAN ports 9-15) Ports 4,6,7,8 belong to CS VLAN • trunk port: carries frames between VLANS defined over multiple physical switches – frames forwarded within VLAN between switches can’t be vanilla 802.1 frames (must carry VLAN ID info) – 802.1q protocol adds/removed additional header fields for frames forwarded between trunk ports

Classic Ethernet  VLANs  Multiple Switches EA C451 INET TECH 802.1Q VLAN frame format

type

preamble dest. source data (payload) address address CRC 802.3 frame

type

preamble dest. source data (payload) address address CRC 802.1Q frame

2-byte Tag Protocol Identifier Recomputed (value: 81-00) CRC

Tag Control Information (12 bit VLAN ID field, 3 bit priority field like IP TOS)

Classic Ethernet  VLANs  Frame Format EA C451 INET TECH Presentation Overview

Conclusion Deployment Scenarios Gigabit Ethernet Classic Ethernet Introduction

Lecture Outline EA C451 INET TECH Brief History of Ethernet

Gigabit Ethernet  Brief History of Ethernet EA C451 INET TECH Ethernet Versions

Name Technical Name Maximum Speed

Ethernet 802.3, CSMA/CD 10 Mbps

Fast Ethernet 802.3u 100 Mbps

Gigabit Ethernet 802.3z 1 Gbps

10 Gbps Ethernet 802.3ae 10 Gbps

100 Gbps Ethernet 802.3ba 100 Gbps

400 Gbps Ethernet 802.3bj 400 Gbps

Gigabit Ethernet  Ethernet Versions EA C451 INET TECH Group (LAG)

Gigabit Ethernet  LAG EA C451 INET TECH LAG – Multiplexing by another name

Gigabit Ethernet  LAG EA C451 INET TECH Presentation Overview

Conclusion Deployment Scenarios Gigabit Ethernet Classic Ethernet Introduction

Lecture Outline EA C451 INET TECH Ethernet in Supercomputers

Interconnects used on the Top 500 Supercomputers Deployment Scenarios  Supercomputers EA C451 INET TECH Inside the Data Center

Deployment Scenarios  Data Centers EA C451 INET TECH Inside the Enterprises

Deployment Scenarios  Inside the Enterprises EA C451 INET TECH Ethernet for Interconnecting Campuses

Deployment Scenarios  Campus Interconection (WAN) EA C451 INET TECH Ethernet in Apartments

Deployment Scenarios  Apartments EA C451 INET TECH 10Gb Ethernet MAN

Deployment Scenarios  EA C451 INET TECH Ethernet for All Seasons

Deployment Scenarios  Ethernet for All Seasons EA C451 INET TECH Presentation Overview

Conclusion Deployment Scenarios Gigabit Ethernet Classic Ethernet Introduction

Lecture Outline EA C451 INET TECH Ethernet with Supporting Technologies

Conclusion EA C451 INET TECH