CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer...

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1 CMPE 150- Introduction to Computer Networks CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks

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Transcript of CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer...

Page 1: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

1CMPE 150- Introduction to Computer Networks

CMPE 150

Fall 2005Lecture 18

Introduction to Computer Networks

Page 2: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

2CMPE 150- Introduction to Computer Networks

Announcements

• Midterm on 11.04.– In class, closed books/notes.

• Homework 3 is up.– Due on 11.07.05.

• Lab this week: discussion/review sessions for midterm.

• Lab next week: – Layer 2.

– Ethernet.

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3CMPE 150- Introduction to Computer Networks

Today

• Finish MAC.

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4CMPE 150- Introduction to Computer Networks

Ethernet Cabling

• The most common kinds of Ethernet cabling.

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5CMPE 150- Introduction to Computer Networks

Ethernet Cabling (Cont’d)

• Three kinds of Ethernet cabling. • (a) 10Base5, (b) 10Base2, (c) 10Base-T.

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6CMPE 150- Introduction to Computer Networks

Ethernet Topologies

• Cable topologies. (a) Linear, (b) Spine, (c) Tree, (d) Segmented.

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7CMPE 150- Introduction to Computer Networks

Switched Ethernet

• A simple example of switched Ethernet.

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8CMPE 150- Introduction to Computer Networks

Switched Ethernet (Cont’d)

• Point-to-point connections to multi-port hub acting like switch; no collisions.

• More efficient under high traffic load: break large shared Ethernet into smaller segments.

Hub

Switch

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9CMPE 150- Introduction to Computer Networks

Fast Ethernet

• IEEE 802.3u• 100Mbps.

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10CMPE 150- Introduction to Computer Networks

Gigabit Ethernet

• (a) A two-station Ethernet. (b) A multistation Ethernet.

. IEEE 802.11z.

. All point to point.

Page 11: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

11CMPE 150- Introduction to Computer Networks

Gigabit Ethernet (Cont’d)

• Gigabit Ethernet cabling.

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12CMPE 150- Introduction to Computer Networks

Standardized MACs

TopologiesBus Ring

Round robin

Reservation

Contention

Token bus(802.4)Polling (802.11)

DQDB(802.6)

CSMA/CD(802.3)CSMA(802.11)

Token ring(802.5; FDDI)

Techniques

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13CMPE 150- Introduction to Computer Networks

Wireless LANs

Page 14: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

14CMPE 150- Introduction to Computer Networks

Wireless LANs

• 2 modes of operation:– Infrastructure mode.

– Ad hoc mode,

Page 15: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

15CMPE 150- Introduction to Computer Networks

Wireless LANs

• (a) Wireless networking with a base station.• (b) Ad hoc networking.

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16CMPE 150- Introduction to Computer Networks

IEEE 802.11

• IEEE standard for WLANs.• Standardizes the PHY, MAC, and LLC.– LLC is the same as Ethernet.

Page 17: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

17CMPE 150- Introduction to Computer Networks

The 802.11 Protocol Stack

• Part of the 802.11 protocol stack.

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18CMPE 150- Introduction to Computer Networks

IEEE 802.11 Stack (Cont’d)

• Distributed access control mechanism (DCF) based on CSMA with optional centralized control (PCF).

•

Physical Layer

DCF

PCFMAClayer

Contention-freeService (polling)

ContentionService(CSMA)

LLC

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19CMPE 150- Introduction to Computer Networks

802.11

• Distributed coordination function (DCF) uses CSMA-based protocol (e.g., ad hoc networks).

• CD does not make sense in wireless.– Hard for transmitter to distinguish its own

transmission from incoming weak signals and noise.

• Point coordination function (PCF) uses polling to grant stations their turn to transmit (e.g., cellular networks).

Page 20: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

20CMPE 150- Introduction to Computer Networks

Why a new MAC for wireless?

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21CMPE 150- Introduction to Computer Networks

Why a new MAC for wireless?

• The range of a single radio may not cover the entire system.

Page 22: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

22CMPE 150- Introduction to Computer Networks

Why a new MAC for wireless?

• (a) The hidden station problem.• (b) The exposed station problem.

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23CMPE 150- Introduction to Computer Networks

802.11 MAC

• DCF: CSMA or CSMA/CA.• PCF; uses polling (centralized round-robin)

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24CMPE 150- Introduction to Computer Networks

What’s CSMA/CA?

• CSMA with collision avoidance.• Radios are usually half-duplex.– Cannot send and listen at the same time.

– CSMA/CD not possible.

• CSMA/CA means both physical- and virtual carrier sensing.– Tries to avoid hidden terminals.

Page 25: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

25CMPE 150- Introduction to Computer Networks

How does CSMA/CA work?

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26CMPE 150- Introduction to Computer Networks

802.11 Fragments

• A fragment burst.

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27CMPE 150- Introduction to Computer Networks

REVIEW

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28CMPE 150- Introduction to Computer Networks

REVIEW (1)

• Introduction, overview, terminology.• The Telephone Network (PSTN or POTS).• Addressing.• Data networks.– Communication model.– System components.

• Connecting end systems:– Point-to-point (dedicated) link.– Multiple access (shared) link.– Switched point-to-point.

Page 29: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

29CMPE 150- Introduction to Computer Networks

REVIEW (2)

• Types of data networks:– Coverage: LAN, MAN, WAN.– Type of connection.– Topology.

• Protocols, Layering, Protocol Architecture (Stack), PDUs.

• Examples of protocol stacks.– OSI ISO.– TCP/IP.

• Protocol stack operation.– Encapsulation/de-encapsulation.– Overhead.

Page 30: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

30CMPE 150- Introduction to Computer Networks

REVIEW (3)

• Types of networks:– Circuit-, message-, and packet switching.

• Types of network services:– Connection versus connection-less service or

datagram versus virtual circuit.

• Physical layer (PHY).– Function.– Analog versus digital transmission.– Digitization.

Page 31: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

31CMPE 150- Introduction to Computer Networks

REVIEW (4)

• PHY (Cont’d).– Sampling frequency.

– Bit rate.

– Signals and Systems.• Fourier analysis.• Nyquist’s Theorem.• Shanon’s Theorem.• Bandwidth.

– Guided transmission.

– More on the PSTN.

Page 32: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

32CMPE 150- Introduction to Computer Networks

REVIEW (5)

• PHY (Cont’d).– More on the PSTN.• Components.• Modems.• Modulation.• Baud rate versus bit rate.• Full-, half-, and simplex transmission.• Broadband access: ADSL, Cable, Wireless LL.• Trunking.

– Mux’ing and De-mux’ing.

– Wireless transmission.

Page 33: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

33CMPE 150- Introduction to Computer Networks

REVIEW (6)• PHY (Cont’d).

– Wireless transmission.– Satellite.– Mobile phone system.

• DLL.– Functions.

• Framing, error-, and flow control.

– Framing.• Different framing mechanisms.• Frame fields.

– Error control.– Flow control.

Page 34: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

34CMPE 150- Introduction to Computer Networks

REVIEW (7)

• DLL.– Error control.• Error detection versus error correction.• Mechanisms for error detection/correction.

– Error + Flow control protocols.• Stop-and-Wait.• ARQ.• Sliding window.• Go back N• Selective repeat.

Page 35: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

35CMPE 150- Introduction to Computer Networks

REVIEW (8)

• DLL (Cont’d).– Window size and sequence numbers.– Bandwidth-delay product.– Example DLL protocols,

• MAC.– Why MACs?– Where is the MAC in the stack?– MACs and LANs.– Multiplexing.• FDM, TDM. Dynamic TDM.

Page 36: CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 18 Introduction to Computer Networks.

36CMPE 150- Introduction to Computer Networks

REVIEW (9)

• MAC (Cont’d).– Types of MACs.– Contention-based MACs.

• Aloha family.• CSMA family,

• Ethernet.– Ethernet MAC.– BEB.– Cabling.– Ethernet evolution.

• Wireless LANs.– IEEE 802.11.


CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 13 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 13 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 27 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 27 Introduction to Computer Networks.

CMPE 150 -- Introduction to Computer Networks Instructor: Patrick Mantey mantey@soe.ucsc.edu mantey/ mantey@soe.ucsc.edu Office:

CMPE 150 -- Introduction to Computer Networks Instructor: Patrick Mantey [email protected] mantey/ [email protected] Office:

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 26 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 26 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 11 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 11 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 1 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 1 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 9 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 9 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 19 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 19 Introduction to Computer Networks.

CMPE 150 Fall 2005 Lecture 18

CMPE 150 Fall 2005 Lecture 18

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 17 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 17 Introduction to Computer Networks.

CMPE 150/L : Introduction to Computer Networks · CMPE 150/L : Introduction to Computer Networks Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 18 1

CMPE 150/L : Introduction to Computer Networks · CMPE 150/L : Introduction to Computer Networks Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 18 1

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CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 6 Introduction to Networks and the Internet.

CMPE 150/L : Introduction to Computer Networks · 2019. 9. 12. · CMPE 150/L : Introduction to Computer Networks Chen Qian . Computer Engineering. UCSC Baskin Engineering. Lecture

CMPE 150/L : Introduction to Computer Networks · 2019. 9. 12. · CMPE 150/L : Introduction to Computer Networks Chen Qian . Computer Engineering. UCSC Baskin Engineering. Lecture

CMPE 150 Fall 2005 Lecture 7

CMPE 150 Fall 2005 Lecture 7

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 10 Introduction to Computer Networks.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 10 Introduction to Computer Networks.

CMPE 150/L : Introduction to Computer Networks · CMPE 150/L : Introduction to Computer Networks ... small # of well-connected large networks ... put malware into hosts via Internet

CMPE 150/L : Introduction to Computer Networks · CMPE 150/L : Introduction to Computer Networks ... small # of well-connected large networks ... put malware into hosts via Internet

CMPE 150 Fall 2005 Lecture 21

CMPE 150 Fall 2005 Lecture 21

CMPE 150 Fall 2005 Lecture 17

CMPE 150 Fall 2005 Lecture 17

CMPE 150 Fall 2005 Lecture 25

CMPE 150 Fall 2005 Lecture 25

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 2 Introduction to Networks and the Internet.

CMPE 150- Introduction to Computer Networks 1 CMPE 150 Fall 2005 Lecture 2 Introduction to Networks and the Internet.