Presentation is loading. Please wait.

Presentation is loading. Please wait.

CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman1 Computer Networks Chapter 1 - Fundamentals.

Published byMelissa Reeves Modified over 8 years ago

Similar presentations

Presentation on theme: "CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman1 Computer Networks Chapter 1 - Fundamentals."— Presentation transcript:

1 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman1 Computer Networks Chapter 1 - Fundamentals

2 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman2 Computer Networks Need to share –Information –Resources Communication vs. Storage Transmission across: –Space (communication) –Time (storage)

3 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman3 Virtuality Architecture –Layered –Hierarchical Algorithms –Information hiding, ADTs, objects Protocols –Distributed coordination algorithms Programs –Modularity

4 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman4 Layered vs. Hierarchical Both –Peer-to-peer communication –Encapsulation –Protocol = common language/behaviors Layered –Layer i serves layer i+1 ONLY –Layer i gets service from layer i-1 ONLY Hierarchical –Lower layers serve higher layers

5 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman5 Layered vs. Hierarchical Issues –Flexibility –Efficiency –Modularity –Maintainability –Scalability/manageability –Future adaptability

6 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman6 Comparative Architectures 7 - Application 6 - Presentation 5 - Session 4 - Transport 3 - Network 2 – Data Link 1 - Physical User Application Data Link Control DDCMP Physical1 - Physical Path Control Transmission Ctl Data Flow Control Transport Functional Management Data Services Network Services Protocol Network Application ISO - OSI IBM - SNA DEC - DECnet

7 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman7 OSI Reference Architecture Physical (L1 = PHY) Data Link (L2 = MAC/Link) Network (L3) Transport (L4) Session (L5) Presentation (L6) Application (L7)

8 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman8 PHY Layer Hardware Physical manipulation of medium (modulation) Physical sensing of medium (detection) Low level synchronization (bits/symbols/frames) Forward error correction/error detection Mechanical/electrical interconnect and medium

9 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman9 Link Layer Firmware Framing Addressing Medium access control (MAC) Backward error detection/correction Reliable delivery of frames from one STA to a directly connected STA Pacing Upward multiplexing

10 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman10 Network Layer Software/firmware Packets/cells Routing Packet fragmentation/reassembly Backward error correction Delivery of frames from source to an indirectly connected destination Congestion control

11 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman11 Transport Layer Software on end host: End-to-end layer Reliable communication stream –Messages –Byte stream –Ordering –BEC Upward Multiplexing Delivery of messages/byte stream from source process to destination process Congestion control

12 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman12 Session Layer Software on end host: end-to-end layer Stream management Dialog control Packet chaining (atomic delivery) Downward Multiplexing Authentication Connection-oriented

13 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman13 Presentation Layer Software on end host Common utilities –Encryption –Compression –Uniform formatting (XML, ASN.1,…) Standardized representations Interfacing to local resources

14 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman14 Application Layer Software on end host Specific application programs –FTP –Remote terminal (rlogin, telnet, ssh,…) –Email –HTTP May also be layered in distributed software system

15 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman15 Encapsulation application transport network link physical application transport network link physical source destination M M M M H t H t H n H t H n H l M M M M H t H t H n H t H n H l message segment datagram frame (thanks – Kurose & Ross) Receive SDU from higher layer Hide uninterpreted SDU as payload of PDU

16 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman16 End-to-end Data Transport (thanks – Kurose & Ross)

17 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman17 Service Models Interface –Connectionless –Connection-oriented Reliability –Best effort –Reliable Combinations

18 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman18 Service Interface Interface –Connectionless: memoryless Send packet Receive packet –Connection-oriented: stateful Initialize (set up connection) Use (send/receive) Close (release state)

19 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman19 Service Reliability Reliability –Best effort Lost packets Duplicate packets Delayed/reordered delivery Damaged packets –Reliable Undamaged packets All packets sent delivered in timely fashion Delivered in order sent

20 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman20 Message Conventions 1-REQ 2,3 2 - Tx 3 - Rx 4 - IND5 - RSP8 - CNF 6 - Tx7 - Rx 6,7 Request/ConfirmIndication/Response

21 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman21 Combining Service Models Best Effort Reliable ConnectionlessConnection-Oriented UDP, IP, IPX, CLNP, DECnet, Appletalk, CLNS,… ATM TCP, X.25, CONS ???

22 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman22 Network Service vs. Implementation Service Implementation ConnectionlessConnection-Oriented UDP, CLNS TCP, DNA ???Connectionless Connection-Oriented X.25, ATM, CONS, SNA

23 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman23 Network Properties Scope Scalability Robustness Autoconfigurability Tweakability Determinism Migration

24 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman24 Network Properties - Robustness Types of Errors –Link/node failure –Data errors (esp. undetected!) –S/W errors –H/W errors –Human Errors Features

25 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman25 Network Properties - Robustness Types of Errors Features –Safety Barriers –Self-stabilization –Fault detection –Byzantine robustness

26 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman26 Reliable Data Transfer Models –Errors –Receiver capacity Requirements –Duplexity –Timers –State

27 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman27 Data Transfer Model Events –What can happen at node, channel Frames –What do they hold Duplexity –Simplex, half duplex, full duplex Time costs –What does it take to complete transfer Metrics –How do we measure the costs

28 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman28 Data Transfer - Events Node –New frame to send from HLE –Frame/ACK arrival – good frame –Frame/ACK arrival – damaged frame –Timeout –Attempt to receive next frame by HLE Channel –Error – damage frame –Error – lose frame

29 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman29 Data Transfer - Frames Forward Control Info –Type –Sequence number –Timestamp –Length –Addressing –Error Detection (FCS) Reverse Control Info –ACKs –Flow control/pacing –Piggybacking Information –payload Dst Src Type SN TS Len … Payload FCS

30 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman30 Channel Model - Duplexity Simplex – only one way Half duplex – one way at a time Full duplex – simultaneously both ways A B A B A B Simplex Half Duplex Full Duplex

31 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman31 Data Transfer - Delays Processing –Source –Destination Transmission –Time to put bits on wire Propagation –Time for bit to traverse channel Src Dest Src Proc Transmission Dest Proc Propagation Src Proc Data frame ACK frame ACK Tx Tx REQ Rx REQ Rx CNF Tx CNF

32 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman32 Data Transfer - Metrics Utilization –Time sending info/total time Storage requirements –At source –At destination Channel type –duplexity Timers –Retransmission –ACK transmission

33 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman33 Reliable Data Xfer - Utopia Infinitely fast receiver Simplex channel No errors 100% utilization by protocol Src Dest

34 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman34 Stop&Wait Data Xfer - Pacing Finitely fast receiver Half duplex channel No errors <100% utilization by protocol –U Protocol = T Tx /T cycle –T Tx = L (bits)/R (bps) –T cycle = T Tx +T prop +T proc + T prop +T proc Src Dest OK Data time Cycle time

35 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman35 Reliable Data Xfer – PAR (Positive ACK and Retransmit) Finitely fast receiver Full duplex channel Channel errors Utilization factor due to errors –U errors = T good / T good + T bad U = U protocol x U errors Src Dest ACK - * - X

36 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman36 Reliable Data Xfer – PAR need for sequence numbers Src Dest ACK - * - X Src Dest ACK - * - X Frame 1 Frame 2 Frame 2 - duplicate Missing ACK ACK Frame 1 Frame 2 Frame 2 - duplicate Missing ACK

37 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman37 Reliable Data Xfer – 1-bit ARQ Src Dest ACK 1 - * ACK 0 - X Src Dest ACK 1 - * ACK 0 - X Frame 0 Frame 1 Missing ACK Frame 0 Frame 1 Missing ACK ACK 0 accept discard duplicate

38 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman38 Reliable Data Xfer – GBN ARQ Src Dest * - Missing D3 D 0 D 1 ACK 1 Accept D0 D 2 D 3 (resent) D 4 D 5 ACK 2 ACK 3 Discard D4 Discard D5 D 4 D 5 ACK 6 ACK 5 Accept D1 Accept D2 Accept D3 Accept D4 Accept D5 ACK 4 Multiple sequence #’s Channel errors Discard out of order frames on Rx Resend all frames from missing on forward Rx buffer size of 1 Tx buffer size of N

39 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman39 Reliable Data Xfer – SR ARQ Src Dest * - Missing D3 D 0 D 1 ACK 1 Accept D0 D 2 D 3 (resent) D 4 D 5 ACK 2 ACK 3 Buffer D4 Buffer D5 D 6 D 7 ACK 8 ACK 7 Accept D1 Accept D2 Accept D3 Accept D6 Accept D7 ACK 6 Multiple sequence #’s Channel errors Buffer out of order frames on Rx Resend only missing frame Rx buffer size of N Tx buffer size of k

40 CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman40 Protocol Utilization –ARQ SrcDest T data T cycle Protocol util. depends on k U proto = kT/(T+2  ) T = Tx time = D/R  = propagation delay U proto = k/(1+2  )  =  /T =  /(D/R) Utilization factor due to errors varies 

Download ppt "CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman1 Computer Networks Chapter 1 - Fundamentals."

Similar presentations

OSI Model OSI MODEL.

OSI Model OSI MODEL.
OSI Model OSI LAYER / MODEL.

OSI Model OSI LAYER / MODEL.
CEN 5501C - Computer Networks - Spring 2007 - UF/CISE - Newman1 Computer Networks Chapter 1 - Fundamentals.

CEN 5501C - Computer Networks - Spring UF/CISE - Newman1 Computer Networks Chapter 1 - Fundamentals.
Lecture 2 Protocol Layers CPE 401 / 601 Computer Network Systems slides are modified from Dave Hollinger.

Lecture 2 Protocol Layers CPE 401 / 601 Computer Network Systems slides are modified from Dave Hollinger.
OSI Model MIS 416 – Module II Spring 2002 Networking and Computer Security.

OSI Model MIS 416 – Module II Spring 2002 Networking and Computer Security.
OSI Model.

OSI Model.
Computer Network Architecture and Programming

Computer Network Architecture and Programming
EE 4272Spring, 2003 Protocols & Architecture A Protocol Architecture is the layered structure of hardware & software that supports the exchange of data.

EE 4272Spring, 2003 Protocols & Architecture A Protocol Architecture is the layered structure of hardware & software that supports the exchange of data.
OSI Reference Model An overview. Standards and the internet International Organization for Standardization ISO 70’s.

OSI Reference Model An overview. Standards and the internet International Organization for Standardization ISO 70’s.
TCP: Software for Reliable Communication. Spring 2002Computer Networks Applications Internet: a Collection of Disparate Networks Different goals: Speed,

TCP: Software for Reliable Communication. Spring 2002Computer Networks Applications Internet: a Collection of Disparate Networks Different goals: Speed,
Chapter 2 Network Models.

Chapter 2 Network Models.
The OSI Model A layered framework for the design of network systems that allows communication across all types of computer systems regardless of their.

The OSI Model A layered framework for the design of network systems that allows communication across all types of computer systems regardless of their.
 The Open Systems Interconnection model (OSI model) is a product of the Open Systems Interconnection effort at the International Organization for Standardization.

 The Open Systems Interconnection model (OSI model) is a product of the Open Systems Interconnection effort at the International Organization for Standardization.
Gursharan Singh Tatla Transport Layer 16-May-2011 1

Gursharan Singh Tatla Transport Layer 16-May
OIS Model TCP/IP Model.

OIS Model TCP/IP Model.
Fundamentals of Computer Networks ECE 478/578 Lecture #2 Instructor: Loukas Lazos Dept of Electrical and Computer Engineering University of Arizona.

Fundamentals of Computer Networks ECE 478/578 Lecture #2 Instructor: Loukas Lazos Dept of Electrical and Computer Engineering University of Arizona.
Communication Network Protocols Jaya Kalidindi CSC 8320(fall 2008)

Communication Network Protocols Jaya Kalidindi CSC 8320(fall 2008)
What Can IP Do? Deliver datagrams to hosts – The IP address in a datagram header identify a host IP treats a computer as an endpoint of communication Best.

What Can IP Do? Deliver datagrams to hosts – The IP address in a datagram header identify a host IP treats a computer as an endpoint of communication Best.
Process-to-Process Delivery:

Process-to-Process Delivery:
2-2008UP-Copyrights reserved1 ITGD4103 Data Communications and Networks OSI Reference Model Lecture-5: OSI Reference Model week 5- q-2/ 2008 Dr. Anwar.

2-2008UP-Copyrights reserved1 ITGD4103 Data Communications and Networks OSI Reference Model Lecture-5: OSI Reference Model week 5- q-2/ 2008 Dr. Anwar.

Similar presentations

Ads by Google