Protocol Layering - PowerPoint PPT Presentation

Loading...

PPT – Protocol Layering PowerPoint presentation | free to view - id: 4da8b9-YmQ2M



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Protocol Layering

Description:

Protocol Layering Sender Receiver Layer N Layer N. . .. . . Layer 2 Layer 2 Layer 1 Layer 1 Network Motivation for Protocol Layering - The Programming Language ... – PowerPoint PPT presentation

Number of Views:152
Avg rating:3.0/5.0
Slides: 20
Provided by: BrettT6
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Protocol Layering


1
Protocol Layering

2
Motivation for Protocol Layering - The
Programming Language Analogy
  • Computer programming
  • Program -gt Compiler -gt Assembly Code -gt
    Assembler -gt Machine Code -gt Hardware
  • Internet programming
  • Application -gt Transport Protocol -gt
    Connectionless Datagram Delivery Protocol -gt
    Physical Network

3
The Internet Protocol Suite
  • Internetworking does not use a single protocol to
    transmit data
  • Imagine how hard it would be to write one that
  • Ran on all underlying network technologies
  • Transmitted and routed all traffic on the
    internet
  • Handled hardware failure, network congestion,
    delays, data loss, data corruption, data
    duplication, sequencing errors
  • Internetworking uses a set of cooperating
    protocols (each with its own job)

4
Benefits of Protocol Layering
  • Complexity hidden from application-level
    programmer
  • Physical network details hidden in low-level
    protocols
  • Each layer of software can be written, tested,
    and modified independently

5
Protocol Layering
  • Each layer provides services to the layer above
    and utilizes services from the layer below

6
Protocol Layering
  • The path of a datagram

7
Functionality of the Layers
  • ISO 7-Layer Reference Model

8
ISO 7-Layer Reference Model
  • Physical Layer (ISO Layer 1)
  • Service transmission of a raw bit stream over a
    communication channel ensuring a reliable
    delivery of 0s and 1s
  • Functions conversion of bits into electrical or
    optical signals
  • Examples X.21, RS-232-C

9
ISO 7-Layer Reference Model
  • Data Link Layer (ISO Layer 2)
  • Service reliable transfer of frames over a link
  • Functions synchronization, error control, flow
    control
  • Examples HDLC, CCITT, LAP-D
  • Network Layer (ISO Layer 3)
  • Service provide switching and routing functions
    to transfer data between hosts
  • Functions routing, addressing, switching,
    congestion control
  • Examples IP, X.25, CLNP

10
ISO 7-Layer Reference Model
  • Transport Layer (ISO Layer 4)
  • Service control delivery of messages between
    hosts
  • Functions connection management, error control,
    flow control, multiplexing
  • Examples TCP, UDP, ISO TP0 - TP4
  • Session Layer (ISO Layer 5)
  • Service support communication between
    cooperating application programs
  • Functions session management, synchronization,
    recovery
  • Examples ISO session protocol, RPC

11
ISO 7-Layer Reference Model
  • Presentation Layer (ISO Layer 6)
  • Service handle compatibility issues
  • Functions virtual device support, syntax
    conversion, cryptography
  • Examples ASN.1, ISO presentation protocol
  • Application Layer (ISO Layer 7)
  • Service provide network access to application
    programs
  • Functions (application specific)
  • Examples Telnet, FTP, E-mail, WWW

12
ISO 7-Layer Reference Model
  • Designed by committee - International
    Organization for Standardization (ISO)
  • Reference model, not an implementation
  • Implemented by a set of protocols known as X.25

13
TCP/IP Internet Layering Model
  • Functionality of the layers

Objects Passed Between Layers
Conceptual Layer
14
TCP/IP Internet Layering Model
  • Network Interface Layer (TCP/IP Layer 1)
  • Service accepts IP datagrams and transmits them
    over a specific network
  • Functions conversion of datagrams to physical
    frames
  • Examples device drivers
  • Internet Layer (TCP/IP Layer 2)
  • Service connectionless datagram delivery
  • Functions inter-host communication, routing
  • Examples IP

15
TCP/IP Internet Layering Model
  • Transport Layer (TCP/IP Layer 3)
  • Service provide reliable end-to-end
    communication
  • Functions flow control, sequencing,
    acknowledgments
  • Examples TCP
  • Application Layer (TCP/IP Layer 4)
  • Service (application specific)
  • Functions (application specific)
  • Examples Telnet, FTP, E-mail, WWW

16
Internet Model vs. ISO Model
  • Similarities
  • Differences

17
The Protocol Layering Principle
  • Layered protocols are designed so that layer N
    at the destination receives exactly the same
    object sent by layer N at the source.

Application
Identical message
Identical packet
Identical datagram
Identical frame
Network
18
Boundaries in the TCP/IP Model

Boundary
Software outside the operating system
Software inside the operating system
Only IP addresses used
Physical addresses used
19
Protocol Layering
  • Advantages
  • Disadvantages
About PowerShow.com