Networking 2

Bandwidth

It is like number of  lanes on a highway

Switch

Many Collision domain

One broadcast domain

Bridge

One collision domain

One broadcast domain

Hub

One collision domain

One broadcast domain

OSI Model

  To address the problem of networks increasing in size and in number, the International Organization for Standardization (ISO) researched many network schemes and recognized that there was a need to create a network model.

v  This would help network builders implement networks that could communicate and work together.

ISO - International Organization for Standardization

OSI - Open System Interconnection

IOS - Internetwork Operating System

The OSI Reference Model

7. Application - This layer deals with networking applications.

Examples:

v  Email

v  Web browsers

PDU - User Data

6.  Presentation - This layer is responsible for presenting the data in the required format which may include:

v  Code Formatting

v  Encryption

v  Compression

PDU - Formatted Data

5.  Session

v  This layer establishes, manages, and terminates sessions between two communicating hosts.

v  Creates Virtual Circuit

v  Coordinates communication between systems

v  Organize their communication by offering three different modes

v  Simplex

v  Half Duplex

v  Full Duplex

   Example:

§  Client Software

o   ( Used for logging in)

   PDU - Formatted Data

4.  Transport

v  This layer breaks up the data from the sending host and then reassembles it in the receiver.

v  It also is used to insure reliable data transport across the network.

v  Can be reliable or unreliable

v  Sequencing

v  Acknowledgment

v  Retransmission

v  Flow Control

   PDU - Segments

3.  Network

v  This layer breaks up the data from the sending host and then reassembles it in the receiver.

v  It also is used to insure reliable data transport across the network.

v  Can be reliable or unreliable

v  Sequencing

v  Acknowledgment

v  Retransmission

v  Flow Control

       PDU – Segments

2.  Data Link

v  Sometimes referred to as the “Cisco Layer”.

v  End to End Delivery

v  Provide logical addressing that routers use for path determination

v  Segments are encapsulated

v  Internetwork Communication

v  Packet forwarding

v  Packet Filtering

v  Makes “Best Path Determination”

v  Fragmentation

   PDU – Packets – IP/IPX

1.  Physical

v  Sometimes referred to as the “Cisco Layer”.

v  End to End Delivery

v  Provide logical addressing that routers use for path determination

v  Segments are encapsulated

v  Internetwork Communication

v  Packet forwarding

v  Packet Filtering

v  Makes “Best Path Determination”

v  Fragmentation

   PDU – Packets – IP/IPX