Video Description

Transport Layer- Organize data into segments

  • Reliable end-to-end transport

    • Loss recovery

    • Flow control

    • Data ordering

    • Data duplication

  • Or just Best Effort delivery

  • Segmentation

  • Dividing data in small fragments that can be transmitted over network

  • Different networks have different Maximum Transmission Unit (MTU)

  • MTU defines maximum size of one data piece carried through the network

  • Data is being divided and transmitted to recipient via transport layer

  • The MTU size is being acknowledged by transport layer

  • MTU acknowledgment is during discovering routine and while establishing connection with the recipient

  • Reassembly

  • Done at the receiving end

  • Transport layer protocols reconstructs data to its initial form

  • Data can be received in different order

  • Transport layer rearranges pieces of data in the correct order

  • Sequencing

  • Using sequencing identifiers

  • Avoids losses and duplication

  • Fixes the issue of following data different paths

  • Organizing data in groups of subdivided data segments

  • Identifying the order of groups of data sending and interpretation

  • Connection oriented

  • Reliable and more secure

  • Establishing two way connection between the nodes before data transmission

  • When the browser is trying to open the webpage, transport layer would send synchronization packet to the web server

  • Browser expects synchronization-acknowledgement response

  • When it receives response, it sends its own response to the server

  • After this process is done the data can be transmitted

  • Connectionless oriented

  • Not reliable

  • Best-effort delivery

  • No connection establishment prior to data transmission

  • Less security

  • Allows data flooding

  • Used with delay-sensitive data (Real Time)

    • Audio calls

    • Video streaming

Network Layer- Organize data into packets

  • Responsible of end-to-end addressing and routing

  • Identifies unique logical address for machines

  • Selects the best path for destination

  • Routers work in the network later

  • Performs fragmentation if segmentation is not enough

  • Receives the segments of data from Transport layer

  • Converts them to packets by adding addressing information

    • Source address

    • Destination address

  • Finds a route for data to be delivered to the receiver

  • Routes may differ because it is being determined based on the following:

    • Network overload

    • Quality of Service (QoS)

    • Cost of alternative routes

    • Delivery priorities

Logical Address- Unique identifier

  • Bound to geographical location

  • Used for end-to-end routing

  • Can be changed

  • Not vendor oriented

  • Common example is the IP address in TCP/IP

Network and Transport Layers- Network layer defines the following:

  • Source machine

  • Destination machine

  • Transport Layer guarantees either of the following according to the used protocol:

    • End-to-end reliable delivery

    • End-t0-end Best-effort delivery

Course Modules