Time
3 hours 38 minutes
Difficulty
Beginner
CEU/CPE
2

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

Video Transcription

00:00
this lecture
00:02
handles the transport and that will Claire's.
00:06
These are the two main layers that concern the network specialist. The network engineers.
00:14
The Transport Layer Layer number four.
00:17
It organizes data into segments. The word segment is the unit off
00:24
data at the transport layer at Layer number four, where it is a packet at layer number three and a frame at layer number two, and bits and bytes at the physical layer. Layer number one.
00:38
The transport layer is responsible for the end toe end delivery
00:43
in either reliable form or just best effort delivery.
00:50
When we try to explain the word reliable, we refer toe loss recovery,
00:56
which means that data transmitted arrives at the receiver side with no losses.
01:03
We also refer toe the Floo Control, the adjustment off the flu between the sender and receiver according to the natter conditions and according to the requirements of the
01:15
where, if there are also two data ordering, sometimes data arrive at the receiver side out of order.
01:23
Arrive
01:25
Data number two before data number one. Data number one is late. Do you tow taking a congested path over the network? That's why they're the number two arrived earlier. I mean, the piece off the
01:40
this piece of data number two needs to be reordered
01:42
in reassembly process to be put in the right place after data number one.
01:52
One of the responsibilities off the transport layer is the data deed application. Sometimes data is son twice and received twice the same piece off data.
02:01
So
02:04
we need a form or an identify that says that this data is a duplicate. This data is another copy off a certain data that has been received. So we need a deed application process to eliminate the extra copy.
02:19
Once more,
02:20
you either son and receive in a reliable communication or in best effort, delivery. It's the two modes where the transport layer works
02:35
the functionalities off the transport layer, our number one the segmentation.
02:39
The segmentation means dividing data into small fragments called segments that can be transmitted over the network.
02:47
Different networks have different maximum transmission unit there for different MTU.
02:54
The empty U defines the maximum size off one data piece carried through the network. This is the definition off. The MQ
03:04
data is being divided and transmitted to the recipient via the transport layers.
03:10
The empty you size is
03:14
agreed upon between the sender and the receiver
03:17
while establishing the connection and during the routine discovery.
03:23
The empty you size
03:24
is one of the parameters off the network that must be agreed upon between the sender, the receiver and the communication devices.
03:37
The second functionality off the transport layer is the reassembly. Reassembly means assembling the pieces off data arriving at the receiver side,
03:46
so the same form or the same initial form that has been
03:51
send from the center.
03:53
This reassembly is done at the receiving end.
03:57
The transport layer protocols reconstruct data into its initial for
04:03
data can be received in different order, different than the form that has been sending it.
04:11
So it is the responsibility off the transport trail to rearrange those pieces of data into the correct order. The original order, the order by which it has bean sent
04:25
the third function, like of the transport layer, is sequencing. Using the sequencing, identify roar sequencing number
04:32
tow. Avoid the loss on divided application. Each piece of data is
04:38
noted by sequence number or sequence identified.
04:42
This sequencing fixes the issue off following data. Different path is so, you know,
04:48
from the sequencing identified the correct sequence of data.
04:53
This sequencing helps in organizing data in groups, off subdivided data signals
04:59
and in identifying the order of groups off date ascending and interpretation.
05:05
The communication in the transport layer is either connection oriented. This type of communication that is called connection oriented is reliable and more secure.
05:15
It is based upon establishing two way connection between the notes. I mean the sending and receiving notes before data transmission.
05:25
For example, when a browser is tryingto open a webpage, the transport layer would send synchronization packet, tow the Web server from the browser.
05:34
The brother then expect synchronization, acknowledgement response.
05:40
When it receives this response from the server, it sends its own response to the server back.
05:45
After this process is done, the data can be transmitted.
05:48
We can hear See that no data has been transmitted Before the connection establishment is complete,
05:59
the transport layer can establish a connection. In another move that is called connection less oriented. This is a non reliable connection. This connection depends on the best effort delivery between the thunder and the receiver. No connection establishment prior to data transmission. It is less insecurity because it does not
06:18
guarantee that loss, recovery or the re ordering off later if received out of order.
06:27
It allows sometimes for data flooding for sending big chunks off data over the Net or causing it to flood to be saturated with unwilling to traffic.
06:38
But this type off connection less oriented communication is essential in some types of communication where data is really time data is delay sensitive, such as the audio data in the audio calls
06:53
or the video data in the video streaming sessions.
06:58
Now let's move to the third layer. Layer number three, the network clear.
07:02
Remember that we count layers from down to up.
07:06
This layer organizes data into packets. Now remember that data in the fourth layer is schooled,
07:14
segment and hear. If it's cool, packets
07:17
responsible this layer off end to end addressing and routing. And let's
07:24
know by heart these two words addressing and routing. These are the main functions off the network. Clear.
07:31
The network clear identifies unique logical address for each machine over the network. The address is unique. The address cannot be repeated. The address is logical
07:45
and
07:46
related to the geographical location off the machine. It is not a physical address it's something logical that can be changing according to the change of the geographical location off the machine.
07:58
This not clear. Select the best path for destination.
08:03
This what we call the routing process
08:05
routers. The devices that are called routers work in this network. Layer reads and understands data upto this third layer layer three they're not were clear.
08:18
This layer performs fragmentation. If segmentation was not enough to divide the data to be suitable for sending and receiving, we add another process that is fragmentation. Tow the data to divide data into smaller chunks,
08:35
not clear at the receiver. Side receives the segments off data from the transport layer.
08:39
Converts then converts segments into packets by adding the address ING information. The source is the destination
08:48
and then finds route for later to be delivered to the receiver.
08:52
Routes
08:54
that are designed to any
08:58
group of data may differ because it is being the determined based on the following.
09:03
It is either the least network overload the drought over the best route from the point of view off the quality of service, or it is the least
09:13
drought in Khost
09:16
or according to some delivery priorities,
09:18
which means that the data has a priority more than other data, so it should take a path that is faster than other data would take.
09:28
These are
09:30
the most common
09:31
criteria for route definition.
09:37
When we say that the network layer is responsible for identifying logical address, we must give some details about the logical address. It's a unique identifying it is bound to geographical location off the machine. It is used for end to Andrew outing. Since bound to the geographic location,
09:54
it can be changed it according to the change of the bigger geographical location off the machine.
09:58
It is not vendor oriented, as we will see in the next
10:03
lectures there. The physical address is vendor oriented.
10:07
The common example for this type of address is the I. P address in the TCP I P Protocol suit.
10:15
Let's sum up both layers. The network and transport layer the network clear. Our identifies the source machine and the destination machine in any session, while the transport layer guarantees either and toe and reliable delivery or end toe and best ever delivery for data across the same
10:35
machines.
10:35
These are the main functions off the network and transport layers in the ISA west. Sorry. Seven layers.
10:45
Thank you

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