So welcome back, guys.
Now we will going to study the functioning of Alerta device called Al to switch.
So remember the problem of trashing of rest of the machines, which is present in the subnet, when
two machines communicate with each other, let us deploy and to switch in the network and understand
how it solves the problem of trashing.
Alto's is also called a bridge, and it is a little device, so remember, any device is set to be lowered
to device if the primary functioning of that device is dependent on only Mac addresses.
The Alta switch works only with Mac addresses specified in the Internet header of a frame and therefore
allow to switch is classified as layer to device.
Similarly, if you come across any other layer to device, and if that layer to device works with only
Mac addresses, then it is obvious that that particular device will be classified as layer to device
and to such interface.
Do not have any MAC address or IP address configuration it has just bought.
No, which are just numerical values.
So in this topology you can see that we have an to switch in the diagram and this and the switch has
four ports there to support.
We want you to put P three and put before and to switch interfaces.
Do not have any IP addresses or Mac addresses.
And so it's only have both numbers, that is numerical values, of course.
You can see that the horse machines, E, D and F are present in the same subnet as before.
So you can see that the host machine E the and F opposite in the same subnet with network dot one dot
1.0, slash twenty four right there to switch, which is also called a bridge, maintains a table called
my table.
And this table is populated using a procedure called Learning.
So shortly we will going to discuss the concept of Mac learning.
My table contains the mapping between the Mac address and port number.
So we going to discuss that.
What is Mac learning, how it is done and how it is used to populate the Mac table of to switch now
going forward, you can see that here we have shown a fully populated Mac address table for this L2
switch that does Mac learning has already been done by this and the search and using Mac learning this
and to search has populated its Mac admissable now from the table.
If Altisource receives a packet with destination Mac address is equal to any from any interface other
than before.
That is this.
And to switch suppose receives a frame and the destination Mac address in that frame is specified as
m e right.
So what will this Alta switch do this and will look up in its Mac table with m e as a key.
So with me as a key.
This is the matching entry in the Mac address table of the two sides.
And therefore from this entry the L to switch would know that it has to forward the frame out of port.
No P for.
Right, so the packet or the flame will go out of the port no before because of this matching entry.
So there's only one receives the packet and no other machine in the subnet will unnecessarily Trest
with the packet, which is not destined to end.
So I apologize that when we talk about routing and data LeClaire, we should call packet a frame.
So remember our data unit, which is being transmitted over a wire.
Using Alta routing is referred to as frame, so you can see that in this topology, the Altisource make
use of its MAC stable in order to know that on which outgoing board no, it should forward the frame.
So if you do a little recap, if there was no Alto's switch, then the frame still would have been delivered
to a destination host machine E, but the host machine D and F would have also unnecessarily received
the frame and therefore unnecessarily were being trashed.
But now and to search using its macabre stable completely avoids this situation.
So going forward now, let us see how well two thirds populate its Mercado's table, so you have given
a following topology where you have Ultrasuede connected to three host machines E, D and F, so Al
to switch our brains makes an entry in the MC table by inspecting the contents of Internet header of
a frame.
So remember the point that Altisource inspects only the Internet header of a frame.
So any kind of frame which has Internet header when received by ultrasuede from any port, the alta
switch inspects the Internet head of the frame and based on the information in Internet header, the
Altisource takes an action that does it either populate an entry in its Mac address table or it decides
to forward the frame on outgoing port.
No.
One and two states do not have an entry and do not move Witchboard to forward the packet to it floods
the packet out of all the ports.
So suppose this Altisource receives a packet with the destination Mac address c m.
And now suppose that Alto's switch do not have any matching entry in its Mercado's table which matches
to the Mac address m.
So in this case this to search will forewords the frame out of all the outgoing ports.
So this is called flooding of frames with unmourned Mac addresses.
Now, Altrusa, it's populates the table by actually inspecting the source Mac address, the specified
in the Internet head of the frame it receives and altrusa its forewords frame to correct port number
by inspecting the destination.
Mac address is specified in the Internet header of the frame.
It receives the ALTAS, which populates its Mac address table by inspecting the Mac address specified
in the Internet header of the frame that is Altitude's forewords.
The frame on the correct outgoing board number by inspecting the destination Mac address is specified
in the Internet header of the frame.
So the Altisource takes two actions.
It populates the Mercado's table and it forwards the frame using its Mercado's stable.
Now, let us discuss step by step that how well the search populates its address stable and how else
to search for words, the flame using its Mercado's table.