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So let's return now to their discussion of circuit switching versus packet switching.
So, the debate between the two runs far and deep.
There, there's a lot of different comparisons that have been made, and so we
just want to understand the, the main ones, the main pros and cons to each.
So, for circuit switching, there's one main
advantage and that is the guarantee of quality.
So you can guarantee under circuit switching,
you can guarantee at given amount of performance.
Given amount of
how many bits per second you're going to get?
Because the, the network is dedicating the
resource to you, right, so for whatever resource
you have, you're going to get the entirety of that and be able to have that.
so that's the main thing is that each session has one dedicated circuit.
Whether that circuit is frequency, time.
Or codes as we had said is still dedicated
and the throughput and the delay performance will not change.
Under packet switching that's
not true because we're sharing all the network resources.
So packet switching is what we call best effort service.
that's what it calls it says, we're going to
do the best that we possible can to make
sure that your packet gets there with a
certain throughput, but there's no guarantees that's going to happen.
And links get congested, messages arrive out of order and so on.
So there's a lot of things in packet switching that can
affect the performance and you know, that's, that's not, that, that's not
going to, packet switching can not guarantee a performance within a
given bound so that's one of the downsides of packet switching.
Now, on the other hand, packet switching has a few advantages.
the first one, we'll look at two of the
advantages the first one is ease of connectivity, right?
So you don't really need to allocate the network resources first, right?
You don't have to under circuit switching right, if you had
a link or something you would need to set up the session
on the link, right, in time, right, so you have to say, okay, well now, you're
going to have the session talking to this
receiver for this amount of time here, right?
And for that time it's going to be yours.
So you have to do session establishment.
Under packet switching you don't have to do,
everybody sends their packets right through to the network.
And then the network deals with the ordering and re-ordering.
So again transmit at will and protocols need to be followed 'cuz your
devices have to follow the network protocols where IP, depending up on what
layer we're at, which is something we'll talk about more in the next lecture.
Then, the third main, one, there advantage, for the packets
second advantage of packets distribution, the third comparison point.
First one, guaranteed quality, second one, ease
of connectivity, the third one is scalability.
Yeah, this is the main one we're going to look at.
you could support under Packet Switching, a
really large number of diverse sessions, right, and,
a way you achieve, scalability, is through having
a really efficient, means of doing the switching.
And so packets switching usually happens to have high efficiency for two reasons.
The first one is statistical multiplexing and the second one is resource pooling.
And we're going to look at both of these in detail in just a second.