the next topic of discussion
is your third wide area or serial encapsulation type or framed really.
Now frame really is a non broadcast, multi access technology.
so friend really is a non broadcast monthly access topology technology as opposed to Ethernet, which is a broadcast multi access technology.
Now multi Axis simply means that no more than two devices can be on the network at the same time.
Frame relay supports more than two devices being on the network at the same time, just like Internet.
However, unlike Internet, there is no layer to frame relay
broadcast address. An Ethernet,
a destination broadcast address is all lefts
in frame. Really, there is no where you could send a broadcast from one device to all devices, using one address as the destination address in the frame
to explain frame. Really, I've drawn out this topology on the board.
You see the D C router on the left hand side,
connected to around a router that says F F stands for frame, really,
and the D C router is connected to the frame relay router.
The sea on top stands for Custom Reg. So this D. C. Router is your customer edge router. The rest of your network, your enterprise network lays behind the D C router, the be router
or the first frame relay switch, which actually is a router with special configurations. On it
is your first be router or the provider edge router,
the provider edge of self explanatory. It's the last router on the provider side that connects through the customer edge.
Then you have the friend really cloud, which is this collection of frame relay switches that the service provider has laid out throughout the world and doesn't done the groundwork already connected to each other in a full mash or an almost full mesh. On the other side, you have
the two provider edge routers, one connecting to your remote side in Paris
or the customer edge router in Paris and the other one connecting to the remote side in London or the customer edge in London.
Now, let's say, at the D. C end,
you wanted a circuit
to the Paris router,
and you had another branch for off your company in Paris.
trying to lay your own line between D. C. And Paris and go broke in the process. Or you could call up a service for lighter and ask them
to lease out a circuit,
the cost of which you will pay per month
between the D. C and Paris site.
Now, once you call them, call your service for lighter. They might build you a circuit
between all these frame relay switches, which again are just routers with certain configurations on them
and the Paris router.
In frame relay terminology, this circuit between two remote sites is called a permanent virtual circuit
Next, let's imagine that we have 1/3 sight come up in London. We have doing prosperously. So third side comes up in London and we need a circuit between D. C and London also.
So the service for lighter build us another circuit
between D. C. And London,
and this circuit again
is called a permanent
Now, if you look at this apology,
Paris and London don't have a direct connection between each other. So all traffic between London and Paris must pass through the D. C end.
This kind of apology is called ah Hub and spoke topology
Instead of paying for an extra circuit between London and Paris
and paying a monthly fee for it,
this company decided that they were gonna pass traffic between London and Paris through D. C.
This type of a set up is called a hub and spoke topology, the D C and being the hub and the Paris and London end and being the spokes.
Now, if you see the d C end is terminating two circuits, one circuit, one part permanent virtual circuit is going to Paris on the other permanent virtual circuit is going to London.
So the engineer sitting at the D. C router how does he separate the circuit going to Paris from the circuit going to London.
data link connection. Identify or I D
Now, when you call up your service for lighter, your service provider will let you know. For example, the Del C 100
is going to Paris and L C 200
is going to London. You can think off a DLC
your Mac address for
so Mac addresses are two Ethernet. What Adele see is to frame really del sea is basically your lair to address for frame, really to identify
or two separate PVCs from each other.
So in this scenario, if I take the circuit
with the DLC number 100 I end up in Paris from D. C.
And if I take the circuit, or you could think of it as a train 200
from D. C. I end up in London. Now these del seas are locally significant, which means these Del sees
have these values of 102 100 just between the customer and A D. C. And the first provider
router, which is your P.
So, for example, going to Paris. The DLC is 100 between the D. C
and the first frame relay a router
or the sea and the P E ej.
After that, it might change through 1 50
5 13 etcetera, etcetera. So the DLC or the PVC, the circuit coming back from Paris to D. C will not have the same identify, will not have the same data link connection I d.
So the DLC coming back from London to D. C. will not be 200. It will be another number. Let's make it 2 22 when I go change my encapsulation type on my customer edge router or the D C router. Let's suppose this interference is cereal zero
and instead of p p p r S t l c I changed encapsulation type to frame. Really? The d C router start sending and receiving what are called lm eyes or local management interface.
So you're l am I the word l am. I stands for local
management interface Alum Eyes are used for two purposes
The first purposes when she changed encapsulation too
Frame really on your edge on your customer edge and you start receiving Elem eyes from the provider EJ The alum eyes announced all your del sees to you.
Now the Alum eyes will just announce all you'd Elsie's to you. You still will have to call the service provider to find out which Del Sea is taking you. To what location? The second purpose of the L. A. My is to report the end
to end circuit health.
So if if at any time, anywhere in the middle of the circuit fails
you will find out that the PVC is down
or the DLC is inactive.
True, The reception off Ella Mayes.
Now Alum eyes by default are sent every 10 seconds between the provider edge and the customer edge. So the customer had sends and receives atomized every 10 seconds. Now that we have changed encapsulation to frame really And we have learned all our del sees from the provider edge.
And now we're sending and receiving Elem eyes.
If you assign an i p address to this serial 000 interface, lets
pretend that we're going to assign 1 51 01 45.1 to this side
and the other side is already configured as 1 51 a 1 45.2 We can make this slash
for all we care for now, just for this example.
set an I P address on the serial 000 interface
and in worse, our request is sent down the circuit
or resolve the I P address
off the other end of the circuit.
Now it is called inverse are because let's look at art.
and our resolve remote I p or the destination I p or the I p at the other end of the link
The Mac address also associated with that I p, which is also at the other end of the link.
An inverse are resolves. Ah, locally received Elsie because remember, Del C 100 is being received by the D. C end sent from the frame relay network by the provider and so locally received Elsie
to the remote I p at the other end.
In fact, basically, I'm saying
to the remote I p, which is 1 51 01 45 got to
I am basically saying if I take the LC 100 or go down del C 100 I can get to the I p 1 51 01 45 2 which is
the other site in Paris.
So once again, one shoe
Ah, sign an i p address to an interface
an inverse our request to send down
to resolved i p address at the other end.
So this is ah, layer to layer three mapping just like art does,
except it's called inverse are because in this case you are mapping
a locally received Elsie toe, a remote I P and Self a remote I p to its remote Mac.
There are two types of frame really interfaces,
multi point frame relay and point to point framed. Really.
Main interface is like as 000
are always multi point interfaces
and multi point interfaces always sent out in verse. Our requests, unless inverse artist turned off
so multi point into fish is always sent out in verse on requests
by default, unless you turn off in verse are
the other type of infer interfaces for him really can have our your sub interfaces.
Now you can have a multi point someone defaced or a point to point sub interface.
Some interfaces do not send out inverse our request By default, you will have to do something manually to make it work,
and we will see that happen in our lab.
At this point, we're done with the frame relay lecture, so let's hop onto our lab and see how this works