In a later video I'll show you a why shock capture showing you what the traffic or frames looked like
when sent between two sites.
But for the moment the high level picture is as follows a P.S. In one local area network is sending
traffic to a P.C. and another local area network.
When the traffic is sent across the land and in this case we're using ethernet the IP packet is encapsulated
in an Ethernet frame so add a layer to the encapsulation used is Ethernet so as an example it could
be Ethernet to when the frame arrives at the rudder the rudder will strip the layer two headers and
then send the frame across the when using for example HDL.
So if this point to point connection is configured with a layer to encapsulation of each deal see the
Ethernet headers are removed and the original IP packet that was sent by P.S. 1 is encapsulated in HDL
C and is forwarded across the serial link to a to When rather to receives the HDL C frame it strips
the HDL C headers and forwards the original IP packet sent by P.S. 1 onto the local area network using
an Ethernet header so the packet is encapsulated in Ethernet and an Ethan at frame is sent from router
2 to P.S. to using ethernet so we have Ethernet on the local area network on the left the when encapsulation
used is used between right one and rudder two.
In this example it's HDL C and then on land too and Ethernet encapsulation is used once again the two
layers that we going to concentrate on in the oversized model for when technologies is the physical
layer and the data link layer at the physical layer.
The physical presentation changes from what you've seen in an Ethan and environment.
So rather than using RJ 45 connectors and for instance catch six cabling X 21 or V 35 cables would be
used.
So the physical characteristics of the when interface are different to the physical characteristics
of Ethernet at least two rather than using an Ethan encapsulation you would encounter encapsulation
such as frame relay BP HDL C A.T.M. and NPL less.
You may however to day also encounter Ethernet when connections which are becoming more and more popular.
But for the CCMA when discussing it point to point when connection we are going to be concentrating
on a BPP and HDL C encapsulation.
So what kind of when devices would you typically see for point to point connections.
Well you'll typically find rudders rather than switches connecting remote sites together.
You'd also encounter a CSU DSP or channel service unit data service unit which allows you to connect
to a list line connection using for example an X 21 or V 35 cable.
This converts the signals to the required format for when transmission.