Let's do some testing.
One writer one interface cereal 0 1 0 encapsulation.
I've said this to me before I do that.
Notice there are various options and I'll say this too.
And what we should see is that the interface goes down and there you go line protocol these don't show
interface serial 0 1 0 0.
What you'll notice is the physical interfaces up but the line protocol is down.
So there's a problem at the layer to this interface is using PDP where as router to show interface serials
0 1 0.
So what is routed to using as we can see here ratus using HDL see the physical interface is still up
to the line protocol is down because different solutions are being used.
The one side is using the other side is using HTL see physical clock rate is there but the line protocols
are down.
So on the site I'll change the encapsulation
to BP and hopefully we should see the interfaces come up and they you go into faces come up and on the
side interfaces come up.
What I'd like you to see is that different encapsulations can be used on interfaces on a router but
across a point to point link.
Both sides have to agree on encapsulation.
So as an example on this 1841 router Sariel 0 1 0 is using PDP but on this interface serial 0 0 0 encapsulation
is HDL C..
That means that this cable is using HDL C and this cable is using GPP the 1841 rodded to device needs
to be using PDP and the 17:21 needs to be using HDL.
So the same encapsulation has to be used on both ends.
If I shut down an interface I'm going to shut down.
Serial is 0 1 0.
Notice on this side we see that the interface went down and the line protocol went down.
Show interface serial is 0 1 0.
Here the physical interface has gone down as well as the line protocol.
If there's a problem between the DTV and the DC we are going to see the physical interface go down shut
it on the side.
You should see the interface come up in the same way if I shut it down on this side
we'll see the interface go down on Rotto one and there you go into face went down the line protocol
and don't shut it.
It may take a few seconds and that's because
the keep alive the same every ten seconds on a link.
So it may not be instant.
Here it is because this cable is connected back to back.
But in the real world that may not be true may take a while for the interface to go down to come up.
So what do you need to remember.
It's fairly easy to configure serial interfaces on the one interface.
We changed the encapsulation but on the other we didn't.
So all we need to do is no shut the interface and put an IP address on and configure the relevant bandwidth.
If it is a DC interface like in this example we need to put the clock rate on.
So on DC interfaces you put the clock rate but not on DTV interfaces on a DTV you put the bandwidth
and the relevant encapsulation HPLC once again is the default.