About five minutes ago and it executed three times so let's enable always be a fun ride and see how
the output changes.
So not to show the interface brief will allow me to see the interfaces configured on this router and
as you can see here in 1:59 has been configured on several ones like Sarah and 10 1 3 1 has been configured
on serial 1 slash one that's configure a loopback on the Sharada interface back to zero IP address
and it's configured as portable to tapping the command Rodda OSPF to will enable OSPF on this router
with Prozess ID.
And in this case lets enable OSPF using this format
Savi same she said just enable OSPF on all interfaces and lets put those interfaces in areas Zerah as
you can see here.
A neighbor relationship or adjacency is being formed maybe 10 1 5 1 on serial 1 slash 0 has gone from
the loading state to the full state the full state means that the rod is exchanging links that updates
with one another.
This can get confusing maybe 10 1 5 1 is not directly connected to us IP address 10 1 5 1 is not directly
connected to router 2.
However that IP address is the Rodda ID of router 1 and routed to has formed the neighbor relationship
with Rotto one and thus the Rodda ID ferrata one is shown in the output not the IP address of serial
one selects Zira by the same token on Router one notice a neighbor relationship has been formed with
quadruple to on serial once Zerah notice that the process id Arado one is one whereas the process id
on Rodek t is t process IDs are local to the rodders and do not have to be the same.
So I Can Talk To Come on show IP OSPF interface and you can see that OSPF has enabled them a loopback
interface.
Serial 1 slash one interface serial 1 selection zero interface which are the three interfaces configured
on route.
Going back to Route 1 and topping the come on show IP OSPF will allow me to see that the SPF algorithm
has now been executed five times because new rods have been added to the topology.
Show IP OSPF neighbor will allow me to see my OSPF neighbors Rato one at the moment only has a neighbor
relationship with Rodda to notice the relationship is full notice the dash.
The dash means that no election has taken place on this interface.
And the reason why is that its a point to point link on a fast ethernet network you would see various
states share like Diyar with designated Rodda BTR for backup designated Rodda and D or other.
In other words the neighbor is neither a DVR or a BT.
It's important to realize this C'mon show be OSPF neighbor is giving me information about my neighbor
Rodda not about me.
In other words neighbor with IP address quadruple two is connected to our local cereal once there is
zero interface and the neighbor's IP address on that interface is 10:01 to be on router 2 show IP OSPF
neighbor will allow me to see similar information from out of one notice Rotto ones neighbor ID is 10
1 5 1 now.
As per best practice we should be using a loopback for the Rodda Id rather than a physical interface.
So in Router one lets create a loopback interface
ON-TOPIC come on do show IP OSPF interface and you'll notice that the router ID has remained the same.
You'll also notice that the loopback interface is not in the list of interfaces and the reason for that
is that we only enabled OSPF on specific interfaces so topping that come on do show.
Run pipe section OSPF will allow me to see the configuration of OSPF in the running configuration.
And as you can see here OSPF has not been enabled on the loopback interface.
So let's talk rodder OSPF one network and let's specify a loopback address.
Now topping to come on do show ID OSPF interface shows me that Mahratta ID is still 10 1 5 1.
Let's talk this game on clear IP OSPF process and say yes to clear all OSPF processes.
As you can see the neighbor relationship went down and then reestablished Choe IP OSPF interface to
show me that the Rodda ID is still 10 1 5 1 now could remove OSPF and re-enable it.
That's a bit of a blunt instrument to change the route ID.
So I'm going to go Confiteor Rodda OSPF one router ID and then specify the Rodda ID is quite Ripl one.
And notice what the router says either reload or use the clear IP OSPF Prozess c'mon for this to take
effect.
So they'd stop clear IP OSPF process say yes to all processes and see what happens.
Once again the neighbor relationship went down and reestablished topping to come on show IP OSPF interface
shows me that the Rodda ID is now set to quadruple one on router to show ID always V.F. neighbor noticed
the neighbor relationship has changed to use the loopback address of quadrupole one that lets enable
always get router three to ensure full connectivity between all subnets
show IP interface brief will allow me to see the interfaces configured on the serrata.