The BTR will become the Diyar if the deal fails.
Designate a rod as a chosen only segment basis.
So in this example on this Ethan it's segment or two may be chosen as the designated Rodda.
But on this segment between our four and our seven or four may be chosen as the designated Rodda on
a physical segment basis a designated route is chosen.
So just because R4 is not a designator out on the segment does not mean that our form is not a designator
out on the segment every Ethan that segment requires the election and maintenance of a designated Rodda.
So from an update point of view if this link goes down or one is updating its designator or a using
this multi-course it Race 2 to 4 0 0 is 6 or 2 the designated Ratta updates all of its neighbors on
that segment.
So are 3 or 6 or 5 and are 4.
Get the update about the change of four floods that update 2 or 7 or 7 will then flood that update to
any neighbors that it may have not shown in this diagram.
The same with our 5 or 6 or 3 and so forth.
The update will be flooded at the topology.
Just as in this example where all four received the update from or 2 and then sends that to our 7.
So just to sum up designated rodders or Dior's elected Firstly based on the highest priority the range
is from 0 to 255.
The default value is 1 0 disables the ability for this Rotto to become a designator out of backup designated
route.
If the priorities are the same the Rodda with the highest Rodda ID will become the designated Rodda.
It's important to realize that preemption doesn't exist with designated route.
So in this example it's a priority of routed to set to 10 and the priority of Route 5 was set to 5.
And in the election took place or two would become the designated route.
However a or two went down Route 5 would become the designated route if and for instance or 3 would
become the backup designate Arata.
Let's assume that the priorities of the other route is 0 6 to 1 that route 3 has the highest Rodda ID
Sarada 3 becomes the designated Rodda.
When our t comes back again it will not become a designated Rodda or backup designator Rodda.
In other words it's not preemptive because R5 is already the designated Rodda and or three is the Becket
designated Rodda or two will just accept that fact and will become known as a deal or other or brother
depending which team you prefer.
It will not try and preempt another election and try and become the designated Rodda.
All other parties including our two will become the others in a typology like this.
It spoke about the shortest path algorithm algorithm the SPF algorithm places each Rodda at the root
of the tree and calculates the shortest path to each node using the digesters algorithm based on the
cumulative cost that is required to reach that destination.
So as an example if Radu one wants to get to a network behind router 2 it's going to determine the best
route based on the cost which uses a formula 10 to the eight divided by bandwidth.
So as an example this is a T1 link router one once is in traffic Draut too.
Will it take this T1 link or will it use the pod via Rodda 3 using a team make and 10 make link now
REPP using POP count would send the traffic directly to our team.
But what would always be Ifti OSPF by default uses a reference bandwidth of 10 to the 8.
You can change this and you need to and you've gig and 10 gig lengths.
OSPF has been around for many years and in the early days there were no Spizz such as the 10 gig and
so forth.
So today if youve got a gig and 10 gig links you're going to want to change the reference bandwidth.
But for now let's assume that we're using the default.
So the cost of a link is 10 to the eight divided by the bandwidth in bits per second.
A one kilobits per second equals 1000 bits per second one megabits per second is one million bits per
second 10 megabits per second is 10 million bits per second.
So the cost of a 10 megabits per second link is 10 to the eight divided by 10 million which gives you
a cost of 10 using the same formula for a length.
So for this link between our one and our t the cost is 10 to the 8 divide it by 1 5 4 4 triple 0 which
gives you a cost of 64.
So the cost using this link would be 64.
The cost if the traffic was sent via our two would be as follows 10 to the 8 voted by 10 million which
is 10 but they are two lengths of 10 meg.
So the total cost is tweenie.
So the cost Vaj the T1 is 64.
But the cost via the 10 meg links is 20 OSPF is going to choose the link via R2 to send traffic 2 or
3 because the cost is lower based on this formula tend to be divided by bandwidth.
So the formula used for costing is 10 to the 8 divided by then with how you can change the reference
bandwidth by using this on with in the OSPF process order cost reframes bandwidth and then specifying
a value in megabits per second.
The default is 100.
In other words the reference bandwidth is 100 megabits per second 100 megabits per second has a constant
OSPF of one if you change this to a thousand as an example a gigabit link would be seen as the reference
bandwidth.
Or if you change it to 100000 a hundred gig link would be used as a reference bandwidth.
You need to do this c'mon and all routers where you have interfaces with bandwidth is greater than just
Ethernet.
You can also change the cost on an interface.
So are all the then OSPF calculating the cost of the link based on the bandwidth you can set the OSPF
cost by stopping the common IP OSPF cost and then specifying haveli.
It's very important that the bandwidth statements on your interfaces be configured correctly because
that's what OSPF Diem's the speed of the link to be hijo does the same thing.
It uses bandwidth as part of the calculation when working out the shortest route to destination.