Now what?
Now what I'm going to do is I want.
I don't think I can say is the host name.
Let me call it up one.
It is a good design.
But the problem is, if your hub goes down.
Your hub is not working.
Will your spokes communicate to each other?
They will for two hours.
There's not a problem.
After two hours, when they go to reregister themselves to the hub, they will not.
And if they want to go to a new spoke, which they have not talked to earlier, will not be able to
go because the control plane traffic is not allowed.
So as long as they have the mappings two hours, no problem.
But the moment that overrides the moment the time is over, they will not be able to communicate to
others.
How will I fix that?
I will have two hubs.
One of them will be active during both of them will be active at the same time.
The good thing about that is both of them will be active.
One of them goes down, the other one is already active.
It's not like if you have done failover in firewalls, if you have, then one state is active, one
is standby, so the other one is not working at all.
But when one guy dies, the other one comes up right.
That's a different case than this here.
I will not do that here.
Both of them will be active at the same time.
So if R4 wants to resolve his mappings, he can either go to 1 or 2, depending upon which is available,
and then after that, go forward.
Let's do that.
For that.
What I'll do is I'll go to R2 first.
No interface, Tunnel zero, remove the tunnel, create it again.
IP address 192168.1.2.
Starting from R1 again, I removed it, so I'll have to do everything again.
Tunnel Source Serial zero zero Tunnel Mode.
MultiPoint IP and IP Network ID ten IP Map Multicast to dynamic.
That's all
good, right?
That's enough.
The only problem here will be you will have no mappings because the spokes don't know that the hub has
gone down.
They think they have already registered themselves.
Right.
So if the hub goes down here, what you'll have to do is you'll have to either wait for two hours because
after that they'll come and register themselves again or go to the tunnel.
No IP network ID ten IP and network ID, the new IP, bring it back in again.
Or you could just show shut and no shut.
Both will work the same.
No IP and network ID ten IP and network ID.
This time of the year?
No.
Interesting.
So you see that it's not.
So I'll just shut and I'll have to wait for the command then.
I don't want to do that.
Shut.
Right.
So show IP neighbors.
No neighbors.
So I'd be happy.
The mappings are for three, four, five, two two are not done anything.
What I'll do is on two no interface channel zero.
I'll remove the tunnel from two.
I don't want to to be part of the I don't want him to come and register himself to the top.
The mappings are here.
12168.1.2.1.2.
I'll use connectivity.
1.21.3 has one problem.
IPsec is the.
I'm running protection.
Right.
I'll have to clear the protection.
No IP, no Crypto IPsec Tunnel protection.
Problem.
What is happening right now?
The hello packet coming from one side is coming encrypted.
The other side has not run encryption because he's not running.
Right.
The second half.
Second half.
Why can't you.
Definitely, though, I would do that.
But the problem is I made a mistake.
I removed the tongue from R1, which was the hub.
That's why I'm bringing it back up again.
I removed the tunnel completely from R1 that caused the problem.
Otherwise I didn't have to do that.
I'm moving back to what I was doing before.
So now it's okay, Now it's back to normal right now.
So if you do, you ship it out.
You should have ten dot zero network if you want to go to ten .4.4.41.5.5.5 with a source of ten .4.4.4.
You can right?
So you'll have the resolutions right here.
Phase three is working.
Now I want R2 to be the other half.
So what I'll do is I'll go to Interface Tunnel zero IP address 192168.1.2.
Right.
Source the same.
Zero zero.
Final destination.
Don't have.
It's a tunnel.
So tunnel mode and.
Then I need to do the same exact thing that I used to do on the other half.
Yes.
On the spokes?
Yes.
On the spokes, if you check.
Do show run in tunnel interface Channel zero.
If you check your interface Tunnel zero right now, your NHS is home.
You also have home IP and NHS 182 168.1..
You also have the mapping for it.
182 static map for the other hub is 151 .16.2.
26.
R2.
So I added this guy.
I also mapped the other guy.
What else do I need to do?
Multicast.
I'm sending my multicast only to R1 right now.
I also need to send it to R2.
So IP and map multicast.
151 dot 26 dot.
He has IP multicast, he doesn't know what the destination for that multicast is.
The outside destination.
220 400 ten.
He doesn't know where to send it to.
So the outside header should be one.
It should send it to 16.1.
It should also send it to 26.2.
So if you use this again, this is your config now.
192 168 1.11 92 1681.2.
My mappings are for both, my multicast is being sent to both of them.
Correct.
I'll copy the exact same thing.
That's the best thing about Dmvpn is you can copy paste because I want all of them to point to the same
guy.
I'll copy it from one spoke.
Paste it on the others because nothing changes.
They're all pointing to the same guy.
Also, our five
pointed to the same.
Correct.
They're all sending their multicast to R2.
So you'll see the neighbors are coming up from R2 side.
But from here also, I need to say map multicast to all the dynamically learned frames.
So.
So if you see right now, what is going to happen is these spokes will not go only go register themselves
to R1, they will also register themselves to R2.
And when he is sending the multicast, he sends it here as well as here.
R1 replies, R2 replies.
So R4 now will have two neighbors, not just one will be a problem.
I can use the ten dot and go to R1 and R2.
Yes, load balance it.
And then what about it is contiguous in what kind of discontiguous?
Reached in darkness to the both of them.
Yeah.
Both of them have the hubs.
Both of them have the mapping.
So if I'm going from this hub, he will redirect.
If I'm going from that hub, he will redirect.
Both are active, right?
It doesn't matter for me which hub am I using to make a decision because.
Yeah.
Okay.
What do you mean by that?
What is in the middle?
Nothing is in the middle.
See our for to reach our three.
He has two ways.
You can either go this way or you can go this way.
You mean you have the 192?
168?
It's like having an explosive.
Yeah, but I'm not using summary.
Right.
He's sending it out at 10.4.
He's sending it as out as 10.3.
But R1 and R2, R1 and R2 are summarizing it.
That's okay.
So R4, if he wants to go to any ten network, he's going from there, either from here or from there?
No, you can go anywhere.
Load balance.
You can either go from here or it can go from there.
Now, depending upon which one is closer to him, it will use that one.
Check this out.
What I've made here are four and R3 to go to each other.
They have two paths.
Now, earlier they had only one path.
Now I have two paths.
But the good thing is that both paths have everything.
This has all the network IDs.
So.
You just keep the table on there.
Before that, let me see if my neighbors are up.
It's up from here.
Are they up from here?
Not them yet.
I need to shut No, shut.
Right.
Because I just added the multicast command.
Either shut and no shut or an IP network, whether it's shut because sometimes with an IP network.
Your mappings will be incomplete.
It doesn't go.
If you don't wait for enough time, it will not be complete.
So go back here.
No.
Shut on the spokes.
No, shut, No, shut.
Both neighbors are up.
So IP neighbors.
From here also show IP neighbors from our five also.
Now the right right.
You want to see the route from, let's say, R3.
Now, my spokes are only three.
R3, R4 and R5.
Let's check from R3 show IP route.
10.2 is going from 180 to 168.
1.2.0 is going from 1.1 show IP.
IP That's before.
This is before using the command.
No IP Split Horizon.
IP split.
No IP split horizon.
One is not forwarding the other house.
Now he'll forward the other house and you'll see that if you do a show IP route here now you should
have all the routes, but going from 1.2, I need to do what?
Auto summary.
So now you'll see ten dot zero both ways.
You have to do that one already before from the before.
I didn't change the IP, I removed the tunnel.
Yeah, both of them.
It it is.
It is there.
It's already there.
The command auto summary.
I was using it from before.
Right.
Why doesn't it.
It is summarizing.
Check this out.
It is summarizing it.
Now for our three to go anywhere it has.
How many summaries?
Two ways of going there.
1.21.1.
So now you check your traffic can go to both of them.
Ten .4.4.4 from the source of 1.3.3.3.
This is just one hop.
Then the next part will go.
Now we can go to either this guy or that guy.
He went to both.
He sent his resolution to both.
He got a reply.
From whom?
From to two replied first.
So he goes from two.
Now, if you check if you check your topology right here, you'll see that for R4 two, go to R3 for
10.42, go to 10.3.
The next stop is whom this as well as.
So he will send the packet from, let's say here or the other side.
If he sends from this guy.
Right, the redirect will be sent and he will resolve the request, resolve, request, resolve, send
direct, or he can choose the other one.
You can send this traffic from here, depending upon what source you're using.
If it sends from here, redirect will be sent by this guy.
They'll resolve it and direct scope to spoke communication.
You have a 150.
Minus eight.
And you do what normally work in the area.
And I wouldn't.
You wouldn't?
It would, but it would cause the problem of what you're talking about is you have two networks, right?
They're both 150.
I mean, not like that.
This is ten.
Then when you when you summarize it, he summarizes it out as, what, ten?
So you have two routes now.
One is directly connected to the other one is will work on the longest match, right?
So from here when you ping ten .2.2.2, it doesn't match this, it will match this.
So will forward the packet.
That wouldn't be a problem.
And you have a you have a network in the middle, let's say maybe 170 directly connected.
Sure.
Yeah.
Okay.
Yeah, sure.
And you have ten networks on either side.
Okay.
So when you summarize it, you have a router, you have ten networks coming from either side.
Yep.
Ten Network is coming as summarized network from here.
Ten Network is going as summarized.
This is the reason we would need this, not.
No, not because of that.
See, right now, this will work.
This is not a problem.
This is not.
Why?
Because he installs a null graph.
Why would this be a problem if I'm sending from this side a packet to ten .4.4.09.4.4.0.
He doesn't know where it is, but he knows that he has a summarized out.
He would send it to the other side.
He doesn't have 10.4, but he has ten dot zero.
He will send it back.
Then he would send it back.
See, we have one in the middle.
One another out in the middle.
Yeah.
He doesn't know where to code it.
Right.
You have ten.
He's.
Yeah.
He doesn't know where to forward what we have R1, R2 and R3.
R1 is summarizing it to ten dot zero.
Yes.
In R3, summarizing the same thing as ten dot something.
Yeah.
Router in the middle.
Let's check.
See when I'm giving the route, I'm giving it to this guy.
I'm telling him it's ten .0.0.
Who is summarizing this guy?
Yeah, he's sending it to this guy telling him I'm ten .0.0 is doing the same thing.
He is also semi summarizing it as turned zero.
And how does the middle router would not know.
Here we need this partition here.
Yes in this if you have a router in the middle you would require.
But the good thing about EGP is what it installs a null route.
Do you remember?
Yeah.
So when he summarizes he has a null route installed so that if any other packet comes to him it will
stop it.
It will stop that route.
Right.
Isn't this the same that you have?
No, these are two different networks.
In this case, what you're doing here is these are two different networks.
This is 150 and this is 172.
What we are doing is same network.
It's like connected to a switch.
This is the same network.
So whatever routes I'm giving him is summarized.
Whatever I'm giving him is summarized.
He knows where to send it, right?
He's supposed to send him 10.2.
10.3.
10.4.
To whom?
To this guy.
But he doesn't send it as 10.1, two, three.
He sends it as 10.6.
Same information from R1 and he's not getting the summarized information.
He's getting the actual information.
It's not a summary on the spokes.
Here.
You said auto summaries on the spokes.
So when he was getting the network, he was getting it as ten .0.0.0.
Here are one.
The hub is not getting ten dot zero.
He's getting the actual networks.
The habit.
You have to see.
This is 10.3.
Right.
When it comes to the hub, it's coming in as, what, 10.3?
Right.
But when he's supposed to forward this 10.3 summarising it as 10.0, but he knows where to forward it
to, right?
Yeah.
So when R4 receives it, he receives it as ten .0.0.0.
Receive it from R2.
Yes it will.
So it has two paths now to go to 10.00.
One is from R1, one is from R2.
Now this is the same situation.
It doesn't have to see.
You have to understand that in this case, what we have, the case that you have right now would be
R1 having two different paths, two different networks, R3 and R4, and both of them are connected
to the network of ten .0.0.0/8.
So when he forwards it out he tells him I am ten .0.0.0/8.
When he forwards it here he says I am ten .0.0.
Will this be a problem?
It will not be a problem, right?
Because he has two paths.
You can either go this side or you can go that side.
It's not a problem.
This network actually will be ten .1.1.11.2.2.2 or something like that.
He will summarize it and send it out as ten .0/8.
Now he's getting it from two different directions.
Two different guys, two different next hops.
Not a problem.
He will load balance some traffic will send this way, some traffic he'll send the other way.
Different scenario.
Right.
That's what is happening right now.
So now you have two paths, one through R1, the other one through.
Both of them are giving the route so it doesn't matter for all of them.
They will always have redundancy at R5.
So if you go to R5 and you check your IP route, you'll see you always have redundancy at make sure
that your mappings, whenever you're having a dual hub, make sure the mappings are not incomplete.
Your mapping should never be incomplete because if that is incomplete, the one side goes down, he
will not be able to cover.
The whole purpose of this meeting was to shut it down.
The hub goes down 15 seconds he will take to make sure he understands that the hub is down.
But will that affect anything here?
My traceroute will still work because I don't need my hub for this.
Right.
If I want to go to ten .5.5.5, I would require the hub.
Did I forget to use the
redirect?
I didn't use.
I.
You say that the traffic was not going down?
The traffic didn't go down.
Traffic was still going even though the hub died and the other hub came up.
Your traffic did not have a.
Do have.
Everything is the same between the two.
These are now our tools.
It has all the mappings, right?
All the hub requires is the mappings.
It has the mob mappings of all the spokes.
It's that the request replies redirect, replies, resolution, request forwards.
The resolution request resolution request forwards.
The resolution request redirects to ops.
When the request doesn't matter any one of the three since since the spokes are no load balancing right.
One will go this way.
One will go that way.
One will go this way.
The request.
That's purely based on the routing table.
Session based.
Host based.
Yeah.
One session.
Exactly.
Just like it happens in IP based on IP routing, it's load balancing is purely based on.
It has nothing to do with anything else.
Is this clear?
Everyone play, right?
Dual Hub.
Tomorrow we'll do OSPF.