So now, let's talk about VRRP, Virtual Router Redundancy Protocol.
So, great news, VRRP and HSRP are very, very similar except for terms and some of the features that are on by default or off by default,
which is fantastic because this gives you the opportunity to learn a lot about HSRP like you have today and then carry a lot of that knowledge over to VRRP.
So, with VRRP, instead of using the terms active and standby, they use the terms master and backup.
Notice there's no listener like we had with HSRP. So, with HSRP, active, standby, listener, whereas in this case you have master and backups.
So, you could have one or more backups. So, if you had five routers and you wanted them all to be part of the same group, you'd have one master and the rest would all be backups in that case.
So, router with the highest priority, forwards packets, responds to ARP requests, sends and receives hello packets, same thing as we discussed with HSRP.
And then when it comes to the backup routers, router with second highest priority, third, fourth, fifth, sixth, in this particular case, sends and receives hello packets, waits for master to fail, so it can become the master.
So, on Cisco routers, by default, you are technically using VRRP version number two by default.
But we just refer to it as VRRP and VRRP version two only supports IPv4 networks, just like we talked about HSRP version one only supporting IPv4.
To support IPv6, you got to do HSRP version number two.
Okay, well, with VRRP, we're actually using version two.
And if we want to use IPv6, we have to use VRRP version number three.
All right.
So, the command we would utilize in that particular case to change it, I'll type it in here.
AFHRP.
It would be in global configuration mode, actually.
So, in global configuration mode, so config FHRP version VRRP v3 is what we'd use in Cisco IOS in order to use VRRP version number three.
Preemption is also enabled by default with VRRP, so it's not something that you're going to have to configure.
It's automatically on, and you really don't want to shut it off.
So, when you look at the configuration for VRRP, it's very, very, very similar, except I don't have to do preemption.
So, let's go ahead and do a live configuration here of this.
And so, what we can do is let's type in interface VLAN 20 here.
And in this case, let's remove standby 20 IP 10.0.2.254.
So, I want no standby.
So, do show run interface VLAN 20.
All right.
So, let's go ahead and do VLAN 20.
So, we'll make this one the master, and we'll make this one the backup.
So, that's what we'll do.
So, this is the master, and this is going to be our backup for interface VLAN 20.
So, DSW2.
Let's do DSW1 first.
So, we'll type in interface VLAN 20.
We'll type in VRRP 20 with the IP address of 10.0.2.254, and then we'll type in VRRP.
Oh, no.
I'm going to leave this one as the lower priority.
So, we're going to have DSW2 have the higher priority when it's all said and done.
So, you'll see here that I'm the master right now.
Why?
Because I'm the only one.
There's nobody else here to compete against me.
So, let's go over to DSW2.
We'll type in interface VLAN number 20, and we'll type in VRRP group number 20, and give it the IP of 10.0.2.254.
And what's going to happen in this particular case?
Let's see what happens.
Okay.
So, I give myself the backup status, but I promoted myself to master.
Why?
We have the same priority.
Why did I promote myself to master?
Same priority, but I have the higher IP address.
Okay.
So, there's a prime example of same priority, but a higher IP address.
Remember, preemption is enabled by default here, so that's why we promoted ourself to master.
So, I'm going to type in anyways VRRP 20, and then we're going to say our priority.
Let's increase our priority anyways.
One of the things about VRRP is that if you give yourself a priority of 255, you automatically become the master no matter what.
Not a big gift for the exam, though.
That makes sense, because you have the highest priority, right?
So obvious.
All right.
What else do we want to talk about here when it comes to VRRP?
So, we've covered priority.
We've covered the IP address.
Let's take a look at do show VRRP.
So, what are we going to see here?
We're going to see the virtual IP address.
You're going to see the MAC address.
So, there's the MAC address.
I want you to remember, 00005E, and then 0001 for VRRP version 2, and then we have 14.
So, 14 being the group number.
So, remember, what group does this MAC address belong to?
It's not 14.
It's 20.
So, you're going to have to do that conversion like I showed you with HSRP.
All right.
Let's take a peek at our notes here.
Preemption is automatically enabled, as you can see.
You'll see that our hello interval is one second by default with VRRP, whereas with HSRP it was three seconds.
It's already faster.
By default at one second.
And you'll see that the down interval or the dead interval is 3.57 seconds.
So, 3.57 times the actual hello, and that's legit.
It's actually like 3.57.
They round it to 3.6.
So, 3.6 times the hello.
It's actually 3.57 times the hello is your automatic down interval.
So, if we set it to something like 2, then it would be 3.57 times 2 would be our down interval at that time.
So, it automatically adjusts for you the down interval.
So, what about interface tracking?
So, when it comes to interface tracking with VRRP, it's going to be the exact same as we saw when I configured it for HSRP.
So, we would have to create a tracking object and then attract the tracking object to VRRP.
So, the command would be VRRP, then your group number, and then track.
And then you can go ahead and attach your tracking object to it.
So, let's say we have tracking object to seven, and then decrement your priority, but whatever you need.
So, like I said, everything we learned about HSRP still applies here to VRRP.
So, we'll take a look at our slides right now.
And so, under normal conditions, this is how traffic, let's say, is flowing right now.
If, let's say, DSW2 failed, well, then our backup is going to become our master at that particular point in time,
and our traffic is going to automatically adjust that way.
When everything goes back to normal on DSW2, then we're going to preempt and take over and become the master again,
and DSW1 is going to become the backup, and we're going to failover.
And, again, we send out a GARP, just like we do with HSRP.
So, we send out that GARP, so that way there we can update the MAC address tables of our switches.
So, if we go to somebody like ASW1 right now, we should see that ASW1 has the MAC address.
ASW1 has the MAC address for that HSRP group.
There it is.
Oh, upstream interface tracking.
What are we going to have to do?
Create a tracking object like we did for HSRP.
Create the tracking object, apply it to our VRRP group.
So, just like we did with HSRP, though, we maybe want to track this interface and track this interface
and maybe decrement this one by a certain value.
So, what is our priority right now?
I think our priority is a total of 200, and this one is 100 right now.
So, maybe decrement this one by 51, decrement this one by 51.
And so, that way there, if we lose both, then we'll fail over and use DSW1.
But if only one of them fails, then we can continue using DSW2.
In this example here, we'll see that our tracking object right now is up.
So, since our tracking object is up, our traffic is flowing through DSW2.
And we'll see right now that it's up.
But if it goes down, we'll decrement by 200.
So, our priority right now is 200.
So, let's go ahead and bring down interface gigabit 1 size 0 size 14.
And so, since that interface has gone down, tracking object has gone down.
Therefore, we go back up, and DSW1 becomes our master.
So, just like with HSRP, and if we look at this output now, we'll see that tracking object 5 is down,
decrement 200.
So, 200 configured minus 200 equals 0.
So, all the same.
And then what about further upstream?
So, if we had a failure further upstream, it would be the same thing.
You'd need an IPSLA.
So, you set up your IPSLA instance, in this case a ping, set your frequencies, set your schedule,
and then create your tracking object that is keeping track of that IPSLA instance,
and then attach the tracking object to your VRRP command.
So, in this particular example now, the SLA instance is down.
So, because the SLA instance is down, that means that our tracking object is going to be down.
And so, because the tracking object is down, we're going to decrement our priority.
So, priority is now 0 because the tracking object is down.
That's attached to the IPSLA instance.
With VRRP, as I said, our timers are more aggressive by default.
So, your timer is 1 automatically for the hello time.
You can make the millisecond values as well.
As you can see from here, VRRP 20 timers advertise milliseconds.
And as we said, the dead timer is automatically going to adjust based on the hello timer that you specify.
We said it's, what, 3.57 when it's all said and done?
Rounds up to about, like, 3.6 times.
And then also, forget about preemption.
Preemption delay, I should say, is that, again, you don't want to take over as the master too early
if the rest of the network's not converged yet.
Because if the rest of the network's not converged and you take over as master
and you start receiving traffic, then you might not be able to get where the traffic needs to go,
and then you're going to have to drop it anyways.
So, you're going to want to measure how long it takes for your network to converge under various situations
and set a timer that is going to be appropriate for all situations combined.
And then authentication.
Let me check this device here.
Authentication is something that has been available and then not been available for VRRP.
That's right.
That is true.
Let's see if it is on this.
Yes, it is.
For this Cisco platform and device, it is.
So, VRRP authentication.
And you'll notice it's only plain text authentication.
It's not MD5 authentication that is supported.
And there are a lot of the RFC itself.
Last time I checked, which was a while ago, but the RFC did not even include authentication as an option.
And as a result of that, a lot of vendors don't actually offer authentication for VRRP.
But Cisco does, and they only support plain text authentication on a lot of different products.
So, just something to keep in mind that maybe your device, if it's a non-Cisco device,
and it doesn't support authentication, it's because the RFC, the industry standard,
does not recommend authentication for it.
That was last time I checked.
They might have an amendment or update it to it now,
but that's not something that would probably show up the RFC information on the certification exam.
But, you know, if they ask you to configure VRRP authentication on the certification exam,
well, then obviously they're asking you to configure something that is supported.
So, you would just go ahead and do it, and it would more than likely be plain text in that case.
All right, folks, so that is our cover of VRRP.
Very quick, a lot quicker than our HSRP discussion.
But like I said, you already know everything.
It's just now, what are the differences?
So, you know the differences, as we've covered them here, so that way they're on the certification exam.
You know the differences, and you'll be able to make decisions based on those differences.