In the section we're going to talk about h is R P protocol
a first up redundancy protocol.
F H R P is a computer networking protocol which is designed to predict the default gateway used on a
summer work by allowing two or more others to provide backup for the address in the event of a failure
of an active rather the backup brother will take over the address usually within a few seconds.
In practice such protocols can also be used to protect other services operating on a single IP address
not just Rather's
hot standby rather protocol HSR AP is a running protocol that allows host computers on the Internet
to use multiple roles that act as a single virtual rather maintaining the connectivity even if the first
hop rather fails because other others are on standby and they're ready to go.
Rachel IP and MAC addresses are shared between the two brothers and there is no load balancing and verified
by the show stand by comment as you can see that in our figure we have two brothers and their rather
one and rather two and please pay attention that I am using SRP to protect the default gateway for here
and here if there is a problem in the brothers.
This interface or if that rather fails completely.
For example we can have an power problem or we can have a cable problem in the end interface connecting
between switch and the rather if this rather is the active one the HSR IP protocol will switch the traffic
to the standby rather.
This is actually what HSR is doing but there is no load balancing.
As I said for example if this one is the active rather rather one is the active further the traffic
flows in that direction and there is no packet in here.
When this guy fails the traffic is switched to this direction.
And if I configure preemption on rather one
for example let's say that I have fixed the power unit problem and if I configured preemption as well
this rather will become the active Gateway again.
And this guy will act as a standby
so let's take a look how we select the active and the standby gateways in the HSR pit.
As you can see that in the figure we have two others again and the rather with the highest IP address
will be active by default.
But the selection can be changed with the H S IP priority value the rather with the highest HSR P prior
to Wally becomes active and default prior to value is one hundred the active and the standby rather
send the help packets to the H SRP group multicast others in three seconds.
If the hell a packet does not arrive in 10 seconds the standby rather becomes active.
Okay let's say that this guy is active again and this guy is standby if I want to change the roles if
I want to make this guy as an active I need to increase the price to only off this rather when I increase
the prior to early this guy will be active and traffic will flow in this direction instead of this direction
in HSR PD the active Gateway propagates this Michael risks and says that hey guys use this mac address
Widget X X is the HSR p group identifier to reach the this IP address which is H S IP standby IP
let's talk about the topology now we have a P.C. in here which has an IP address of 10 that more hundreds
the gateway address of the P.C. is turned up 1.
And please pay attention that that's the HSR P IP so I'm at I'm gonna attach this IP address to this
interface of the rather one and I'm going to attach this IP address to this interface of rather too
and I'm going to attach a standby IP for both of them and that's gonna be turned up 1.
And I'm going to define the gateway as ten that one.
So what do the thing about this for example why I'm not attaching the tender to as Gateway let's say
that the gateways tend up to if the gate they will be turned up to I would follow this line to send
the packets to wider network read but when this rather fails if this if there's a problem with the structure
in the network
because of the 10 that too will fail.
Also I wouldn't go to why they're in network but if I configure this one whenever this rather fails
rather to will be the active rather and take the traffic onto it and I'm going to reach the wider network
again without any interruption.
Let's take a look to the HSR preemption feature.
If the active rather fails the standby rather is activated and it remains active even if the previous
active Raptor is returned.
Pre-emption process forces rather to a new age SRP selection
and here are the states of the HSR brothers.
We have six six states and the first state is initial.
This is the beginning state.
It indicates HSR SRP is not running.
It happens when the configuration changed or the interface is first turned on in the lone state through
other has not detriment.
The virtual IP address and has not yet seen an authenticated hallow message from the active rather in
the state the rather will still wait to hear from the active rather in the lizard state through other
nodes both IP and make addresses of the virtual runner but it's not the active or standby in this big
state.
The rather sends periodic H.S. IP hellos and participates in the selection of active or standby rather
in the standby state through other monitors how the packets from the active rather and it will take
the active state when the current active rather fails and in the active state rather forward packets
that are sent to the H IP group.
The.
Also sends periodic Hello message
and here is the configuration of the HSR IP first I it to fix the IP addresses for my configuration
the IPL this in here is
turn it up to and here is 30 that three and my gateway s
third it up 1 and my HSR IP is also
what I do in the configuration as I'm going under the interface mode and I'm assigning the IP addresses
at thirty two and 30 that 3 to the physical interfaces these are for here and for here then I'm going
to attach the stand by IP by using standby.
And standby group no and IP and the IP address okay.
And then the same thing on rather two to I just have two different configurations for either one in
here sent by one prior to one hundred and fifty.
This line shows me that rather one is the active rather for this HSR P topology because of the default
loli of the project is 100 if I choose the one hundred and fifty.
This guy will be the active one and here as you can see that I types them by 1 pre-empt comment.
Which means I have configured the pre-emption.
For example if this rather fails
this guy will be the active front but when this rather is back this guy will be standby again and rather
one will be active because I configure the pre-emption to verify DHS IP configuration.
I'm using the show standby command and I can see the group no state active virtual mac address and standby
Rather's IP as well by typing this show standby by command I can use different gateways for different
villains in HSR P2 and this is what multi Group H SRP is doing for me.
For example for villain Sim and realign 20 I'm using this guy as primary and I'm using this guy as the
secondary for villain to an end villain 10.
Then I'm getting under the interface villain for example interface villain 10 I'm attaching a lower
priority for v lantern and higher priority for villain 20 which means this is gonna be active for villain
to any and this is gonna be in Sam by mode for the villain.
10
SRP has another great feature that is known as HSR interface tracking.
As I told you in the first slide HSR P always is responsible for protecting the default gateway these
interfaces but when I try to connect to Internet I have also this interfaces as well.
So what HSR P is doing with interface tracking HSR P is watching that if this interface is up or not
is the interface fails for example.
If serial 0 0 interface fails well the HSR is doing.
This is Dick demanding the private label for either one and rather B is becoming the active brother.
So I'm not having an interruption so traffic is flowing in this direction
so another thing that SRP can do is object tracking.
For example let's say that I have no problem in this in this interface to and everything is OK in my
local area network.
Here is my local area network.
My brother is working fine and mostly there is no problem in this interface or this interface.
Everything is OK but there may be a problem on the
ISP network maybe I have our central rudder in here that I am collecting to traffic from the branch
offices but HAARP object tracking does.
I can ping here this interface of my HQ rather and if pink fails to the HQ rather
I can change the traffic's pattern again and maybe I can use another ISP and another central rather
and so that my traffic won't interrupt here's the object traffic configuration as well.
I'm defending an IP solely and I'm trying to pin this IP address as you can see that I have a local
area network switch and I rather went and a rather two and on the other side.
I have a core rather which has an IP address of somewhat
then I'm defining it for a frequency which means that I'm gonna ping here each 5 seconds then I'm defining
the study of the finished time of the HSR.
I'm sorry IP silly then I'm tracking this IP SLA
at the end whenever there is a problem I'm going to Dickerman.
The pride truly and the other rather will switch as a active
HS IP pro as the following two types of authentication and their plaintext and they and the five.
If you want to configure and the five you can use the standby group authentication and the five key
string and the key string number and this strength the group number is arbitrary you can choose anything
that you up if you want to configure it plaintext you can use them by for example 1 authentication and
you can use the string that you want all rather is in a HSR pick group send help packets by default
the helo timer is set to 3 seconds and that timer is set to 10 seconds.
It means that a helo packet is sent between the HSR please stand by group devices every two seconds
and the stand by the W becomes active in a helo packet has not been set for 10 seconds.
If you want to modify the helo and hold on time you can use standby standby group number timers and
helo time or hold time command.
There are two versions of the H SRP and their version one and the version to version 1 is the default
version of the protocol H is IP version 2 allows group numbers of up to 4000 and 9 is 6 thus allowing
you to use villain number as the group number.
Although as in an HSR IP group must have the same version configured otherwise dialup messages are not
unders to.