This section onward we are going to discuss about NSX t routing how NSX t is performing the routing
and we will see that we have the distributed outer and the service routers.
So we'll see that.
All right.
So let's begin.
Now I want to highlight here for the very important points that may be confusing as well.
So first off.
First of all we'll see here that the idea that distributed it out there is not a VM and deer on both
hypervisor is have the same IP address.
So when we are talking about the routing or the routing process it's the same routing process that we
learn in Cisco or Juniper on any routing windows.
Correct.
The same thing is happening means you have multiple say for example line segments.
And if you if we have supposed different type of land segments means one of the land is having subnet
20 other land having 780 then because these are in these particular land are in different subnets then
they need to do routing lookup means whatever the VM you have here.
If they want to communicate to the VM in the other network the subnet then the routing lookup will happen.
So routing process will happen and the routing will do ARP lookup as well.
So those things will happen.
So whatever outers are doing all those functions will be happen.
The thing we need to remember here are note here is that it's not a VM and we'll see that different
type of variation it's inside this.
But this is nasty VM.
The second important thing here in the north you can see that in modern datacenter we have 70 percent
of the work load or 70 percent of load towards east with traffic.
So we have two type of traffic.
One is going from east to west where we can see that we have 70 percent of work load and other one is
obviously north to south.
So remaining will be remaining load will be over not just out correct.
So now knowing these things let's go and check we have few diagrams as well to understand this.
Now if you see here the logical representation so you have the logical topology and the physical topology
logical called topology is seem like you have Cisco for example CSR and then you have multiple 2 9 5
0 or maybe 3 case which is connected so in that case if different because what is happening all the
interfaces of routers they are in different subnet so one subnet wants to communicate with other subnet
the routing lookup will happen correct.
Now here again see the physical topology how we look like.
So we have the leaf and this find this structure at this point of time we know that okay we have the
Williams that is whole over hypervisor us.
So we have multiple Williams now here you can see that this D R is nothing by the kernel module installed
over hypervisor.
So here you can see that the friends that either this particular D are is a kernel module or where hypervisor.
So this idea is a kernel module but over hypervisor are this B R.
And we'll see that the D R and D or maybe is R.
So these are an aside.
That's the exact term distributed routing or distributed outer service routers they are installed over
each and what's the use of age or circumference between.
We'll see that we have slides for that.
So dear and sir why they're different.
Why what's the difference.
All those things will we'll see but here I'll see if you see the diagram when you want to go to the
van at that time obviously want to do some sort of lacked some sort of load balancing some sort of phreaking.
So that's why you need some services.
So in that case it's our will come and it will be in use.
So basically for north to south us out to NA traffic you are using a sign over it.
And if you need a road block up on the same edge at that time we can do there.
So whenever you are doing the routing related things you have the idea either over edge or over the.
So for example hypervisor.
Now when you're doing the traffic movement from east to west.
So at that time your rotors will come into the picture.
So let's quickly go and check a few of the features that we have with the idea before that you hear
it clearly and see that in the single key routing.
So we have actually two different type of tier of routing.
So we have so for example single tier routing and then we have Tier 0 and Tier 2 that is nothing but
double gears a two tier architecture.
Also we have and that's the recommended.
So we have is recommending that we use two tier architecture routing process and in our lab section
we are going to use two tier routing process but there is no limitation.
You can have your diaries are in single tier also in second tier two tier also and you will see that
that either it's a single year or two tier architecture in both the cage we can have distributed routing.
We can have service routing so both the components we can have and both the components having different
type of rules.
So let's see first of all that distributed routers.
What is their role and use.
So here you can see that there is essentially a router with logical interface.
They have actually logical virtual interface.
So you have a router with logical interface.
For example if one live to live three so three subnets representing three logical interfaces they are
nothing but the kernel modules install over the hypervisor across all their transport including the
edge nodes so they can be expanded from hypervisor daily.
As you note you can defy the diagram that we have discussed then the traditional data plan functionality
of routing and so all they will do they will do a routing and our lookups like the use of routers or
whatever Lotus functionality there.
And I will do that same each live virtual mic MAC address and IP address representing the default gateway
to its logical segment so we know that that router generally they are connected with switch.
Now in this which you have we have inwardly yes actually.
So you have n we the as this switch whenever they want to reach their gateway obviously they will contact
the this interface that the gateway interface are this loud they will work as a gateway for a little
segment then this is very important.
This flip point the IP address is unique per live and remains the same anywhere in the segment logic
where the switch exists the virtual Mac associated with each live remains constant in each hypervisor
allowing the default.
When Mac remained the same during the emotions what it is telling let me show you in the diagram if
you see this diagram you'll find that this D R is distributed across.
So for example Host 1 and host 2.
Now here you can see in Host 1 and horde hosts who host 2 they have the live the live one life to live
3 for example but this will be the live one and live too in other hypervisor.
So there clearly you can see the gateway access over all the hyper devices are Sim and the virtual Mac
will be the same.
So it will look like this.
This is a logical representation by physically the diagram is like this now here we can go and verify
that how the packet is moving.
So suppose in the same hypervisor hypervisor one Web wants to communicate with app.
So what will happen at that time because they are in their different subnet one is in subletting there
is in 20 so obviously they will go and do the R look up they will go and check where is magnified because
this IP their destination IP is not in my local subnet.
So here he will go and do the query to that out here out.
Please give me this particular IP then what router will do.
They will do the.
Blue look up and here is the interesting thing I'll show you in the next slide that I have all the points
but what will happen suppose this router will try to do the harp lookup so he will try to find out the
IP associated Mac or virtual Mac no suppose he is not able to find it.
Then he will send that query to the control plane.
Remember initially when we have a study of all these things I told you that you have local control plane
and you have global control plane or centralized control and CCP.
So CCP controlled plane and local control.
Correct.
So then this rotor gear will go and query to the controller if controller having that resolve thing
it will inform or this is the are looking for.
Otherwise controller will do the flag and try to do a reverse proxy try to get IP back and then it will
give this there okay.
Meanwhile in this case you can see there out lookup is happening locally to the hypervisor and then
they will go and communicate.
So let me quickly show you the slide where we have all these things so suppose.
Standard eleven wants to communicate with twenty dot eleven.
It will go and connect to the router and the gateway interface now deal performs the routing lookup
for this particular IP because it is connected with other interface and lookup is performed at other
intervals left to our table to data mine the MAC address associated with the IP.
If our printer does not exist the controller discredit the local control controller will ask to the
central controller if there is no response from the controller the ARP request is flagged.
Okay so according to the Gateway AAP is happening routing lookup is happening then was the MAC address
of app 1 is learn the URL to look up this platform in the local map table to determine how to reach
at 1 and the packet is in the returned packet means for the return packet from app follow the same process
and routing would happen.
Lu Li to the idea that that's the key local routing is happening and actually we are reducing the load
over the routing work workload so overall routing work load will be reduced.
Now suppose if you have to do the communication.
So for example this IP wants to communicate with this IP but they are in the different hypervisor.
So at that time to round look at will happen road lookup will happen idea.
So we tried to contact his local.
Then the packet will forwarded to a source to destination this router.
These are ones for example.
This is later on but logically there are only so these are when we do the road lookup but for the destination
to source this routing will do the lookup and that's the only difference we have addressed.
All the things will be the same that whatever we have.
So now clearly you can see that how the routing has been simplified here in the process and that's the
use of the user.
So let us stop here and next section will steady about user.