NSX-V Lab: Logical Switches


Welcome to Part 12 of the NSX-V Lab Series. In the previous post, we covered configuring our Transport Zones.
In this post we will configure our Logical Switches and connect our test app to them.

What is a Logical Switch?

An logical switch reproduces switching functionality (unicast, multicast, broadcast) in a virtual environment completely decoupled from underlying hardware.
Think of Logical switches the same as VLANs, in that they provide network connections for VMs.
The VMs can then communicate with each other over VXLAN if the VMs are connected to the same logical switch.
A logical switch has a segment ID, like a VLAN ID.
A VLAN ID can only range from 1 to 4094 but a Segment ID can range between 1 to 16,777,215

The Build

To create Logical Switches we need to go to surprise surprise ‘Logical Switches’ 🙂 Then Click ‘+ ADD’

The first switches I always create are the HA network switches these are used by the DLR’s and ESG’s (When in Active Standby mode).
You don’t need to create the HA network first but since most builds I do don’t have customer networks at this stage the normal or is to create the HA network, deploy the DLR, then create the customer networks. However the order doesn’t matter.
The HA network can be either Global or Universal dependent on the use case for the Lab I’ll create both to show the differences. First a global HA Logical Switch.
Give it a name, Select the Global TZ from the Transport Zone dropdown list in this case that’s the SiteA-TZ.
Notice that Universal Synchronization is greyed out thats because the TZ is only global so it’s not a option.
You can change the Replication Mode on a per logical switch basis but we won’t be doing that so leave it at the default which comes from the Transport Zone configuration.
Leave IP Discovery checked and MAC learning disabled. Click ‘ADD’

The logical switch takes the first available Segment ID, as this is a global switch it uses an ID from the global range which for Site A is 5000-5999

Next I’ll create a Universal HA network.
The process is the same give it a name and this time pick the Universal-TZ.
Notice Universal Synchronization is On by default and cannot be changed.
Click ‘ADD’

We can see the networks on the vDS’s for the compute and Edge hosts.
Notice the Universal HA Network has taken the first Segment ID from the Universal range which was 1000-10999

The next network I will create is the Transit network. This network will connect the Distributed Logical Router (DLR) to the Edge Services Gateway.
As the DLR will be a universal DLR (UDLR) I use the Universal-TZ.
Remember Universal means it will span both sites.

Now we need to add our test app switches for Web, App and DB.
We will use the Universal TZ so that the VM’s can be migrated to Site B without changing their network.

We now have all our logical switches configured

As they appear on the vDS.

I now need to connect my test App VM’s to the new networks.
Simply edit the VM, on the network adapter click the drop down and click ‘Browse’ then select the desired network from the list and click ‘OK’
Do this for all VM’s that need to connect to the logical switches.

an ifconfig of my Web VM 1

If I try and ping the network default gateway it won’t work, this is because the gateway will reside on the UDLR which we haven’t deployed yet.

I can however ping web VM 2 which is on a different host. so we have Layer 2 connectivity.

That’s it for logical switches. The next step is to deploy our Distributed Logical Router.

NSX-V Lab Part:13 NSX-V Distributed Logical Routers

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