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Section 2.1.2 - Deploy services to logical switch

Deploying Services to a logical Switch


Now it’s time to do some actual work with a logical switch.  A logical switch is similar in function to a VLAN on your physical switches.  You will add routers, firewalls, subnets and hosts to your logical switch.  This can be done through the API or the Web Client.

Assign and configure IP addresses

A logical switch is a Layer 2 object and IP addresses are Layer 3.  The only way I can think of to assign IP addresses to a Logical switch is to add a DLR or Edge interface to the logical switch and make it the default gateway for the Logical switch.  At that point you can either statically assign IPs or configure DHCP relay.  I will statically assign a DLR interface in this demo and show how to use DHCP relay later.


Connect a Logical Switch to an NSX Edge

You can add a logical switch to an Interface on an Edge services Gateway, but then you would not get the benefits of using the logical routers.  You would basically force all traffic through a North/South device and result in some inefficient traffic patterns.  You can use a Logical switch as a transit network between your ESG and your DLR.


To start, go to NSX vCenter Plugin -> NSX Edges

1. Go to the Edges, Double Click on the DLR in this case.  A logical switch can also be attached to an ESG




2. Select your ESG or DLR.


3. Click the green ‘+’ to configure a new interface.  A DLR can have up to 999 Interfaces and 1 uplink.  An Edge Gateway can have 1 Uplink and 9 interfaces.   

  • Select Internal for an Interface

  • Click on the change link and select your network

  • Click the green ’+’ to add an IP address.  This will end up being your default gateway for your virtual machines on this logical network.

  • Click ok



Nice and easy.  You now have a Distributed Logical router attached to a logical network.  Now 1 thing to note here.   You have created a network segment that is isolated from any other network traffic and you have not CHANGED the physical network topology at all or even made ANY changes in the physical world.  



Deploy services on a logical network


I am not sure what they mean by deploying services here.   Again a Logical switch is an L2 object.  I assume it means configuring NATs, Firewalls and load balancers.  That will be covered later.



Connect/Disconnect Virtual Machines

Ok, you have a logical network, a logical router, a default gateway and an IP range.  Now to make your brand new logical network do some work.   Let’s attach some VMs to it.


To add a VM to a logical switch you can either edit the VM and point the NIC to the proper DVPortGroup using the standard UI  or use the logical switch manager.   The logical switch manager is probably a better route mainly because it’s easier to identify the Logical switch you are working with.  The Standard method from the DVSwitch can have a long list of objects to choose from and induce user error.


Add a VM to a logical switch


1. From the logical switch manager, select your switch and Click the add VM icon



2. Select your VM. Doubleclick to move the VM to the Right. Click next


3. Select the NIC



4. Click finish


Test logical switch connectivity  


Once you have a VM or 2 on the logical switch you now should be able to ping other hosts on the network.   Move them between your ESX hosts and make sure you can continue to ping.  If Ping fails when you move a VM from one host to another you may have a configuration error with your vTEPs.