In vSphere 5.1 and earlier version of VMware vSphere there was only one single TCP/IP stack for all the traffic types such as management, vMotion and virtual machine traffic. Because of this common TCP/IP stack method all the configured vmkernels had to use some common parameters like, same default gateway, memory heap, ARP and routing tables. This was a limitation of this edition and it ended up some common issues.
As a result of finding solutions for those issues VMware allowed to create multiple TCP/IP stacks with vSphere 5.5. After releasing the vSphere 6.5 VMware created a separate TCP/IP stack for vMotion and provisioning traffic other than the default stack. But still there is no option in the GUI to create a custom TCP/IP stack and we need to use the esxcli commands in the command line interface to create a custom stack. But still there are some limitations.
Let’s see how we can create a custom TCP/IP stack in VMware
Use esxcli network ip netstack list to view the available TCP/IP stacks and use esxcli network ip netstack add -N “<tcp_ip_stack_name>” to add a new TCP/IP stack
What are the Limitations?
Unfortunately, custom TCP/IP stack aren’t supported for management traffic, fault tolerance traffic, vSphere Replication and VSAN traffic. When you select a created custom TCP/IP stack traffic, those options automatically disable themselves (see below screen capture when adding a vmkernel) at this point you can use this custom TCP/IP stack only for IP based storage like iSCSI and NFS.
That’s it for now. Hope you enjoyed my post!