Prior to vSphere 5.5, did all VMkernel interfaces share a single TCP/IP stack?

Prior to vSphere 5.5, all VMkernel interfaces did indeed share a single TCP/IP stack. This means that any VMkernel Port Groups created for various services such as management, vMotion, and storage traffic utilized the same underlying network stack for their communication processes.

This unified approach simplified network configuration and management, allowing administrators to handle networking for multiple types of traffic through one consistent stack. It reduced complexity, as there was no need to configure separate stacks or manage specific settings for each service.

With the introduction of vSphere 5.5, VMware changed this architecture, allowing for multiple TCP/IP stacks. This improvement enabled better isolation and performance for different types of network traffic, particularly beneficial for high-demand environments or when different traffic types required specific handling or prioritization. However, before this revision, the sharing of a single TCP/IP stack was the standard configuration for all VMkernel interfaces.