The difference in environments is that this one had the interruptprocessing for each Ethernet adapter bound to a CPU on the node in which the adapter resides.
In the environments described in this article, the default Ethernet adapter interruptprocessing took place on CPUs on the first node regardless of the node where the adapter actually resided.
When an operating system is interrupted because of a hardware event (such as the presence of a packet through a network adapter), the processing begins in an interrupt.