Update features docs for v3.4

docs/features/devices-cabling.md

@@ -65,6 +65,10 @@ Each device can have an operational status, functional role, and software platfo
 
 Sometimes it is necessary to model a set of physical devices as sharing a single management plane. Perhaps the most common example of such a scenario is stackable switches. These can be modeled as virtual chassis in NetBox, with one device acting as the chassis master and the rest as members. All components of member devices will appear on the master.
 
+### Virtual Device Contexts
+
+A virtual device context (VDC) is a logical partition within a device. Each VDC operates autonomously but shares a common pool of resources. Each interface can be assigned to one or more VDCs on its device.
+
 ## Module Types & Modules
 
 Much like device types and devices, module types can instantiate discrete modules, which are hardware components installed within devices. Modules often have their own child components, which become available to the parent device. For example, when modeling a chassis-based switch with multiple line cards in NetBox, the chassis would be created (from a device type) as a device, and each of its line cards would be instantiated from a module type as a module installed in one of the device's module bays.