Catalyst Unified Data Access Plane (UADP) Switches
UADP is a family of ASIC based switches hailing to 2013 with version 1.0. Cisco presents these ASICs as poster children for the value add of Cisco's craft over capabilities of merchant silicon. Here unified refers to inclusion of hardware to run the CAPWAP protocol and enhance the speed of WLAN controllers.
One of the features of UADP is that it provides for a high speed interconnect to build stacks of switches. As such, it seems to have been designed with the access layer specifically in mind.
There are five versions of UADP: 1.0, 1.1, 2.0, 2.0 XL and 3.0. This is highlighted in snipped from a white paper. Earlier Catalyst switches that preceded the UADP ASICs (3750, 2960) are listed in the Other shared memory section. These switches are very old.
UADP partitions packet memory with the largest chunk (64 percent) in a dynamic pool for burst absorption. A large chunk (25 percent) is reserved for the stacking ports with the balance dedicated to ports as a minimum allocation. Cisco white paper refers the reader to cisco.com for further details -- without any guidance where said details might be found.