This read-write integer sets the Compliant Burst Size, in cells, used by UPC policing for VBR and ABR connections, controlling how large a traffic burst above the sustained rate the connection is allowed before being policed, and defaults to 1024 on MGX release 3.0.0.0 and above. Admins increase this for connections expected to send bursty traffic that would otherwise be penalized by strict rate policing. For example, an admin provisioning a VBR connection for bursty file-transfer traffic might raise ingrUpcCBS above the 1024 default to better tolerate its burst pattern without triggering discards.