Hi,
In HCS, PGW interfaces with CUBE(SP) and central PSTN break-out trunks (SIP and SS7). CUBE(SP) as SIP proxy controls signaling from and to CUCM leaf clusters to PGW, and acts as a media anchoring device to control media flow between enterprises.
PGW is used as an aggregation layer for routing the calls to the PSTN and serves as a central break out (CBO) for HCS 8.6.2. PGW is installed on the Cisco Unified Computing System (UCS) platform and is deployed in active/standby mode.
At the bottom of the bullitin it reads:
"Cisco HUCS/HCS customers are requested to work with the Cisco account team for support and migration options."
Thanks