As you can see, several of the commands are the same as in PacketCable 1.x. The Gate Set message is used to initialize and modify gates as well as to control and update the state of a gate on the CMTS. The Gate Info message is used to query gate status, and the Gate Delete message is used to delete specific gates and their associated DOCSIS service flows. In PCMM, DOCSIS service flows and their associated gates on the CMTS are deleted via the receipt of a Gate Delete message from the PS. This is different from PC 1.x, where service flows and gates are usually deleted based on DOCSIS signaling from the MTA, and the Gate Delete message is used only under error conditions.
Notice that the Gate Allocation messages have been removed, as well as the Gate Open and Gate Close messages. Remember, the Gate Open and Gate Close messages were used by the CMTS to notify the CMS when a gate was committed or deleted. In PCMM, this functionality is rolled into the Gate Report State message, which notifies the PDP of gate changes that are not the result of a Gate Set message. One example: If a type 2 or 3 multimedia client commits its resources, the CMTS sends out a Gate Report State message to the policy server. Another example when this message would be sent is the expiration of a timer. Another use of the Gate Report State message is for notification of a gate reaching its traffic volume limit.
The PDP-Config message can be used when the COPS connection is first established. If the PDP is an Application Manager, this message contains the AMID(s) that are used by the PDP, and if the PDP is a Policy Server, this message contains the PSID(s) that are used by the PDP. This information allows a PEP to associate gate states for a PDP when the previous COPS connection is lost.
A PDP can request synchronization between its gate database and a PEP gate database by sending a Synch-Request message. Parameters such as the AMID, PSID, and Subscriber Identifier are specified in the Synch-Request as filtering criteria indicating which gate's information should be returned. A Synch-Report message is returned to the PDP for each gate matching the criteria. As you might imagine, the response to a synchronization request can consist of many responses; the PEP indicates it has finished sending responses by sending a Sync-Complete message. You find two types of synchronization requests: full and incremental. If it receives a full synchronization request, the PEP returns information for all active gates matching the filtering criteria. An incremental request returns only the information for gates whose state has recently changed. This is used in situations where the COPS connection was recently lost. When it receives an incremental synchronization request, the PEP returns information for all gates with an outstanding unconfirmed Gate-Report-State message.
The Msg-Receipt message is used by the PDP to tell the PEP that it has successfully received a message that the PEP indicated required acknowledgement. The PEP indicates it requires an acknowledgement by including the Message Receipt Key object in the message it sends to the PDP.