COPS signalling between a cable operator's call server and its CMTS to authorize per-call QoS.
IANA registers 2126 as PktCable-COPS, assigned to CableLabs. It carries the Common Open Policy Service protocol (RFC 2748) in PacketCable's Dynamic QoS architecture: the Call Management Server acts as the policy decision point and the CMTS as the policy enforcement point, and the CMTS opens gates that reserve DOCSIS bandwidth for a voice call only when the CMS authorizes it over this connection. This is operator infrastructure — you meet it inside a cable headend, not on a customer network.
Do not expose
Anything that can talk COPS to a CMTS can influence which sessions get authorized bandwidth. Keep it on the operator's internal signalling network.
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