{
  "port": 2126,
  "protocol": "tcp",
  "service": "PacketCable COPS",
  "oneLiner": "COPS signalling between a cable operator's call server and its CMTS to authorize per-call QoS.",
  "whatItIs": "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.",
  "exposure": {
    "verdict": "never",
    "note": "Anything that can talk COPS to a CMTS can influence which sessions get authorized bandwidth. Keep it on the operator's internal signalling network."
  },
  "checkCommand": "nc -vz TARGET 2126",
  "links": [
    {
      "title": "RFC 2748 — The COPS (Common Open Policy Service) Protocol",
      "url": "https://www.rfc-editor.org/rfc/rfc2748.html",
      "kind": "spec"
    },
    {
      "title": "IANA Service Name and Transport Protocol Port Number Registry",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml",
      "kind": "iana"
    }
  ]
}