# WHATPORT(3918)

## NAME

port 3918 — PacketCable Multimedia COPS — The COPS channel a cable policy server uses to install QoS gates on a CMTS under PacketCable Multimedia.

Protocol: TCP  
IANA: pktcablemmcops

## DESCRIPTION

IANA registers 3918 as pktcablemmcops. In a PacketCable Multimedia deployment an application manager asks a policy server for bandwidth on a subscriber's cable modem, and the policy server pushes that decision to the CMTS as a COPS Gate-Set message; Cisco's CMTS documentation states plainly that COPS sessions on PCMM use TCP port 3918 by default. This is distinct from PacketCable DQoS, which uses a different port. You will only find 3918 inside a cable operator's network, between policy servers and CMTS routers.

## EXPOSURE

**Do not expose.** Whoever can speak COPS to this port can allocate QoS on a subscriber's service — an operator control plane that must stay inside the operator's own network.

## CHECK

```sh
nc -vz TARGET 3918
```

## SEE ALSO

- docs — [Cisco cBR — PacketCable and PacketCable Multimedia (COPS sessions on PCMM use TCP 3918)](https://www.cisco.com/c/en/us/td/docs/cable/cbr/configuration/guide/b_docsis_packetcable_pktcblmultimedia_xe17_3/pktcbl.html) (cisco.com)
- spec — [RFC 2748 — The COPS (Common Open Policy Service) Protocol](https://www.rfc-editor.org/rfc/rfc2748.html) (rfc-editor.org)
- iana — [IANA port registry — 3918 (pktcablemmcops)](https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=3918) (iana.org)

---

HTML: <https://whatport.net/3918/> · JSON: <https://whatport.net/3918.json> · full dataset: <https://whatport.net/ports.json>