SNMP

showstack / protocols / snmp

Also called Simple Network Management Protocol.

The long-standing network device monitoring protocol. In live entertainment it is how switches, UPSs, projectors and increasingly amplifiers and processors report status into a monitoring dashboard.

Device managementOpenIETFVerified

Management Housekeeping, no deadline

Discovery, monitoring, configuration, backups, updates. Useful, and none of it has a deadline of its own.

What kills it. Nothing kills it. That is the problem: with no deadline it has no manners, and it will happily starve everything that does have one. Putting it on a show VLAN is the commonest self-inflicted wound in the industry.

Why this one, and not what the category suggests. Monitoring. The definitive no-deadline protocol.

The four flows, and why the model is worth having →

Ports

udp/161 SNMP agent

udp/162 SNMP trap receiver

What goes wrong

SNMPv1 and v2c send the community string in clear text and are effectively unauthenticated. On a venue network reachable from anywhere, that is a real exposure; v3 exists for a reason.

Traps are fire-and-forget UDP. A trap that never arrives looks exactly like nothing having gone wrong.

Vendor MIBs are what make the data meaningful. Without the MIB you get numbered OIDs and no idea which one is the temperature.

What speaks SNMP (12)

Product	Direction	Notes
Wireshark Wireshark Foundation	in	Decodes SNMP.
Cisco Catalyst 9200 Series Cisco	bidirectional	SNMP agent and traps, the usual way a venue monitors its switches.
Cisco Catalyst 9300 Cisco	bidirectional	Monitoring.
Crestron CP4N Control System Crestron	bidirectional	Monitoring.
Evertz 5601MSC Master Sync and Clock Evertz	bidirectional	Monitoring.
Kinesys Libra Kinesys	out	Monitoring, depending on configuration.
Luminex GigaCore 16Xt Luminex Network Intelligence	out	SNMP monitoring of switch state.
Luminex GigaCore 26i Luminex Network Intelligence	bidirectional	Monitoring.
Medialon Showmaster Pro Medialon (Barco)	bidirectional	Monitoring.
NETGEAR M4250 (AV Line) NETGEAR	bidirectional	SNMP monitoring.
RTS ADAM Intercom Matrix RTS (Bosch)	bidirectional	Monitoring.
Symetrix Radius NX 12x8 Symetrix	bidirectional	Monitoring.

Typical use

Monitoring switch port status and errors on a show network
Alerting when a UPS goes to battery
Projector lamp hours and status in an installation

Sources

RFC 3411: SNMP management frameworks — IETF primary

Understand the mechanism

Show networks

Something wrong, or missing?

Known gaps on this entry: implementations. If you can source one of them, that is a ten minute pull request.

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