Collection protocols
Overview of the protocols supported by Prelude Collector — gNMI, SNMP, NETCONF, and CLI — and how to choose between them.
Prelude Collector talks to network devices over four protocols. Each one is a transport: it connects to a device, retrieves or subscribes to data, and hands raw values to the collector's transform and output pipeline. Once the data is inside the collector, the rest of your configuration — Models, Mappings, Transforms, Snapshots, Outputs — behaves the same regardless of which protocol fetched the data.
A Device can have several Protocol records attached at the same time. Mix and match: gNMI for streaming counters, NETCONF for configuration state, SNMP for environmental sensors, CLI for the one show-command that nothing else exposes.
Supported protocols
| Protocol | Style | Typical port | Best for |
|---|---|---|---|
| gNMI | Streaming (gRPC) | 6030 / 57400 | Modern routers and switches with YANG support. Lowest overhead, sub-second freshness. |
| SNMP | Polling (UDP) | 161 | Universal vendor coverage. Counters, environmentals, anything in a MIB. |
| NETCONF | Polling (SSH) | 830 | Configuration-shaped data on devices that ship a YANG tree. |
| CLI | Polling (SSH) | 22 | Last resort — data only exposed by show commands. |
When to use which
For a full decision tree and vendor-by-vendor reality check, see Choosing a protocol. The short version:
- If the device speaks gNMI and the data lives in its YANG tree, pick gNMI.
- If you need configuration-shaped data (interfaces, policies, ACLs) structured as a YANG tree, pick NETCONF.
- If you need broad vendor coverage or the device is older, pick SNMP.
- If the data is only available in
showoutput, pick CLI and plan to maintain templates per software version.
Common building blocks
Whichever protocol you pick, the same four objects show up:
- Device — the network element.
- Protocol — credentials, port, and transport options for one device.
- Subscription — a binding between a Device and a Model that drives one collection cycle (or one continuous stream).
- Snapshot — the resulting data, published to your output backends.
For definitions of every term used on this page, see the Glossary. For a tour of how the data moves through the collector, see Data Flow.
Per-protocol references
- gNMI — streaming telemetry over gRPC.
- SNMP — polling SNMP v2c and v3.
- NETCONF — XML/YANG over SSH.
- CLI — show-command scraping over SSH with TTP templates.
For exact request and response shapes, see the API reference for Protocols.