Protocols

Four backends, one operation surface. Each page below covers what a protocol amounts to on these devices, what the library does with it, and the quirks worth weighing when you pick one.

• SNMP
  • Switches that speak it
  • What it can do, per switch
  • Transports
  • What is read from where
  • Vendor subtrees
  • Model identification
  • VLAN writes
  • PortList widths
  • Gotchas
  • API
• NSDP
  • Switches that speak it
  • What it can do, per switch
  • The wire format
  • What NSDP can and cannot do
  • Write authentication
  • Cross-checked against other implementations
  • Gotchas
  • API
• HTTP web UI
  • Switches that speak it
  • What it can do, per switch
  • Five web-UI protocols, not one
  • Endpoint specs
  • Reads are gated on verification
  • Gotchas
  • API
• FASTPATH CLI
  • Switches that speak it
  • What it can do, per switch
  • Three transports, one command surface
  • Two transport facts learned the hard way
  • Commands per model
  • Verification gates
  • Certificate deployment
  • Using the CLI backend
  • API

Shape of the code

Each protocol is split the same way, which is worth knowing before you read the source:

Layer	Responsibility
protocols/<name>/	Pure protocol knowledge: OIDs, packet formats, page URLs, command strings, and parsers. No I/O, no sockets — which is why almost all of it can be tested against captured bytes.
transport/	Getting bytes to and from a device: transport/sync/ and transport/aio/ for SNMP and NSDP, transport/http/ for the web UI, transport/cli/ for SSH, telnet and the serial console.
<name>_read.py / <name>_write.py	The model-driven operations, mapping a facade call to this protocol’s mechanism for this model.
virtual/faces/	The other side of the same wire: a mock switch answering the protocol for real. See The virtual switch.

The facades in src/netgear_switch/sync_api.py and src/netgear_switch/aio_api.py sit on top and choose exactly one backend per operation — see Concepts.

Choosing a backend

Backend	Best for	Watch out for
SNMP	Bulk reads, monitoring, anything scripted. The richest data source on managed switches.	Write access is often restricted, and an unauthorised request is silently dropped rather than refused.
NSDP	Plus switches, where it is one of only two options. Also discovery.	Broadcast-based, so the sending interface matters. No PoE, MAC table, LLDP or sensors.
HTTP	Reaching a switch through a firewall that only allows the web port, and PoE control on Plus switches.	Sessions expire; page sets vary widely between models. 7 distinct page dialects across this fleet.
CLI	FASTPATH switches when you want the switch’s own view, and the only route for copy scp:// certificate deployment.	One TCP round trip per command; per-port statistics need one command per port.