SNMP Walker

SNMP Walker

ID: uniflow.plugin.snmpwalker Category: IT Infrastructure Version: v1.2.0 Min Uniflow Version: Uniflow ≥ v1.4.0

SNMP Walker Plugin Reference Manual

1. Overview

Plugin Name: SNMP Walker

Type: IT Infrastructure

Identifier: uniflow.plugin.snmpwalker

Description

Poll SNMP devices and listen for traps.


2. Technical Architecture

The SNMP Walker plugin operates as an SNMP manager and MIB walker client over UDP. It executes single GET queries, GET-NEXT iterations, and GET-BULK walks across target network device OIDs, handles SNMPv1, SNMPv2c, and SNMPv3 security credentials, and hosts an inbound trap listener socket on UDP port 162 for receiving async SNMP TRAP and INFORM packets.

System Interaction & Exposed Catalog Routes

The SNMP Walker plugin acts as an SNMP Client polling OID trees across network switches, routers, UPS devices, and PDUs. It decodes ASN.1 BER data types (Integer, OctetString, TimeTicks, Counter32/64) into Uniflow telemetry.

Catalog Routes & Node Integration

Input Event Triggers (Input Nodes):

  • snmp.oid_polled - Emitted on OID poll response arrival.
  • snmp.walk_completed - Emitted when an OID tree walk finishes.
  • snmp.device_unreachable - Timeout or unreachable host event.
  • Executable Actions (Action Nodes):

  • snmp.get_oid - Queries a specific OID value.
  • snmp.set_oid - Writes a value to an SNMP OID.
  • snmp.execute_walk - Triggers an SNMP Walk over an OID subtree.
  • Architecture Diagram

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    3. Configuration Parameters

    The following configuration fields are available in the User Interface for this plugin:

    Configuration SettingDescription
    Host / IP AddressSpecifies the host / ip address.
    UDP PortNumeric value specifying the udp port.
    Poll Interval (ms)Numeric value specifying the poll interval (ms).
    Timeout (ms)Numeric value specifying the timeout (ms).
    Retry Interval (ms)Numeric value specifying the retry interval (ms).
    SNMP VersionSpecifies the snmp version.
    Read CommunitySpecifies the read community.
    Write CommunitySpecifies the write community.
    UsernameSpecifies the username.
    Context NameSpecifies the context name.
    Auth ProtocolSpecifies the auth protocol.
    Auth PasswordSpecifies the auth password (secure).
    Privacy ProtocolSpecifies the privacy protocol.
    Privacy PasswordSpecifies the privacy password (secure).

    4. Exposed Routes & Data Types

    This plugin exposes catalog fields across the following rule graph nodes:

    Input Source

    The Input Source node reads polled remote network device MIB OID values.

    Human-Readable Field NameData TypeDescription
    Discovered / Configured OID Point  String` / `Int32` / `Int64` / `Double` / `Bool
    Telemetry value polled via SNMP GET/WALK from target network host (e.g., sysUpTime, ifInOctets).

    Output Target

    The Output Target node acts as an action sink node to issue SNMP SET operations on target device MIB OIDs.

    Target NameData TypeAssociated ParametersParameter Data TypeRequiredDescription
    Configured Writable OID Point  String` / `Int32` / `Double
    ValueString / Int32 / DoubleTrueValue payload to send via SNMP SET command.

    5. Usage Examples

    Scenario A: UPS Battery Capacity SNMP OID Polling Dispatches Email & Modbus E-Stop Relay

    Workflow Overview:

    SNMP Walker polls an APC UPS management card OID (upsAdvBatteryCapacity .1.3.6.1.4.1.318.1.1.1.2.2.1.0). When battery level drops below 20% (upsAdvBatteryCapacity < 20), Uniflow executes two actions:

    1. Sends an emergency SMTP email notification.

    2. Writes a Modbus TCP coil (Coil 5 = True) to trigger orderly load shedding.

    Rule Node Configuration:

    1. Input Source Node: SNMP Walker Poller

  • OID Target: .1.3.6.1.4.1.318.1.1.1.2.2.1.0
  • Exposed Field: upsAdvBatteryCapacity (Int32)
  • 2. Logic Filter Node: LessThan

  • Expression: upsAdvBatteryCapacity < 20
  • 3. Output Target Node A: Email Client Sender

  • Action Target: Send Email (email.send_email)
  • To: it-ops@factory.local
  • Subject: CRITICAL: UPS Battery Below 20%
  • 4. Output Target Node B: Modbus Client Writer

  • Action Target: Direct Access
  • Type: Coils
  • Address: 5
  • Value: True
  • Logic Flow Diagram:

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    Scenario B: Emergency Stop Signal Issues SNMP SET Command to Power Distribution Unit (PDU)

    Workflow Overview:

    When an emergency stop button is pressed (SIA Receiver BA burglar/emergency alarm), Uniflow issues an SNMP SET command (snmp.set_oid on OID .1.3.6.1.4.1.318.1.1.12.3.3.1.1.4.1 = 2 [Immediate Off]) to instantly cut power to server rack outlet 1 on a switched PDU.

    Rule Node Configuration:

    1. Event Input Node: SIA Receiver Listener

  • Event Code: BA
  • 2. Logic Pass-Through Node: Constant Value

  • Value: 2 (PDU Outlet Off)
  • 3. Output Target Node: SNMP Walker Writer

  • Action Target: Configured Writable OID Point (snmp.set_oid)
  • OID: .1.3.6.1.4.1.318.1.1.12.3.3.1.1.4.1
  • Value: 2
  • Logic Flow Diagram:

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    Architecture Flow Diagram — Full Preview