# GETNEXT command

pysnmp.hlapi.twisted.nextCmd(snmpEngine, authData, transportTarget, contextData, *varBinds, **options)

  Performs SNMP GETNEXT query.

  Based on passed parameters, prepares SNMP GETNEXT packet (RFC 1905 Section 4.2.2) and schedules its transmission by `twisted` I/O framework at a later point of time.

  Parameters:

    - snmpEngine (`SnmpEngine`) – Class instance representing SNMP engine.

    - authData (`CommunityData` or `UsmUserData`) – Class instance representing SNMP credentials.

    - transportTarget (`UdpTransportTarget` or `Udp6TransportTarget`) – Class instance representing transport type along with SNMP peer address.

    - contextData (`ContextData`) – Class instance representing SNMP ContextEngineId and ContextName values.

    - *varBinds (`ObjectType`) – One or more class instances representing MIB variables to place into SNMP request.

  Other Parameters:

    **options –

    Request options:

    > - lookupMib - load MIB and resolve response MIB variables at the cost of slightly reduced performance. Default is True.

    > - ignoreNonIncreasingOid - continue iteration even if response MIB variables (OIDs) are not greater then request MIB variables. Be aware that setting it to True may cause infinite loop between SNMP management and agent applications. Default is False.

  Returns:

    deferred (`Deferred`) – Twisted Deferred object representing work-in-progress. User is expected to attach his own success and error callback functions to the Deferred object though `addCallbacks()` method.

  Raises:

    PySnmpError – Or its derivative indicating that an error occurred while performing SNMP operation.

  Notes

  User success callback is called with the following tuple as its first argument:

  - errorStatus (str) : True value indicates SNMP PDU error.

  - errorIndex (int) : Non-zero value refers to varBinds[errorIndex-1]

  - varBinds (tuple) :

      A sequence of sequences (e.g. 2-D array) of `ObjectType` class instances representing a table of MIB variables returned in SNMP response. Inner sequences represent table rows and ordered exactly the same as varBinds in request. Response to GETNEXT always contain a single row.

  User error callback is called with errorIndication object wrapped in `Failure` object.

  Examples

      >>> from twisted.internet.task import react
      >>> from pysnmp.hlapi.twisted import *
      >>>
      >>> def success(args):
      ...     (errorStatus, errorIndex, varBindTable) = args
      ...     print(errorStatus, errorIndex, varBindTable)
      ...
      >>> def failure(errorIndication):
      ...     print(errorIndication)
      ...
      >>> def run(reactor):
      ...     d = nextCmd(SnmpEngine(),
      ...                 CommunityData('public'),
      ...                 UdpTransportTarget(('demo.snmplabs.com', 161)),
      ...                 ContextData(),
      ...                 ObjectType(ObjectIdentity('SNMPv2-MIB', 'system'))
      ...     d.addCallback(success).addErrback(failure)
      ...     return d
      ...
      >>> react(run)
      (0, 0, [[ObjectType(ObjectIdentity(ObjectName('1.3.6.1.2.1.1.1.0')), DisplayString('SunOS zeus.snmplabs.com 4.1.3_U1 1 sun4m'))]])
      >>>