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  1. OpenNMS
  2. NMS-7183

LLdp link discovery: lldpRemLocalPortNum value 0




      the linkd should be able to get the lldp link from both the lldp devices.
      if you check the walk of ITPN0113 you kown that everythink is file, while cheching the
      ITPN0112 I found this information related to the lldp link to ITPN0112:

      iso.0.8802. = INTEGER: 4
      iso.0.8802. = Hex-STRING: F4 B5 2F 5E F0 80
      iso.0.8802. = INTEGER: 7
      iso.0.8802. = STRING: "623"
      iso.0.8802. = STRING: "SPO_STANISLAWIE_ROUTE11"
      iso.0.8802. = STRING: "ITPN0113"

      consider that the index lldpRemTable Entry is defined:

      lldpRemEntry OBJECT-TYPE
      SYNTAX LldpRemEntry
      MAX-ACCESS not-accessible
      STATUS current
      "Information about a particular physical network connection.
      Entries may be created and deleted in this table by the agent,
      if a physical topology discovery process is active."

      INDEX {

      { lldpRemTable 1 }

      LldpRemEntry ::= SEQUENCE {
      lldpRemTimeMark TimeFilter,
      lldpRemLocalPortNum LldpPortNumber,
      lldpRemIndex Integer32,
      lldpRemChassisIdSubtype LldpChassisIdSubtype,

      in this case we have three numbers identifying the entry.


      The second number 0 is lldpRemLocalPortNum for this entry. But and here is the point there is no "0" as identifier for LocalPortNum.

      As you can see checking the LLDP-MIB we have that the definition is..

      LldpPortNumber ::= TEXTUAL-CONVENTION
      DISPLAY-HINT "d"
      STATUS current
      "Each port contained in the chassis (that is known to the
      LLDP agent) is uniquely identified by a port number.

      A port number has no mandatory relationship to an
      InterfaceIndex object (of the interfaces MIB, IETF RFC 2863).
      If the LLDP agent is a IEEE 802.1D, IEEE 802.1Q bridge, the
      LldpPortNumber will have the same value as the dot1dBasePort
      object (defined in IETF RFC 1493) associated corresponding
      bridge port. If the system hosting LLDP agent is not an
      IEEE 802.1D or an IEEE 802.1Q bridge, the LldpPortNumber
      will have the same value as the corresponding interface's
      InterfaceIndex object.

      Port numbers should be in the range of 1 and 4096 since a
      particular port is also represented by the corresponding
      port number bit in LldpPortList."

      SYNTAX Integer32(1..4096)

      You see that the value 0 is not allowed for this case.

      So because the show lldp nei seems to have the right data I have to guess that the snmp agent put the wrong information in the lldpremotable.

      In any case I can made a check for detecting this anomaly situation and create a fix.

      Client Ticket




            rssntn67 Antonio Russo
            rssntn67 Antonio Russo
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