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  1. Observium
  2. OBS-5295

Juniper EX2300 tagged VLAN ports not mapped from Q-BRIDGE-MIB

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Details

    • Bug
    • Resolution: Fixed
    • Major
    • None
    • None
    • Discovery
    • None
    • Observium Community Edition 26.1.14545
      Ubuntu 22.04
      Juniper EX2300-24T
      Junos 23.4R2-S7.4
      SNMPv3 authPriv

    Description

      Observium correctly discovers the VLANs on a Juniper EX2300-24T, but tagged trunk port membership is not mapped correctly in the VLAN Port Matrix.

      Junos reports VLAN 100 as:

      VLAN Name: firewall-vlan
      Tag: 100
      Layer 3 interface: irb.100
      Interfaces:
          ge-0/0/22.0,tagged,trunk
          ge-0/0/23.0,tagged,trunk
      Number of interfaces: Tagged 2, Untagged 0
      

      Raw SNMP returns:

      Q-BRIDGE-MIB::dot1qVlanStaticEgressPorts.100 = STRING: "512,513"
      

      During Observium discovery with OBS_SNMP_HEX, the same value is returned as:

      dot1qVlanStaticEgressPorts.100 = "35 31 32 2C 35 31 33"
      

      which decodes to:
      512,513

      BRIDGE-MIB returns:

      dot1dBasePortIfIndex.512 = 536
      dot1dBasePortIfIndex.513 = 537
      

      These map to ge-0/0/22 and ge-0/0/23.

      In includes/discovery/vlans/q-bridge-mib.inc.php, the value is processed by:

      $binary = hex2binmap($vlan['dot1qVlanStaticEgressPorts']);
      

      This treats the value as a standard PortList bitmap. On this Junos platform, the value is instead an ASCII comma-separated list of bridge-port numbers encoded as hex.

      The result is that VLAN 100 is discovered, but Observium reports no ports assigned to it.

      I tested a local Junos-specific workaround that decodes the ASCII port list and maps the bridge-port numbers through dot1dBasePortIfIndex. After this change, the VLAN Port Matrix correctly shows VLAN 100 tagged on ge-0/0/22 and ge-0/0/23.

      This appears to be a Q-BRIDGE-MIB VLAN discovery compatibility issue with Junos on the EX2300 platform.

      Attachments

        1. ex2300-discovery-debug.txt
          334 kB
          Jason Collins
        2. ex2300-poller-debug-sanitized.txt
          970 kB
          Jason Collins

        Activity

          People

            landy Mike Stupalov
            jascol Jason Collins
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            Dates

              Created:
              Updated:
              Resolved: