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Home > Success Center > Network Performance Monitor (NPM) > VLAN 4095 is displayed in reports

VLAN 4095 is displayed in reports

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Updated November 14, 2016

Overview

This article explains the condition where VLAN ID 4095 is visible in a report, even though a user has not configured it on their system (it is not visible for example in a Show Config output).

 

VLAN 4095 and VLAN 0 are both reserved VLANs across many vendor equipment. As a result, it may appear when polling VLAN information from a device.

Environment

  • All NPM versions
  • Cisco, Juniper, ESX

Detail

It is possible to filter the VLAN to exclude it from a report, whether in Web Reports or Report Writer. It is also possible to exclude the VLAN from the database through SQL.

  1. Go to Node Details > List Resources.
  2. If the VLAN is shown, clear the selection.

 

Alternative solution

  1. Click Edit on the List of VLANs resource.
  2. If a filter option is available, add a filter where VLAN <> 4095. Otherwise, click Edit and create a Feature request to allow filters in the List of VLANs resource.

 

Workaround
Build a SQL report for all VLANs, excluding VLAN 4095 and turn this report into a web resource.

Notes:

  • Vendors reserve 4095 for VLANs, For example, Cisco reserves VLAN 1 (in addition to VLANs 0 and 4095).
  • VLAN identifier (VID) is a 12-bit field specifying the VLAN to which the frame belongs. The hexadecimal values 0x000 and 0xFFF are reserved.
  • The reserved value 0x000 indicates that the frame does not carry a VLAN ID. In this case, the 802.1Q tag specifies only a priority and is referred to as a priority tag.
  • The ID value 0xFFF is reserved for implementation use. It must not be configured or transmitted. It can be used to indicate a wildcard match in management operations or filtering databse entries.
  • On bridges, VID 0x001 (the default VLAN ID) is often reserved for management VLAN. This is vendor-specific.
  • All other values may be used as VIDs, allowing up to 4,094 VLANs.

    Example:

 

 

 

Last modified
18:00, 13 Nov 2016

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