eG Monitoring
 

Measures reported by CtxNsVlanTest

A NetScaler appliance supports Layer 2 port and IEEE 802.1q tagged VLANs. VLAN configurations are useful when you need to restrict traffic to certain groups of stations. You can configure a network interface as a part of multiple VLANs by using IEEE 802.1q tagging. You can configure VLANs and bind them to IP subnets. The NetScaler then performs IP forwarding between these VLANs (if it is configured as the default router for the hosts on these subnets).

The NetScaler supports the following types of VLANs:

  • Port-Based VLANs: The membership of a port-based VLAN is defined by a set of network interfaces that share a common, exclusive Layer 2 broadcast domain. You can configure multiple port-based VLANs. By default, all network interfaces on the NetScaler are members of VLAN 1. If you apply 802.1q tagging to the port, the network interface belongs to a port-based VLAN. Layer 2 traffic is bridged within a port-based VLAN, and Layer 2 broadcasts are sent to all members of the VLAN if Layer 2 mode is enabled. When you add an untagged network interface as a member of a new VLAN, it is removed from its current VLAN.
  • Default VLAN: By default, the network interfaces on the NetScaler are included in a single, port-based VLAN as untagged network interfaces. This VLAN is the default VLAN. It has a VLAN ID (VID) of 1. This VLAN exists permanently. It cannot be deleted, and its VID cannot be changed. When you add a network interface to a to a different VLAN as an untagged member, the network interface is automatically removed from the default VLAN. If you unbind a network interface from its current port-based VLAN, it is added to the default VLAN again.
  • Tagged VLANs: 802.1q tagging (defined in the IEEE 802.1q standard) allows a networking device (such as the NetScaler) to add information to a frame at Layer 2 to identify the VLAN membership of the frame. Tagging allows network environments to have VLANs that span multiple devices. A device that receives the packet reads the tag and recognizes the VLAN to which the frame belongs.

By continuously tracking the traffic over the VLANs, you can quickly identify the VLAN that is handling the maximum traffic. The CtxNsVlanTest test does just that.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Data_received Indicates the amount of data received over this VLAN during the last measurement period. MB Compare the value of these measures across VLANs to identify the VLAN that is experiencing the maximum traffic.
Data_transmitted Indicates the amount of data transmitted over this VLAN during the last measurement period. MB
Packets_received Indicates the number of packets received over this VLAN during the last measurement period. Number Compare the value of these measures across VLANs to identify the VLAN that is experiencing the maximum traffic.
Packets_transmitted Indicates the number of packets that were transmitted over this VLAN since the last measurement period. Number
Broadcast_pkts_sent_recv Indicates the total broadcast packets that were sent and received on this VLAN during the last measurement period. Number  
Packets_dropped Indicates the number of inbound packets that were dropped upon reception by this VLAN during the last measurement period. Number Ideally, the value of this measure should be zero.