RX Drops Variable for Traffic on a NetScaler Appliance Interface
Article ID: CTX125544
Updated On:
Description
This document contains information about the RX Drops Variable for the traffic on a NetScaler appliance interface.
The RX Drops Variable for the Traffic on a NetScaler Appliance Interface
When you display the statistics for the network interfaces of a NetScaler appliance, the value of RX Drops variable might reflect a large amount of traffic being dropped by the appliance, as shown in the following screen shot:
By default, the Layer 2 (L2) mode is disabled on the NetScaler appliance. This causes the appliance to drop packets that are not destined for its Media Access Control (MAC) address or packets tagged for a virtual Local Area Network (VLAN) that you have not bound to an interface. This includes but not limited to the following traffic types:
- The Bridge Protocol Data Units from IEEE Spanning Tree Protocol are dropped. This can be a concern because these packets are used to detect the L2 loops. As a result, it is critical to ensure that the appliance in the L2 mode does not create a switching loop in its environment before enabling the mode.
- The broadcast messages that are received on an interface associated with a VLAN is not forwarded to non-VLAN fixed interfaces.
- The ICMP and UDP traffic exceeding the value set for Packet Rate filters are dropped. This is as per the design of the NetScaler software.
- The packets with bad checksum are dropped.
In a high availability setup of the NetScaler appliances, the secondary appliance processes only IP packets with Destination IP as NetScaler IP (NSIP) address, Destination MAC as the MAC address of NetScaler appliance, and the Address Resolution Protocol (ARP) packets that have the target IP as NSIP. The NetScaler appliance drops all other traffic. The secondary appliance does bridge or route packets.
The following table lists the handling of various traffic on a NetScaler appliance under different conditions:
|
L2 Mode |
L3 Mode |
NetScaler MAC and NetScaler Owned IP |
NetScaler MAC and Non-NetScaler IP |
Non-NetScaler MAC |
|
ON |
ON |
Process |
Route |
Bridge |
|
OFF |
ON |
Process |
Route |
Drop |
|
ON |
OFF |
Process |
Drop |
Bridge |
|
OFF |
OFF |
Process |
Drop |
Drop |
Note: If the RX Drop counter does not increment and you are unable to determine the cause for the same, contact Citrix Technical Support for further assistance.
Issue/Introduction
