Network Communication Failure Observed When NetScaler VPX HA Pair on SDX Configured with VMACs
Article ID: CTX219266
Updated On:
Description
One way communication is observed when VMACs are used on NetScaler VPX instances on SDX pair. Pings failed and no responses seen to ARP requests.
Resolution
The behavior seen is due to the use of VMAC and sharing of LA channel combination. The LA channel is created at the SVM on each SDX appliance. The vrID is then created within the VPX configuration. With the use of VMAC, the same virtual MAC address is present on both the SDX appliances.
As an example, if VPX-1 Primary is sending a packet to VPX-2 Primary in another SDX, the NIC consults its MAC table and will see that the destination MAC is one its own virtual interfaces. So instead of sending the packet on the wire, it may forward it directly to the secondary. This can cause unpredictable behavior.
The recommendation is to remove the VMAC from the configuration.
Problem Cause
Use of VMACs on NetScaler VPX causes logical loop on XenServer.
Issue/Introduction
