Ravichandra Sutrave

Hi Hari, The maximum number of interfaces that can be attached to a NetScaler VPX on a public cloud platform depends on the specific instance type and the cloud provider's limitations. For AWS, we support upto 15 interfaces. This is the maximum number of interfaces among the supported instance types for Netscaler. Refer AWS document.For Azure, we support upto 8 interfaces. Refer Azure document.For GCP, we support 8 interfaces which is the maximum GCP allows. Refer GCP document.Regards, Ravi

The main issue with USIP is the reverse traffic will be directed towards client IP instead of SNIP. Hence it will not be routed to Netscaler. We need a way to route this response traffic from back-end server to Netscaler. This should work with HA no matter which instance is active. We can use the fact that the Netscaler will move all the routes pointing to previous primary to new primary in HA across AZ using private IP. We can create a route table associated with server subnet and add a route to send this traffic to Netscaler ENI. As the destination in the route will be netscaler ENI, it will be moved to new primary after failover. Even though this route is not for the CIDR outside VPC CIDR, the route will still move to new primary ENI. Tis is due to the failover logic that has been implemnted in a generic way to move any routes pointing to previous primary to new primary. Below diagram explains this before and after HA failover. We have 2 route tables: For VIP traffic in client subnet. VIP is selected in a CIDR outside the VPC CIDR. This route table is associated with client subnet. It will route all client traffic towards VIP to Netscaler ENI (ENI in cient subnet).For Response traffic from server. As USIP is used, the destination IP of response traffic will be client IP. So this route will need to route all traffic towards client IP to netscaler ENI (ENI in server subnet). This route table is associated with client subnet.After failover, both these routes (in fact any route in any route table in the same VPC) pointing towards Netscaler ENI will move to new primary after failover. Due to this generic logic of failover we don't need any extra code and existing logic will take care of this use case. We will document this in our feature documentation. References: https://docs.citrix.com/en-us/citrix-adc/current-release/networking/ip-addressing/enabling-use-source-ip-mode.html https://docs.citrix.com/en-us/citrix-adc/current-release/deploying-vpx/deploy-aws/vpx-ha-pip-different-aws-zones.html