AWS offers different types of web services, such as Amazon Simple Storage Services (S3), Amazon Elastic Cloud Compute (EC2), and Amazon Virtual Private Cloud (VPC). Amazon VPC allows you to run AWS resources (for example, EC2 instances) in a private, virtual network. Amazon EC2 instances are available as instance types that map to hardware archetypes on the basis of factors such as number of EC2 Compute Units (ECU), number of virtual cores, and memory size.
The NetScaler VPX AMI is packaged as an EC2 instance that is launched within an AWS VPC. The VPX AMI instance requires a minimum of 2 virtual CPUs and 2 GB of memory. An EC2 instance launched within an AWS VPC can also provide the multiple interfaces, multiple IP addresses per interface, and public and private IP addresses needed for VPX configuration. Currently, on Amazon AWS, VPX can be launched only within a VPC, because each VPX instance requires at least three IP addresses. (Although VPX on AWS can be implemented with one or two elastic network interfaces, Citrix recommends three network interfaces for a standard VPX on AWS installation.) AWS currently makes multi-IP functionality available only to instances running within an AWS VPC. A VPX instance in a VPC can be used to load balance servers running in EC2 instances.
An Amazon VPC allows you to create and control a virtual networking environment, including your own IP address range, subnets, route tables, and network gateways.
Note: By default, you can create up to 5 VPC instances per AWS region for each AWS account. You can request higher VPC limits by submitting Amazon's request form (http://aws.amazon.com/contact-us/vpc-request/).
VPX on AWS Architecture
An EC2 instance of NetScaler
VPX (AMI image) is launched within the AWS VPC. The following figure shows a typical VPX on AWS deployment.
Figure 1. VPX on AWS Architecture
The figure shows a simple topology of an AWS VPC with a NetScaler
VPX deployment. The AWS VPC has:
- A single Internet gateway to route traffic in and out of the VPC.
- Network connectivity between the Internet gateway and the Internet.
- Three subnets, one each for management, client, and server.
- Network connectivity between the Internet gateway and the two subnets (management and client).
- A single NetScaler VPX deployed within the VPC. The VPX instance has three Elastic Network Interfaces (ENIs), one attached to each subnet.