Explanation: Amazon Elasticache clusters can be run in an Amazon VPC. With Amazon VPC, you can define a virtual network topology and customize the network configuration to closely resemble a traditional network that you might operate in your own datacenter. You can now take advantage of the manageability, availability and scalability benefits of Amazon ElastiCache Clusters in your own isolated network. The same functionality of Amazon ElastiCache, including automatic failure detection, recovery, scaling, auto discovery, Amazon CloudWatch metrics, and software patching, are now available in Amazon VPC.
Reference:
http://aws.amazon.com/about-aws/whats-new/2012/12/20/amazon-elastic…