Normally, cloud computing services and applications are delivered to users through an Internet connection. This is one of the pillars of cloud computing, making it distributed, accessible and affordable from wherever and, increasingly, via various wireless devices. But what about organizations that want something more than a “best effort” service delivery through the Internet?
Well, obviously there are several alternatives, including managed networks, e.g. MPLS, ATM and, in the future, many other types of virtual networks that run across multiple physical networks or substrates.
But then there is the possibility of Content Delivery Network or CDNs like Akamai and Limelight Networks, which promise a better than best effort service or content delivery. Although the CDNs use in fact the Internet as the mechanism for carrying traffic, they strategically distribute replication servers (sometimes called Surrogates) in the network that replicated content stored on a origin server or servers farms. Users accessing content from a particular server are directed to the most appropriate “surrogate” based on multiple criteria, including distance, network congestion, etc., determined by a load balancer in the network that calculates the most efficient delivery route. CDN providers use a combination of technologies to provide better than best effort service delivery, including the distributed surrogates, or caching servers, mention, but also by using different proprietary protocols/algorithms than the native Internet uses for inter-network communications, i.e. the Border Gateway Protocol, and by reducing drag caused by TCP multiple round trips to set up and tear down connections.
It is interesting to note that already some cloud providers have started to integrate CDNs into their products offering. This includes for example Rackspace that offers a storage solution called CloudFiles that is integrated with the Limelight CDN. Through the CDN, content can be distributed, cached and shared in edge locations throughout the world – so that users gain access to content from a nearby surrogate.
It will be interesting to follow this trend as see if and how more and more cloud service providers will integrate CDNs to their service offerings.
Long-distance interconnections (WAN and MAN) between data centers are obviously based on IP standards (over ATM, Ethernet, SONET/SDH) and, more recently, on MPLS with QoS and native interconnection capabilities. For high bandwidth and ultra-low latency, 
This is not surprising. Quality of service delivery in the Cloud is intrinsically integrated with the network, its infrastructure and capacity. As migration to the Cloud continues, network operators face increasing challenges of upgrading the network infrastructure. This includes fixed infrastructure, including last-mile and first-mile as well as mobile networks like 3G and 4G. Many operators are already challenged with current unsatisfactory ROI – mainly due to flat pricing structures and “all-you-can-eat” data packages. How operators can justify increased investments in network infrastructure without changing pricing models remains difficult to see – unless they are, perhaps, also the Cloud provider themselves.
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