This article originally appeared in the March 2011 issue of NGN.
For many, cloud networking is abstract, associated with hosted consumer content such as Gmail and hosted enterprise applications such as Salesforce.com (News - Alert), not with the communications infrastructure. However, this over-simplification misses its essence.
Let’s start with an example – many people have washing machines, but not everyone uses them at the same time; at any given time many are idle. If we and our neighbors could magically transfer our laundry to and from a Laundromat somewhere else, we would have a much more efficient laundry system. This is unlikely to happen, since moving laundry around is complex and expensive.
Unlike laundry, however, some things can easily be moved around at almost the speed of light. The cloud concept strongly applies to digital media. Books are being replaced by e-readers. Trips to the video store are being replaced by streaming video. Given the richness, complexity, variety, and volume of this digital content, service providers and operators attempting to deliver on the promise of smarter homes for any-device-any-content-any-time, must focus on maximizing the utilization of their resources.
Distributed resources can efficiently perform processing tasks that otherwise would require provisioning each endpoint for peak utilization. The network has to find where resources (washing machines) are available, decide how best to distribute the content requiring remote processing (find available washing machine), and if necessary, figure out how to bring the processed content back to where it's needed (ensure that clothes return to their owners). These functions essentially define cloud networking.
In practice it gets more complicated, since some resources may be unavailable (washer is being repaired) or assigned to other tasks. There may be constraints on the mapping between processing elements and the content (not all washers can handle a large duvet cover), and contents (laundry) may have different priorities (I’m running out of shirts!) or need to be processed in a certain order.
Cloud networking has added significant value to providers of consumer services. Google (News - Alert) and Amazon, for example, have implemented clouds. But what about operators of broadband wireless, DSL, or cable networks? They also serve consumers, but they are typically conduits to Internet content, not the application providers. Could cloud networking benefit them too? The answer is yes.
Many services network operators offer are transparent to the end user. Counting the packets sent to and received from each user requires a network-aware device. Limiting the rate of peer-to-peer and video traffic requires an application-aware device. Filtering inappropriate content requires a destination-aware device. To apply such session-aware services in the path of traffic, operators have implemented a complex hierarchical network that includes feature-rich access routers (BRAS, CMTS, GGSN, PDN-GW, etc.), deep -packet inspection (DPI) systems, and application-level proxies such as cache servers.
Instead of leveraging resilient, self-healing routing algorithms to route packets across their networks, operators implemented static routes. This ensures that packets associated with a specific session always flow through the same set of systems, which in turn ensures consistency of services. Reliability comes almost for free with standard TCP/IP routing schemes, but operators doubled and tripled their infrastructure to ensure redundancy in case of failure in the data path.
Unlike standard routing protocols, static routes are more difficult to switch over in case of failure. Operators thus introduced VRRP protocol to switch over IP packets, STCP protocol for session control at the TCP level, application-aware load balancers to switch over traffic between application servers. They also leveraged service records in DNS to facilitate geographical distribution for further redundancy. The result is a complex, unmanageable nightmare. With video traffic exploding, bandwidth consumption increasing, competition mounting, and consumer expectations skyrocketing, the problem is getting worse by the second.
Cloud networking introduces a revolutionary paradigm. Don't think of physical servers as performing tasks, think of tasks as virtual resources. Some sessions need access to these resources, others do not. The network needs to be smart enough to recognize available resources, automatically adapt to changing conditions, and route each session through the required resources. This is exactly the definition of cloud networking. Whether the operator offers an end-user application or an intermediate in-line service, the cloud networking paradigm, implemented using grid computing and grid networking technologies, is the correct way to build a scalable, feature-rich, flexible, and robust network to serve large number of exceedingly capable devices such as smart mobile phones and multimedia devices in the smart home. Their networks are so enormously complex that if operators do not implement cloud networks soon, they will be left in a cloud of dust, far behind the successful cloud-based Internet application providers.
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Edited by Stefania Viscusi