Gary Middleton, business development manager – Global Network Integration at Dimension Data looks at virtualizing the network

Data centre networking is a current industry hot topic, receiving significant focus from businesses, vendors and the market in general. In fact, leading industry analysts have calculated that organisations spent a staggering $10.4B on data centre networking during 2009 and predict that this will increase and overtake spending on servers by 2013.

Virtualisation is one of the key technology trends driving this spend. By running multiple machines on a single physical server, organisations can enjoy increased utilisation and simplified processes while reaping the rewards of operational and capital cost reductions. However, without a robust, high-speed network at its core, the data centre cannot evolve to a point where it can effectively support virtualisation, rendering cloud computing out of reach.  This is forcing organisations to re-examine the networks in their data centres.

The first step in enabling the data centre network (DCN) to support virtualisation is to create a foundation for the DCN by re-architecting the server-side network. The most important aspect of this re-architecture is upgrading the bandwidth of the network to 10Gbps (Gigabits per second) in order to cope with virtualisation and other demands that will be placed on it. Within cloud computing architectures, the need for strong data centre networking is even more important because when you bring external service providers into the equation, the network connecting the service provider to the user needs to be flawless.

Virtual machine (VM) switching technology should also be included in this re-architecture - to bring the virtual world closer to the network by extending the network edge to the VM - as well as top of rack switching techniques that can significantly increase data centre network flexibility and deliver cost savings in the form of reduced cabling. Deploying VM switching enables consistent network management across the entire network and a true separation of network management from server and virtual server management.

Another critical component of upgrading data centre networking for virtualisation is re-addressing key network services. Every piece of IT infrastructure relies on network services to function:  if they fail, all IT systems will come to a stop. Building network services that can scale with the growth of the network and the number of IP addresses, but that are also agile enough to cope with virtualisation, is an important step. For example, VMs can be provisioned in a few minutes, but getting an IP address allocated for that VM can take 30 – 40 minutes, and often much longer. This management gap needs to be reduced so that the network services can fully support an agile IT infrastructure based on virtualisation.

Application delivery technologies also provide important functions - acceleration, availability and security - and any successful virtualisation project needs to take this into consideration. These devices improve the user’s experience when connecting to applications by accelerating, caching and compressing IP traffic.  They are also able to load balance across multiple servers and VMs (even when they are in different data centres in different locations) and so ensure that the applications are always available and that there is sufficient capacity for them to run without delays and failures. What’s more, these devices are able to look deep into the application transactions and provide a level of security that traditional products are not able to provide.
As the server-side network becomes the platform for the converged data centre network, it becomes possible to take advantage of convergence and collapse the storage network on the traditional ethernet network. A unified fabric - by which technology vendors mean the convergence of the computing and storage traffic onto a single network - can be achieved when the organisation has a strong network foundation in place based on 10Gbps that can handle the additional traffic load
that storage will introduce, and a network that supports Fibre Channel over Ethernet (FCoE).

If you are now wondering about the effort required, the economic rationale for creating a virtualisation-ready data centre network is truly compelling.  The reduction of network devices, server racks, network cards and cabling can realise capital savings of around 50%. A less complicated infrastructure - entailing simpler, cheaper management - will enable significant operational savings - fewer devices mean lower maintenance and software licensing expenses, while around a 30% reduction in power consumption leads to dramatically reduced energy costs and a greener corporate conscience.