SDN for Cloud IT

This is the second article in a series of four dealing with software-defined networking (SDN). My first article discussed Cloud IT. Now I’ll focus on necessary changes for business agility. And that begins with two worlds that haven’t always seen eye-to-eye: the worlds of IT (applications) and IP (network).

These two specialist disciplines may reside in the same organization, but there has long been animosity between them and misunderstanding of the dark arts each does. It manifests itself in the day-to-day interactions. I’m sure you have heard office comments like “this application is slow, must be the network” or ”it’s not the network, the application was upgraded last night”.

A lot of this animosity comes from the different languages these two teams talk. The base vocabulary is the same but the nuances in dialect create the divide. Application developers talk of domains, tiers, hosts and users, whereas network teams talk of IP subnets, addresses, control lists, VLAN tags and routes.  The constructs are similar but the terminology can lead to frustration as the IT team works out how and where to push their application data onto the network and the network team responds to create the network configurations to get the application traffic to the end users.

So how does the SDN mindset change this? Well it starts with understanding the purpose of the network. It’s there to link the business information to the business information consumers, be they customers, partners or employees. And this is where the implementation of the right SDN can improve the situation using two key principles: Abstraction and Automation.

Abstraction:  With SDN a shift in the way applications interact with the network can be made from the ”lost in translation…“ process of today -- where applications are forced to deal with the network implementation detail --  to an IT-friendly design of network services based on a simple IT language for defining the network that the application needs. 

Automation: The second principle that aligns closely to abstraction is automation. This is a rethinking of how network services are activated -- and a move from a configuration driven approach with layers of operational complexity to a policy-based auto-instantiation model where network services are instantiated using defined business (information security) and network policies the instant an application is deployed. 

With these two principles in place with SDN, your networks can be freed up to follow the dynamic nature of Cloud IT. How do I know this? Well these principles are well entrenched in the large networks we use everyday from telecommunication service providers.

Think about your smartphone. Let’s say you jump on a plane in Melbourne for business in New Zealand. When you land you turn on the handset and within minutes your voice messages, emails, social media updates etc. start flowing in. How so?

The world’s mobile networks communicate with each other to exchange information so they can make an informed decision on authorizing you on the local network and which services to permit on your handset, be that voice, data or texting. This happens in a matter of minutes due to the automation of the information exchange between the carriers and the policy-driven process of implementing pre-defined service templates.

Now imagine the alternative. You land in New Zealand, find a landline and call back to Australia to speak to your mobile operator. You tell them you are in New Zealand and ask for your calls, texts and data to be forwarded to you. That’s all doable albeit highly manual, and about the time you board the plane back to Melbourne your handset will start receiving your communications. Not a great mental image is it?

With Cloud IT, the virtual machines that host your business applications are akin to that smartphone. They should be able to use any available resources in the cloud and the network should react to their deployment and automatically instantiate the network services to make that application instantly available to its users. This is the power of SDN and its policy-driven auto-instantiation capability. That is, if you chose the right SDN.

This is great for any compute assets or applications that have been virtualized, but what about legacy IT systems or physical network functions -- physical firewalls for instance?

With the right SDN solution the policy-driven auto-instantiation of network services that incorporate non-virtualised workloads and legacy firewalls should be seamlessly integrated.

The percentage of non-virtualised assets will depend on the pace of the businesses migration to Cloud IT. But even if this percentage is low (and I think once you investigate it will be higher than you think) not being able to seamlessly integrate them into the SDN based network will hinder the overall benefit of the cloud.

For instance, if you can turn up a new application workload on virtualized compute and have the network auto-instantiated but then you need to wait a day, a few days or even a week for a manual configuration change on a firewall to allow that application to traverse your business networks, then you have negated the benefit of your investments in the cloud and SDN.

SDN really does provide an opportunity to radically rethink how you operate the networks within your business. For the past 30+ years the network has been the product. And looking ahead with Cloud IT, application delivery is the product. As needs change, so should our approach to networks.

In my next article I’ll look at some of the other networks in the business environment (yes there are more than one) -- and how SDN can be applied to drive agility and flexibility into the wide area. 

About the Author

James McInroe is Marketing Director for the Alcatel-Lucent (News - Alert) (News - Alert) (News  - Alert) Software Defined Network venture Nuage Networks.  He is focused on the key product and solution launches for network virtualization of the data center network and beyond including the launch of Virtualized Network Services (VNS), and is a frequent and popular blogger on the subject.