The advantages of SDN

When it comes to the out and out benefits of SDN, they're still very much presumptions and hopes as this area is so new. At present it's hard to fully understand how SDNs will benefit the industry as a whole, and it really depends who you speak to.

Some legacy players feel SDN is the latest of a number of networking fads, whereas others believe SDN will radicalize the whole world of networking.

There are three key areas that can be looked at at present.
• Why is it SDNs can increase efficiency by allowing users to configure a network in one go?

SDNs can increase efficiency by allowing networks to be set up very quickly and ‘virtually’. Not only that, but they can be taken back down again in just as very timely manner. Software Defined Networks offer IT Managers a much easier way to create network connections.

SDN promises efficiency savings in much the same way data centre virtualisation savings are made. Virtualising of networking will mean that a level of flexibility when setting up networks that means capacity if used only when it is needed - which is what SDN is doing, using what the true capacity is needed exactly when you need it.

• How and why do SDNs allow for greater agility and automation in network management
The whole point of virtualisation is in not needing to rely on the traditional physical networks servers and desktops. For network virtualisation for example, if we wanted to set up a network between two sites, we would need to set up physical connections in both places and program all routers and/or switches to support this connection. At best, this will take hours of reconfiguration however for the more complex scenarios this could days or even weeks. With SDNs, a programmer can set up that connection within seconds. Similarly it's also quicker to take down - something that is frequently overlooked.

This allows Network Managers and Developers alike, to set up temporary connections for short term projects, and then remove them on the completion of the venture.

For the network manager, greater automation can be provided through ring fencing. Allowances can be set up to ensure users gain access to what they need, and not to what they don't. All through the software.

One additional point with software defined networks, although it is reasonable straight forward to see who is connected to what, it is normally very difficult for the IT Team to see and understand what is being passed over the network.

This is certainly an area Riverbed does very well in with its Cascade offering, whereas even the data being passed over the virtual network to virtual servers can still be monitored and interrogated to see what applications are going through the SDN tunnel.

• How Virtualising the network through SDNs could be the key to private cloud success

The whole concept of a private cloud is this idea that it is very scalable, elastic and is paid for on a flexible OPEX model – "pay-as-you-go".

The traditional method for the enterprise to connect to the public cloud would be via internet, via a leaded line or VPN connection provided by their telecom provider (paid a fixed rate, likely to be in the thousands, for the extra bandwidth). And this is going to incur a charge whether the enterprise is using it or not; thus contrary to the whole cloud model.

SDN proposes a virtual network connection that can be brought into and out of service rapidly. Clearly this makes a lot more sense than a nailed down, always on, offer from traditional solutions." And a clearer fit with the whole concept of Cloud.