Changing the rules of data centre networking

By Cat Yong

When Dell acquired Force 10 Networks, in 2011, the data centre networking vendor could have been viewed as the final component; along side storage and compute; vital for its transformation into an enterprise solutions company today.

Mahesh Natarajan, Dell’s San Jose-based senior product manager and expert in Software Defined Networks (SDN) as well as Dell Active Fabric technology, described, “Prior to Force 10, Dell had acquired storage company Compellent, and that gives us a total of 3 classes of storage now. In Dell’s portfolio there is also a very robust server line up, and we are into our 12th generation of servers, rack-based and blade-based.

“Now with our Force 10 acquisition, we have a very compelling networking portfolio which includes our legacy PowerConnect switches.”

He further opined, “If you look at it now, Dell is now one of the leading providers of enterprise solutions for customers of all sizes, even Web 2.0 start ups.”

But besides, being the final component for their range of pre-integrated infrastructure solutions, Force 10 is also turning out to be the much needed piece that is helping Dell’s customers address current trends in data centre networking.

Fixed form factor based switches
According to Mahesh, Force 10 was one of the first companies to really change the rules of the game with respect to data centre networking.

With the advent of increasingly virtualised IT environments, self-service cloud-based consumption, and the resulting explosion of east-west data centre traffic, traditional network deployments based on large chassis-based core solutions, doesn’t cut it anymore.

Mahesh said, “There is a need for a change in the way that network infrastructure is being deployed in the data centre.”

He pointed out that Gartner had recently acknowledged Dell Force 10’s recognition of and approach to this east-west data centre traffic with fixed format switches. “These allow large horizontal scalability, is more technically elegant and more economically viable.”

Fixed form factor switches are common at the access layer, but according to Mahesh, Force 10 was one of the first to introduce the concept of a distributed fabric at the core layer, with fixed form factor switches.

“If I had a large chassis-based core with 512 ports in it, to add the 513th core, becomes a mutli-million dollar decision, and it is also disruptive to the current operations,” said Mahesh.

In contrast, the pizza box-sized fixed format switch which saves on space and power, can function as an entity by itself or be ‘stitched’ together with other fixed format switches to form a scalable fabric networking layer, that is ready to address new and demanding IT workloads.

SDN approaches
Software defined networking (SDN) came about because the way workloads are consumed has changed drastically. Not to mention a new breed of workloads have emerged also, due to trends like big data, mobility, IT-as-a-service and more.

For one, there is a more imminent need for real-time intelligence in the network.  Mahesh also observed, there needs to be a significant level of automation, as well as an amount of integration with the type of workloads that are being deployed.

More than ever before, IT is expected to be delivered from a self-service, cloud-based portal in hours if not almost real-time, and the server, storage, network components need to work in tandem to make this happen.

“Today, server resources can be deployed in a matter of minutes because of virtualisation, and storage more or less is also the same. But the biggest bottleneck has been the network.”

In its purest form, SDN is abstracting the control plane or logic out of the switch and putting it into a server. If changes are applied to this control plane in the server or controller, it will be propagated to all the other switches in the network.

The protocol or standard for this controller to talk to switches in the network is evolving to become OpenFlow.

“If you talk to many players in the industry, SDN is equivalent to this approach of controllers talking to switches, but from Dell’s point of view, this is only one way to deploy SDN, and it does not consider legacy switches without OpenFlow support,” said Mahesh, while adding that they do have switches that support OpenFlow as well as Layer 2-3 protocols.

What Dell has also done further is to support the hypervisor approach to SDN, which is to provide a tunneling capability on top of the physical networking layer. This approach is called Network Virtual Overlay (NVO), and Dell offers part of this NVO solution by way of an NVO gateway built into their switches, which allows virtual machines to communicate with the physical environment.

Dell supports two NVO specifications, one called Virtual Extensible LAN (VXLAN) created by VMware and Cisco, while the other is called Network Virtualisation Using Generic Route Encapsulation (NVGRE) which is largely backed by Microsoft.

The S600 switch which Dell recently shipped last October, incorporates the VXLAN NVO gateway as well as also OpenFlow support.

A third way Dell offers SDN solutions is by addressing legacy environments.  Mahesh explained, “Legacy deployments can still continue and still be able to have programmability, still be able to have automation.

“And for that, one of the capabilities Force 10 brought to Dell is its open automation portfolios.  This is a set of software offerings which allow for rapid configuration of switches.”

For example, Dell’s switches have capability to recognise a vMotion effect, and change the switch ports capability automatically.

“All these capabilities are available today for legacy switch deployments,” said Mahesh.

One other nifty feature is automated fabric deployment.  “Dell’s Active Fabric Manager can automate the generation of the networking architecture design, and translate that into an actual build!”

Mahesh pointed out that most management tools focus on operations of the networks, but Active Fabric Manager allows for a holistic end-to-end deployment of fabrics. Also, “If you don’t get the design right, everything else you do after that is going to be in a break-fix mode.”

How holistic
Despite being able to lay claim to being one of few vendors with a complete infrastructure offering, Mahesh is first to admit that as of today, Dell has not done any type of application-level integration like a few of their competitors have. “What we are looking at instead is specific type of workloads being deployed for example voice communications, or video on demand or Hadoop clustering… each have different needs of the network.”

Apparently, based on deep level inspection of what kind of traffic is traversing the network, the network would be able to adjust itself and provide the right level of networking capabilities based on that. “That is where we are headed with SDN,” Mahesh opined.

Mahesh shared, “Our SDN story is much more holistic and customers would choose one or more from these three options.”

He also conveyed Dell Networking’s VP of product marketing, Arpit Joshipura’s view about a new concept dubbed the software-defined enterprise (SDE). “Dell is at an advantageous position right now with servers, networks and storage portfolios. The infrastructure we offer underneath is all standards-based and interoperable with other leading vendors.

“There would be an abstraction layer for the data centre infrastructure, and if you want to deploy an application or service, the server, storage and network resources are pushed to this layer and it will talk to the underlying infrastructure. “

According to Mahesh, all this will tie into to a higher level orchestration engine like VMware’s vCloud, or Open Stack, and he revealed that a software defined enterprise controller or infrastructure controller that would bring together storage, network and server resources, is in the works and due for release early next year.

Mahesh also opined, “SDN is huge, but we are also looking at SDE. SDN will take a few years to reach maturity, and we are recommending to customers that if they use a fabric-based architecture now, the evolution to SDN would be much smoother.”