SD-WAN: Streamlining Branch Office Connectivity

Traditional WANs are expensive and complex. Enterprises can tackle the problem by extending SDN from the data center to the WAN.

Brendan Ziolo

December 4, 2015

3 Min Read
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With the advances in SDN-based private clouds, large enterprise data centers have become more agile and responsive. Yet the traditional wide area network (WAN) model of using a dedicated connection and hardware has become costly and inefficient. To experience the full power of the cloud, you need seamless connectivity that is flexible and dynamic across both domains.

In the past, enterprises purchased network connectivity such as managed IP-VPN services through a service provider. These connections were often done with proprietary hardware and the network services were tightly connected to a dedicated network infrastructure. The networking team then had to roll out routers to the branch and create a hub-and-spoke architecture using a highly manual process.

Additionally, since WAN bandwidth was so expensive, WAN managers had to try to squeeze out as much performance as possible. They had to either overbuild the network to account for peak use or reconfigure it on the fly, a costly and highly manual solution.

Software-defined wide area networking (SD-WAN) addresses these issues. SD-WAN solutions can connect branches to the head office by transforming the network into an open and programmable cloud infrastructure. Rather than the traditional hub and spoke model, enterprises can deploy a partial or fully meshed architecture and transport traffic along the most efficient path.

Enterprises benefit from SD-WAN in a couple of ways. For one, it provides the enterprise with more control over the network infrastructure while also reducing the overall capital and operational expenses. Second, it provides the enterprise with more agility and responsiveness to fully take advantage of the cloud.

These benefits come from the ability of SD-WAN to abstract the business services from the network transport. This means enterprises can offload non-mission critical or high bandwidth traffic to the most efficient and cost effective path, be it through Internet or mobile broadband. Following a policy-based approach, enterprises can augment their available bandwidth and add redundancy in case the primary IP-VPN circuit fails.

The typical WAN environment can be very complex. The “SD” part of SD-WAN lets enterprises simplify it by creating and pushing out policies to manage various parts of the network. Grouped together into templates, these policies can be deployed automatically whenever a new branch is added or an application is changed.

Policies can be set up to manage network traffic, launch new branches or set security restrictions so that everything can be controlled from a centralized location. Everything can be managed automatically from the head office instead of having dedicated teams make manual changes on site.

Setting up a new branch office becomes quick and easy with an SD-WAN approach. The enterprise can simply deliver the branch hardware via courier and local employees can plug it in. Once connected, the hardware “phones home” to be configured based on established policies.

Since enterprises are moving towards SDN in the data center, they should also consider SD-WAN in their branch offices. The key to a seamless integration between the two is to remove the network management boundaries separating them and to use a single network policy framework across both domains.

The last thing an enterprise wants to do is simply create new silos between their data center and branches. To maximize the flexibility and responsiveness of the cloud, the network needs to be just as dynamic and responsive. With a software-defined approach in both the data center and the branch, the enterprise can do just that.

About the Author(s)

Brendan Ziolo

Head of Large Enterprise Strategy, Nokia

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