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SD WAN Overview

Where is SD WAN going?

The utopian vision for a complete SD WAN solution would be a single interface that combined your SD WAN CPE with the various underlay providers and networks, that also integrates into the ticketing platform for assurance. You would be able to monitor and control not only your SD WAN CPE but further into the network to be able to measure application performance and diagnose any issues. You’d be able to place an order at the start of the process and see it accurately reflected on you bill at the end. 

We may be some way off this dream. At present the SD WAN management function is fairly simple; the central controller just needs to be able to communicate with the SD WAN CPE and as every SD WAN CPE company has their own controller this is a given. When we expand the requirements to other components and systems we can see that there is a major piece of work to combine this eco-system. 

SD WAN makes promises that you can change your bandwidth in an instant. Well if your central controller doesn’t control the underlay and the overlay then this isn’t possible.

In the future there may also need to be a different commercial model from the carriers and their third party tail providers. At present with most carriers the commercial model is based around fixed monthly pricing for an agreed speed on a standard access bearer, for example 20Mbps on a 100Mbps bearer. If you want to change the port speed, then there is a change in the commercials so a quote needs to be supplied and an order placed. Further complications come with international MPLS as they tend to use tiered long line access circuits from third parties. To make a change to the port speed the carrier will often have to ask their third party to change their tiered access circuit before they can also make the changes to their own network.

If one of the advantages of Hybrid Networking is that you can provide your own locally sourced internet connectivity, then this makes controlling the underlay with the overlay very difficult indeed. 

However, there are moves afoot to address this interoperability. The Metro Ethernet Forum (MEF) is a non-profit industry association made up of over 200 members. MEF members include Tier 1, 2 and 3 service providers, hardware and OSS/ orchestration software providers, as well as test labs, test equipment and test software providers. MEF are maybe best known for creating standards for Metro Ethernet that international carriers could all sign up to and are now looking at SD WAN orchestration with MEF 3.0. MEF 3.0 introductory video . Having an industry standard may give rise to separate SD WAN Orchestration vendors but in the meantime companies will need to develop their own solutions with each of their chosen overlay and underlay providers.