Cost savings? Is SD-WAN so straightforward?
Saving investment on WAN is very attractive for enterprises. Software defined wide area network (SD-WAN) can provide a convincing return on investment.
Expensive, low bandwidth private WAN lines can be replaced by cheap, high bandwidth public network lines, while achieving the same quality of experience and security requirements for business applications. This is the commitment of the "market architect", but from a financial point of view, is SD-WAN so straightforward?
As for this question, IT will tell you "It depends" just like answering other questions. Let's discuss several factors that need to be considered when evaluating SD-WAN. Purchasing SD-WAN is not simply using cheaper lines.
Manipulating data flow WAN optimization, which is used by many companies, can manipulate data flow, thus giving full play to the performance of delay sensitive protocols. Using compression, de duplication, application proxy, tokenization, caching and related technologies, WAN optimization can make data walking on the WAN feel like walking on the LAN. SD-WAN and WAN optimization are not the same, and SD-WAN does not evolve from WAN optimization, as analysts say. They are different but obviously related technologies. Enterprises need to consider these two technologies and their potential integration problems.
A possible integration scenario is to transfer the optimized data stream from the WAN optimization device to the SD-WAN device. However, if the SD-WAN device cannot recognize the type of traffic optimized by the WAN optimized device, it will not know how to upload data to the WAN on the basis of meeting the business policy requirements. What you will finally get is to transmit the WAN optimized traffic on the suboptimal path.
An alternative is to first pass the traffic through the SD-WAN device and then transfer it to the WAN optimization device. However, this method is structurally flawed. SD-WAN encrypts data to ensure sufficient security of transmission on the public network, but the encrypted traffic is often not well optimized. The WAN optimization device usually decrypts the encrypted traffic, optimizes it, re encrypts it, and finally transmits it to the WAN. This is feasible for HTTPS data, but I don't know whether the WAN optimization architecture can also work for the IPsec used by most SD-WAN manufacturers.
The most satisfactory combination of WAN optimization and SD-WAN is the special integrated equipment provided by the manufacturer. Although the market is developing very fast and new methods are sure to emerge, there are only two methods at present. Silver Peak's Unity SD-WAN provides an authorization function called "Boost", which adds WAN optimization to Unity to form a fully integrated program.
It is rumored that Riverbed Technology's SteelConnect device provides SD-WAN for path optimization and WAN optimization for application performance.
The bigger question is, do you actually need WAN optimization and SD-WAN? In recent years, many protocols, such as Microsoft Server Message Block, have evolved to work well without WAN optimization. It is not so useful to optimize special applications to overcome the inefficient protocol delay in front of WAN delay.
The biggest advantage of acceptable user experience in today's WAN optimization is compression and de duplication. Even so, encrypted data streams cannot be simply encrypted and de duplicated, and this type of data stream is becoming more and more common, so the advantages of WAN optimization are also diminishing.
Because Internet lines tend to be cheaper and cheaper, compared with dedicated MPLS lines, enterprises can bear the cost of increasing WAN bandwidth. In addition, SD-WAN can transmit data from more than one line at the same time, which can increase the available WAN resources. This raises the question of whether WAN optimization needs to achieve an acceptable user experience? This is a delicate question, which can only be answered by analyzing your special WAN traffic combination.
The compensation for canceling the dedicated WAN line contract in advance will affect the return on investment (ROI) of the SD-WAN project. This is a problem that enterprises cannot ignore. The enterprise must postpone the SD-WAN project until it has capital investment, unless the operating cost of the project is very, very low. You can use this type of project as a tool to negotiate with service providers. Even if you already have an existing contract, you can also get a new contract to reduce the price or provide new services. Your sales representative would rather keep you in the dark than lose you completely. Use it as your advantage, tell them frankly what you need to consider, and use it to get what you think is worth.
Some organizational structures will deliver IT services through contracts and service level agreements (SLAs), which may challenge the adoption of SD-WAN solutions. If the performance of all Internet lines at a specific SD-WAN site is poor, you may miss the previous SLA guarantee. Generally speaking, there is no service guarantee for Internet lines. In fact, you may encounter the same SLA problem in the scenario of dedicated WAN lines. The difference is that in the case of only Internet lines, if you do not meet your SLA commitments, then you have no room to transfer responsibilities. If the line is online and usable, then this is all you can expect. In the case of a dedicated WAN, you can contact technical support or your account manager to help you solve the problem.
Being tied to an SLA If you are already tied to an SLA, that doesn't mean you don't need to consider SD-WAN. Instead, you should keep some dedicated WAN lines with strict quality assurance as part of the entire SD-WAN design. SD-WAN manufacturers may make mistakes in the overall scheme of internet-as-WAN, but you don't need this.
In SD-WAN design, it must be understood that each SD-WAN forwarding device needs to include at least two Internet lines for selection. Therefore, in order to maximize the service quality of the private WAN on the public network, it is necessary to connect at least two Internet lines at each site. Ideally, the lines are from different vendors. This will make your SD-WAN design more practical and can better support your SLA needs.
If you are a public cloud user, some SD-WAN products can access cloud services by forwarding traffic to the most efficient Internet line, thus improving the performance of cloud based applications. Manufacturers like Riverbed and VeloCloud focus on this area. They can provide SD-WAN gateways co located at important cloud providers.
But not all SD-WAN products can provide valuable functions for public cloud services, so if this is important for your application performance portfolio, you need to study which enterprises provide the functions you need.
Finally, you also need to consider SD-WAN providers and market conditions.
