Software definition Wan (SD-WAN) It's a software defined network (SDN) It is a typical application in Wan business scenario , This kind of application is used to connect a wide range of enterprise networks 、 Data Center 、 Internet applications and cloud services .SD-WAN Inherit SDN Separation of control and forwarding 、 Centralized control, etc , Deploy software control system in Wan , Provide rapid business deployment 、 Business intelligence management and other functions , For cloudy 、 Multinets 、 The interconnection between multiple terminals provides a new solution .


A typical SD-WAN Application scenarios can be divided into three categories : One is the interconnection of enterprise branches ; Second, enterprises go to the cloud ; Third, multi cloud interconnection .


  • The typical application case of enterprise branch interconnection is that enterprises deploy edge devices in each branch , And then drain to the operator's WAN Network to achieve high performance between branch structures 、 Safe and reliable interconnection ;

  • Similarly , In the enterprise cloud scenario, the enterprise flows to the operators through the edge devices WAN The Internet , Speed up traffic into the cloud ;

  • The typical application case of multi cloud interconnection is SD-WAN Service providers build a multi cloud private network , Support access to all kinds of public cloud 、 Private cloud 、 Mixed clouds, etc , Combined with the automatic configuration and scheduling ability of network controller , Enterprise users can use the Internet to build tunnels to flexibly access the WAN , Compared with the traditional physical private line access mode , It can greatly improve the opening efficiency of WAN services 、 At the same time, reduce the cost of WAN service .


Whether it's the enterprise branch interconnection scenario , Or enterprise cloud scenarios , Or cloud connected scenarios , It means that the cloud network infrastructure is evolving in the direction of interconnection , There is no longer a relatively closed internal autonomy between cloud and network , It's a shift to a relatively open collaboration .


But at the moment, SD-WAN However, there are some problems that can not be ignored :SD-WAN Most network controllers are provided by single point operators , For the sake of their own business interests, operators will only dispatch the traffic of enterprise users to their own Wan , So enterprise users are using SD-WAN Facing the problem of single operator lock-in , To a certain extent, this restricts SD-WAN The development of .


So , We innovatively propose a new business model :SD-WAN The network controller is no longer the only one provided by the operator , It's provided by a neutral third party or multiple parties , The controller can schedule efficient and low-cost network services for users from a global perspective , Solve the problem of single operator lock-in , So that many operators can participate in the fair .


The new business model introduces the mechanism of multi-party participation , The problem of single lock-in of operators is avoided , But there are still the following problems :


(1) from SD-WAN As you can see in the architecture , To achieve agile management 、 To reduce costs, etc , With the help of SD-WAN The commercial solution of technology transforms the traditional distributed control network architecture into the centralized control network architecture , This exacerbates data tampering 、 A single point of failure 、 The problem of privacy leakage .

(2) In a multi-party business scenario , The transaction mode will support the dynamic switching of user network among many operators , But there are more uncontrollable factors in business scenarios involving multiple parties , It is difficult to guarantee the credibility of each participant and transaction , such as : Users use different operators' network services in a settlement cycle , For the specific use of network traffic, we need a clear bill , If the bill is only generated by the operator, users will not be convinced , So we need a credible billing mechanism to support . In addition, the operators are relatively equal, and one party is not allowed to control the transaction rules and process , That is, the traditional centralized platform is no longer suitable for multi-party participation 、 Application scenarios of peer autonomy .


Blockchain can establish trust between different nodes , With equal autonomy 、 Data together maintain tamper proof features , Can be in SD-WAN Blockchain technology is introduced into the solution , With the help of smart contracts , Establish a credible scheduling mechanism and mutual trust trading mode .


Trusted scheduling mechanism : It's about tradition SDWAN The controller faces a single point of failure 、 The risk that the credibility of instructions is difficult to guarantee , Regarding this , With the help of blockchain Technology , Turn scheduling strategy into smart contract , Deployed in the blockchain system , When SDWAN After the controller listens to the user's published requirements from the blockchain platform , User requirements and operator network parameters will be sorted out as input parameters to trigger scheduling policy contract , Generate decision results directly from the blockchain , Avoid the problem of unreliable single point controller scheduling .


mutual trust The trading model of : The trading mode of mutual trust can be elaborated from the following points :


(1) Point to point trading : The transaction mechanism based on blockchain can write transaction rules into smart contracts, and trigger the execution of contracts through permission control mechanism , So as to control the whole transaction process , In a scenario where multiple operators participate , After the scheduling decision results are generated , Users and operators sign contracts directly through the blockchain to establish a trading relationship , When the network quality provided by operators no longer meets the needs of users , New scheduling result generation , Users will directly sign contracts with new operators through the blockchain system to establish a trading relationship .

(2) Fund custody : Based on blockchain Technology , It can transform the fund custody agreement into a smart contract , No super permissions ,SDWAN When the control level urges the two parties to enter into a trading relationship , Automatically trigger the fund custody contract , Freeze the buyer's funds , According to the results of the transaction to set different capital transfer strategy , Both sides of the transaction trigger the execution of the smart contract with their respective authority .

(3) Reward and punishment mechanism : With the help of blockchain Technology , stay SDWAN In the business scenario, it is aimed at the operators 、 Reputation evaluation model of users, etc , Transform the credit value increase and decrease rules into an automatically executed smart contract , The business participants are included in the credit evaluation system based on smart contract , for example : When operators provide qualified network services for users , The operator's reputation will increase , When the quality of network service provided by the operator does not meet the conditions in the contract , The operator's reputation will be reduced , The operator's reputation value will account for a certain weight in the scheduling strategy , Reward and punishment mechanism contributes to the healthy development of business .


In addition, the blockchain nodes jointly maintain the data stored in the blockchain , It has the advantage of preventing tampering , Once the data is linked by consensus , Even if the consensus node exits, it will not cause data loss or invalidation . You can design this SD-WAN Business scenario retroactivity mechanism : stay SD-WAN In the business scenario ,SD-WAN The decision basis and decision instructions of the control level will be broadcast in the form of transaction 、 Stored in the blockchain system , Network traffic provided by operators can be distributed collected through blockchain , As the basis of settlement , And the tariff settlement process will also be recorded through the blockchain system . When there is a disagreement between the two sides of the transaction , The data obtained from the blockchain can be used as evidence for accountability .


Although blockchain technology is promising in SDWAN Provide a trusted solution in the business scenario of , But because of technical constraints 、 The constraints of ideas , There is still no demonstrative significance at this stage SDWAN Landing scene .


Technical constraints are mainly reflected in system stability 、 Business model support capabilities 、 Application security, etc , Most blockchains cannot satisfy at the same time “ Efficiency ”、“ De centralization ” and “ Security ” Other requirements , It is impossible to solve the triangle problem . At this stage, the transaction throughput of the blockchain 、 Block capacity 、 Trading capacity and other aspects are subject to varying degrees of restrictions , This leads to network congestion , High frequency business needs such as bank transfer 、 It's hard to meet the needs of securities trading, etc . Privacy protection 、 Smart contract loopholes 、 Consensus mechanism 、 Private key protection 、 Calculate the force ***、 Cryptography algorithm security and so on , Make the blockchain secure at the bottom 、 There are still some challenges in application security .


The concept constraint is also an important reason to limit the large-scale application of blockchain , Because blockchain technology is an emerging and disruptive high-tech technology . It is difficult for non professionals to understand the decentralization of blockchain in a short time 、 Equal autonomy 、 Data tamper proof features . This brings barriers to the popularization of blockchain technology and the exploration of application mode of business scenarios .


Blockchain technology is still being updated and iterated , Application patterns are still being explored , Complex business scenarios can reflect the characteristics of blockchain “ There is no substitute for ” The advantages of application scenarios still need to be explored , The landing of complex scenes must be supported by more secure and reliable technology . I believe that with the development of blockchain Technology , Its presence SDWAN It plays an irreplaceable role in business scenarios .