IDG\nSoftware-defined WAN (SD-WAN) technology is sweeping across the industry, growing from an emerging technology in 2017 to become mainstream in 2018.\nResearch firm IDC predicts SD-WAN revenues will hit $2.3 billion in 2018, growing 69% on a compound annual growth rate to reach more than $8 billion by 2021. \u201c2017 saw a lot of early adopters of SD-WAN that were limited to maybe two or three sites,\u201d says IDC networking analyst Brad Casemore. \u201cNow, rollouts are getting a lot bigger; we\u2019re starting to see hockey-stick inflection point.\u201d\n+ MORE AT NETWORK WORLD: SD-WAN: What it is and why you\u2019ll use it one day +\nAnd experts say as SD-WAN deployments become ubiquitous for organizations with branch and remote offices, more big changes will accompany it.\n\u201cWe\u2019re moving from SD-WAN 1.0 to a 2.0 phase,\u201d explains Lee Doyle of Doyle Research. SD-WAN 1.0 was all about hybrid WAN; aggregating MPLS and Internet connections to reduce bandwidth costs and increase performance. \u201cSD-WAN 2.0 is all about multi-tenancy, improving the management and monitoring and better security.\u201d Doyle says SD-WAN 2.0 moves beyond just the WAN toward an entire software-defined branch.\nWhat is a SD-Branch?\nDoyle says WAN virtualization technology will soon mean organizations do not need branch router infrastructure. IP\/VPN, firewalls and Internet connections will be aggregated into software, reducing \u2013 if not replacing \u2013 the need for hardware in the branch office. \u201cSD-WAN vendors are rapidly adding capabilities into the software,\u201d Doyle says.\nOne of the biggest trends to watch for in 2018 will be further integration of security services in SD-WAN environments, says Casemore. ZScaler and Websense are software-based security platforms that have both partnered with SD-WAN vendors including Viptela, VeloCloud, Riverbed and Talari, among others.\nSD-WAN has seen the most pickup in enterprises with a lot of locations, such as banks and retail businesses. Capital One \u2013 one of the 10 largest banks in the U.S. with 45 million customer accounts \u2013 has more than 700 branch offices, each of which need a reliable Internet connection. The bank has transitioned in recent years to offer non-traditional banking centers in the form of caf\u00e9s that encourage customers to browse the Internet while doing their banking. \u201cNow, if our Wi-Fi is down, then the customer can\u2019t bank with us,\u201d says Jason Abfalter, director of technology for Capital One\u2019s retail and direct banking division. \u201cThe network needs to be always-up and secure.\u201d\nThis use case led Capital One to begin a massive SD-WAN deployment across the company\u2019s network. Capital One is able to segregate a reliable, multi-band Wi-Fi connection for customers from the secure traffic conducting back-end official banking duties. Abfalter says as the deployments ramp up in 2018, he\u2019s looking to further integrate security tools like URL filtering and firewall capabilities into the SD-WAN software.\nMobile backup in SD-WAN\nIncorporating mobile connectivity as a backup in SD-WAN is expected to be another major advancement in the market in 2018, Doyle says. Large corporations already have data plans from a cellular provider, and in some cases they\u2019re able to pool data across the organization and use cellular connection as a backup to broadband connections in a fail-over situation. All this can be managed by SD-WAN software deployed in the branch. Doyle says as prices for LTE and 4G continue to drop, this option will become an expanded use case.