Cloudy Skies Bring Heavy Traffic to Buienradar’s Weather Websites

• 应用基础设施与中间件 - API 集成与管理
• 网络安全和隐私 - 网络安全
• 平台即服务 (PaaS) - 连接平台

• 商业运营

• 系统集成

Buienradar’s network was split across a primary and secondary data center, each with a cluster of web servers connected using carrier-grade routers and switches. The network traffic, mainly HTTP, was spread across the servers using load balancers. However, the relatively low performance numbers of the company’s legacy load balancers meant they had to be deployed in Direct Server Return (DSR) mode, causing server responses to bypass the load balancer and disabling many advanced features. When the legacy load balancers reached end of life, Buienradar sought a more robust replacement. Additionally, Buienradar needed a new generation server load balancer capable of providing Global Server Load Balancing (GSLB) to handle their distributed network with geographically separate data centers. Another criterion was the impending depletion of IPv4 addresses, necessitating readiness for IPv6 clients.

Buienradar is a Dutch website that provides real-time, radar-based weather information for the Netherlands and other parts of Europe. The website, www.buienradar.nl, allows users to monitor rainfall conditions by entering a location, generating a rainfall map of the desired region. It is among the most popular websites in the Netherlands and is the number one site for weather-related information. The site receives approximately 5 million unique visitors per month, with spikes up to 15 million during severe weather. The website handles between 4–5 Gbps of sustained traffic, even during mild weather. The Netherlands' low-lying geography and elaborate system of levees and dams make weather reports crucial for the local populace, with more than 20 percent residing on land below sea level.

Buienradar chose to install the A10 Application Delivery Controllers (ADC) for several reasons. Firstly, the A10 ADCs provided IPv6 support, enabling Buienradar to meet its goal of having its sites ready for “World IPv6 Day” on June 8th, 2011. The A10 ADCs can utilize Server Load Balancing–Protocol Translation (SLB-PT), acting as an IPv4/IPv6 gateway, and support native IPv6 for an end-to-end IPv6 network. Secondly, the A10 ADCs offered GSLB support, essential for Buienradar’s two separate data centers to ensure client requests are routed to the closest data center. The GSLB feature can direct user requests based on response times for ping or DNS requests or integrate with geo-location services. Lastly, the DNS Application Firewall feature ensured the availability of critical DNS infrastructure by allowing legitimate DNS protocol traffic while denying non-DNS traffic, reducing the load on backend servers by up to 70 percent.

• The A10 ADCs enabled Buienradar to deploy in Routed mode instead of DSR mode, giving greater control of traffic returning to clients and leveraging advanced features on outbound traffic.
• Enhanced security for web and DNS servers was achieved, sparing Buienradar the cost and complexity of installing and managing a separate, dedicated firewall solution.
• The A10 ADCs provided an affordable solution with maximum throughput for periods of heavy traffic, allowing the website to handle peak loads during severe weather effortlessly.

• The A10 ADC offers 10 Gbps throughput capacity.
• 64-bit scalability enables support for tens of millions of concurrent sessions.
• The DNS Application Firewall feature can reduce the load on backend servers by up to 70 percent.