What To Look For When Testing China CDN Vendors

OPINION – When it comes to validating China CDN vendors, the recommended approach is to utilize an independent third party monitoring company to run a performance test. Each test entails a side-by-side comparison over a given amount of time. But, since China’s broadband infrastructure is so fragmented, the standard performance tests do not apply. Third party monitoring tools provide a very limited picture.

Author: John McIlwain, Director Product Management, CDNetworks

Here are the three most common limitations that must be considered when testing China CDN vendors

  1. The Great Divide – China’s network of state-owned ISPs has one of the world’s most well-known peering issues, causing widespread website outages and connectivity problems. Standard performance monitoring will seldom reveal how a CDN provider addresses these performance challenges because of the monitoring provider’s limited backbone presence.
  1. Geographic Limitations – In a country with 22 provinces and the fastest growth of broadband usage, there are not enough agents to indicate true website performance over such a large geography outside of the major municipalities. Unless your website visitors reside in Beijing or Shanghai, then your testing data is very limited. It’s the equivalent to making a performance decision based on the response times from New York to Los Angeles.
  1. CDN Bias – It’s the unspoken industry secret. CDNs can map their network closer to the agents of performance monitoring services by optimizing their routing scheme or by physically hosting POPs closest to those agents. While this bias is true globally, it is especially common in China and makes performance testing inaccurate.

While these pitfalls make evaluations difficult, it is not impossible. Now the question becomes how do organizations use these same performance-testing tools to achieve a fair and accurate test without hiring a hundred local China users with stop watches?

Here are some recommended best practices for performance monitoring in China:

  • The Last Mile Effect – This means utilizing a monitoring service that measures automatically from the actual end user and not the data center. This will allow one to evaluate CDN performance by overcoming the ‘CDN bias’ and can better represent a company’s geographic presence in China. The downside to last mile of course, is the variety of variables that can affect performance for each participating end user (local machine, connectivity, etc.). This is why we recommend using last mile monitoring alongside standard performance monitoring.
  • china cdnReal User Monitoring vs. Synthetic – For real-time traffic monitoring, companies such as CatchPoint, SOASTA and Cedexis provide RUM solutions that collect data directly from a user’s browser, capturing performance metrics such as bandwidth and page load times. All three can measure results in mainland China. Synthetic monitoring simulates agents sitting in datacenters, so you will want to ensure they have agents in mainland China and not just “near” China, such as Hong Kong.
  • China Based Performance Monitoring – Look at how major Chinese companies monitor their websites. com is a popular performance monitoring service for large web-based companies in China. Tingyun provides data for every metropolitan region inside China (30+ monitoring agents). On top of this, they analyze the performance against the two major ISPs in China, giving you visibility into ‘The Great Divide.’
  • Local Agent Monitoring – Similar to last mile monitoring, the local agent monitoring method actually uploads copies of the monitoring software and makes them available as monitoring agents in your local machines. If the application you are looking to accelerate is an internal application, this can address all the limitations previously mentioned.
  • Evaluate the Numbers Beyond the Graph – When using standard performance monitoring, look at the performance of individual objects for ‘connect time’, ‘1st byte time’ and ‘download time’. If the numbers for ‘connect times’ for one CDN vendor are vastly different from the other vendors, then this is a red flag that one of the CDN’s results is most likely skewed. At this point proceed with caution and cross-reference with another monitoring provider.

These testing tools and methodologies can go beyond CDN vendor testing and into your production environment for ongoing website performance measurement and alerting.

About CDNetworks and John McIlwain

John McIlwain CDNetworks
John McIlwain

CDNetworks is a global content delivery network (CDN) with fully integrated cloud security DDoS protection and web application firewall. The company accelerates more than 40,000 websites and cloud services over a network of more than 200 global PoPs in established and emerging markets including China and Southeast Asia. CDNetworks’ offices are located in Singapore, the U.S., UK, South Korea, China, and Japan.

As Director Product Management for CDNetworks, John McIlwain is responsible for analyzing market opportunities, creating products/services on schedule, and launching and managing the services to ensure they meet overall financial goals.

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