Recently, there are always people in the group complaining, obviously on the high defense CDN, site access speed but like an old cow pulling a cart. I took a look at the configuration on the music - these days, really think that buying a high defense package can be a one-off ah? Last year, our team took over a financial platform project, the customer smashed the money with a well-known high-defense CDN, the results of user complaints page loading more than 8 seconds. A check found that the default configuration is not optimized according to business scenarios, the speed can be faster than the ghost.
High-defense CDN is essentially a "courier with a shield", not only to withstand DDoS attacks, but also to quickly deliver the content to the hands of users. However, the default configuration of many vendors is "defense first", speed optimization has to do it yourself. I have tested three mainstream service providers (including CDN5 and CDN07), and found that the default node allocation strategy can be worse than 40% delay. Today, we will break open the crumbs to talk about how to optimize from the node, cache, routing at three levels, so that you can both keep the security and earn back the speed.
First, pour cold water: but any program that tells you "one-click fully automated optimization" is basically an IQ tax. Speed optimization is a dynamic process, combined with business characteristics and user distribution to get. Here I directly on the dry goods, configuration cases are verified in the real environment, before copying the homework remember to replace the domain name and IP with their own.
First, node selection: do not let your traffic half circle the globe
Many people choose nodes only look at the "physical distance", in fact, the delay and link quality is the key. Last year, we optimized our cross-border e-commerce site and found that although we used CDN07's Japanese nodes, domestic users had to go through a detour to the U.S. before they could go back to Asia - the reason was that the default routing policy did not bind the operator.
Hands-on program:
1. Mandatory carrier line binding. Don't use "Auto Assign", directly specify the operator according to the main user group. For example, if there are a lot of domestic users, you can configure triple-play lines separately:
2. Enable edge computing nodes. Like CDN5's 'Edge Scripting' feature that caches dynamic content at edge nodes closer to the user. We have used this solution on the login page to reduce the API response time from 900ms to 230ms:
3. Automatic node failover. Don't rely on the CDN vendor's default health check - I've tested some vendors with up to 5 minutes between tests. Do your own redundancy at the architectural level:
Second, the caching strategy: separation of motion is not just lip service
The most outrageous configuration I've seen is caching PHP dynamic pages for 7 days, and all users see is expired data. The caching rules of a high-defense CDN must be more granular than those of an ordinary CDN, because each request must be filtered and cleaned more often.
The Golden Rule:
Last year, when optimizing a government platform, we found that although we configured caching, because we didn't distinguish the URL pattern, the policy document page was cached for 24 hours. Later, using this set of rule system, the pressure of the source station directly dropped by 70%:
Special reminder: Be sure to set up a "cache degradation" policy in a high-defense environment. Automatically switch to a static copy in the event of an attack, we had configured such a rule on CDN5:
Third, route optimization: TCP tuning parameter is the hidden barrier
The problem of 90%'s slowness actually lies in the TCP link layer. The high defense CDN because more cleaning link, TCP parameters need to be more fine-tuned. 08Host's technical director told me last year, their customers have 30% speed problems by adjusting the kernel parameters to solve.
Key adjustment points:
1. TCP Fast Open (TFO): Reduces handshake delay by three times. Measured 20% increase in first connection speed after enabling:
2. congestion control algorithm: BBR is recommended for high latency networks and CUBIC for normal networks. we have measured the data on CDN07 nodes:
3. Persistent Connection Optimization: Increase the keepalive timeout appropriately to avoid building connections frequently:
Black Tech Program: Intelligent routing scheduling. Our self-developed set of this system can choose the optimal path in real time, and helped a game company reduce cross-border latency by 40% last year:
Real-world comparison: three vendors optimization effect
We did tests with the same configured site on three CDNs (after vs. before optimization):
These data come from our internal test platform (simulating 100 concurrent requests), and actual results may vary depending on business characteristics.
Summary
High-defense CDN speed is not a simple switch a few functions, have to be carefully diagnosed like an old Chinese doctor pulse. The core to remember three points:Nodes should be accurate, caching should be precise, and routing should be stableThe most important thing to remember is that you should not believe in "fully automated optimization". Don't believe in the "fully automated optimization" nonsense - there is no one-size-fits-all solution, only the configuration that best fits the business scenario.
Finally send an egg: encounter speed problems first check the CDN console "real-time monitoring" to see whether the delay peak and traffic curve match. Last year, we relied on this to find that a vendor node in the evening peak period crazy packet loss, and finally changed the node group to solve the problem. Speed optimization is a protracted battle, keep observing and adjusting is the king.
