Recently helped a friend's company to deal with a CDN billing disputes, see the billing figures I almost sprayed coffee on the screen - good guy, the monthly consumption directly soared to six figures, it turns out that their traffic bursts during the fixed bandwidth billing model. Internet business these days, if even the high defense CDN how to billing did not understand, a minute may be billed to teach people to do.
The billing method of high defense CDN is essentially a risky game between you and the vendor. Which model to choose is not only about cost, but also directly affects the business resilience and flexibility in responding to unexpected traffic. I have experienced the DDoS hit to the night of the autistic, but also seen because of the billing model to choose the wrong activities led to the collapse of the budget of the team, today will be the four mainstream billing model to break open the rubbing to speak through.
The traffic billing model is best suited for scenarios with high business volatilityThe principle is simple. The principle is very simple: how much traffic to pay how much money, like driving an electric car, running a kilometer counting a kilometer of electricity. Many startups prefer this model, after all, the initial business volume is not stable, fixed bandwidth is easy to waste resources. But don't believe the vendors' propaganda of "more favorable traffic unit price" - they won't tell you that sudden traffic may trigger the ladder price, and the unit price during the peak period may be doubled.
Having tested the traffic billing strategies of three vendors, CDN5's traffic package design is more user-friendly. They provide a traffic pool sharing feature that allows multiple domains under the same account to share traffic packages, avoiding the situation where a domain name's sudden traffic exhausts resources while other domain names have idle quota. Look at an actual configuration example:
But the pit of this model lies in the uncontrollable cost of sudden attacks. Last year, an e-commerce platform had a promotion and suffered a CC attack that caused the monthly traffic budget to run out in one day, and the final bill was 47 times higher than usual. So if you choose pure traffic billing, be sure to set up a usage warning and automatic melting mechanism.
Bandwidth billing is the true choice for stable business. Use 95 peak bandwidth billing (take the maximum value after taking the first 5% high point of the monthly bandwidth peak) or monthly maximum bandwidth billing. This model is equivalent to a monthly unlimited traffic, especially suitable for video stations, download stations and other continuous high-bandwidth scenarios. 08Host's 95 billing algorithm is fairer, they will automatically exclude the abnormal bandwidth peaks generated by the D-attacks, to avoid the user to pay for the attack traffic.
I use bandwidth billing for my own tech blog, because the number of visits is stable and has a certain base. Comparison of the actual test found that when the monthly traffic exceeds a certain threshold (usually more than 20TB), bandwidth billing than traffic billing to save more than 30% cost. However, pay attention to the vendor's "guaranteed bandwidth" clause - some vendors require a commitment to a minimum bandwidth, even if the actual usage fails to meet the commitment value to pay.
Pay-per-defense billing is a lifesaver against unexpected attacks. This model usually only charge the basic bandwidth fee, once triggered DDoS cleaning only per charge. CDN07's "defense token" mechanism is very interesting, after the purchase of the defense package is equivalent to the number of times the defense is preset, the cost of a single cleaning ranges from dozens of thousands, depending on the scale of the attack and the duration of the attack.
Last year, a game company on-line with this model, in the event of 350Gbps SYN Flood attack, a single defense costs only 800 yuan, if the use of all-weather high-defense mode will need to pay tens of thousands of dollars a month. However, attention should be paid to the cleaning threshold settings - it is recommended that the trigger sensitivity be adjusted according to business characteristics to avoid misjudging normal traffic as an attack resulting in unnecessary cleaning costs.
Hybrid billing is becoming mainstream in the industry. Smart large enterprises are starting to play a combination: basic traffic packages + resilient bandwidth + per-use defense. This model not only controls the base cost, but also retains the elasticity to cope with emergencies. A first-tier e-commerce platform's self-research CDN scheduling system uses this strategy, and their cost algorithm is worth referring to:
Do stress test extrapolation for actual selection. Use historical traffic data to simulate the cost of different billing models, focusing on testing burst traffic and attack scenarios. It is recommended to use A/B testing if you have the conditions, so that different business lines can run for three months with different billing modes, and the data will tell you the optimal solution.
Don't get sidetracked by sales tactics. A vendor once recommended me the "Unlimited Defense" package, but in the contract annex, I found out that I have to be charged separately for cleaning traffic over 500G per second. Now I ask vendors to provide a complete white paper on billing algorithms, focusing on the rules for determining abnormal traffic, the peak calculation cycle, and the details of over-billing.
Finally, a practical suggestion: small and medium-sized sites use a combination of traffic billing + defense packages, large projects use bandwidth billing + per-attempt defense, and mega-platforms should negotiate a custom hybrid plan. Remember that all billing models can be negotiated, especially annual payment customers can usually get 7-8% discount, or even ask the vendor to provide attack traffic free billing privileges.
The next time you see an abnormal spike in CDN bills, don't be in a hurry to scold the vendor, and check whether the billing model matches the business characteristics. A customer had a video-on-demand business mismatch into the flow of billing, a monthly loss of more than 100,000 yuan, adjust the billing model immediately after the savings of 40% cost. Good billing strategy is the best defense weapon - these days, even the CDN have to learn to "prevent teammates".
