Recently to help a few video station to do architecture optimization, stepping on the pit stepped on my scalp numb. Especially the CDN billing method this piece, several customers are confused to choose the program is not suitable, the end of the bill out of the direct eye - an online education buddies and even because of the flow of sudden, single-month CDN costs directly soared to 100,000 +.
Video business and ordinary websites are not the same thing at all. High-definition content ate up bandwidth like a black hole, coupled with DDoS and CC attacks such a common occurrence, there is no reliable high-defense CDN is simply running naked. But many people are stuck in the first pass on the billing method: in the end, should we choose to pay by traffic or pay by bandwidth?
Don't believe the sales blowing sky-high, these two billing model is essentially gambling probability. According to the traffic is the actual report, with 1G counting 1G of money; according to the bandwidth is the package charge, whether you use full, bought 100Mbps will have to pay 100Mbps of money. I take three common vendors real test data to speak - CDN5, CDN07 and 08Host, their billing strategy can simply force people into actuaries.
Let's look at per-traffic billing first.CDN5's offer is $0.18/GB, looks pretty cheap right? But the traffic fluctuations of the video business can scare people to death. One weekend suddenly a Netflix brought fire to a customer's science video, 24 hours ran 80TB traffic. At this price, a day of light traffic costs 14,400 yuan, not counting the cost of high defense. This kind of sudden traffic in the traffic billing system is a gold swallowing beast.
On the flip side, look at the per-bandwidth billing.CDN07's 95 billing is sort of the industry standard, taking off the highest 5% peak point each month and billing for the highest remaining peak value. For example, if you buy a 500Mbps bandwidth package, you pay a fixed 15,000 yuan per month. Even if one day a sudden burst rushed to 2Gbps, as long as it is not consistently too high, the final billing may still be calculated according to 800Mbps. Seems to smooth out sudden bursts of traffic right? But here's the pitfall - if your business is smooth, it's money well spent.
I'll do a comparison test with real data. Running a week's worth of video service with the same node on 08Host, the traffic pattern is exactly the same:
Total cost of billing by traffic: 12TB 7 days $0.21/GB = $17,640
Cost per bandwidth billing (95th peak billing): take 95th percentile bandwidth value of 580 Mbps * unit price of $230/Mbps = $13,340
See? Bandwidth billing in this case Cheap 25%. but don't worry. switch to another scenario - when weekend traffic drops to a daily average of 4TB and peak bandwidth is only 200Mbps:
Traffic billing: 4TB 7 0.21 = $5880
Bandwidth billing: 200 Mbps * 230 = 46,000 yuan (monthly price)
Good lord, it's 7x more expensive straight up! This is the biggest trap of bandwidth billing: traffic troughs are still paying for peaks.
The video business is the most deadly traffic prediction is simply more difficult than the stock market. I have experienced the most outrageous is a customer, usually 100GB average daily traffic, because a social news suddenly reprinted by the major media, a day dry 37TB. if you use the bandwidth billing package, when you buy 100Mbps bandwidth directly crash, not only the service is interrupted, the exceeding amount of bandwidth billed by the amount of each GB to be charged 0.38 yuan, more expensive than the standard price 80% -CDN vendors chicken thief on chicken thief in this, mixed billing excess part of the unit price skyrocketed.
The cost of high defense should also be calculated separately. 08Host's D protection price is 80 yuan per month per Gbps protection, but the traffic billing mode of protection traffic should also be billed! For example, carry 10Gbps attack for an hour, about 4.5TB of traffic, light attack traffic to pay 945 yuan. And bandwidth billing mode, as long as the value of the protection bandwidth does not exceed the purchase, the attack traffic does not count - this point is often targeted video station is crucial.
The three vendors' strategies differed greatly when tested in real life:
CDN5 is suitable for sudden traffic business, their traffic billing step discount is very real, with 100TB after the unit price can be cut to 0.12 yuan / GB. And high defense package comes with 20Gbps protection, unlike some vendors protection and acceleration separate billing.
The advantage of CDN07's bandwidth billing is that it stabilizes the business, especially the 24-hour live broadcast of this kind of smooth bandwidth curve. Their 95 billing algorithm is more conscientious, and the peak points removed are 2% more than others, which can save a lot in the long run.
08Host's hybrid billing is instead suitable for most video sites. Basic bandwidth monthly + excess traffic billed by volume, both to control costs and to cope with emergencies. I helped a live gaming platform to build a program: 200Mbps bandwidth monthly + excess traffic $0.15/GB + 50Gbps high defense package. A month down than pure bandwidth billing to save 40%, than pure traffic billing to spend 25% less.
Tell us something dry about how to choose:
If your video business traffic fluctuates more than 300%, decisively choose per-flow billing. Don't be fooled by the monthly price of bandwidth billing, who in the video industry can guarantee smooth traffic every month? Especially for UGC platforms, a random burst of content can make the traffic curve blow up to the sky.
Bandwidth billing is more cost-effective if the business is a stable output like long video on demand or corporate training. Especially for business with low traffic at night, the 95 billing model can help you cut down the bandwidth cost at night trough.
Always be aware of hidden costs! Some vendors' traffic billing does not include HTTPS encryption costs, with an additional charge of $0.02 per GB; bandwidth billing does not include TCP connection costs, with an additional charge of $0.1 for each of more than 50,000 connections. The most pitiful thing I've seen is a vendor charging video slicing requests per API call, and a million requests is another big few thousand in costs.
Always press test data before signing a contract. Have the vendor open a test account for you and run it for 7 days with real business traffic. Look at the bandwidth graph and cost simulation graph in the console, which is 10,000 times more reliable than what the sales said. Don't forget to simulate attack scenarios to see the billing rules after the high defense is triggered - some vendors automatically upgrade to more expensive packages as soon as the high defense is triggered, and it's too late to cry.
Finally, let's dump a tyrannical theory: even CDNs have to defend themselves against teammates these days. Don't think that once you have chosen a billing method, everything will be fine. Checking the billing details every week is the right thing to do. When I did an audit for a client, I found at least three billing errors: double billing of back-to-source traffic, billing compressed traffic as uncompressed volume, and even miscounting traffic from other clients....
Video business selection CDN is like matching insurance, can not figure cheap to buy simply can not be compensated, can not buy excess coverage of white throw money. The core principle is: with traffic billing to deal with uncertainty, with bandwidth billing to lock the certainty of the cost, with a hybrid program to find the balance point. Don't forget the negotiation skills - when the traffic is large directly to the sales director to ask for discounts, don't be silly to pay according to the price of the official website.
Now look at the online education customer I initially mentioned, and finally changed to CDN5's elastic bandwidth package: guaranteed 100Mbps per month, the peak can be burst to 2Gbps billed at 95, and the high defense package includes 50Gbps protection. One month's cost from 110,000 down to 32,000, while ensuring that students watch 4K video without lag. The billing method is chosen correctly, really save a set of real estate down payment.
