Abstract: Use Alibaba Cloud's public network products in the most cost-effective way, choose billing by traffic and billing by bandwidth in the most correct way, and choose prepaid and postpaid products in the most appropriate way. Minimize the cost of using the public network for enterprises.
introduction
Network, computing and storage are the three major infrastructures of data center and cloud computing. In traditional data centers, the network is relatively complex, and an independent team is often required to be responsible for network operation and maintenance. Thanks to cloud computing technology, the use of the network on Alibaba Cloud has become very simple. We allocate an independent network environment VPC for each user. There are virtual routers and virtual switches in the VPC, and the virtual routers and virtual switches are automatically connected. Together, the ECS attached to the switch will automatically obtain the private network IP. Using cloud computing technology and through a series of automated processing, the tedious work of powering on equipment, connecting network cables, configuring IP, configuring spanning tree protocol, and configuring routing in the original traditional physical computer room is eliminated. Users only need to click on the console to create a VPC network and follow the prompts to set a few parameters. A completely independent network container including routers and switches can be successfully activated within a minute.
After the network container is built, you can directly add cloud server ECS, cloud database RDS and other resources to it to build a cloud data center.
To build a data center on the cloud, most of them need to provide external services or have Internet network access capabilities. At this time, you can use Alibaba Cloud's powerful multi-line BGP Internet public network to provide external services, and directly have the same quality network capabilities as Taobao and Tmall.
What is multi-line BGP?
There are two concepts here. One is multiline. Refers to the fact that Alibaba Cloud's data center and multiple operations have physical line connections. One is BGP, which simply advertises the public IP on the server to all interconnected operators through the BGP routing protocol. Through multi-line BGP, a single server only needs to use one public network IP, and this public network IP can be found by users of all operators connected to Alibaba Cloud, and directly connected to Alibaba Cloud data through direct links center.
More lines on the cloud means more users can be reached by the network's tentacles, and the user experience will be better. Alibaba Cloud's data center currently has a total of 89 BGP links at home and abroad, basically covering the world's mainstream operators, and its network tentacles are all over the world. If the service is deployed to Alibaba Cloud, it can provide users around the world with a smooth access experience.
Multi-line BGP public network cloud products
在阿里云上多线BGP的公网云产品有EIP，SLB，NAT网关，VPN网关等。
EIP是弹性公网IP产品，主要的特点是让网络和业务功能组件解耦，支持和其他云产品做绑定和解绑，云产品绑定EIP后即可具备公网能力。当前阿里云支持EIP绑定ECS，即将支持EIP绑定SLB，NAT，VPN网关和其他云产品。
SLB是负载均衡产品，分为公网负载均衡和私网负载均衡两大类。公网负载均衡产品上面有一个公网IP，可以对外提供服务。
NAT可以当一个简易的基于状态的防火墙使用，只允许通过SNAT建立起连接的外部用户访问。还可以通过DNAT端口映射的方式可以节省公网IP的消耗。
VPN网关当前主要提供IPSEC加密隧道，是打通线上线下数据中心的一种低成本解决方案。
具体每个产品的正确使用姿势和隐藏功能后续会有专题介绍。
按带宽计费和按流量计费的选择
上述所有的公网云产品都支持按流量计费和按带宽计费，具体该怎么在云上选择按流量计费和按带宽计费呢？
当然是怎么省钱怎么去选，我们先拿杭州地域的按流量计费和按带宽计费价格来看。
| 计费方式 |
杭州 |
| 按流量计费 |
0.8元/GB |
| 按带宽计费 |
[1-5] Mbps: 0.96 元/Mbps/天 |
| >5Mbps: 3.36元/Mbps/天 |
上图中带宽的费用分两个区间，一个是1到5Mbps的，一个是大于5Mbps的。所以也需要分两个区间讨论：
1. 1-5Mbps带宽的按流量和按带宽选择
可以计算一下带宽为2Mbps，一天会产生多少流量。一分钟产生2Mbps*60s=120Mbits的数据，折算成字节是120/8=15MB。一天产生的字节数是15*60*24=216,00MB。折算成GB是21,6000/1024=21.1GB。21.1GB如果按0.8元/GB算价格是21.1*0.8=16.88元。但实际上在大多数情况下带宽不会24小时跑满的，假如全天整体上带宽利用率在30%，那么所需要付的费用是16.88*0.3=5.06元。而选择按带宽计费，假设带宽值为2Mbps，那么一天需要付费0.96*2=1.92元。 按流量的费用远大于按带宽所需付的费用。
2Mbps带宽的按流量计费和按带宽计费价格
如果用图表的方式表达每天的平均带宽使用率和按流量和按带宽计费的价格的话会比较直观，如果是1-5M带宽，带宽平均利用率达到10%以上，按流量计费的价格就高于按带宽计费了，所以应该选择按带宽计费。如果流量较少，那边还是选择按流量计费便宜。
小贴士：什么是带宽利用率？
如果不特殊说明，本文中的带宽利用率都统一指出阿里云方向带宽利用率。
带宽利用率是指实际使用带宽/总带宽的比率。例如：假设总带宽为2Mbps，如果一天24小时中，有8个小时没流量，有8小时带宽为1Mbps，另外8个小时跑满了2Mbps。那么带宽利用率就是：[(8*0)+(8*1)+(8*2)]/(24*2)=50%
2. 大于5Mbps带宽的按流量和按带宽选择
以50Mbps的带宽为例，按带宽计费的每天的金额是5*0.96+(50-5)*3.36=156元/天。
流量价格在不同带宽利用率下，价格不同，按上面类似的算法可以计算出不同带宽利用率情况下50Mbps带宽所产生的流量费用，整体上如下图所示。
50Mbps带宽的按流量计费和按带宽计费价格
由上图可见，如果带宽利用率小于35%，那么采用按流量计费省钱，如果带宽利用率大于35%，那么按带宽计费省钱。
预付费产品优惠多多
带宽预付费产品
预付费相当于是先把钱交了之后在使用，这种模式能降低服务提供商的财务压力，并且可以增加用户的粘性，所以一般有价格上的优惠。在阿里云，包月的预付费带宽是后付费带宽的8折。比如后付费10Mbps的带宽的价格是(5*0.96+(50-5)*3.36)*30=4680，那么包月的价格大概是后付费价格的8折，即3744元。如果是包年会在包月价格价格基础上乘以12后再打85折。整体上算下来包年的价格是后付费按带宽价格的8折*85折=68折。
可以再想一下，是包年预付费按带宽划算还是按流量计费划算。还是老办法用数字和图表分析一下，我们以50Mbps的带宽以包年的单价分析一下。
通过上面的图可以看出，当前每天的带宽利用率小于25%的时候，按流量省钱。如果每天带宽利用率大于25%，那么包年的带宽方式省钱。
流量预付费产品
全时流量包
阿里云现在推出了预付费公网流量包产品，可以自动抵扣按流量计费的ECS，EIP，SLB，NAT所产生的流量。其中一个5TB的全时月流量包，最多可以较之前节省1393元。
全时指的是一天24小时都可以使用。与之对应的是闲时流量包。
闲时流量包
闲时流量包只能在北京时间凌晨0点到早8点使用。但价格基本上是后付费流量价格的6折左右，价格优势十分明显。特别适合能控制自身流量的客户，比如有定期的向外部同步数据需求的客户。
共享带宽大客户省钱的福音
上面提到，带宽利用率如果大于35%的话，按带宽计费是省钱的。而一般大客户的带宽利用率普遍高于35%，也即一天中至少8小时以上服务器是活跃状态。
在共享带宽产品未推出之前，每个服务器需要单独购置一份带宽，这种使用方式相对共享带宽方式来讲是一种土豪的使用方式。
如下图所示，假设与三台ECS服务器，如果单独购买带宽的话分别是30Mbps，40Mbps，50Mbps。那么总计需购买120Mbps的带宽。而采用共享带宽的话，其实购买的总带宽75Mbps就够了。而且每台服务器都与机会能跑到75Mbps的带宽峰值。
Relatively speaking, it can save (120-75)/120=37.5% of the cost and save a considerable amount of bandwidth operating costs.
If you use shared bandwidth, the bandwidth usage can be greatly improved, and it can easily run to more than 50%. From the above analysis, it can be seen that, compared with billing based on traffic, the higher the bandwidth utilization rate in billing based on bandwidth, the more money you save.
Taking the bandwidth of 50Mbps as an example, it can be seen from the figure below that if the bandwidth utilization rate reaches 70%, the cost of billing by bandwidth is basically half of the cost of billing by traffic.
The high bandwidth utilization scenario of shared bandwidth can save half of the money compared to metered billing, which is a conclusion that makes big customers excited and excited.
Prepaid Shared Bandwidth
Shared bandwidth also has a prepaid model, and the monthly price is also postpaid by 20% off the shared bandwidth price billed for bandwidth. The annual price is the monthly price*12*0.85. The overall price of the annual package is 62% off the price of postpaid shared bandwidth.
The shared bandwidth postpaid model can already save a lot of costs. Assuming that the shared bandwidth postpaid model has already saved 30% of the cost, the cost savings available for the annual prepaid package is 30%/0.68=44%. Overall, prepaid Shared bandwidth is a real money saver.
Original link: http://click.aliyun.com/m/30448/