Network Load Balancer (NLB) supports the payasyougo billing method. This topic describes the billable items and billing rules of NLB.
Overview
Item  Description 

Billing method  The payasyougo billing method allows you to use resources before you pay for them. Bills are generated and fees are deducted after each billing cycle. 
Billing cycles and bill generation time 

Billable items of NLB
The bills for an NLB instance consist of three parts: instance fees, LCU fees, and Internet data transfer fees.
Network type  Instance fee  LCU fee  Internet data transfer fee 

Internetfacing  Charged  Charged  Charged 
Internalfacing  Charged  Charged  Not charged 
Instance fee
You are charged NLB instance fees on an hourly basis. The billing cycle is 1 hour. If the usage duration in a billing cycle is less than 1 hour, the usage duration is rounded up to 1 hour. Billing begins when the instance is created and ends when the instance is released.
Instance fee = Instance unit price (USD/hour) × Duration of usage (hours)
Billable item  Instance unit price (USD/hour) 

Instance fee  0.02 Note You are not charged NLB instance fees for a limited period of time. 
LCU fee
A Load Balancer Capacity Unit (LCU) is the smallest unit used to measure resources consumed by Network Load Balancer (NLB) instances.
LCU usage calculation
LCU fee per hour = LCU unit price (USD/LCU) × Number of LCUs consumed per hour
Number of LCUs consumed per hour = Max {Number of LCUs based on new connections per hour, Number of LCUs based on concurrent connections per hour, Number of LCUs based on data transfer per hour}
The performance metrics of a single LCU vary with the protocol of NLB listeners.
 Transmission Control Protocol (TCP) listeners
Metric Description Time unit LCU coefficient How the number of LCUs per hour is calculated Number of new connections (CPS) The number of new connections processed per second. Second 800 The system collects all CPS values within a billing cycle and then divides the largest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Largest CPS value/LCU coefficient
Number of concurrent connections (CONNS) The number of concurrent TCP connections per minute. Minute 100,000 The system collects all CONNS values within a billing cycle and then divides the largest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Largest CONNS value/LCU coefficient
Data transfer The data transfer over TCP processed by NLB. Unit: GB. Hour 1 GB The system divides the total amount of data transfer over TCP within a billing cycle by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Total amount of data transfer/LCU coefficient
 User Datagram Protocol (UDP) listeners
Metric Description Time unit LCU coefficient How the number of LCUs per hour is calculated CPS The number of new UDP connections processed per second. Second 400 The system collects all CPS values within a billing cycle and then divides the largest CPS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Largest CPS value/LCU coefficient
CONNS The number of concurrent UDP connections per minute. Minute 50,000 The system collects all CONNS values within a billing cycle and then divides the largest CONNS value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Largest CONNS value/LCU coefficient
Data transfer The data transfer over UDP processed by NLB. Unit: GB. Hour 1 GB The system divides the total amount of data transfer over UDP within a billing cycle by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Total amount of data transfer/LCU coefficient
 Secure Sockets Layer (SSL) listeners
Metric Description Time unit LCU coefficient How the number of LCUs per hour is calculated Number of new connections The number of new SSL connections processed per second. Second 50 The system collects the values of the number of new SSL connections processed per second within a billing cycle and then divides the largest value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Largest CPS value/LCU coefficient
Number of concurrent connections The number of concurrent SSL connections per minute. Minute 3,000 The system collects the values of the number of concurrent SSL connections per minute within a billing cycle and then divides the largest value by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Largest CONNS value/LCU coefficient
Data transfer The data transfer that over SSL processed by NLB. Unit: GB. Hour 1 GB The system divides the total amount of data transfer over SSL within a billing cycle by the LCU coefficient to calculate the number of LCUs. The number of LCUs is calculated by using the following formula: Number of LCUs = Total amount of data transfer/LCU coefficient
The number of LCUs that are consumed by an NLB listener per hour is calculated based on the dominant metric. The LCU fee for an NLB instance is the sum of the LCU fees of each listener.
LCU unit price
The number of LCUs consumed each hour is rounded up to the nearest integer.
Billable item  LCU unit price (USD/hour) 

LCU  0.005 
LCU billing example
Metric  TCP  UDP 

CPS (second)  The largest CPS value within the hour is 4,000. The number of LCUs that are consumed is:
 The largest CPS value within the hour is 2,000. The number of LCUs that are consumed is:

CONNS (minute)  The largest CONNS value within the hour is 720,000. The number of LCUs that are consumed is:
 The largest CONNS value within the hour is 420,000. The number of LCUs that are consumed is:

Data transfer (hour)  The data transfer over TCP processed by NLB within the hour is 10 GB. The number of LCUs that are consumed is:
 The data transfer over UDP processed by NLB within the hour is 8 GB. The number of LCUs that are consumed is:

In this example, the metric in which a TCP listener uses the most LCUs is data transfer and 10 LCUs are used. The metric in which a UDP listener uses the most LCUs is the number of concurrent connections and 9 LCUs are used.
LCU fee per hour for TCP listeners = 0.005 USD × 10 = 0.05 USD
LCU fee per hour for UDP listeners = 0.005 USD × 9 = 0.045 USD
LCU fee per hour for the NLB instance = LCU fee per hour for a TCP listener + LCU fee per hour for a UDP listener = 0.095 USD
Internet data transfer fee
You are not charged for Internet data transfer fees if you use internalfacing NLB instances. You are charged Internet data transfer fees only if you use Internetfacing NLB instances. Internetfacing NLB instances use EIPs to provide services over the Internet. If you use an Internetfacing NLB instance, you are charged an instance fee and a bandwidth fee or a data transfer fee for the EIP. For more information, see Payasyougo.