NAT Gateway Specifications¶
NAT gateway specifications determine the maximum number of SNAT connections supported by a NAT gateway.
An SNAT connection consists of the source IP address, source port, destination IP address, destination port, and a transport layer protocol. The source IP address is the EIP, and the source port is the EIP port. An SNAT connection uniquely identifies a session.
The data throughput of a NAT gateway is determined by the sum of the EIP bandwidths used by its DNAT rules. For example, if a NAT gateway has two DNAT rules, and their EIP bandwidths are 10 Mbit/s and 5 Mbit/s, respectively, the throughput of the NAT gateway is 15 Mbit/s.
The timeout period of an SNAT connection over TCP is 900 seconds.
The timeout period of an SNAT connection over UDP is 300 seconds.
When creating a NAT gateway, select the specifications based on your service requirements. Table 1 lists the NAT gateway specifications.
Specifications | Maximum Number of SNAT Connections |
|---|---|
Micro | 1000 |
Small | 10,000 |
Medium | 50,000 |
Large | 200,000 |
Extra-large | 1,000,000 |
Note
If the requests exceed the maximum connections allowed by your NAT gateway, your services will be adversely affected. To avoid this situation, create alarm rules for the SNAT connection in Cloud Eye.
The DNAT rules of a NAT gateway are irrelevant to the NAT gateway specifications. A maximum of 200 DNAT rules can be added to a NAT gateway. The number of SNAT rules that you can add for a NAT gateway has no relationship with the NAT gateway specifications.