AR-46 (ERPU’s memory is 512M) only works as NAT router, and it is attached with 1000 users (there are 600 concurrent users); GE serves as upstream interface after CAR of 100M. When it performs NAT via Esay IP, the packet loss at interface will reach 5% when nat session reaches 20000, at which point, the rate of upstream interface keeps at 10Mbit/s.
Note: PAT is used when failure occurs, and then change it to NPAT.
Change the NAT of Easy IP to that of address pool.
Use and address pool with 8 IP addresses to perform NAT, and the problem is solved, and the traffic at interface is restored to 50Mbit/s, restoring the services.
1 The AR-46 using ERPU of 512M supports 750000 pieces of nat sessions in theory, so 20000 sessions should not be the ceiling of NAT of the router.
2 Because Easy Ip is used, the problem is suspicious of being resulted from rate that AR-46 performs NAT for one IP address. For the limit of port number at transmission layer of one IP address, it can translate 65535 sessions in theory.
3 For the upper layer gateway device, it is a challenge for one IP address to have 20000 connections, and this is likely to lower the forwarding efficiency of gateway device.
If there are not many users, use Easy IP for NAT. If there are more than 100 users, use address pool for NAT(NPAT) if permitted.