Questions and answers

cgnat_faq_1

cgnat_faq_2

cgnat_faq_3

cgnat_faq_4

cgnat_faq_5

cgnat_faq_6

cgnat_faq_7

Why an address pool of at least 2 or 4 addresses is recommended to create?

Lock free scheduling algorithm implemented in the DPI is designed to distribute sessions over the working threads, so it imposes restrictions on the public IP address which can be assigned to subscriber from the pool:

- It is required that the number of addresses within the pool is at least the number of working threads (2 for the Stingray SG-6 and 4 for the Stingray SG-10 and further) in order to ensure that public address is assigned to subscriber.

To find out the number of working threads flows:

expr $(ps -p `pidof fastdpi` H -o comm|grep wrk|wc -l) / $(ps -p `pidof fastdpi` H -o comm|grep rx|wc -l)

- If there is the only address in the pool, then the address can be assigned just for those subscribers that are used by balancing algorithm, not all subscribers.

How to determine which public address from the pool the subscriber will receive?

To see which public address was assigned to a private one, you can use the command

fdpi_ctrl list status --service 11 --ip 192.168.4.20

In NAT 1: 1, the public address is allocated immediately when the service is assigned, in CG-NAT at the time of the session start

Also, the public address allocated to the subscriber is reported to Radius Accounting for the purpose of logging it in billing.

It is impossible to predict in advance which address will be issued to a subscriber from the pool: it depends on various factors and, in particular, on the current load of the pool.