| a. Charging (Billing), Filter user traffic |
| b. Routing mobile originated traffic, GTP Tunneling to SGSN |
| c. Interface external networks |
| d. All of the above |
| Answer: All of the above |
| a. Charging (Billing), Filter user traffic |
| b. Routing mobile originated traffic, GTP Tunneling to SGSN |
| c. Interface external networks |
| d. All of the above |
| Answer: All of the above |