Destiny is causing my cable modem to reset after playing for long periods of time.
Most consumer cable modems are designed to restart automatically if they detect too many errors in the data they are receiving. This is commonly called an "error rate reset threshold." This threshold is usually defined by the number of errors detected in a specific period of time, and is intended to force the cable modem to establish a new connection with your Internet Service Provider (ISP).
When not playing Destiny, your normal internet usage may not produce enough errors to reach the reset threshold. However, the increased internet usage from playing Destiny can be enough to pass the error rate reset threshold, resulting in a modem reboot.
To resolve this issue, please contact your ISP and request that they perform diagnostic tests to determine if your modem is rebooting itself due to errors.