Unresolved Socket Limit Behavior in Google Colab Runtimes

The goal is to understand how many concurrent TCP connections a Colab free‑tier runtime can maintain before connection errors appear, and whether this cap is defined per notebook or per runtime instance.

Current observations suggest that opening more than a few hundred sockets to external services triggers failures, yet Google Colab’s official documentation does not specify a socket or file‑descriptor limit. The 90‑minute inactivity timeout and 12‑hour daily usage caps are well documented, but the socket limit remains ambiguous. Additionally, when a single runtime is shared across multiple notebooks, users report inconsistent connection behavior, raising the question of whether the limit is shared globally or isolated per notebook.

What is the documented maximum number of open sockets allowed in a Colab free‑tier runtime? Does this limit reset when the runtime is restarted, or does it persist across notebook sessions? If a single runtime is shared among multiple notebooks, how is the socket limit applied—per notebook or per runtime?