The network will decide at any given moment whether it needs more UP's. It's not a user controlled issue. But to promote your chances, you should have a reasonably fast connection, free bandwidth for both uploads & downlds. You'll also need to ensure that Disable UP capabilities is not checked under Speed options. Oh ... & you need to make sure you're not firewalled. Incoming must be true. See this test:
Bug Report instructions & sample image Is the result True/False?