In my setting I only have the DSL modem on the line Typically when this sort of response problem hits, I can see limited bandwidth because both inbound and outbound sides appeared to be throttled. This is using the monitor on Linux.

When I am lucky, the next day, what ever C&W had been doing is no longer happening and I am getting my correct bandwidth.

If you are running on DSL, check the line sync speed in the settings of your dsl modem, check for things such as filters on all phones etc, try the connection with only the dsl modem on the line,

would be interested in assisting you.