Train strikes and the London Underground

[r0ck]

Can anyone tell me if the whole of the London Underground will be open on the day of the train strikes (specifically Saturday 17th December) I'm unclear whether the strike is the national rail or includes the tube. Thank you!

tfl.gov.uk/campaign/strikes

"Strikes will affect national rail services nationwide. Most TfL services, including most of the Tube, will continue to run. However, there will be some disruption where track is operated by Network Rail."

Followed by a list of which services might be affected.