SLOC is an acronym used by NATO to refer to the Atlantic Sea Lanes Of Control, or as Sea Lines Of Communication, depending who you ask. Essentially, these are the critical trans-Atlantic shipping routes that would be used to resupply and reinforce NATO forces in Europe from the CONUS in the event of war in Central Europe. Convoy tactics would likely be used to protect the SLOCs from Soviet attack submarines, and in addition U.S. Navy and British Royal Navy SSNs would likely surge northward to create a barrier at the GIUK gap to prevent Soviet attack submarines from transiting into the Atlantic.