Not cables. Not bungee ropes. Nothing elasticated. WWE's ropes are just big, horrible, thick ropes with tape wrapped around them to make them look nice. These connect to the ring posts via a simple bolt. Each corner is done at once meaning the last corner is always a challenge, serious strength is needed. The ropes are then tightened "just right". There's nothing scientific to this, Charles Robinson, and the rest of the ring crew for that matter, just know when they are perfect. That's experience for you. Robinson is famous for saying: "Don't get a welt (on your back)? They're not tight enough." Brutal.