[A] [B] [C] [D] [E] [F] [H] [I] [L] [M] [N] [O] [P] [Q] [S] [T] [U] [V] [W] QoS 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st decision making DiffServ 2nd 3rd 4th 5th 6th 7th 8th 9th EXP field Explicit Congestion Notification IP IP best effort mapping models per-hop-behavior |