What is the difference between knock-up and suppression effects? Both are hard cc that stops movement and abilities, but I was a curious if there were difference between the two other then animation?
Displacement effects (knock ups, knock backs, etc) are not affected by tenacity or any crowd control clearing effects like Cleanse or Quicksilver Sash. Displacements effects can be prevented by spell-shields however, like Banshees Veil and Morgana's Black Shield.
Suppression effects involve a channel by the caster and can only be stopped in one of three ways:
- Quicksilver Sash
- Gangplank's ability Remove Scurvy
- An ally canceling the caster's channel with a hard stun, silence, or displacement
If this answer becomes out of date or can be improved, let me know.
A unit that is made airborne is moved in a specified direction or to a specific point. For the duration, the unit is also stunned and cannot move, attack, cast abilities, activate items or use the summoner spells Flash and Teleport. [Source]
Reduction: Only the stun component duration is reduced by tenacity.
The Quicksilver item active removes all forms of CC, including airborne effects if a blink or dash ability is used after activation. [Source]
In summary, a knock up consists of two parts:
- The actual "airborne" effect, where your character is in the air. The duration is not reduced by tenacity.
- A stun. The duration is reduced by tenacity.
Because of this, it is possible to escape mid-knock up after the stun using a blink or dash, or earlier by removing the stun.
A unit that is suppressed is unable to control its movement, declare attacks, cast abilities, activate items or use any summoner spell for the duration. [Source]
Reduction: The duration is not reduced by crowd control reduction.
Essentially, there are more ways to reduce/remove the effects of a knock up than a suppression, but it requires a gap-closer. Since most players take Flash, this isn't a big deal. A suppression ability, on the other hand, cannot be reduced by tenacity or removed by Cleanse, requiring players to buy an item with the Quicksilver item active.
Suppressions can be stopped. Knock-ups usually last a much shorter time and require you to take more risk - and tend to be AOE (affect more than 1 target).
Suppression can be stopped with knockups/silence/knockback/etc.
Knock-ups are not affected by Tenacity or Cleanse, but is usually only followed by a slow.
Suppression will not allow you to use any abilities or summoner spells except Cleanse, Quicksilver Sash, or Pirate's oranges.
Suppression stops attacks, abilities (unless they remove it), movement, and summoner spells.
Knockup makes you airborne which prevents attacks, abilities, and movement, but not summoner spells.
Knockups cannot be removed.
Suppression can be removed by anything that removes CC, including a Quicksilver Sash or abilities like Olaf's Ragnarok, Gangplank's Remove Scurvy, or Alistar's Unbreakable Will.