How does damage mitigation work on a portal? I heard that links and shields make it sturdier and harder to take down, but exactly what's the math behind this?
The mitigation stacks additively and its damage reduction is hard-capped at 95%.
A portal with 4 VR shields and with 10 links has
The % damage reduction in action
An L8 burster with 2700 damage will do:
I am leaving the following only for historical reasons
# IMPORTANT! # for old players
If you are an old player and you don't use shields much or you didn't play long time for some reason, it may happen that you will have OLD + NEW shields in your inventory. Don't know why it works like that, but if you drop all the shields of same rarity and pick them up again, they will get renewed.
EDIT 1 (7 Mar 2014)
The shield strength changed once again, from
EDIT 2 (3 Jun 2014)
New shield strength :) - from
EDIT 3 (21 Dec 2014)
New shield type was introduced as a result of sponsorship deal with the international investment banking firm AXA. The so called AXA Shield is very rare and its mitigation is 70. More reading here...
EDIT 4 (4 Feb 2015)
Significantly increased values for stickiness started to show for newly placed shields in the JSON answer in intel. (Reddit: Shield stickiness gone mad in IITC.)
Shields mitigations are :
The mitigation of the shields is a percentage of absorption of damages. A (common) shield with a mitigation of 10 will absorb 10% of the damages made by the buster. A second (common) shield with mitigation 10 will catch 10% of the remaining damages.
For example, let's imagine a burster making 100 of damages on a resonator. First common shield will absorb 10% so damages will be reduced to 90. A second common shield will absorb 10% of the 90 damages and will reduce damages to 81...
In the worst/better case with 4 very rare shields mitigation 30, a burster making 100 damages will be reduced to 24.
To compute the total mitigation of shields on a portal you have to just multiply the percentages. A very rare shield will eat 30%, to compute the effects you'll have to do
So the way of computing shield mitigation is :
To that, you have to add a defense mitigation made by links. The formula seems to be :
This will give you another mitigation to "add" (multiply) to the shield one to obtain final mitigation.
Then to compute the damages the formula is :