A link is a beam of energy between two portals. Links are useful for creating control fields, blocking enemy links, transporting artifacts, and increasing portal mitigation. When creating a link, the portal at which you are standing is referred to as the origin portal, while the other is called the remote portal.
There are a number of requirements for creating a link:
- Both portals must be owned by your faction.
- Both portals must have all eight resonators deployed.
- At least one resonator must be above critical energy level on both portals.
- You must be standing within 40 meters of the origin portal.
- You must have at least 250 XM in your reserves.
- You must hold the portal key for the remote portal.
- The origin portal’s link range must be at least as far as its distance to the remote portal. A portal’s link range is displayed on its info card, and can be increased by upgrading its resonators or installing link amps.
- There must be no existing links (of either faction) which would intersect your link.
- There cannot already be eight outgoing links on the origin portal. (You can see a link’s direction by observing the pulses of light that travel in the oppsite direction. In other words, outgoing links have pulses of light moving towards the origin portal.) This limit can be increased with SoftBank Ultra Links.
- The origin portal cannot be inside a control field. (The anchor portals of a control field are not considered to be inside it.)
- The remote portal cannot be inside a control field unless the origin portal is an anchor of that field.
Note that when viewing a portal’s info card, the “Link” button will light up and ADA will say “link possible” if the first five requirements have been met. This doesn’t necessarily mean that you can actually link anything. The scanner doesn’t check any of the other conditions until it starts looking for remote portals to link to. Yes, ADA is a tease.
Creating a Link
To create a link, tap the origin portal, then tap the “Link” button. You will see an overhead view of your current location. After a few moments, the scanner will load the list of portals you can link to the origin portal. Any linkable portal that is visible in the overhead view will have a rotating reticule around it. Tap the desired remote portal to select it and see information about that portal. Alternately, you can tap the key tab on the right edge of the screen to open a drawer that will show all the portals you can link to, even if they’re too far away to appear in the overhead view; tap one to select that portal. Once you’ve selected a linkable remote portal, the “Confirm” button will light up. Tap it to create the link.
When you create a link, 250 XM is deducted from your reserves, the key to the remote portal is consumed, and you get 313 AP. Note that if you only have one key for a portal and you use that key to link to it, you won’t be able to remote recharge that portal anymore until you get another.
The link range of a portal with no link amps is computed with the following formula:
R = 160L4
…where R is the link range in meters,and L is the average level of the portal’s resonators. Thus, the maximum possible link range for a portal with no link amps is 160×84 = 160×4096 ≈ 655 km. Installing link amps on the origin portal will increase its range.
The scanner will only consider a limited range when attempting to determine which keys in your inventory are blocked by other links; potentially linkable portals that are further away than this range will have a yellow border. The only way to know for sure whether that portal can be linked is to attempt the link.
Links increase a portal’s damage mitigation, making it more resistant to attacks. However, each link you add has less effect than the last; after around three or four links, the returns start diminishing significantly. The exact formula for link mitigation is:
…where n is the number of links attached to the portal and e is Euler’s number (approximately 2.71828). Installing SoftBank ultra links (a link amp variant) can amplify link mitigation.
The maximum mitigation that can be obtained on a single portal via links is 70, but achieving this level of link mitigation requires 386 links. Also, total portal mitigation (from both links and shields) tops out at 95, so if you already have 95 mitigation on a portal, adding more links does not increase it (although it could make the portal stay stronger longer when shields start going down).
Because links obstruct other links, pay attention to what your link may be blocking if you put it down. (It can be good to box in the enemy, but bad to do that to a friend.) Be aware that the intel map is rendered in Mercator projection, but links follow the shortest path over the curvature of the Earth. (In other words, they are segments of great circles.) This means that links appear curved when displayed on the intel map. Be sure to take this into account when planning very long links.
Because of the diminishing returns when it comes to link mitigation, it is better to have a lot of portals with a few links than a few portals with a lot of links. For example, a portal with three links gains 38 mitigation, while one with 10 links gets 58 mitigation. So 10 portals with three links each gives a cumulative mitigation of 380, while three portals with 10 links each only gives a cumulative mitigation of 174. Also, although you experience decreasing mitigation returns with each link, the AP gained by an attacker for taking them down continues to grow linearly. After four links, the mitigation/AP tradeoff turns to the attacker’s favor. Of course, putting up the links grants more AP than the attacker gets for taking the portal out, but that AP is distributed across all the agents that put up the links, while the single attacker who drops the links gets all the AP.
When a link is broken, the portal key used to create the link is dropped at the origin portal. Look on the ground near the portal for small yellow objects: those portal keys go to remote portals.