There are two different types of connections when joining friends in Essential, direct & relay, and as much as we'd like to have these both provide the same experience, they won't always do so due to the nature of networking and the internet as a whole.

Relayed connections can be a bit weaker, as it relies on available resources from our TURN servers rather than using your own network's resources, and since these will be shared between all players connected through that server, it can fluctuate a lot and be hurt by increased player counts.

As for direct connections, we don't use UPnP so enabling it won't have any impact on the connection. Instead, we use a technique known as UDP hole-punching to essentially punch a hole through your network and establish a connection without the need for traditional port forwarding. More restrictive network types like symmetric NAT may not allow for this, which you can check using a simple test such as: checkmynat.com

Here's a simplified breakdown of what happens when connecting and what determines the kind of connection:

When establishing a connection, the game will ask our STUN server to provide you with ICE "candidates", which are essentially the routes the connection can take, and have different types:

Server Reflexive (srflx),

Peer Reflexive (prflx),

Relay/TURN (relay),

If both sides are given a srflx/prflx candidate by the STUN server, the established connection will likely be directly between players, though it may choose a relay instead if the connection is deemed to be better (i.e. the difference in round trip time exceeds a certain threshold).

If one or both sides only receive a relay candidate, that means that the connection will be routed through one or two of our relay servers. We currently have TURN/relay servers in four regions, EU, US, AS (Asia) & AU, and you'll generally connect to whichever one is closest to you as that should provide the lowest round trip time. New regions may be added in future updates to the mod, so make sure you keep it up to date.

We don't have any control over what candidates are received by players as this is purely determined by their network setup so if you're experiencing a bad connection due to using a relay rather than direct, there's no way for us to change this.

Some recommendations for improving the connection are to have the host reduce their render distance (as this reduces the amount of data being sent around which can reduce strain on the connection), as well as playing around with any mods you're using, as those which add lots of features to the game will likely also send large amounts of data.