The netcode of League Of Legends 'Project L': A melting pot of relays and GGPO

Project L is currently the hottest title in the fighting game community. And amongst the explosive hype, almost no one questions the quality of what netcode it will utilize as leading its development, is the very man who birthed rollback netcode, Tony Cannon of Radiant Studios (currently the technical lead for Project L).

But one cannot simply pass off Project L as just another game with rollback netcode, as Project L is attempting to integrate the core networking technologies that have been used in Riot’s past games, along with the rollback netcode. What this means is that Project L will be the first major rollback fighter that doesn’t use P2P (peer-to-peer) connections at its core.

Perhaps Project L will pave the way for a new standard for fighting game netcode, or perhaps it’s overcomplicating it by trying to mash up as many solutions as possible. Either way, this is a brief overview of how Project L’s unique netcode will function after a brief reveal in the RiotX Arcane Epilogue.

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How 'Project L' combines rollback netcode with Riot’s core networking technology to deliver a fresh experience

Project L combines rollback netcode with 'Riot Direct' technology in hopes of making more connections between players across the world feasible. 'Riot Direct' is a more glorified term for relaying to server-based connections, but we’ll look into it with more detail in the words of one of Riot’s employees down below.

Riot Direct

In the words of Riot employees Cody Haas and Ivan Vidal:

"Riot Direct is basically a web of cables and routers specifically used for Riot’s packets, including packets for critical game-running processes. To provide a little context, internet service providers (ISPs) default to hot-potato routing - this means they want to get customer traffic out of their network as soon as possible using the most cost-effective exit point. The way this impacts their customers (our players) varies widely based on the application they’re running and its overall bandwidth requirements. The internet is a complicated place where we can’t just connect two points with a straight line. Each region is built based on individual geography, politics, and community policies, and whether via land or sea, we always need to adapt to their infrastructure. "

It's important to note that, Valorant and League Of Legends used dedicated servers along with Riot Direct to deliver the experience that they do, Project L on the other hand will only be using Riot Direct as a bridge substituting the P2P connection that they normally would use in a fighter.

"By having Riot Direct present around the globe in key locations, we’re close to other ISPs, so we can connect directly using Private Network Interconnecting (PNIs) or via internet exchanges. This way, ISPs can fully offload traffic going to our games close to the source, so we avoid the internet as much as possible. Each one of these locations is called a point of presence (PoP)."

PoP's used for League Of Legends (Image via Riot Games)

As can be seen from the picture above, along with the lack of servers in regions like India, there are no PoPs either in any of these regions. That's why League hasn't seen the same kind of play as games like DoTA 2 in India.

The same cannot be said for Valorant though.

Alongside having Indian servers, there is a PoP located in Mumbai that is responsible for the highly acclaimed netplay that Valorant has in the country (Image via Riot Games)

Valorant is ridiculously popular in India, and for good reason as its incredible netplay can be directly attributed to the implementation of Riot Direct in India.

"Once traffic is inside Riot Direct, we use cold-potato routing. We use the best possible path back to players by keeping traffic inside our backbone for as long as necessary. To achieve this, we need to create specific policies that take into consideration all the carriers we peer with as well as the geographical constraints of each available path. Here’s how it works. When someone decides to play one of Riot’s games, their client receives an address it needs to send packets to. The packets leave the player’s computer and travel onto their local network to an internet service provider’s (ISP) network. Ideally, the packets quickly leave the ISP’s network and enter Riot Direct’s network at one of our PoPs. So basically, the PoP says 'Hey, if you’ve got traffic trying to get to these addresses, hand it all to me, because I know the way there.' Traffic can then quickly and easily travel through one of Riot Direct’s dedicated fibers to the correct game server."

Naturally this leads us to the question, has something like this been done before? Or is this the first attempt to create a netcode model like this for a fighter like Project L?

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Virtua Fighter 5's polarizing delay based netcode

Virtua Fighter 5 that released earlier this year was a wonderful game that only made the mistake of compromising on the implementation of rollback netcode. But as a last ditch attempt, the network model was revamped to use Google relays to complement the delay based netcode in the hope that most routing issues would be solved.

The results were mixed at best. This approach is in a way the most similar to what Riot is currently trying to pull off. But it isn't nearly as refined as Riot Direct, and it will surely be interesting to see how Project L works out with GGPO as the cherry on top.

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A reason to have faith: Tony Cannon

As mentioned earlier, Tony Cannon is the technical lead of Project L and a figurehead of the FGC (fighting game community) for inventing rollback netcode as a response to the horrible delay based solutions that were being implemented by developers in the early 2010s.

His version of rollback netcode, popularly termed GGPO is the standard for fighters releasing today and has outperformed many of his competitors trying to use their own versions of rollback netcode (most notably, Street Fighter V's homebrew rollback).

Tony Cannon from the Arcane Epilogue presentation (Image via Riot Games)

Aside from his technical prowess, Tony has also made immense contributions to the FGC through forming EVO and the Shoryuken wikis. He has the mindset of someone who has truly embraced the community fully, and Project L couldn't be in better hands.

Project L will most definitely be a spectacular tag team fighter on both a gameplay level and technical level.