Choosing how a multiplayer game connects players comes down to a few decisions that are easy to blur together. This explainer separates them, then maps each to the kinds of games it suits. For the wider netcode picture (ping, tick rate, prediction), start with Edgegap's Netcode Fundamentals.

What's the Difference Between Authority and Hosting?

Every multiplayer architecture answers two questions. Which machine has the final say on what happened? And whose hardware runs that machine?

Unreal Engine's networking documentation states the first part plainly: "The server, as the host of the game, holds the one, true, authoritative game state." The same docs define two ways to run that server. A dedicated server is "a server with no local players." A listen server is "a server that also has a local player who is hosting the game."

Both are authoritative. Only one is dedicated.

That's why "authoritative" and "dedicated" aren't synonyms, even though they're often used that way. Headless is a third, separate term. It describes a build with no rendering, audio or input, not where that build runs.

What Is a Dedicated Server?

A dedicated server runs the game on a machine no player controls. Clients send inputs. The server decides what happened and sends the result back.

Rocket League is a well-documented example. In 2015, Psyonix founder Dave Hagewood explained that "one of the reasons we decided to use dedicated servers was to take control over the authoritative physics." When ball physics decides the match, nobody's living-room PC gets to referee it.

Moving authority off player machines changes four things at once:

• No host advantage. No player sits at zero latency to the authority while everyone else waits on a round trip.

• No host migration. A player quitting is a disconnect, not the end of the session.

• No host hardware ceiling. Tick rate, player count and bandwidth are set by the studio, not by whichever player was picked to host.

• A place for server-side systems. Input validation, persistence, telemetry and replays need a machine the studio trusts.

Authority only protects what actually runs on the server, though. Bungie learned this with Destiny's Crota raid, where boss logic built on client-side systems let players force a favorable outcome by pulling their network cable. Edgegap's Destiny 2 network architecture deep dive covers that case. Aimbots and wallhacks also run on the client, so they still need a separate anti-cheat layer. Our Overwatch deep dive shows how a server-authoritative game still predicts on the client without trusting it.

Dedicated Servers: Genres, Games, Benefits and Drawbacks

• Key game genres: first-person shooters, battle royales, hero shooters, sports, fighting games, survival and persistent worlds, and any mode with ranked play or an in-game economy.

• Examples of games using studio-run dedicated servers: Fortnite, Roblox, League of Legends, VALORANT, APEX Legends, PUBG: BATTLEGROUNDS, Overwatch, Rocket League, Dota 2, Sea of Thieves, Dead by Daylight, Call of Duty (which "uses a client-server model to host matches," per Activision), Counter-Strike 2's official matchmaking and Rivals of Aether 2.

• Examples of games with community-hosted dedicated servers: the studio ships a server build, and players or hosting companies run it. Counter-Strike 2 community servers, Rust (alongside Facepunch's official servers), Minecraft (Java server software and Bedrock Dedicated Server, with Mojang-hosted Realms as the official option) and Valheim's free dedicated server binary.

• Example of a game that moved from player hosting to dedicated servers: Dead by Daylight replaced its killer-hosted listen server. "Average ping time is now less than 60ms compared to 120ms with our previous listen server," Fadi Beyrouti, Head of Technology at Behaviour Digital, said in 2019.

• Key benefits: server-side authority, no host advantage, no host migration, consistent performance for every player, and a trusted place for validation, persistence and telemetry.

• Main drawbacks: compute cost per match, a server build to maintain alongside the client, and latency that depends on where servers are placed.

What Is Peer-to-Peer Networking?

Peer-to-peer covers two different designs.

Host-based P2P is the listen server from the table above. One player's game is the server, and everyone else connects to it. The host's connection, hardware and honesty all shape the match. If the host leaves, the session ends or attempts a host migration. Edgegap's Halo: Reach deep dive shows how much engineering Bungie put into making that hand-off survivable.

Full-mesh P2P has no host owning the simulation. Every peer runs the same deterministic simulation from the same inputs. Paul Bettner and Mark Terrano, then at Ensemble Studios, described this approach in their GDC 2001 paper 1500 Archers on a 28.8, covering how Age of Empires kept large battles in sync over modem connections by exchanging commands rather than unit state. The cost is connection count. A full mesh of n players needs n(n-1)/2 connections, which keeps lobbies small.

Both designs hit the same obstacle. Most players sit behind NAT, and a growing share sit behind carrier-grade NAT, which can block direct inbound connections entirely. The standard toolkit has three parts: STUN discovers a player's public address, TURN (RFC 8656) relays traffic when a direct path fails, and ICE (RFC 8445) coordinates the attempts.

Peer-to-Peer: Genres, Games, Benefits and Drawbacks

• Key game genres: friends-only co-op, local and LAN play, and deterministic lockstep strategy games.

• Examples of games using peer-to-peer: Halo: Reach (host-based, with host migration), Age of Empires (full-mesh lockstep), Mortal Kombat X and Injustice 2 (rollback between two machines), Super Smash Bros. Ultimate, GTA Online and Red Dead Online (peer-hosted sessions), Elden Ring (player-hosted co-op and invasions), Monster Hunter (player-hosted quests), Street Fighter 6 for PC-to-PC matches, and Valheim when a player hosts a world from inside the game.

• Examples of hybrid models: Destiny 2. "Every activity in Destiny 2 is hosted by one of our servers," Bungie engineering lead Matt Segur wrote in 2017, while describing the game as "a hybrid of client-server and peer-to-peer technology."

• Key benefits: no server compute cost, and one codebase that runs entirely inside the game client.

• Main drawbacks: the host can alter the match, the host has a latency advantage, sessions end or migrate when the host leaves, player IP addresses are exposed, and NAT blocks a share of direct connections.

That fallback is where relays come in.

What Is a Relay Server?

A relay server forwards traffic between players who can't reach each other directly. It solves network connectivity. It doesn't run the game.

Unity's documentation for its Relay service describes the setup: "you can use Unity Relay to initiate a connection between multiple clients and a host." The host is still there. The relay carries its traffic.

Michal Buras, then Lead Network Engineer at Highwire Games, covered relays in his September 2024 talk at Live Service Game Summit (video). His summary of the privacy benefit: "Your private address is not shared with anyone except the server which relays the information between you and the other player." Valve's Steam Datagram Relay documentation makes the same point: "Relaying the traffic protects your servers and players from DoS attack, because IP addresses are never revealed."

The trade-off is the extra hop. "A relay server adds an extra node to your game packet that it has to pass through, which introduces latency," Buras explained. A relay only reduces latency when its network path beats the public internet path, which Valve notes can happen for some players on its own network. Placement decides which way it goes. Valheim's crossplay mode runs on Microsoft's PlayFab backend and routes traffic through a relay, and Iron Gate's own documentation warns those players are more likely to see lag, timeouts and disconnects, as covered in Edgegap's Valheim deep dive.

Relays: Genres, Games, Benefits and Drawbacks

• Key game genres: player-hosted co-op and casual games whose players sit behind NAT or firewalls, and crossplay sessions across platform networks.

• Examples of games using relays: Among Us, which "always uses relay servers," according to Innersloth's lead developer; Tekken 8, built on Diarkis networking middleware; Street Fighter 6, Deep Rock Galactic and Warhammer: Vermintide 2, which fall back to Steam Datagram Relay when a direct connection isn't available (GameNetworkingSockets issue #398); and Valheim servers started in crossplay mode, where, per Iron Gate's server guide, "the server transmits data via a relay server and therefore does not require Port Forwarding."

• Key benefits: NAT and firewall traversal, hidden player IP addresses, protection from denial-of-service attacks between players, and fast integration with no server build.

• Main drawbacks: an extra network hop, no validation of gameplay, the host's advantage and hardware limits remain, host migration is still needed, and routing depends on where the relay provider has locations.

Do Relays Stop Cheating?

No. They narrow the exposure compared with raw peer-to-peer, and that's where the benefit ends.

A relay is better than direct P2P on one front. Nobody learns anyone else's IP address, so players can't be targeted with denial-of-service attacks by the people they're matched with.

The game itself is still player-hosted. The hosting player owns the match state and can alter it, through memory editing or lag switching, with or without the relay in the path. The authoritative logic also ships inside the game build every player downloads. Anyone can decompile that build to study how the host validates the match, then modify it. A relay never sees any of this. It only forwards packets.

Data around the session can leak too. Buras showed lobby data on a released title being read with an off-the-shelf debugging tool, exposing "all the other player's private information in plain text." His conclusion: "this is a massive amount of risk for a commercial game to bear."

Adding checks to the relay doesn't change the category. When Buras's team considered a relay that would "serialize packets, maybe analyze them to prevent cheating," it didn't hold up. "If you're computing, it's not a relay server anymore," he said. "It becomes a form of a dedicated server."

The same applies to in-game economies. Purchases, inventory and progression need validation on a machine the studio controls, and a relay isn't one.

Which Model Fits Which Game?

Once authority sits on a server, the remaining question is how much that server needs to do. Edgegap's dedicated server glossary describes four scopes, each costing more CPU per player than the one before it.

Among Us shows how far the relay-style scope can go. Innersloth's lead developer explained in 2020 that its relay servers "are partially authoritative so I can avoid expensive physics calcs on the servers (allowing me to scale cheaper) but still handle most hacks, host migration, etc." In Buras's terms, a relay that checks the game has become a small dedicated server.

Fighting games are often assumed to need direct peer connections because of rollback. Rivals of Aether 2 runs rollback netcode on dedicated servers, as covered in Edgegap's Rivals of Aether 2 breakdown.

Peer-to-peer, with a relay for connectivity, still fits a narrow set of cases: friends-only sessions with no ranked mode, no economy and no strangers in the lobby, and deterministic lockstep games where every peer already runs the full simulation. Outside those, the question is which size of dedicated server, not whether to use one.

What Does Each Model Cost?

Peer-to-peer avoids compute cost, since players supply the hardware. It doesn't avoid every cost. Relay bandwidth is usually billed by usage, and host migration is real engineering work. Buras put the trade-off directly: "while the upfront of relays were cheap, the host migration solution you have to build becomes extremely expensive." His full cost breakdown is in Edgegap's recap of the talk.

Dedicated servers used to mean reserving capacity per region, paying for it whether players showed up or not, and staffing the DevOps work to keep it running. On-demand orchestration changes that. Edgegap's orchestration platform starts a server when a match is made, in roughly 3 seconds on average, across 615+ locations at a single price for every location. A relay-style or multi-room server can run on a fraction of a vCPU, which brings its cost close to a relay's while keeping authority off player machines. In one AAA studio's deployment, server placement produced a 58% average latency reduction versus public cloud, with sub-50 ms latency for 78% of players (case study).

How the Pieces Fit Together

Authority decides who is trusted. Hosting decides whose hardware runs the trusted simulation. Relays decide how packets get there when a direct path fails.

Kept separate, the trade-offs are clear. A relay makes a player-hosted game connectable and keeps IP addresses private. A dedicated server, at whatever size the game needs, takes the host out of the match. The netcode built on top, from prediction to rollback, is covered in Edgegap's Netcode Fundamentals and Call of Duty netcode insights.

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This article cites the works listed in Sources. All rights in the original content are owned by their respective owners.

• Epic Games, Networking Overview for Unreal Engine, Unreal Engine documentation.

• Dave Hagewood, founder of Psyonix, interviewed by GamesBeat, July 20, 2015.

• Paul Bettner and Mark Terrano, then at Ensemble Studios, 1500 Archers on a 28.8: Network Programming in Age of Empires and Beyond, GDC 2001.

• Michal Buras, then Lead Network Engineer at Highwire Games, Live Service Game Summit talk, September 10, 2024 (full transcript).

• Valve, Steam Datagram Relay, Steamworks documentation.

• Valve, GameNetworkingSockets issue #398, GitHub, 2026.

• Unity Technologies, Relay, Netcode for GameObjects documentation.

• Iron Gate Studio, A Guide to Dedicated Servers, Valheim support.

• Matt Segur, then Engineering Lead at Bungie, Destiny 2 weekly update, May 26, 2017 (via Stevivor).

• Roblox, Client-server runtime, Roblox Creator documentation.

• AWS for Games, Epic Games taps AWS Local Zones for Fortnite's NA Central servers, February 14, 2023.

• Call of Duty, Call of Duty Update: An Inside Look at Matchmaking, January 2024.

• Fadi Beyrouti, Head of Technology at Behaviour Digital, in How Dead by Daylight survives the test of time using AWS, AWS for Games, December 17, 2019.

• Innersloth lead developer (u/fwfb), r/gamedev comment on Among Us server architecture, 2020.

• IETF, RFC 8656 (TURN) and RFC 8445 (ICE).