Note: P2P = Peer-to-Peer For both PvE and PvP, this is a laymen's explanation for why "Dedicated Servers" are the Industry Standard vs "P2P systems" for FIrst Person Shooter MMOs This is a long response, so forgive me. But I believe it attempts to adequately paint the picture as to why Dedicated Servers (Dedis) are the industry standard for MMO FPS games vs P2P systems. [b][u]Background: [/u][/b] Destiny is 100% a massive multiplayer online (MMO) world (it requires being online with other players for your playing experience. Unlike how Halo's PvE content could be played "offline" for example). An important side note: the entire line of Halo's games utilize "Dedis" to create its game world "Stability". However; with Destiny, Bungie/Activision chose to rely on an inferior "P2P connection system" for the game world interaction with other players both for PvE and it's PvP content. [b][u]The major differences between a "Dedis" system and a "P2P" system:[/u][/b] In summary, with "Dedis" Clients/players receive processed data from the server and display it with minimal issues and resource utilization from the players internet setup/system and console itself. In the alternative, with the "P2P" model there is no server. Each "peer" instead receives the raw input streams of each other player and determines the results itself (this is done using the players resources which are largely inferior to a game company's "Dedis" System. [b][u]P2P is generally considered obsolete for action games and in particular online Multiplayer First Person Shooters[/u][/b] (see the multiple resources listed below). [b][u]"P2P" has many disadvantages vs "Dedis"[/u][/b] * It is very difficult to keep all peers synchronised. Minute differences between peers can escalate over time to game-breaking paradoxes. * It is very difficult to support new peers joining part-way through a game. * Each peer must communicate with all other peers, limiting the number of connected players. * Each peer must wait for every other peer's message before simulating the next "network frame", resulting in all players experiencing the same latencyas the player with the worst connection. In online gaming, lag is a noticeable delay between the action of players and the reaction of the server in a video game. The tolerance for lag depends heavily on the type of game. a twitch gameplay game such as a first-person shooter with a considerably higher pace may require significantly lower delay to be able to provide satisfying gameplay (this relevant to PvE and PvP). Perhaps the most common type of lag is caused by network performance problems. Losses, corruption or jitter(an outdated packet is in effect a loss) may all cause problems, but these problems are relatively rare in a network with sufficient bandwidth and no or little congestion. Instead, the latency involved in transmitting data between clients and server plays a significant role. Latency varies depending on a number of factors, such as the physical distance between the end-systems, as a longer distance means additional transmission length and routingrequired and therefore higher latency. Routing over the Internet may be extremely indirect, resulting in far more transmission length (and consequent latency) than a direct route. In addition, insufficient bandwidth and congestion, even if not severe enough to cause losses, may cause additional delays regardless of distance. As with the hardware issues, packets that arrive slowly or not at all will make both the client and server unable to update the game state in a timely manner. The noticeable effects of lag vary not only depending on the exact cause, but also on any and all techniques for lag compensation that the game may implement (described below). As all clients experience some delay, implementing these methods to minimize the effect on players is important for smooth gameplay. Lag causes numerous problems for issues such as accurate rendering of the game state and hit detection. In many games, lag is often frowned upon because it disrupts normal gameplay. The severity of lag depends on the type of game and its inherent tolerance for lag. Some games with a slower pace can tolerate significant delays without any need to compensate at all, whereas others with a faster pace are considerably more sensitive and requires extensive use of compensation to be playable (such as the first-person shooter genre). Due to the various problems lag can cause, players that have an insufficiently fast Internet connection are sometimes not permitted, or discouraged from playing with other players or servers that have a distant server host or have high latency to one another. Extreme cases of lag may result in extensive desynchronization of the game state. On a non-P2P system, Lag due to an insufficient update rate between client and server can cause some problems, but these are generally limited to the client itself. However, on a P2P system, other players may notice jerky movement and similar problems with the player associated with the affected client, but the real problem lies with the client itself. If the client cannot update the game state at a quick enough pace, the player may be shown outdated renditions of the game, which in turn cause various problems with hit- and collision detection. If the low update rate is caused by a low frame rate these problems are usually overshadowed by numerous problems related to the client-side processing itself. Both the display and controls will be sluggish & unresponsive. While this may increase the perceived lag, it is actually a different kind than network-related delays. When these issues occur to the "host" of the P2P connection the same problem on the "host acting server" may cause significant problems for all clients involved. If the "host acting server" is unable to accept packets from clients fast enough and process these in a timely manner, client actions may never be registered.*** When the "host acting server" then sends out updates to the clients, they will experience freezing (unresponsive game) and rollbacks. Without any form of lag compensation, found in Dedicated Server hardware systems, the P2P clients will notice that the game responds only a short time after an action is performed. This is especially problematic in FPS's, where enemies are likely to move as a player attempts to shoot them and the margin for errors is small. This all happens when the player "host" in a P2P system has substantially less resources and issues than a "dedicated server" that would be hosting the game play of the multiplayer group. * It decreases the capability of higher frame rates (i.e. 60vs30 fps). What this means is ...generally, games consist of a looped sequence of states, or "frames". During each frame, the game accepts user input and performs necessary calculations (AI, graphics etc.). When all processing is finished, the game will update the game state and produce an output, such as a new image on the screen and/or a packet to be sent to the server. The frequency at which frames are generated is often referred to as the frame rate. As the central game state is located on the server, the updated information must be sent from the client to the server in order to take effect. In addition, the client must receive the necessary information from the server in order to fully update the state. Generating packets to send to the server and processing the received packets can only be done as often as the client is able to update its local state. Although packets could theoretically be generated and sent faster than this, it would only result in sending redundant data if the game state cannot be updated between each packet. A low frame rate would therefore make the game less responsive to updates and may force it to skip outdated data (bullets that don't register, etc...this effects PvE and PVP). This can be especially noticeable in raid and strike modes when group synchronization is key to completing a specific objective or team damage. * Negatively affects the max "tick rate" potential of the game. The Tick rate is the rate at which a game server runs simulation steps. A "tick" is a number associated with each sim step which is broadcast to clients to help them synchronise with the server. There are 3 reasons to limit the frequency of server sim steps to a predefined tickrate: to conserve server and client bandwidth, to conserve server CPU time, and to allow clients to be certain of how much time has elapsed between each tick. The last point is important for internet games, as network updates from the server can arrive at different intervals or even an incorrect order. The disadvantages of an obsolete P2P system are responsible for creating many of the major issues plaguing D1's gameplay, for both PvE and PvP for the last 3 years, not to mention how it restricts larger multiplayer scale and quality of game content being utilized within the game. Dedicated gaming servers are an industry standard for AAA Massive Multiplayer Online (MMO) games. Dedis are highly preferred and utilized for these games in particular for both multiplayer PvE and PvP. This is especially important considering the unique degree of how Destiny's PvE content (unlike most any other game), not just its PVP content, requires significant internet "Stability". Some Sources: https://www.bungie.net/en/Forum/Post/227274057/0/0/1 Link to an opinion post explaining game play issues: https://www.bungie.net/en/Forum/Post/227272499/0/0/1