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I've found a common subject in forums asking about using VPNs to reduce latencies between the gamers and the game servers. I've even found some blog posts confirming this.

From my understanding, using a VPN shouldn't reduce latency at all, unless routers somehow treat encrypted packets differently.

What's the truth here? Does the type of VPN make a difference?

SUMMARY OF COMMENTS/ANSWERS: While in the ideal net neutral world latency over a VPN should be greater or equal to latency over a public network, in the real world with crappy ISPs latency could actually be reduced by using a VPN. Pity! Especially because it leads to a "try it an see" approach on each particular ISP.

Unless we are talking about something like ISP provided VPNs (MPLS or similar) that can have a different routing and priority characteristics. But if you get one of these you are usually aware and paying for it. Not very likely in casual gaming scenarios.

Vinko Vrsalovic
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    A VPN might be able to get around traffic shaping/throttling. If you have a crappy ISP that slows gaming related activity. But evil ISP will almost certainly also be slowing VPN traffic. – Zoredache Mar 13 '13 at 23:48
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    This is marked as a duplicate, but the other question is for office-to-office VPN; this is for gamers and game servers. All things being equal, this would be a duplicate. But things today are not equal. Your ISP (Comcast, ATT) will almost certainly be throttling your traffic (or at least _someone's_ traffic, if multiple players are involved). The only way to prevent this (other than technological subterfuge) is through legislation that guarantees net neutrality. (Search for: vpn + traffic shaping {comcast|att}) – michael Mar 14 '13 at 03:12
  • Btw, encryption is different than VPN. You can have encrypted data that is treated differently than data over a VPN; e.g., comcast purportedly uses a network filter application (sandvine) that intentionally disrupts non-comcast user's connections (sending a TCP/IP reset (RST) flag); a VPN should prevent this type of "attack". (footnote: the fcc actually ordered comcast to stop doing this, but at some point they might author/pass legislation that allows/encourages it again.) – michael Mar 14 '13 at 03:25
  • @michael_n Don't all VPNs use some kind of encryption? That's what I meant. You can of course send/receive encrypted data and not partake in a VPN. – Vinko Vrsalovic Mar 14 '13 at 08:59
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    A MPLS VPN by the carrier may very well mean shorter latencies as it could be routed differently than normal traffic, and it could be prioritized. Although I do agree that most VPN solutions, like IPSEC over WAN will always add latency (although compression in theory can lower the latency for large packets). It's a shame I couldn't post an answer. – 3molo Mar 14 '13 at 09:31
  • For admins: this is a similar question, but different enough to warrant different answers. @3molo: I also wish you could. – Vinko Vrsalovic Mar 14 '13 at 09:43
  • @VinkoVrsalovic right, exactly. encryption itself isn't enough to make yourself "private", no more than a ski mask makes one invisible in broad daylight; so, ISP's just poke everyone they don't recognize with a sharp stick just to hear 'em squeal (and they'll stop only if they recognize your voice). VPN's turn out the lights, so all they hear is the pitter-patter of footprints in the dark. It's a relatively sharp-stick-free environment. (Apologies for the extended metaphors; I'm just entertaining myself.) – michael Mar 14 '13 at 12:29
  • @VinkoVrsalovic If this isn't a duplicate, then it's off-topic. We don't do questions for gamers looking to optimize their latest twitch-fest here. [Please visit the FAQ](http://serverfault.com/faq). – HopelessN00b Mar 14 '13 at 13:07
  • @HopelessN00b I'm thinking about offering a very latency sensitive gaming service. I need to know what can be done to improve the experience and what the limits are and where are they. This is totally on topic from that POV, IMO. – Vinko Vrsalovic Mar 14 '13 at 13:28
  • No, it's not. "Help me design a CDN" is also not a topical question. Maybe for different reasons, but it ends in the same place. – HopelessN00b Mar 14 '13 at 13:30
  • @HopelessN00b I disagree. It's absolutely and completely a request for expert answers related to managing computer systems in a professional capacity. – Vinko Vrsalovic Mar 14 '13 at 13:35

2 Answers2

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Nope, a VPN can't alter physics to change the speed of light.

MDMarra
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    I would have thought there would be overhead that could actually possibly slow it down by a nanosecond or three, since there's encryption/decryption taking place at the endpoints... – Bart Silverstrim Mar 13 '13 at 23:45
  • Yep, if anything it will perform worse. – MDMarra Mar 13 '13 at 23:47
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    The gods unfortunately are unkind, and can choose to change the physics of the internets for us helpless mortals at their whim. The gods being of course Comcast (properly uppercased as canon dictates), and we must play by their rules. Masking our presence, trafficking in private networks, may stave off Their capricious ways, if only for the time being. Fare thee well, traveller. – michael Mar 14 '13 at 02:58
  • It is possible to influence the path you take on the internet by tunneling traffic. This is all really dependent on how your ISP manipulates their traffic to/from their peers and upstream providers, so you might not gain anything, or you might take a different path that takes a longer physical path and actually increase your latency. – cpt_fink Mar 14 '13 at 05:16
  • Assuming traffic is routed the same, the non-VPN latency is a lower bound. VPN can (at best) do epsilon worse. – tacos_tacos_tacos Mar 14 '13 at 09:51
  • The question To VPN or Not To VPN is, in this case, unrelated to routing, but rather the intentional throttling (traffic shaping) or [intentional disrupting](http://www.dslreports.com/shownews/87077) (e.g., [TCP reset](http://en.wikipedia.org/wiki/TCP_reset_attack#Comcast_Controversy) ) of your connection. The VPN hides your conversation from your ISP, who may be engaged in a malicious meddler-in-the-middle "attack". – michael Mar 14 '13 at 11:58
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A VPN could make a difference if it somehow traversed a route with less latency or hops than your "normal" network. This is rarely the case.

Joel E Salas
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  • But the VPN traffic will still follow the same route to the VPN endpoint that non encrypted traffic would and then it would still have to get from that endpoint to the game server. Even under ideal conditions, I can't imagine a situation where this would actually be true. – MDMarra Mar 13 '13 at 23:48
  • @MDMarra, you are assuming a point to point VPN. It is rare, but occasionally my link between my home computer, and work computer will fail (Comcast is evil). But both my home computer and work computer are connected to a third machine on a different network via a VPN. It is remotely possible that I could get a better link via the VPN server then directly. But as Joel said, this is very rare. – Zoredache Mar 13 '13 at 23:51
  • I'm not saying it makes sense, I'm saying it's totally possible – Joel E Salas Mar 13 '13 at 23:52
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    @MDMarra Joel is correct, "It is totally possible" to send traffic with different destination IP's in different directions on the internet. Since your VPN tunnel has the tunnel head-end as the destination IP, you can be routed differently than a packet direct to the service IP. Only once your real packet exits the tunnel do both tunneled and non-tunneled packets have the same destination IP. – cpt_fink Mar 17 '13 at 05:02
  • Of course that's how VPNs work, but under what circumstances will that be a more efficient path than the publicly routed Internet? The answer is somewhere between "never" and "almost never" which is the point of the question. – MDMarra Mar 17 '13 at 12:43
  • I was working from Europe with a server in Australia. Direct connections had a latency of 395ms. Through a VPN ... 340ms. Obviously the VPN company was using better international links with a lower latency. – TJez Jun 25 '15 at 13:12