We all had that case before, you were talking to a friend, and suddenly the call dropped. You kept talking for a couple of seconds until you realized, your call ended. . This is a pretty good example on what you are going to learn next. We all agree, the best way to end a call is to say goodbye, because that way, both ends know that they will hang up. Your friend can call another friend and so can you as nobody is waiting for the other person to confirm. If a connection drops both sides (server + client) need to process this information. While on your device, it's pretty obvious that the connection is gone, it can take a couple of seconds for the tiger engine (which is handling hundreds of thousands of live connections per second) to confirm and update the other VPN nodes around the world that you are gone.
Let us explain. When you tell your friend something, he is listening and will not constantly interrupt you. From time to time he will be confirming his attention by mumbling stuff like "ok, yes, mmmh" to let you know that you are not just having a monolog. If you take a breath or suddenly stop to talk, your friend won't hang up immediately but rather ask you , hey, are you still here? This is where the "handshake" comes along. In a the VPN technology, periodically, both sides will handshake and confirm that they are still here and connected. In a case of a sudden disconnect (when you don't say goodbye) our VPN is still waiting a bit as in the example given above. If the VPN node would not do that, each tiny pause (e.g. packet loss) would disconnect you. Imagine that your friend would hang up on you each and every time if you would not reply to him every single second ;-).
All 300+ VPN Servers across the globe need to know, if you are still "talking" in the sense of being connected to a VPN node, or not. The reason given is, because some subscription types only allow 1 connection at each time. To avoid connecting twice at the same time, our VPN nodes need to be aware of you and to which VPN node you are currently connected. Each node needs to confirm that either (case 1) you said goodbye, in which case the connection was terminated correctly, then all VPN nodes will be updated to allow a new incoming connection from you. The first VPN node that gets your new connection will then tell the other ones that you are currently connected and that the other nodes should not allow your connection until you disconnect. (case 2) a connection was lost, so that it can be cleared. However due to the influence that a lost connection might not be "lost" but still waiting for your device, the trouble starts to happen.
In most of the cases, customers are trying to reconnect immediately. However that "VPN node" -> lets say your friend, is still not 100% sure if you are just silent or you are not there anymore, so he will not pick up a new call (which is your reconnection attempt). He would see your caller ID on the screen but would reject the call as he is still thinking that you are talking to him (but you are not). When he realized that you are gone, he will update all nodes that you are good to reconnect (either to him) or to any other node, but because he told the other servers that he is still talking to you, they won't let you in either, meaning connecting to a different VPN will no sort the problem.
We have a helper (so called terminator) in place that will periodically kill each connection that is not confirmed "or so called hanging" but because we handle hundreds of thousands of connections per second, telling each and every node (in realtime) who is connected to which node, would kill the performance and would impact your speed and the speed of others, therefore the terminator kicks in periodically. Having a plan with one connection can sometime cause issues - so we decided to add more connections in the new plans (Zen, Strong, Hero Tiger). Since this is a commercial decision (because 2,3,4,5... connections could mean multi usage, multi traffic and multi cost for us as service provider) it's unfortunately not just something we can give away for free. Running a global internet service backbone is expensive and bandwidth prices vary per country.
Coming back on what can you do if you can't re-connect or connect to a VPN due to sudden disconnect (when the connection wasn't closed correctly due to the nature of the internet. If you are having one connection, you can consider to upgrade your plan and get additional benefits. The other option is (and we hope the detailed explanation will help you understand this) give the VPN a minute or two, to clear the suddenly disconnected connection (alternatively you can kill a connection also inside the tigervpn customer dashboard) and reconnect. These issues are rare, happen from time to time, but they disappear on itself if you give it a solid minute or two.
We hope this was helpful, insightful and transparent to let you understand the nature, complexity and background of how VPN works and why it sometimes causes issues. Unfortunately the nature of a disconnection is extremely divers, anything can be causing a sudden disconnect.
The list is long, but it can be anything as below
+ App process delay
+ Hibernate status
+ Expired Handshake
+ Delay in completing the process due to heavy CPU load / RAM
+ Slow connection (2G, Edge)
+ Overbooked crowded public Wifi
+ Poor reception
+ Packet loss
+ Driving (train, car)
+ Obstacle as in (outdoor, indoor, house)
+ Poor equipment
+ Old, outdated router
+ Packet loss on ISP
+ Mobile Hotspot
+ VPN over VPN over VPN ...
thanks for reading, the tigerVPN team!