• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
fjholmstrom

Detecting and disconnecting peers that time out?

3 posts in this topic

I've implemented a networking library with uses the techniques described in the "Tribes Networking" paper, now in my current design I have a packet window size of 32 (aka. I can have 32 packets "in transit" at any point in time, if I have not heard about the 32:nd oldest packet, I can't send any new packets out).

 

I also have a time-out that says "if I have not heard anything from this peer in X seconds we should send something", so I send a special "Poke" package from the peer that hasn't heard anything for a while and if the "Poke" does reach the other end it will respond with a "What" package (It's called a "Poke... What?" sequence in code).

 

But my instinct tells me this would not be needed, if there comes a case where I actually end up with the entire window full the peer is most likely gone already? I'm not sure the way I deal with it using Poke/What is ideal either... I suppose in theory (at least assuming non-mobile) stuff you could just disconnect them once the entire packet window fills up with un-acked packages.

 

So basically my question is: How do you usually deal with detecting timed-out peers or peers that are gone? 

0

Share this post


Link to post
Share on other sites

The "poke/what" packet sounds like a "heartbeat," which is sometimes used to keep idle connections alive. NAT gateways may be aggressive in tearing down connections if no traffic has been seen for a few seconds, so keeping the interval < 5 seconds is a good idea.

If you send packets on regular intervals, the heartbeat is not needed. And if you exceed your window size, and time out for a number of seconds, you can probably safely assume that the remote end isn't going to be having a good time playing the game, and treating it as dropped (which it probably is.)

 

What I do these days is keep a certain amount of "slack" (this may be buffer space, or window space, or whatever,) and as soon as that slack is exhausted (out of buffering, out of window space) I declare the other end unable to keep up, and drop the connection. This works for both TCP (buffering) and UDP (window space.)

0

Share this post


Link to post
Share on other sites
The "poke/what" packet sounds like a "heartbeat," which is sometimes used to keep idle connections alive. NAT gateways may be aggressive in tearing down connections if no traffic has been seen for a few seconds, so keeping the interval < 5 seconds is a good idea.

If you send packets on regular intervals, the heartbeat is not needed. And if you exceed your window size, and time out for a number of seconds, you can probably safely assume that the remote end isn't going to be having a good time playing the game, and treating it as dropped (which it probably is.)

 

What I do these days is keep a certain amount of "slack" (this may be buffer space, or window space, or whatever,) and as soon as that slack is exhausted (out of buffering, out of window space) I declare the other end unable to keep up, and drop the connection. This works for both TCP (buffering) and UDP (window space.)

 

Yes, I suppose the Poke/What thing is sort of like a heartbeat. But my library is built like the Tribes Networking paper described and uses a fixed (configurable per client) rate. So a heartbeat is completely unnecessary, as you say. And if one of the connections drop WINDOW_SIZE (defaults to 32 for me) packets *in a row* - their experience will most likely be horrible anyway.

 

While the way you do is kind of "aggressive" (lack of a better word), it  seems like a really clean approach - BTW when you say "slack", what exactly do you mean? Like I've said my window size is 32 packets, would "slack" be more packets on-top of that or?

0

Share this post


Link to post
Share on other sites
BTW when you say "slack", what exactly do you mean? Like I've said my window size is 32 packets, would "slack" be more packets on-top of that or?

I'd say that if you lose 5 packets in a row, you're probably having a bad time, so 32 packets contain a lot of "slack" already!

What constitutes "slack" is actually a game design question. Users are often willing to tolerate worse conditions than you'd like them to, so make sure to give a generous allowance for user pain. 32 packets seems like a fair bit of slack, so you're probably good! (Unless you send 60 packets a second -- 500 ms of slack probably isn't enough.)
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0