[ENet-discuss] icmp/tracert/discovering network topology?

Jay Sprenkle jsprenkle at gmail.com
Mon Jan 11 05:58:18 PST 2010


Thanks for the help but I think you misunderstood the problem  :)

I'm trying to determine if machine 'X' could communicate more quickly to
machine 'Y' or machine 'Z' (and you're on machine 'A'). 'A' pinging 'Z'
won't tell you the time for 'X' pinging 'Z'. etc.

I could:

Get machine X to ping machine Y and Z. This algorithm would be "here's a
list of machines, you figure it out."  If there are a lot of machines in the
list this could be problematic and very slow to discover good connections.

or

Machine 'A' tracert's machine 'X', 'Y', and 'Z'. It now knows the physical
layout of the network and can calculate how many hops there are between the
machines (assuming there's only one path between any two points on the
internet). This algorithm would be "here's my best guess about which
machines will get the best response time from your machine"

The second algorithm is based on some assumptions that may be wrong and uses
the assumption "more hops = bad". Some combination of the two might be
better.


On Mon, Jan 11, 2010 at 7:36 AM, Ruud van Gaal <ruud at racer.nl> wrote:

>  Ping is what most, if not all games use to determine client-server
> 'distance'. The number of hops doesn't say anything since the hardware
> involved can be different greatly, resulting in processing times that vary
> in many magnitudes.
> The only way to be sure is to use ping, which is in fact relatively stable
> in practice. Keep pinging as things progress so you always update the latest
> ping time (taking care to avoid spikes, so slowly progressing ping time to a
> stable value). Don't just calculate ping time once.
>
> I would not know of any method that relates X hops to any useful time
> value. If one route is 9 hops, the other 20, it's certainly not sure whether
> one is faster than the other...
>
> Ruud
>
>
>  ------------------------------
> *Van:* enet-discuss-bounces at cubik.org [mailto:
> enet-discuss-bounces at cubik.org] *Namens *Jay Sprenkle
> *Verzonden:* Monday, January 11, 2010 14:12
>
> *Aan:* Discussion of the ENet library
> *Onderwerp:* Re: [ENet-discuss] icmp/tracert/discovering network topology?
>
> I would think the actual ping time would not be that useful. It would vary
> considerably over time. What I was thinking was the length of the route in
> routed hops, not physical distance, was what I needed to sort by. These
> might measure roughly the same thing but physical organization only needs
> one measurement.
>
>
> On Mon, Jan 11, 2010 at 3:37 AM, Ruud van Gaal <ruud at racer.nl> wrote:
>
>>  Hi,
>>
>> Isn't the ping time more important? In that case, keep ping times on the
>> server (probably already done by ENet, search the ENetPeer class) and get
>> the list from the server ordered by ping.
>> I wouldn't say the distance in computers is of much use for most
>> situations.
>>
>> Cheers,
>> Ruud
>>
>>   ------------------------------
>> *Van:* enet-discuss-bounces at cubik.org [mailto:
>> enet-discuss-bounces at cubik.org] *Namens *Jay Sprenkle
>> *Verzonden:* Sunday, January 10, 2010 20:09
>> *Aan:* Discussion of the ENet library
>> *Onderwerp:* [ENet-discuss] icmp/tracert/discovering network topology?
>>
>>   Good morning,
>>
>> I'm considering adding some extra features to my enet based peer to peer
>> application. I'd like the main server to be smart enough to discover which
>> peers have the shortest connection path to each other. When a peer requests
>> a list of other peers to connect to then the server can deliver an optimal
>> list. The only way I could think of to implement this would be to do a
>> tracert to each peer and sort the list of peers by what common paths they
>> share. Has anyone done icmp packets with enet? I know it's not it's intended
>> function but it doesn't seem like it would be difficult to hack together. If
>> anyone has any better ideas on how to implement this I'd love to hear them.
>>
>> Thanks!
>> Have a good weekend
>>
>>
>>
>> _______________________________________________
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>> ENet-discuss at cubik.org
>> http://lists.cubik.org/mailman/listinfo/enet-discuss
>>
>>
>
>
> --
> Cause united breaks guitars
> http://www.youtube.com/watch?v=5YGc4zOqozo
>
>
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>


-- 
Cause united breaks guitars
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