Re: european servers.. (fwd)

[Chris Behrens <cbehrens@xxxxxxxxxxxxxx>]

On Wed, 29 Oct 1997, Christophe Kalt wrote:

> | Is there a way to keep the functionality (I always want to connect to
> | irc.ced.chalmers.se if possible, and I want to connect to the US if none
> | of my uplinks is connected to the *NET*, not only if they are not
> | connected to me). with the current options, or do we need new server
> | configlines to reach this?
> 
> can't this be done by having your US uplinks setup a L line
> for you? something like "L:*.us::<your server name>:"
> (syntax might be wrong)
> I agree it's probably not the best, since the connection
> will be made then broken, but doesn't it work?
> isn't it enough?

Yes, that does work somewhat, but no it is not enough.  The reason
is that the server with the L: line will pass on "SERVER whatever"
on to everyone, and then break the connection after it figures out
it is hubbing something it shouldn't.  This causes many problems when
the network is lagged, or things are reconnecting everywhere.  A
situation that occured the other day:

Imagine 2 European servers, A and B.
Imagine US servers, C, D, E, F...

The situation was this:   A - B - C
                         /
                       <lag>
                        /
                       D  -  E -<lag>- F

Server C does not see server F, yet.  Server F does not see server A,
yet.  Server C tries to auto-connect to server F because it is not
connected to another US server, and server F is missing.  Server F
sends "SERVER C" back to server E.  Server C sends back "SERVER F"
back to Server B.  Server F sends "SERVER B" back to server E.
Server F sends "SERVER A" back to server E.  Server F disconnects
server C when it gets "SERVER D" from it.

At this point, the damage is done.  Somewhere along the way, it is
possible for server D and E to split apart now because of colliding
SERVER messages.

It can even become a real mess for F to reconnect to the network if
C keeps trying to autoconnect to it and sending "SERVER F" messages
back through the network.

Damn "Server Exists" stuff.

Ultimate solution to that problem is to put TS on SERVER messages or
something like that.

- Chris

--
Chris Behrens
Software Engineer
Concentric Network Corporation

> 
> | It would be nice with a config that allows me to set that "activate
> | autoconnects in this connection class if all the following servers are not
> | currently listed in the online server list". Wildcards would be nice when
> | specifying this.
> | 
> | For instance, I would put a limitation on my uplinks if there was a
> | com/net/org server online at the moment (since we have none of these in
> | Europe right now).
> 
> this sounds like some kind of "reverse" L line.
> 
> also, the probability of you connecting to the new born
> server before it connects to its normal uplinks is rather
> close to null, isn't it?
>