[Dxspider-support] multiple logins + real time user info

[djk]

Traditionally, until say five or six years ago, a user would connect 
once - to one node - and the cluster of nodes would make sure that that 
user could not connect to any other node in the same cluster. This is 
one of the functions that PC16/17 traffic was used for, and was the 
standard method for determining who was on which node. This part of the 
cluster protocol (together with PC19/21 for node connections) had many 
problems and was the major reason that I came up with PC92. This 
sentence removes, once and for all, the major problems caused by 
"looping" when one tried to obtain some resilience in the network by 
nodes trying to cross connect to different "branches" of the "tree" that 
the original AK1A cluster protocol assumes. But it does also introduce 
some other things (features if you will) whose utility could be debatable.

One of the side "benefits" that was discussed at the time that PC92 was 
introduced, was that users could now also connect to more than one node 
at a time. I could (and still can) see some merit in this - in some 
limited circumstances - for users in difficult networking situations. 
But that was long time ago and internet connectivity has improved well 
beyond the point where this facility is, I believe, useful - or indeed - 
desirable. Especially as there (now) seem to be several users who 
connect to many nodes as a matter of course. This may even be a 
function/feature of some client software that they use (I don't know, 
not my department).

I have had a number of private complaints about the amount of bandwidth 
that running a node (especially a well connected and popular one) takes. 
Having "a lot" of users connecting to more than one node simultaneously 
creates a lot of  additional administrative traffic, which is there to 
allow every node to retain a reasonably accurate view of the cluster to, 
amongst other things, control the number of connections that a user has. 
But even with all this traffic, the "view" that any node has is likely 
to be neither complete nor accurate. This is simply because it takes 
time for an update to traverse the network and situations could change 
during this process. On a node such as GB7DJK with good, stable links, 
it will be pretty close - be still probably not accurate. But for all 
that networks have improved - there still seem to be nodes scattered 
about that can't seem to stay connected stably.

I am working (very slowly) on a newer version of DXSpider and I would 
like to discuss the whole area of user "management". I really do wonder 
whether - in the modern cluster - with 6000+ concurrent users we 
continue to require "real time" user connectivity information in its 
present form.

Please discuss.

Happy New Year

Dirk G1TLH

PS: On a DXSpider node the default maximum concurrent connections that a 
user can have to a cluster is three. A sysop can enforce any limit they 
like on their own node and I know that some sysops set this limit to one.