[Dxspider-support] Re: set/isolate

[Dirk Koopman]

On Sun, 13 Aug 2000, you wrote:
> Hello Dirk,
>
>   Something else I noticed and I wonder if this behaviour is correct?
>   I have a 'set/isolate' on my link with Ian (gb7mbc). This means that
>   spots coming in via Ian are shown to my local users but not send on
>   to my other links right? If that same spot however comes in via one
>   of my other links, it's seen as a 'duplicate spot'. This is of
>   course correct for my spider, but I think it should be send on to my
>   other partners, because there could be a chance that they never saw
>   this spot before.
>
>   Illustration:
>
>   pa4ab-14 my spider has isolated link with gb7mbc this spot arrives:
>
> <- I GB7MBC PC11^3517.8^SU9ZZ^13-Aug-2000^2148Z^wae^DK5OS^DB0RDX-9^H8^~
>
> D PA4AB DX de DK5OS:      3517.8  SU9ZZ        wae           2148Z
>
> (spot stopped for further sending caused by 'set/isolate'
>
> <- I IK1ZNW-6 PC11^3517.8^SU9ZZ^13-Aug-2000^2148Z^wae^DK5OS^DB0RDX-9^H21^~
>
> Duplicate Spot ignored
>
>  (spot stopped too here)
>
> My other links (pi4cc/pi8dxq etc...) never get this one.
>
> Seems not correct to me.

Ummm...

The problem here is to decide what you want to do with spots from isolated 
sources. You have a choice really, you can do as you do and have the isolated 
spot stop at your node or you can apply a filter to all the outgoing 
connections which will then take all spots from the isolated node (as well as 
others) and send them out. 

The problem is that different people isolate for different reasons. Some 
isolate to prevent protocol loops (mainly) others isolate merely to obtain 
spots from more sources (like a clx passive link). Some links you want to 
pass spots back to the isolated node and others you don't. 

I have filters of some sort or other on ALL my links isolated or not.

I know that if I change the behaviour (so that spots are automatically passed 
out) of isolated nodes this would also cause problems so I am afraid that, 
for now until spider nodes have a better protocol, filters are the way to go.

What you need to know is that all spots arriving at a spider node are 
potentially available to be forwarded out to other nodes. Without a filter 
saying otherwise, spots arriving _from_ an isolated node will go no further 
than the node and spots coming in from elsewhere will not go _to_ an isolated 
node.

You could argue, with some force, that having to apply a filter to all the 
non-isolated nodes to pass on spots from isolated ones is a bit naff. I would 
probably agree  with you (with the benefit of hindsight) but it seemed like a 
good idea at the time!

I am looking at filters in general for the next release and I will add this 
to the list. The change in semantics will probably be something like: an 
'input' filter to allow spots into the spot 'pool' and an output filter to 
control 'output' to a particular node from the 'pool'. You will still require 
an output filter to break spot 'isolation' _to_ an isolated node. This, I 
think, is what most people will want but won't break anything much on an 
upgrade.

Dirk G1TLH