Re: Disabling Multicast to run multiple JavaSpace

Hi Timur,

> these are the reasons:
> 
> 1st, our operational guys don't like the multicast announcements. (This
> one must not be counted if you can help me fix the other two.)

Ah that old chestnut. OK I understand why you need to switch off multicast announcement now.

You would be wise to ask for some more technical reasons for their objection to multicast.
If you are thinking of using a J2EE server at some point, most of them use multicast to keep nodes in sync... 
But that is just an observation.

 
> 2nd, I would like to run multiple services, side by side, each with
> their own local Javaspace. I would like to be sure that each service is
> accessing it's own, local Javaspace. Our services use a unicast URL to
> contact their local lookup server. But with multiple spaces up and
> running in the same network, you never know which space you are really
> provided with. (At least I don't.)

Add an Entry to the JavaSpace service registration which will allow you to discover a specific java space.

See the outrigger man page documentation, and look for initialLookupAttributes.

> 3nd, there is a problem running multiple spaces, if there are firewalls
> that blocks everything except multicast packages (so Jini announcements
> slip through). In such an environment, my local lookup-server may
> provide my local service with the address of a Javaspace instance
> running behind a firewall. In this case, there is no way for my service
> to access that Javaspace instance (and my service throws exceptions -
> even though there is a local JS running fine).

Strangely I find this amusing. Most firewalls block multicast traffic. 
Also, how can you talk to the reggie on the otherside of the firewall ?

Sounds like your network guys need to by a few of Richard W Stevens' books to me.....

But getting back your problem ... adding an attribute to the registration will allow you to lookup a specific java space and using a UnicastLookup's in all your configurations should mean you won't issue multicast announcements (Might need to double check this ..).


Hope this helps a tad.

--Jools

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