Re: Gnome VFS - plans for Gnome 2.8

[James Henstridge <james daa com au>]

On 27/03/04 01:15, Ian McKellar wrote:

> On Thu, 2004-03-25 at 16:52, James Henstridge wrote:
>  
>
> > Do we know what actual large organisations are using for service 
> > discovery right now?  If no one is doing service discovery right now, 
> > then we can probably choose the most elegant solution. 
> >    
>
> People are using Rendezvous, though basically they're only using it for
> iTunes music sharing :) And for large organisations (eg: Apple) it
> doesn't work.
>  
Yep.  That is partly because the specifications Rendezvous is built on 
our inherently link local.  The method of assigning IP addresses relies 
on ARP queries to detect collisions.  The serivce discovery and service 
registration is all performed via link-local multicast packets (ie. ones 
that a multicast router shouldn't forward between ethernet segments).  
It is explicitly designed for local use :)

So it is obvious that Rendezvous in its current form isn't the solution 
to everything.  This isn't to say it isn't useful though.

About the only thing you could keep in a larger fixed network is DNS-SD, 
but do it over normal DNS.  If you wanted to support dynamic service 
registration, it could be done via dynamic DNS updates.  Alternatively, 
an organisation might use a static DNS zone file for service discovery.

> I'd like to see GNOME have a protocol agnostic service discovery API,
> but I'm not sure how possible that is.
>  
I don't doubt that you could write an API for protocol agnostic service 
discovery.  What is more difficult would be protocol agnostic service 
registration.  Do you try to register the service for all protocols?  
What do you do if your name is taken in the SLP directory but not the 
mDNS DNS-SD one?

James.

--
Email: james daa com au
WWW:   http://www.daa.com.au/~james/