[Server-devel] Notes on service discovery XS/XO

[pgf at laptop.org]

benjamin m. schwartz wrote:
 > Martin Langhoff wrote:
 > > The short of it is that mdns/dns-sd make sense for a small,
 > > underutilised network of peers. They assume that the network is a
 > > cheap resource, that broadcast messages are cheap, and that there is
 > > no coordinating server.
 > 
 > mDNS assumes all of the above things.  DNS-SD does not.  DNS-SD is
 > perfectly happy to work on a standard DNS server.  From the spec
 > 
 > """
 >    This document proposes no change to the structure of DNS messages,
 >    and no new operation codes, response codes, resource record types,
 >    or any other new DNS protocol values. This document simply specifies
 >    a convention for how existing resource record types can be named and
 >    structured to facilitate service discovery.
 > """
 > (http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt)

the last i looked at (and actually used) dns-sd to solve the
discovery problem, it seemed that dns-sd development had stalled. 
(and i haven't had a reason to look since.)  i believe we used
code from Sun, which was all i could find at the time, and it
wasn't what you'd call production ready.  on the other hand, we
were using it in a somewhat non-standard way -- in fact, we
switched to mdns soon after because it fit our deployment model
better, since we didn't really have a central server.  the XS
model may be a better fit.

(this was all 3 or 4 years ago, btw.)

paul
=---------------------
 paul fox, pgf at laptop.org