[cups.development] New SNMP printer discovery backend

[Michael R Sweet]

Del wrote:
>> Kurt Pfeifle wrote:
>>> I'm very pleased to have seen the new SNMP printer discovery backend added to 1.2 SVN a few hours ago  :-)
>>>
> 
> Sorry to revive an old thread, but a couple of questions to Michael or any discovery developers:
> 
> - Did you consider using SLP (c.f. http://openslp.org/) instead of SMTP?

The few printers that support SLP actually use a vendor-specific
version of it for discovery (HP).  SLP also has extremely poor
performance when you do not have a DA on the network manage
lookups.

Note that CUPS already supports LDAP and SLP for shared printers,
just not for network printer discovery.

> - Did you consider any other discovery protocols?

DNS-SD is supported in CUPS 1.4 and in every version of Mac OS X
since 10.3.

> - Is there a pointer to the discussions/debates that drove the current state?

The discussions on the CUPS forums and any minutes you can find from
the previous printing summits.

SNMP is supported by almost every network printer and by many print
servers, making it the obvious choice for discovering printers.
That said, it does have some limitations - no late binding of the
IP address, and no support for lookups beyond the current subnet.

DNS-SD is our preferred discovery protocol because it ties in well
with existing managed networks and DNS servers but also works on
unmanaged (home) networks thanks to the late address binding.  Many
network printers already support it, too...

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Michael R Sweet                        Senior Printing System Engineer