Title: Message
Thanks John - I'm going to take all 4 parts of your excellent comments
below separately, and comment further. You basically said:
An SOA
without registry by definition is limited
[JMC] Limited in what way? I assume because there is no
dynamic discovery, and if the interface requirements and/or service location
changed, it would require an out-of-band mechanism. I would assert that it is
limited if the technical and business requirements led to an anticipation of
updates to the interface requirements and/or service location on a regular basis
- otherwise, is it *really* limited?
An SOA
without registry by definition is
private
[JMC] So if
a SOA-based system is being used among 2 or more organizations, and
the technical and business requirements *do not lead* to an anticipation of
updates to the interface requirements and/or service location on a regular
basis, then the SOA is "private"? Seems orthogonal to
me...
An SOA
with a registry is open
[JMC] Open to who? If it does not have a registry, it is
not open?
An SOA
with a registry is
dynamic
[JMC] Agree! (one out of 4 ain't bad
;)
Thanks
again!
Kind Regards,
Joseph Chiusano
Booz Allen Hamilton
Strategy and Technology Consultants to
the World
From: Yunker, John [mailto:]
Sent: Wednesday, December 15, 2004 12:06 PM
To: Chiusano
Joseph; Matthew MacKenzie; ebSOA OASIS TC
Subject: RE: [ebsoa] Does
SOA Require Registry-Based Dynamic Discovery?
From
my view the "registry requirement" is more a function of the distributed
nature of the participants, the number and type of services, and the amount of
change. A registry provides a method for decoupling "the use of an SOA"
from "direct communication of the participants about HOW to use the
SOA".
An
SOA without registry by definition is limited and private
An
SOA with a registry is open and dynamic
John
-----Original Message-----
From: Chiusano
Joseph [mailto:]
Sent: Wednesday, December
15, 2004 9:01 AM
To: Matthew MacKenzie; ebSOA OASIS
TC
Subject: RE: [ebsoa] Does SOA Require Registry-Based Dynamic
Discovery?
Thanks Matt. From that I take:
- Discovery in general is required for SOA (cannot function without
it)
- Whether it is (what I will call) "fundamental" discovery - meaning
your first example below - or "registry-based" discovery depends on
technical and business requirements.
I just cannot foresee trying to convince a current or potential
customer that they have to put up $XX,XXX for a registry product if the
technical and business requirements do not call for it, just to comply with
someone's definition of the term "SOA".
Kind Regards,
Joseph Chiusano
Booz Allen Hamilton
Strategy and Technology Consultants
to the World
From: Matthew MacKenzie
[mailto:]
Sent: Wednesday, December 15, 2004
11:57 AM
To: Chiusano Joseph; 'ebSOA OASIS
TC'
Subject: RE: [ebsoa] Does SOA Require Registry-Based Dynamic
Discovery?
My opinion is
that a registry is nothing more than a very explicit service discovery
device.
An SOA does need
a method of discovering services, and consuming them, but this method may
in some cases be subtle. For example, my SOA may operate on the
premise that consumers all are aware of an enumeration of service types,
and their port numbers (think /etc/services in the unix world), and
allowable IP ranges for finding services. Clients may be configured
something like:
{
Services imap, http, ssh, daytime, pop3,
portmap
IPRange 192.168.0.0/24
}
A client with
such a configuration does have a way of discovering services that are
available to it, and of course, a way of binding to
them.
Contrast this
with a registry driven SOA:
{
ServiceRegistry http://foo/registry
}
The only
difference is in the implementation detail and verbosity of information
available. Conceptually, they are the
same.
--Matt
MacKenzie
From:
Chiusano Joseph [mailto:]
Sent: Wednesday, December 15, 2004
11:38 AM
To: ebSOA OASIS
TC
Subject: [ebsoa] Does
SOA Require Registry-Based Dynamic
Discovery?
What is the TC's opinion on
the answer to the question of "does SOA require registry-based dynamic
discovery"? I know that Discovery is a pattern in the .047 spec, which
leads me to believe that the position is that SOA does not *require*
registry-based discovery.
For example, suppose
that:
- 2 organizations are using
Web Services in a "SOA-like" manner (meaning shared services represented
as Web Services, that are invoked by other Web Services).
- There is no registry-based
dynamic discovery, perhaps because the organizations agree that these
service locations are completely (or relatively) stable, and that if the
locations change, there will be some out-of-band mechanism for propagating
updated WSDL documents
Are these 2 organizations
therefore *not* using a service-oriented architecture? That is, does the
second point completely negate the first? Or, is it all really a matter of
business and technical requirements?
Kind
Regards,
Joseph
Chiusano
Booz Allen
Hamilton
Strategy and Technology
Consultants to the World
