Thanks for your feedback Scott and would welcome any comments
you have.
I would be happy to give you more time to formalize your
suggestions.
--Geoff
From: Scott de Deugd
[mailto:dedeugd@us.ibm.com]
Sent: Tuesday, November 04, 2008 3:58 PM
To: ws-dd@lists.oasis-open.org
Subject: Re: [ws-dd] Update to WS-DD FAQ
Geoff, we were
able to take quick pass through this. Having these compared in an FAQ
seems valuable but overall, it's tone leans toward cons for UDDI, pros for Discovery.
We may also want to be sure people do not read into this FAQ that
Discovery is replacing UDDI, or that we are signaling a move to WS-Discovery
through our WS-DD efforts. We for example still have UDDI in our products and
are still looking into how that fits with Discovery for our customers.
The UDDI
description does capture the public registry model it was originally created
for, but that is not how it has been deployed. For example, UDDI is
generally deployed within a service domain of an enterprise where the registry
can be kept up to date.
We are going to
need more time to make sure that this, as a public view, aligns with our
products and direction. That is something we cannot get done by the end of the
week, but would be happy to work on it with you and the TC.
......................Scott
|
Geoff
Bullen <Geoff.Bullen@microsoft.com>
11/03/2008
11:31 AM
|
|
To
|
"ws-dd@lists.oasis-open.org"
<ws-dd@lists.oasis-open.org>
|
|
cc
|
|
|
Subject
|
[ws-dd]
Update to WS-DD FAQ
|
|
Hi all,
As you know,
there is a public facing FAQ about WS-DD on the OASIS web site (http://www.oasis-open.org/committees/ws-dd/faq.php). There has
been some feedback that we should add a response about UDDI and Discovery.
I have worked with Prasad from Software AG and others to create the
following additional entry for our FAQ. If you have any suggestions or
feedback, please let me know. If I don’t hear anything back by the end of
this week, I will go ahead and update the FAQ.
Thanks,
Geoff
What is the
difference between WS-Discovery and UDDI?
These are two
different protocols and the choice of one vs. other or both depends upon the
intended use. In general both protocols have the ability to expose a registry
of services available on the network, and can in fact be used simultaneously to
expose multiple views of the same registry.
UDDI provides a
central registry to store information about available Web services. UDDI
specifies a protocol for querying and updating this common registry of Web
service information. The registry includes information about service providers,
the services they host, and the protocols those services implement. The
registry also provides mechanisms to add other metadata to any registered
information.
With UDDI, the
only services that can be discovered are those that have registered with the
registry. Non-registered services may exist on the network, but, if they
aren’t registered, clients can’t find or consume them. Unless a service
knows where the registry is, it can’t register itself. This foreknowledge
is usually gained by pre-configuration.
UDDI is
intended for heavily managed networks, where the discovery infrastructure (UDDI)
and the services are both manually configured and controlled, and is not
intended for unmanaged or ad-hoc network environments. WS-Discovery is
designed to scale up from unmanaged, ad-hoc, and consumer networks to secure
enterprise networks. The following are some of the points to consider
when making a decision about the protocol for discovering web services.
· WS-Discovery provides an ad-hoc mode of operation where
you can discover the services without the need of a centralized server to host
information about all available services. It provides a protocol to discover
dynamically services that are coming and going from a network. As a
service joins the network, it informs its peers of its arrival by broadcasting
a Hello message; likewise, when services drop off the network they multicast a
Bye message.
· WS-Discovery is fully compose-able with other WS-*
protocol such as WS-Security.
· WS-Discovery is lightweight yet can be used in the
carefully controlled managed environment.
· WS-Discovery managed mode doesn’t require the services
themselves to be manually controlled, instead it works even when the discovery
infrastructure (proxies) are the only parts that are managed.
· Because UDDI is as up-to-date as it is kept updated, the
registry can contain stale, out-dated information about services and entries
for services that are no longer available.
UDDI provides
additional information about services such as SLA, pricing etc. that helps in
deciding a particular service to use at design/development time. WS-Discovery
is more focused on dynamically locating the EPR and other metadata about web
services at runtime.