RE: [ws-dd-comment] WS-Discovery and IPv6 link-local

Dear Stephan,

Thank you for submitting your comment on Public Review Draft 01 of the WS-Discovery specification regarding IPv6 address selection. Your comment was registered in the WS-DD issue database as issue number PR003, and discussed on a recent WS-DD TC teleconference.

The choice of whether to use routable and link-local IPv6 addresses (or both) in WS-Discovery messages depends on specific deployment situations. It is difficult to provide generic guidance on this matter in a generic specification such as WS-Discovery, since deployment needs vary. Rather than attempt to cover the wide range of deployment scenarios within the WS-Discovery specification itself, the Technical Committee encourages inclusion of guidance on the use of WS-Discovery for specific vertical applications or in specific deployment situations in separate specifications for those scenarios. Such guidance could, for example, be provided in profiles which reference WS-Discovery, such as the Devices Profile for Web Services (DPWS).

The TC previously considered proposals to incorporate material into DPWS on “multihomed” devices, including not only the discussion of the choice between multiple IPv6 addresses but also support of both IPv4 and IPv6 addresses simultaneously as well as support of multiple network interfaces. It was determined to require more study and investigation than time would permit for inclusion in the initial version of DPWS, and so work on it was deferred for consideration after the publication of DPWS 1.1. However, the TC intends to include preliminary guidance on multihomed device support in white papers to be published contemporaneously with DPWS 1.1. After further implementation experience and study, this material may then be incorporated into a future version of DPWS. Consistent with this direction, the TC decided to defer further work on issue PR003 as well; it remains in our issue database and will be taken up again later.

The TC would welcome further contributions from you and others on this subject for consideration during development of these white papers and the next version of DPWS. We would welcome you to join the TC, or to make further contributions through the ws-dd-comments email list as appropriate.

Thanks again for reviewing the documents.

Best regards,

Toby Nixon

Co-chair, OASIS WS-DD TC

-----Original Message-----

From: Stephan Poehlsen [mailto:poehlsen@itm.uni-luebeck.de]

Sent: Tuesday, February 10, 2009 11:37 PM

To: ws-dd-comment@lists.oasis-open.org

Subject: [ws-dd-comment] WS-Discovery and IPv6 link-local

Hello,

all nodes in an IPv6 network create an link-local IP address for their interface. Then they are able to multicast the router for further information to get/create a routable IP address. So all nodes have a link-local IP address and maybe an additional routable IP address.

So if a Target Service is running on that IPv6 node with these two ip addresses:

- Which IP addresses are used to sent out the UDP datagram? Two Hello messages, each with a different source IP address or only one?

- Which IP addresses are used for xAddrs in the messages? Both?

Maybe a recommendation in the specification is helpful.

Only if a routable IP address is sent out it is possible to use the Target Service from other sub networks. Of course in this case the information from the Hello message must be transfered out of the subnet (maybe with help of Discovery Proxies).

I am trying to use an architecture where I want to forward the Hello messages to a centralized Discovery Proxy, so it is important for me to know how all specification compliant Target Services behave in the above mentioned IPv6 case with a link-local and a routable IP address. For me it is important to get a routable IP address of course.

Stephan

Stephan Pöhlsen

University of Lübeck Phone: +49 451 500-5386

Institute of Telematics Fax: +49 451 500-5382

Ratzeburger Allee 160 poehlsen@itm.uni-luebeck.de

D-23538 Lübeck, Germany http://www.itm.uni-luebeck.de

Toby Nixon | Senior Standards Program Manager | Windows Device and Storage Technologies | Microsoft Corporation

toby.nixon@microsoft.com | www.microsoft.com | V: +1 425 706 2792 | M: +1 206 790 6377 | F: +1 425 708 4811

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