Re: [mdnsext] WG Review: Extensions for Scalable DNS Service Discovery (dnssd)

Tim Chown <tjc@ecs.soton.ac.uk> Thu, 03 October 2013 18:52 UTC

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From: Tim Chown <tjc@ecs.soton.ac.uk>
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Date: Thu, 3 Oct 2013 19:43:24 +0100
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To: manning bill <bmanning@isi.edu>
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Cc: "mdnsext@ietf.org mdnsext" <mdnsext@ietf.org>, Lemon Ted <Ted.Lemon@nominum.com>, "<ietf@ietf.org> Discussion" <ietf@ietf.org>, IETF-Announce <ietf-announce@ietf.org>, Ralph Droms <rdroms.ietf@gmail.com>
Subject: Re: [mdnsext] WG Review: Extensions for Scalable DNS Service Discovery (dnssd)
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On 3 Oct 2013, at 18:07, manning bill <bmanning@isi.edu> wrote:

>  ----- The following addresses had permanent fatal errors -----
> <dnssdext-request@ietf.org>
>   (reason: 550 5.1.1 <dnssdext-request@ietf.org>rg>: Recipient address rejected: User unknown in virtual alias table)

I think the active list is still mdnsext@ietf.org?
See: http://www.ietf.org/mail-archive/web/mdnsext/current/maillist.html

And the 'header' information below should now probably read something like this:

--- snip ---

Scalable DNS Service Discovery  (dnssd)
------------------------------------------------
Current Status: Proposed WG

Chairs:
 Ralph Droms <rdroms.ietf@gmail.com>
 Tim Chown <tjc@ecs.soton.ac.uk>

Assigned Area Director:
 Ted Lemon <ted.lemon@nominum.com>

Mailing list
 Address: dnssd@ietf.org
 To Subscribe: dnssd-request@ietf.org
 Archive: http://www.ietf.org/mail-archive/web/dnssd
 Pre-WG BoF Archive: http://www.ietf.org/mail-archive/web/mdnsext 


--- snip ---

Tim

> 
> 
> 
> On 3October2013Thursday, at 8:42, The IESG wrote:
> 
>> A new IETF working group has been proposed in the Internet Area. The IESG
>> has not made any determination yet. The following draft charter was
>> submitted, and is provided for informational purposes only. Please send
>> your comments to the IESG mailing list (iesg at ietf.org) by 2013-10-10.
>> 
>> Extensions for Scalable DNS Service Discovery  (dnssd)
>> ------------------------------------------------
>> Current Status: Proposed WG
>> 
>> Chairs:
>> Ralph Droms <rdroms.ietf@gmail.com>
>> Tim Chown <tjc@ecs.soton.ac.uk>
>> 
>> Assigned Area Director:
>> Ted Lemon <ted.lemon@nominum.com>
>> 
>> Mailing list
>> Address: dnssdext@ietf.org
>> To Subscribe: dnssdext-request@ietf.org
>> Archive: http://www.ietf.org/mail-archive/web/dnssdext
>> 
>> Charter:
>> 
>> Background
>> ----------
>> 
>> Zero configuration networking protocols are currently well suited to
>> discover services within the scope of a single link.  In particular,
>> the DNS-SD [RFC 6763] and mDNS [RFC6762] protocol suite (sometimes
>> referred to using Apple Computer Inc.'s trademark, Bonjour) are
>> widely used for DNS-based service discovery and host name resolution
>> on a single link.
>> 
>> The DNS-SD/mDNS protocol suite is used in many scenarios including
>> home, campus, and enterprise networks.  However, the zero configuration
>> mDNS protocol is constrained to link-local multicast scope by design,
>> and therefore cannot be used to discover services on remote links.
>> 
>> In a home network that consists of a single (possibly bridged) link,
>> users experience the expected discovery behavior; available services
>> appear because all devices share a common link.  However, in multi-link
>> home networks (as envisaged by the homenet WG) or in routed campus or
>> enterprise networks, devices and users can only discover services on
>> the same link, which is a significant limitation.  This has led to
>> calls, such as the Educause petition, to develop an appropriate service
>> discovery solution to span multiple links or to perform discovery across
>> a wide area, not necessarily on directly connected links.
>> 
>> In addition, the "Smart Energy Profile 2 Application Protocol Standard",
>> published by ZigBee Alliance and HomePlug Powerline Alliance specifies
>> the DNS-SD/mDNS protocol suite as the basis for its method of zero
>> configuration service discovery.  However, its use of wireless mesh
>> multi-link subnets in conjunction with traditional routed networks will
>> require extensions to the DNS-SD/mDNS protocols to allow operation
>> across multiple links.
>> 
>> The scenarios in which multi-link service discovery is required may
>> be zero configuration environments, environments where administrative
>> configuration is supported, or a mixture of the two.
>> 
>> As demand for service discovery across wider area routed networks
>> grows, some vendors are beginning to ship proprietary solutions.  It
>> is thus both timely and important that efforts to develop improved, 
>> scalable, autonomous service discovery solutions for routed networks 
>> are coordinated towards producing a single, standards-based solution.
>> 
>> The WG will consider the tradeoffs between reusing/extending existing
>> protocols and developing entirely new ones.  It is highly desirable
>> that any new solution is backwardly compatible with existing DNS-SD/mDNS
>> deployments.  Any solution developed by the dnssd WG must not conflict
>> or interfere with the operation of other zero-configuration service and
>> naming protocols such as uPnP or LLMNR.  Integration with such protocols
>> is out of scope for this WG.
>> 
>> The focus of the WG is to develop a solution for extended, scalable 
>> DNS-SD.  This work is likely to highlight problems and challenges with 
>> naming protocols, as some level of coexistence will be required between 
>> local zero configuration name services and those forming part of the 
>> global DNS.  It is important that these issues are captured and 
>> documented for further analysis; solving those problems is however not 
>> within the scope of this WG.
>> 
>> Working Group Description
>> -------------------------
>> 
>> To that end, the primary goals of the dnssd WG are as follows:
>> 
>> 1. To document a set of requirements for scalable, autonomous
>>  DNS-based service discovery in routed, multi-link networks in the
>>  following five scenarios:
>> 
>>  (A) Personal Area networks, e.g., one laptop and one printer.
>>      This is the simplest example of a service discovery network,
>>      and may or may not have external connectivity. 
>> 
>>  (B) Home networks, as envisaged by the homenet WG, consisting of 
>>      one or more exit routers, with one or more upstream providers 
>>      or networks, and an arbitrary internal topology with 
>>      heterogeneous media where routing is automatically configured. 
>>      The home network would typically be a single zero configuration 
>>      administrative domain with a relatively limited number of 
>>      devices. 
>> 
>>  (C) Wireless 'hotspot' networks, which may include wireless networks
>>      made available in public places, or temporary or permanent
>>      infrastructures targeted towards meeting or conference style
>>      events, e.g., as provided for IETF meetings.  In such
>>      environments other devices may be more likely to be 'hostile'
>>      to the user.
>> 
>>  (D) Enterprise networks, consisting of larger routed networks, 
>>      with large numbers of devices, which may be deployments 
>>      spanning over multiple sites with multiple upstreams, and
>>      one more more administrative domains (depending on internal
>>      administrative delegation).  The large majority of the 
>>      forwarding and security devices are configured.  These may
>>      be commercial or academic networks, with differing levels 
>>      of administrative control over certain devices on the network,
>>      and BYOD devices commonplace in the campus scenario.
>> 
>>  (E) Mesh networks such as RPL/6LoWPAN, with one or more links per
>>      routable prefix, which may or may not have external connectivity.
>>      The topology may use technologies including 802.11 wireless, 
>>      HomePlug AV and GP, and ZigBee IP. 
>> 
>>  In the above scenarios, the aim is to facilitate service discovery 
>>  across the defined site.  It is also desirable that a user or device, 
>>  when away from such a site, is still able to discover services 
>>  within that site, e.g. a user discovering services in their home 
>>  network while remote from it.
>> 
>>  It is also desirable that multiple discovery scopes are supported,
>>  from the point of view of announcements and discovery, be the
>>  scope 'site', 'building', or 'room'.  A user for example may only
>>  be interested in devices in the same room.
>> 
>> 2. To develop an improved, scalable solution for service discovery 
>>  that can operate in multi-link networks, where devices may be
>>  in neighboring or non-neighboring links, applicable to
>>  the scenarios above.  The solution will consider tradeoffs between
>>  reusing/extending existing protocols and developing entirely new
>>  protocols. 
>> 
>>  The solution should include documentation or definition of the
>>  interfaces that can be implemented, separately to transport of 
>>  the information.
>> 
>> 3. To document challenges and problems encountered in the coexistence 
>>  of zero configuration and global DNS name services in such 
>>  multi-link networks, including consideration of both the name 
>>  resolution mechanism and the namespace.
>> 
>> It is important that the dnssd WG takes input from stakeholders in
>> the scenarios it is considering.  For example, the homenet WG is
>> currently evaluating its own requirements for naming and service
>> discovery; it is up to the homenet WG as to whether it wishes to
>> recommend adoption of the solution developed in the dnssd WG, but
>> coordination between the WGs is desirable.
>> 
>> Deliverables:
>> 
>> The WG will produce three documents: an Informational RFC on the
>> requirements for service discovery protocols operating on potentially
>> non-neighboring multi-link networks as described above; a Standards
>> Track RFC documenting an extended, scalable service discovery solution 
>> that is applicable to those scenarios; and an Informational RFC 
>> describing the problems arising when developing the extended SD solution 
>> and how it affects the integration of local zero configuration and global
>> 
>> DNS name services.
>> 
>> Milestones:
>> Sep 2013 - Formation of the WG
>> Oct 2013 - Adopt requirements draft as WG document
>> Jan 2014 - Submit requirements draft to the IESG as an Informational
>> RFC
>> Mar 2014 - Adopt wide-area service discovery solution draft as WG
>> document 
>> Mar 2014 - Adopt Informational document on the problems and challenges
>> arising for zeroconf and unicast DNS name services
>> Sep 2014 - Submit wide-area service discovery solution draft to the
>> IESG as Standards Track RFC 
>> Sep 2014 - Submit the zeroconf and unicast DNS "problems and
>> challenges" draft to the IESG as Informational.
>> 
>> 
>