Subject: [mdnsext] Fwd: Extensions to DNS-Based Service Discovery (mdnsext) BoF request

From: Kerry Lynn <[email-masked]>
Date: Mon, 28 Jan 2013 17:20:55 -0500

---------- Forwarded message ----------
From: Kerry Lynn <[email-masked]>
Date: Mon, Jan 28, 2013 at 5:14 PM
Subject: Extensions to DNS-Based Service Discovery (mdnsext) BoF request
To: Ralph Droms <[email-masked]>, Brian Haberman <[email-masked]

Greetings,

Please find enclosed a BoF request for IETF86 in Orlando. This is a
follow-up BoF
to the "Extensions to the Bonjour protocol suite" (mdnsext) BoF held at
IETF85, and
thus we appreciate is the second and final chance to form a WG in this
space.
(Thanks to Tim Chown for preparing this.)

We need to see discussion on the list regarding the proposed charter
below.  Also,
with input from Marc Blanchet, Matthew Gast, and others we have begun to
reorganize the requirements draft around use cases.  See:
draft https://datatracker.ietf.org/doc/draft-lynn-mdnsext-requirements/
I will be prompting a discussion of mdnsext security considerations on the
list so
we can include more ideas in future versions of the requirements draft.

Note that there was some discussion of changing the BoF name after the
first one.
We compromised by keeping the same short name (mdnsext) but changing the
long name to avoid the impression that our scope is too narrowly focused.
It's
something we can discuss on the list and revisit before the WG is
(hopefully)
established.

Regards, -K-

----------
BoF scheduling information:

a. Extensions to DNS-Based Service Discovery (mdnsext)

b. Internet Area

 c. Conflicts: 6man homenet dhc apparea appsawg intarea sdnrg v6ops dnsop
and dnsext

d. Expected Attendance: 200 (at least 164 attended at IETF85)

e. Special requests: None

f. Number of sessions: 1

g. Length of session: 2 hours

Draft agenda:
--------------------

1. Administravia (Chairs, 5 mins)
    Note Well and agenda bashing

2. Goals of the BoF (Chairs, 15 mins)
    Review of IETF 85 mdsnext BoF and progress since

3. Requirements (Kerry Lynn, 30 mins)
    draft-lynn-mdnsext-requirements-01

4. Open discussion (Chairs, 40 mins)
    Open mic; includes draft charter and deliverables

5. Key questions (Chairs, 30 mins)
    Are we ready to form a WG with the agreed charter, subject to mail list
confirmation?
    Note RFC5434 section 1.

Draft charter:
-------------------

Currently, zeroconf networking protocols are generally used to discover
services within
the scope of a single link. In particular, the Bonjour protocols suite,
comprising mDNS
(draft-cheshire-dnsext-multicastdns<http://tools.ietf.org/html/draft-cheshire-dnsext-multicastdns>
 / RFC 6762 <http://tools.ietf.org/html/rfc6762> in AUTH48) and DNS-SD
(draft-cheshire-dnsext-dns-sd<http://tools.ietf.org/html/draft-cheshire-dnsext-dns-sd>
 / RFC 6763 <http://tools.ietf.org/html/rfc6763> in AUTH48), are widely
used for discovery and
resolution of services and names on a single link.

Such discovery is commonly used in many scenarios, including home networks,
commercial and campus enterprise networks, and can be used in certain mesh
networks.
However, the multicast zeroconf protocols are constrained to link-local
scope, so can
only be used to discover services on the same link. In a typical current
home network,
which is a single link, users should experience the desired discovery
behaviour. However,
in future multi-link home networks (as envisaged by the homenet WG) and in
routed
campus or enterprise networks, devices and thus users can only discover
services on the
same link, which is a significant limitation. Such limitations have led to
calls, such as those
by the Educause petition, to develop an appropriate solution to span
multiple links, or to
perform discovery across a wide area (not necessarily on directly connected
links).

In addition, the Zigbee Smart Energy Profile 2.0 commercial standard
currently under
development has specified mDNS as its method of zero configuration
discovery. However,
its use of multi-link wireless mesh subnets (LLNs) and disparate physical
layers will require
extensions to mDNS to allow it to operate across multiple links.

In principle DNS-SD can be used with conventional unicast DNS for wide area
service
discovery spanning multiple links, but in practice this capability is not
widely used
(potentially due to user interface/configuration issues, but potentially
due to protocol
limitations). As a result, as demand for service discovery across wider
area routed
networks grows, some vendors are beginning to ship their own early
solutions. It is thus
both timely and important that efforts to develop improved, scalable
service discovery
solutions for routed networks are coordinated towards producing a single,
standards-
based solution.

Goals

To that end, the primary goals of the mdnsext WG are as follows:

1. To document a set of requirements for wider area service discovery in
routed,
    multi-link networks in the following four scenarios:
    a) Commercial enterprise networks
    b) Academic/educational/university campus networks
    c) Multi-link home networks, such as those envisaged by the HOMENET WG
    d) Multi-link/single subnet (mesh) networks, such as ROLL/6LOWPAN
subnets

2. To develop an improved, scalable solution for wide-area service
discovery that can
     operate in multi-link networks, applicable to the scenarios above.

3. To develop a BCP for the coexistence of zeroconf (mDNS) and unicast
(global DNS)
     name services in such multi-link networks, which should include
consideration of both
     the name resolution mechanism and the namespace.

It is important that the mdnsext 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 mdsnext WG, and thus
coordination
between the WGs is desirable.

Deliverables

The WG will produce three documents: an Informational RFC on the
requirements for
wide-area service discovery protocols; a Standards Track RFC documenting a
wide-area
service discovery solution that is applicable to those scenarios; and a BCP
document
describing the most effective method to integrate mDNS and global DNS name
services.

Milestones

May 2013 Formation of the WG
Apr 2013 Adopt requirements draft as WG document
Aug 2013 Submit requirements draft to the IESG as an Informational RFC
Sep 2013 Adopt wide-area service discovery solution draft as WG document
Oct 2013 Adopt zeroconf and unicast DNS integration BCP draft as WG document
Mar 2014 Submit wide-area service discovery solution draft to the IESG as
Standards Track RFC
Mar 2014 Submit zeroconf and unicast DNS integration solution draft to the
IESG as BCP