Subject: [mdnsext] Draft mdnsext WG charter

From: Tim Chown <[email-masked]>
Date: Mon, 29 Oct 2012 20:53:02 +0000

Hi,

The following text is the current draft charter for the prospective mdnsext WG.

Comments in advance of the BoF are very much welcomed.

Tim

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mdnsext 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 / RFC 6762 in AUTH48) and DNS-SD (draft-cheshire-dnsext-dns-sd / RFC 6763 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.

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. As a result, as demand for service discovery across 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 service discovery across 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 envisgaed 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 spanning multiple links, applicable to the scenarios above. 

3. To develop a solution to seamlessly integrate zeroconf (mDNS) and unicast (global DNS) name services, 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 Standards Track document describing a solution to seamlessly integrate mDNS and global DNS name services.

Milestones

Jan 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
Aug 2013 Adopt wide-area service discovery solution draft as WG document
Aug 2013 Adopt mDNS and global DNS integration solution draft as WG document
Dec 2013 Submit wide-area service discovery solution draft to the IESG as Standards Track RFC
Dec 2013 Submit mDNS and global DNS integration solution draft to the IESG as Standards Track RFC

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