draft-ietf-dnssd-requirements-04.txt   draft-ietf-dnssd-requirements-05.txt 
DNS-SD/mDNS Extensions K. Lynn DNS-SD/mDNS Extensions K. Lynn
Internet-Draft Consultant Internet-Draft Verizon
Intended status: Informational S. Cheshire Intended status: Informational S. Cheshire
Expires: April 11, 2015 Apple, Inc. Expires: September 5, 2015 Apple, Inc.
M. Blanchet M. Blanchet
Viagenie Viagenie
D. Migault D. Migault
Orange Ericsson
October 8, 2014 March 4, 2015
Requirements for Scalable DNS-SD/mDNS Extensions Requirements for Scalable DNS-SD/mDNS Extensions
draft-ietf-dnssd-requirements-04 draft-ietf-dnssd-requirements-05
Abstract Abstract
DNS-SD/mDNS is widely used today for discovery and resolution of DNS-SD over mDNS is widely used today for discovery and resolution of
services and names on a local link, but there are use cases to extend services and names on a local link, but there are use cases to extend
DNS-SD/mDNS to enable service discovery beyond the local link. This DNS-SD/mDNS to enable service discovery beyond the local link. This
document provides a problem statement and a list of requirements. document provides a problem statement and a list of requirements.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 11, 2015. This Internet-Draft will expire on September 5, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3. Basic Use Cases . . . . . . . . . . . . . . . . . . . . . . . 5 3. Basic Use Cases . . . . . . . . . . . . . . . . . . . . . . . 5
4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Namespace Considerations . . . . . . . . . . . . . . . . . . 8 5. Namespace Considerations . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
DNS-Based Service Discovery [DNS-SD] in combination with its DNS-Based Service Discovery [DNS-SD] in combination with its
companion technology Multicast DNS [mDNS] is widely used today for companion technology Multicast DNS [mDNS] is widely used today for
discovery and resolution of services and names on a local link. discovery and resolution of services and names on a local link.
However, as users move to multi-link home or campus networks they However, as users move to multi-link home or campus networks they
find that mDNS does not work across routers. DNS-SD can also be used find that mDNS (by design) does not work across routers. DNS-SD can
in conjunction with conventional unicast DNS to enable wide-area also be used in conjunction with conventional unicast DNS to enable
service discovery, but this capability is not yet widely deployed. wide-area service discovery, but this capability is not yet widely
This disconnect between customer needs and current practice has led deployed. This disconnect between customer needs and current
to calls for improvement, such as the Educause petition [EP]. practice has led to calls for improvement, such as the Educause
petition [EP].
In response to this and similar evidence of market demand, several In response to this and similar evidence of market demand, several
products now enable service discovery beyond the local link using products now enable service discovery beyond the local link using
different ad-hoc techniques. As yet, no consensus has emerged different ad hoc techniques. As yet, no consensus has emerged
regarding which approach represents the best long-term direction for regarding which approach represents the best long-term direction for
DNS-based service discovery protocol development. DNS-based service discovery protocol development.
Multicast DNS in its present form is also not optimized for network Multicast DNS in its present form is also not optimized for network
technologies where multicast transmissions are relatively expensive. technologies where multicast transmissions are relatively expensive.
Wireless networks such as Wi-Fi [IEEE.802.11] may be adversely Wireless networks such as Wi-Fi [IEEE.802.11] may be adversely
affected by excessive mDNS traffic due to the higher network overhead affected by excessive mDNS traffic due to the higher network overhead
of multicast transmissions. Wireless mesh networks such as 6LoWPAN of multicast transmissions. Wireless mesh networks such as 6LoWPAN
[RFC4944] are effectively multi-link subnets [RFC4903] where [RFC4944] are effectively multi-link subnets [RFC4903] where
multicasts must be forwarded by intermediate nodes. multicasts must be forwarded by intermediate nodes.
skipping to change at page 3, line 15 skipping to change at page 3, line 17
This document defines the problem statement and gathers requirements This document defines the problem statement and gathers requirements
for Scalable DNS-SD/mDNS Extensions. for Scalable DNS-SD/mDNS Extensions.
1.1. Terminology and Acronyms 1.1. Terminology and Acronyms
Service: A listening endpoint (host and port) for a given application Service: A listening endpoint (host and port) for a given application
protocol. Services are identified by Service Instance Names. protocol. Services are identified by Service Instance Names.
DNS-SD: DNS-Based Service Discovery [DNS-SD] is a conventional DNS-SD: DNS-Based Service Discovery [DNS-SD] is a conventional
application of DNS Resource Records and messages to facilitate the application of DNS Resource Records and messages to facilitate the
discovery and location of services. naming, discovery, and location of services. When used alone, it
generally refers to the wide-area unicast protocol.
mDNS: Multicast DNS [mDNS] is a mechanism that facilitates DNS-SD on mDNS: Multicast DNS [mDNS] is a mechanism that facilitates
a local link in the absence of traditional DNS infrastructure. distributed DNS-like capabilities (including DNS-SD) on a local link
without need of traditional DNS infrastructure.
SSD: Scalable DNS-SD is a future extension of DNS-SD (and perhaps SSD: Scalable Service Discovery (or Scalable DNS-SD) is a future
mDNS) that meets the requirements set forth in this document. extension of DNS-SD (and perhaps mDNS) that meets the requirements
set forth in this document.
Scope of Discovery: A subset of a local or global namespace, e.g., a Scope of Discovery: A subset of a local or global namespace, e.g., a
DNS subdomain, that is the target of a given SSD query. DNS subdomain, that is the target of a given SSD query.
Zero Configuration: A deployment of SSD that requires no Zero Configuration: A deployment of SSD that requires no
administration (although some administration may be optional). administration (although some administration may be optional).
Incremental Deployment: An orderly transition, as a network Incremental Deployment: An orderly transition, as a network
installation evolves, from DNS-SD/mDNS to SSD. installation evolves, from DNS-SD/mDNS to SSD.
2. Problem Statement 2. Problem Statement
Service discovery beyond the local link is perhaps the most important Service discovery beyond the local link is perhaps the most important
feature currently missing from the DNS-SD/mDNS framework. Other feature currently missing from the DNS-SD-over-mDNS framework (also
issues and requirements are summarized below. written as "DNS-SD over mDNS" or "DNS-SD/mDNS"). Other issues and
requirements are summarized below.
2.1. Multi-link Naming and Discovery 2.1. Multi-link Naming and Discovery
A list of desired DNS-SD/mDNS improvements from network A list of desired DNS-SD/mDNS improvements from network
administrators in the research and education community was issued in administrators in the research and education community was issued in
the form of the Educause petition [EP]. The following is a summary the form of the Educause petition [EP]. The following is a summary
of their technical issues: of their technical issues:
o Products that advertise services such as printing and multimedia o Products that advertise services such as printing and multimedia
streaming via DNS-SD/mDNS are not currently discoverable by streaming via DNS-SD over mDNS are not currently discoverable by
devices on other links. It is common practice for enterprises and devices on other links. It is common practice for enterprises and
institutions to use wireless links for client access and wired institutions to use wireless links for client access and wired
networks for server infrastructure, typically on different networks for server infrastructure, typically on different
subnets. DNS-SD used with conventional unicast DNS does work when subnets. DNS-SD used with conventional unicast DNS does work when
devices are on different links, but the resource records that devices are on different links, but the resource records that
describe the service must somehow be entered into the unicast DNS describe the service must somehow be entered into the unicast DNS
namespace. namespace.
o DNS-SD resource records may be entered manually into a unicast DNS o DNS-SD resource records may be entered manually into a unicast DNS
zone file [static], but this task must be performed by a DNS zone file [STATIC], but this task must be performed by a DNS
administrator. It is labor-intensive and brittle when IP administrator. It is labor-intensive and brittle when IP
addresses of devices change dynamically, as is common when DHCP is addresses of devices change dynamically, as is common when DHCP is
used. used.
o Automatically adding DNS-SD records using DNS Update works, but o Automatically adding DNS-SD records using DNS Update works, but
requires that the DNS server be configured to allow DNS Updates, requires that the DNS server be configured to allow DNS Updates,
and requires that devices be configured with the DNS Update and requires that devices be configured with the DNS Update
credentials to permit such updates, which has proven to be credentials to permit such updates, which has proven to be
onerous. onerous.
o Therefore, a mechanism is desired that populates the DNS namespace Therefore, a mechanism is desired that populates the DNS namespace
with the appropriate DNS-SD records with less manual with the appropriate DNS-SD records with less manual administration
administration than typically needed for a unicast DNS server. than typically needed for a unicast DNS server.
The following is a summary of their technical requirements: The following is a summary of their technical requirements:
o It must scale to a range of hundreds to thousands of DNS-SD/mDNS o It must scale to a range of hundreds to thousands of DNS-SD/mDNS-
enabled devices in a given environment. enabled devices in a given environment.
o It must simultaneously operate over a variety of network link o It must simultaneously operate over a variety of network link
technologies, such as wired and wireless networks. technologies, such as wired and wireless networks.
o It must not significantly increase network traffic (wired or o It must not significantly increase network traffic (wired or
wireless). wireless).
o It must be cost-effective to manage at up to enterprise scale. o It must be cost-effective to manage at up to enterprise scale.
skipping to change at page 5, line 18 skipping to change at page 5, line 25
Enabling service discovery on IEEE 802.11 networks requires that the Enabling service discovery on IEEE 802.11 networks requires that the
number of multicast frames be restricted to a suitably low value, or number of multicast frames be restricted to a suitably low value, or
replaced with unicast frames to use the MAC's reliability features. replaced with unicast frames to use the MAC's reliability features.
2.3. Low Power and Lossy Networks (LLNs) 2.3. Low Power and Lossy Networks (LLNs)
Emerging wireless mesh networking technologies such as RPL [RFC6550] Emerging wireless mesh networking technologies such as RPL [RFC6550]
and 6LoWPAN present several challenges for the current DNS-SD/mDNS and 6LoWPAN present several challenges for the current DNS-SD/mDNS
design. First, Link-Local multicast scope [RFC4291] is defined as a design. First, Link-Local multicast scope [RFC4291] is defined as a
single-hop neighborhood. A single subnet prefix in a wireless mesh single-hop neighborhood. A wireless mesh network representing a
network may often span multiple links, therefore a larger multicast single logical subnet may often extend to multiple hops [RFC4903],
scope is required to span it [RFC7346]. Multicast DNS is therefore a larger multicast scope is required to span it [RFC7346].
intentionally not specified for greater than Link-Local scope, Multicast DNS was intentionally not specified for greater than Link-
because of the additional multicast traffic that would generate. Local scope, because of the additional off-link multicast traffic
that would generate.
Additionally, low-power nodes may be offline for significant periods Additionally, low-power nodes may be offline for significant periods
either because they are "sleeping" or due to connectivity problems. either because they are "sleeping" or due to connectivity problems.
In such cases LLN nodes might fail to respond to queries or defend In such cases LLN nodes might fail to respond to queries or defend
their names using the current design. their names using the current design.
3. Basic Use Cases 3. Basic Use Cases
The following use cases are defined with different characteristics to The following use cases are defined with different characteristics to
help motivate, distinguish, and classify the target requirements. help motivate, distinguish, and classify the target requirements.
They cover a spectrum of increasing deployment and administrative They cover a spectrum of increasing deployment and administrative
complexity. complexity.
(A) Personal Area networks (PANs): the simplest example of a (A) Personal Area networks (PANs): the simplest example of a
network may consist of a single client and server, e.g., one network may consist of a single client and server, e.g., one
laptop and one printer, on a common link. PANs that do not laptop and one printer, on a common link. PANs that do not
contain a router may use Zero Configuration Networking [ZC] to contain a router may use Zero Configuration Networking [ZC] to
self-assign link-local addresses [RFC3927] [RFC4862], and self-assign link-local addresses [RFC3927] [RFC4862], and
Multicast DNS [mDNS] to provide naming and service discovery. Multicast DNS [mDNS] to provide naming and service discovery, as
currently implemented and deployed in Mac OS X, iOS, Windows [B4W]
and Android [NSD].
(B) Classic home or 'hotspot' networks, with the following (B) Classic home or 'hotspot' networks, with the following
properties: properties:
* Single exit router: the network may have one or more upstream * Single exit router: the network may have one or more upstream
providers or networks, but all outgoing and incoming traffic providers or networks, but all outgoing and incoming traffic
goes through a single router. goes through a single router.
* One-level depth: a single physical link, or multiple physical * One-level depth: a single physical link, or multiple physical
links bridged to form a single logical link, that is connected links bridged to form a single logical link, that is connected
to the default router. The single logical link provides a to the default router. The single logical link provides a
single broadcast domain, facilitating use of link-local single broadcast domain, facilitating use of link-local
Multicast DNS, and also ARP, which enables the home or Multicast DNS, and also ARP, which enables the home or
'hotspot' network to consist of just a single IPv4 subnet. 'hotspot' network to consist of just a single IPv4 subnet.
* Single administrative domain: all nodes under the same * Single administrative domain: all nodes under the same
administrative authority. (However, this does not necessarily administrative authority. (However, this does not necessarily
imply a network administrator.) imply a network administrator.)
(C) Advanced home and small business networks (C) Advanced home and small business networks [RFC7368]:
[I-D.ietf-homenet-arch]:
Like B but consist of multiple wired and/or wireless links, Like B, but consist of multiple wired and/or wireless links,
connected by routers, behind the single exit router. However, the connected by routers, generally behind a single exit router.
forwarding nodes are largely self-configuring and do not require However, the forwarding nodes are largely self-configuring and do
routing protocol administration. Such networks should also not not require routing protocol administration. Such networks should
require DNS administration. also not require DNS administration.
(D) Enterprise networks: (D) Enterprise networks:
Like C but consist of arbitrary network diameter under a single Consist of arbitrary network diameter under a single
administrative authority. A large majority of the forwarding and administrative authority. A large majority of the forwarding and
security devices are configured. Large-scale conference-style security devices are configured and multiple exit routers are more
networks, which are predominantly wireless access, e.g., as common. Large-scale conference-style networks, which are
available at IETF meetings, also fall within this category. predominantly wireless access, e.g., as available at IETF
meetings, also fall within this category.
(E) Higher Education networks: (E) Higher Education networks:
Like D but the core network may be under a central administrative Like D but the core network may be under a central administrative
domain while leaf networks are under local administrative domains. domain while leaf networks are under local administrative domains.
(F) Mesh networks such as RPL/6LoWPAN: (F) Mesh networks such as RPL/6LoWPAN:
Multi-link subnets with prefixes defined by one or more border Multi-link subnets with prefixes defined by one or more border
routers. May comprise any part of networks C, D, or E. routers. May comprise any part of networks C, D, or E.
skipping to change at page 7, line 7 skipping to change at page 7, line 20
should be considered in isolation. should be considered in isolation.
REQ1: For use cases A, B, and C, there should be a Zero REQ1: For use cases A, B, and C, there should be a Zero
Configuration mode of operation. This implies that servers Configuration mode of operation. This implies that servers
and clients should be able to automatically determine a and clients should be able to automatically determine a
default Scope of Discovery in which to advertise and discover default Scope of Discovery in which to advertise and discover
services, respectively. services, respectively.
REQ2: For use cases C, D, and E, there should be a way to configure REQ2: For use cases C, D, and E, there should be a way to configure
Scopes of Discovery that support a range of topologically- Scopes of Discovery that support a range of topologically-
independent zones (e.g., from department to campus-wide). If independent zones (e.g., from department to campus-wide).
multiple scopes are available, there must be a way to This capability must exist in the protocol; individual
enumerate the choices from which a selection can be made. operators are not required to use this capability in all
cases -- in particular, use case C should support Zero
Configuration operation where that is desired. If multiple
scopes are available, there must be a way to enumerate the
choices from which a selection can be made. In use case C,
either Zero Configuration (one flat list of resources) or
configured (e.g., resources sorted by room) modes of
operation should be available.
REQ3: As stated in REQ2 above, the discovery scope need not be REQ3: As stated in REQ2 above, the discovery scope need not be
aligned to network topology. For example, it may instead be aligned to network topology. For example, it may instead be
aligned to physical proximity (e.g. building) or aligned to physical proximity (e.g., building) or
organizational structure. organizational structure, (e.g., "Sales" vs. "Engineering").
REQ4: For use cases C, D, and E, there should be an incremental way REQ4: For use cases C, D, and E, there should be an incremental way
to deploy the solution. to deploy the solution.
REQ5: SSD should integrate with current link scope DNS-SD/mDNS REQ5: SSD should leverage and build upon current link scope DNS-SD/
protocols and deployments. mDNS protocols and deployments.
REQ6: SSD must not adversely affect or break any other current REQ6: SSD must not adversely affect or break any other current
protocols or deployments. protocols or deployments.
REQ7: SSD must be capable of operating across networks that are not REQ7: SSD must be capable of operating across networks that are not
limited to a single link or network technology, including limited to a single link or network technology, including
clients and services on non-adjacent links. clients and services on non-adjacent links.
REQ8: It is desirable that a user or device be able to discover REQ8: It is desirable that a user or device be able to discover
services within the sites or networks to which the user or services within the sites or networks to which the user or
skipping to change at page 7, line 50 skipping to change at page 8, line 22
REQ11: SSD must be scalable to thousands of nodes with minimal REQ11: SSD must be scalable to thousands of nodes with minimal
configuration and without degrading network performance. A configuration and without degrading network performance. A
possible figure of merit is that, as the number of services possible figure of merit is that, as the number of services
increases, the amount of traffic due to SSD on a given link increases, the amount of traffic due to SSD on a given link
remains relatively constant. remains relatively constant.
REQ12: SSD should enable a way to provide a consistent user REQ12: SSD should enable a way to provide a consistent user
experience whether local or remote services are being experience whether local or remote services are being
discovered. discovered.
REQ13: The information presented by SSD should closely reflect REQ13: The information presented by SSD should closely reflect the
reality. That is, new information should be available within current state of discoverable services on the network. That
a few seconds and stale information should not persist is, new information should be available within a few seconds
indefinitely. In networking all information is necessarily and stale information should not persist indefinitely. In
somewhat out-of-date by the time it reaches the receiver, networking all information is necessarily somewhat out-of-
even if only by a few microseconds, or less. Thus timeliness date by the time it reaches the receiver, even if only by a
is always an engineering trade-off against efficiency. The few microseconds, or less. Thus timeliness is always an
engineering decisions for SSD should appropriately balance engineering trade-off against efficiency. The engineering
timeliness against network efficiency. decisions for SSD should appropriately balance timeliness
against network efficiency.
REQ14: SSD should operate over existing networks (as described by REQ14: SSD should operate over existing networks (as described by
use cases A-F above) without requiring changes to the network use cases A-F above) without requiring changes to the network
technology or deployment. at the physical, link, or internetworking layers.
5. Namespace Considerations 5. Namespace Considerations
The traditional unicast DNS namespace contains, for the most part, The traditional unicast DNS namespace contains, for the most part,
globally unique names. Multicast DNS provides every link with its globally unique names. Multicast DNS provides every link with its
own separate link-local namespace, where names are unique only within own separate link-local namespace, where names are unique only within
the context of that link. Clients discovering services may need to the context of that link. Clients discovering services may need to
differentiate between local and global names, and may need to differentiate between local and global names, and may need to
determine when names in different namespaces identify the same determine when names in different namespaces identify the same
service. service.
skipping to change at page 9, line 22 skipping to change at page 9, line 43
For example, since mDNS is currently restricted to a single link, the For example, since mDNS is currently restricted to a single link, the
scope of the advertisement is limited, by design, to the shared link scope of the advertisement is limited, by design, to the shared link
between client and server. If the advertisement propagates to a between client and server. If the advertisement propagates to a
larger set of links than expected, this may result in unauthorized larger set of links than expected, this may result in unauthorized
clients (from the perspective of the owner) discovering and then clients (from the perspective of the owner) discovering and then
potentially attempting to connect to the advertised service. It also potentially attempting to connect to the advertised service. It also
discloses information (about the host and service) to a larger set of discloses information (about the host and service) to a larger set of
potential attackers. potential attackers.
Note that discovery of a service does not necessarily imply that the Note that discovery of a service does not necessarily imply that the
service is reachable or can be connected to. Specific access control service is reachable by, or can be connected to, or can be used by, a
mechanisms are out of scope of this document. given client. Specific access control mechanisms are out of scope of
this document.
If the scope of the discovery is not properly set up or constrained, If the scope of the discovery is not properly set up or constrained,
then information leaks will happen outside the appropriate network. then information leaks will happen outside the appropriate network.
6.2. Multiple Namespaces 6.2. Multiple Namespaces
There is a possibility of conflicts between the local and global DNS There is a possibility of conflicts between the local and global DNS
namespaces. Without adequate feedback, a discovering client may not namespaces. Without adequate feedback, a discovering client may not
know if the advertised service is the correct one, therefore enabling know if the advertised service is the correct one, therefore enabling
potential attacks. potential attacks.
skipping to change at page 10, line 24 skipping to change at page 10, line 44
considered as part of any security solution. Authentication of any considered as part of any security solution. Authentication of any
particular service is outside the scope of this document. particular service is outside the scope of this document.
6.5. Access Control 6.5. Access Control
Access Control refers to the ability to restrict which users are able Access Control refers to the ability to restrict which users are able
to use a particular service that might be advertised via DNS-SD. In to use a particular service that might be advertised via DNS-SD. In
this case, "use" of a service is different from the ability to this case, "use" of a service is different from the ability to
"discover" or "reach" a service. "discover" or "reach" a service.
While access control to an advertised service is outside the scope of While controlling access to an advertised service is outside the
DNS-SD, we note that access control today often is provided by scope of DNS-SD, we note that access control today often is provided
existing site infrastructure (e.g. router access control lists, by existing site infrastructure (e.g., router access control lists,
firewalls) and/or by service-specific mechanisms (e.g. user firewalls) and/or by service-specific mechanisms (e.g., user
authentication to the service). For example, many networked printers authentication to the service). For example, networked printers can
already support access controls via a user-id and password. At least control access via a user-id and password. Apple's software supports
one widely deployed DNS-SD + mDNS implementation supports such access such access control for USB printers shared via Mac OS X Printer
controls for printers. So the reliance on existing service-specific Sharing, as do many networked printers themselves. So the reliance
security mechanisms (i.e. outside the scope of DNS-SD) does not on existing service-specific security mechanisms (i.e. outside the
create new security considerations. scope of DNS-SD) does not create new security considerations.
6.6. Privacy Considerations 6.6. Privacy Considerations
Mobile devices such as smart phones or laptops that can expose the Mobile devices such as smart phones or laptops that can expose the
location of their owners by registering services in arbitrary zones location of their owners by registering services in arbitrary zones
pose a risk to privacy. Such devices must not register their pose a risk to privacy. Such devices must not register their
services in arbitrary zones without the approval ("opt-in") of their services in arbitrary zones without the approval ("opt-in") of their
users. However, it should be possible to configure one or more users. However, it should be possible to configure one or more
"safe" zones in which mobile devices may automatically register their "safe" zones in which mobile devices may automatically register their
services. services.
7. IANA Considerations 7. IANA Considerations
This document currently makes no request of IANA. This document makes no request of IANA.
Note to RFC Editor: this section may be removed upon publication as
an RFC.
8. Acknowledgments 8. Acknowledgments
We gratefully acknowledge contributions and review comments made by We gratefully acknowledge contributions and review comments made by
RJ Atkinson, Tim Chown, Guangqing Deng, Ralph Droms, Educause, David RJ Atkinson, Tim Chown, Guangqing Deng, Ralph Droms, Educause, David
Farmer, Matthew Gast, Thomas Narten, Doug Otis, David Thaler, and Farmer, Matthew Gast, Thomas Narten, Doug Otis, David Thaler, and
Peter Van Der Stok. Peter Van Der Stok.
9. References 9. References
skipping to change at page 11, line 41 skipping to change at page 12, line 13
Networks", RFC 4944, September 2007. Networks", RFC 4944, September 2007.
[RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. Levis, P., Pister, K., Struik, R., Vasseur, JP., and R.
Alexander, "RPL: IPv6 Routing Protocol for Low-Power and Alexander, "RPL: IPv6 Routing Protocol for Low-Power and
Lossy Networks", RFC 6550, March 2012. Lossy Networks", RFC 6550, March 2012.
[RFC7346] Droms, R., "IPv6 Multicast Address Scopes", RFC 7346, [RFC7346] Droms, R., "IPv6 Multicast Address Scopes", RFC 7346,
August 2014. August 2014.
[RFC7368] Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil,
"IPv6 Home Networking Architecture Principles", RFC 7368,
October 2014.
[mDNS] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, [mDNS] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
February 2013. February 2013.
[DNS-SD] Cheshire, S. and M. Krochmal, "DNS-Based Service [DNS-SD] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, February 2013. Discovery", RFC 6763, February 2013.
9.2. Informative References 9.2. Informative References
[I-D.ietf-homenet-arch] [B4W] "Bonjour for Windows",
Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil, <http://en.wikipedia.org/wiki/Bonjour_(software)>.
"IPv6 Home Networking Architecture Principles", draft-
ietf-homenet-arch-17 (work in progress), July 2014.
[I-D.sullivan-dnssd-mdns-dns-interop] [I-D.sullivan-dnssd-mdns-dns-interop]
Sullivan, A., "Requirements for Labels to Interoperate Sullivan, A., "On Interoperation of Labels Between mDNS
Between mDNS and DNS", draft-sullivan-dnssd-mdns-dns- and DNS", draft-sullivan-dnssd-mdns-dns-interop-01 (work
interop-00 (work in progress), January 2014. in progress), October 2014.
[EP] "Educause Petition", https://www.change.org/petitions/ [EP] "Educause Petition", https://www.change.org/petitions/
from-educause-higher-ed-wireless-networking-admin-group, from-educause-higher-ed-wireless-networking-admin-group,
July 2012. July 2012.
[IEEE.802.11] [IEEE.802.11]
"Information technology - Telecommunications and "Information technology - Telecommunications and
information exchange between systems - Local and information exchange between systems - Local and
metropolitan area networks - Specific requirements - Part metropolitan area networks - Specific requirements - Part
11: Wireless LAN Medium Access Control (MAC) and Physical 11: Wireless LAN Medium Access Control (MAC) and Physical
Layer (PHY) Specifications", IEEE Std 802.11-2012, 2012, Layer (PHY) Specifications", IEEE Std 802.11-2012, 2012,
<http://standards.ieee.org/getieee802/ <http://standards.ieee.org/getieee802/
download/802.11-2012.pdf>. download/802.11-2012.pdf>.
[static] "Manually Adding DNS-SD Service Discovery Records to an [NSD] "NsdManager | Android Developer", June 2012,
<http://developer.android.com/reference/android/net/nsd/
NsdManager.html>.
[STATIC] "Manually Adding DNS-SD Service Discovery Records to an
Existing Name Server", July 2013, Existing Name Server", July 2013,
<http://www.dns-sd.org/ServerStaticSetup.html>. <http://www.dns-sd.org/ServerStaticSetup.html>.
[ZC] Cheshire, S. and D. Steinberg, "Zero Configuration [ZC] Cheshire, S. and D. Steinberg, "Zero Configuration
Networking: The Definitive Guide", O'Reilly Media, Inc. , Networking: The Definitive Guide", O'Reilly Media, Inc. ,
ISBN 0-596-10100-7, December 2005. ISBN 0-596-10100-7, December 2005.
Authors' Addresses Authors' Addresses
Kerry Lynn Kerry Lynn
Consultant Verizon
50 Sylvan Road
Waltham , MA 95014
USA
Phone: +1 978 460 4253 Phone: +1 781 296 9722
Email: kerlyn@ieee.org Email: kerry.lynn@verizon.com
Stuart Cheshire Stuart Cheshire
Apple, Inc. Apple, Inc.
1 Infinite Loop 1 Infinite Loop
Cupertino , California 95014 Cupertino , CA 95014
USA USA
Phone: +1 408 974 3207 Phone: +1 408 974 3207
Email: cheshire@apple.com Email: cheshire@apple.com
Marc Blanchet Marc Blanchet
Viagenie Viagenie
246 Aberdeen 246 Aberdeen
Quebec , Quebec G1R 2E1 Quebec , QC G1R 2E1
Canada Canada
Email: Marc.Blanchet@viagenie.ca Email: Marc.Blanchet@viagenie.ca
URI: http://viagenie.ca URI: http://viagenie.ca
Daniel Migault Daniel Migault
Orange Ericsson
38-40 rue du General Leclerc 8400 boulevard Decarie
Issy-les-Moulineaux 92130 Montreal , QC H4P 2N2
France Canada
Phone: +33 1 45 29 60 52 Phone: +1 514 452 2160
Email: mglt.biz@gmail.com Email: daniel.migault@ericsson.com
 End of changes. 45 change blocks. 
98 lines changed or deleted 122 lines changed or added

This html diff was produced by rfcdiff 1.42. The latest version is available from http://tools.ietf.org/tools/rfcdiff/