draft-ietf-p2psip-concepts-07.txt   draft-ietf-p2psip-concepts-08.txt 
P2PSIP Working Group D. Bryan P2PSIP Working Group D. Bryan
Internet-Draft Cogent Force, LLC Internet-Draft Cogent Force, LLC
Intended status: Informational P. Matthews Intended status: Informational P. Matthews
Expires: November 9, 2015 Alcatel-Lucent Expires: August 14, 2016 Alcatel-Lucent
E. Shim E. Shim
Samsung Electronics Co., Ltd. Samsung Electronics Co., Ltd.
D. Willis D. Willis
Softarmor Systems Softarmor Systems
S. Dawkins S. Dawkins
Huawei (USA) Huawei (USA)
May 8, 2015 February 11, 2016
Concepts and Terminology for Peer to Peer SIP Concepts and Terminology for Peer to Peer SIP
draft-ietf-p2psip-concepts-07 draft-ietf-p2psip-concepts-08
Abstract Abstract
This document defines concepts and terminology for the use of the This document defines concepts and terminology for the use of the
Session Initiation Protocol in a peer-to-peer environment where the Session Initiation Protocol in a peer-to-peer environment where the
traditional proxy-registrar and message routing functions are traditional proxy-registrar and message routing functions are
replaced by a distributed mechanism. These mechanisms may be replaced by a distributed mechanism. These mechanisms may be
implemented using a distributed hash table or other distributed data implemented using a distributed hash table or other distributed data
mechanism with similar external properties. This document includes a mechanism with similar external properties. This document includes a
high-level view of the functional relationships between the network high-level view of the functional relationships between the network
elements defined herein, a conceptual model of operations, and an elements defined herein, a conceptual model of operations, and an
outline of the related problems addressed by the P2PSIP working group outline of the related problems addressed by the P2PSIP working group
and the RELOAD protocol and SIP usage ([RFC6940], and the RELOAD protocol and SIP usage document defined by the working
[I-D.ietf-p2psip-sip]) defined by the working group. group.
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 November 9, 2015. This Internet-Draft will expire on August 14, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
Copyright (c) 2016 IETF Trust and the persons identified as the
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modifications of such material outside the IETF Standards Process. modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling Without obtaining an adequate license from the person(s) controlling
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outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Editor's Notes and Changes To This Version . . . . . . . . . . 4 1. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. High-Level Description . . . . . . . . . . . . . . . . . . . 4
3. High-Level Description . . . . . . . . . . . . . . . . . . . . 5 2.1. Services . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Services . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2. Clients . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Clients . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3. Relationship Between P2PSIP and RELOAD . . . . . . . . . 5
3.3. Relationship Between P2PSIP and RELOAD . . . . . . . . . . 6 2.4. Relationship Between P2PSIP and SIP . . . . . . . . . . . 5
3.4. Relationship Between P2PSIP and SIP . . . . . . . . . . . 7 2.5. Relationship Between P2PSIP and Other AoR Dereferencing
3.5. Relationship Between P2PSIP and Other AoR Approaches . . . . . . . . . . . . . . . . . . . . . . . 5
Dereferencing Approaches . . . . . . . . . . . . . . . . . 7 2.6. NAT Issues . . . . . . . . . . . . . . . . . . . . . . . 6
3.6. NAT Issues . . . . . . . . . . . . . . . . . . . . . . . . 7 3. Reference Model . . . . . . . . . . . . . . . . . . . . . . . 6
4. Reference Model . . . . . . . . . . . . . . . . . . . . . . . 8 4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 10 5. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 12
6. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.1. The Distributed Database Function . . . . . . . . . . . . 12
6.1. The Distributed Database Function . . . . . . . . . . . . 13 5.2. Using the Distributed Database Function . . . . . . . . . 13
6.2. Using the Distributed Database Function . . . . . . . . . 14 5.3. NAT Traversal . . . . . . . . . . . . . . . . . . . . . . 14
6.3. NAT Traversal . . . . . . . . . . . . . . . . . . . . . . 15 5.4. Locating and Joining an Overlay . . . . . . . . . . . . . 14
6.4. Locating and Joining an Overlay . . . . . . . . . . . . . 16 5.5. Clients and Connecting Unmodified SIP Devices . . . . . . 15
6.5. Clients and Connecting Unmodified SIP Devices . . . . . . 16 5.6. Architecture . . . . . . . . . . . . . . . . . . . . . . 16
6.6. Architecture . . . . . . . . . . . . . . . . . . . . . . . 17 6. Security Considerations . . . . . . . . . . . . . . . . . . . 16
7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 17 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
8. Informative References . . . . . . . . . . . . . . . . . . . . 18 8. Informative References . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Editor's Notes and Changes To This Version
This version of the draft represents almost no change from -06, which
itself was a very minor revision of version -05 and is intended to
restart conversation on this draft in the group, to identify open
issues, address them, and complete work on the document in light of
RELOAD being issued as an RFC.
It is currently believed this draft's terminology is inline with RFC
6940. Please report any discrepancies to the editors of this
document.
Version -03 represented a substantial revision from the previous
version. Until -02, this work was tracking open questions and being
used to help reach consensus on a draft. With the selection of
RELOAD as the protocol for this WG, the focus of the group turned to
completing the RELOAD draft, and the WG directed the editors to
update the document to reflect the decisions made in RELOAD upon
completion.
Please see Section 7 for the list of major open issues.
2. Background 1. Background
One of the fundamental problems in multimedia communication between One of the fundamental problems in multimedia communication between
Internet nodes is discovering the host at which a given user can be Internet nodes is discovering the host at which a given user can be
reached. In the Session Initiation Protocol (SIP) [RFC3261] this reached. In the Session Initiation Protocol (SIP) [RFC3261] this
problem is expressed as the problem of mapping an Address of Record problem is expressed as the problem of mapping an Address of Record
(AoR) for a user into one or more Contact URIs [RFC3986]. The AoR is (AoR) for a user into one or more Contact URIs [RFC3986]. The AoR is
a name for the user that is independent of the host or hosts where a name for the user that is independent of the host or hosts where
the user can be contacted, while a Contact URI indicates the host the user can be contacted, while a Contact URI indicates the host
where the user can be contacted. where the user can be contacted.
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This document gives a high-level description of an alternative This document gives a high-level description of an alternative
solution to this problem. In this alternative solution, the solution to this problem. In this alternative solution, the
relatively fixed hierarchy of Client/Server SIP is replaced by a relatively fixed hierarchy of Client/Server SIP is replaced by a
peer-to-peer overlay network. In this peer-to-peer overlay network, peer-to-peer overlay network. In this peer-to-peer overlay network,
the various AoR to Contact URI mappings are not centralized at proxy/ the various AoR to Contact URI mappings are not centralized at proxy/
registrar nodes but are instead distributed amongst the peers in the registrar nodes but are instead distributed amongst the peers in the
overlay. overlay.
The details of this alternative solution are specified by the RELOAD The details of this alternative solution are specified by the RELOAD
protocol. The RELOAD base draft [RFC6940] defines a mechanism to protocol [RFC6940], which defines a mechanism to distribute using a
distribute using a Distributed Hash Table (DHT) and specifies the Distributed Hash Table (DHT) and specifies the wire protocol,
wire protocol, security, and authentication mechanisms needed to security, and authentication mechanisms needed to convey this
convey this information. This DHT protocol was designed specifically information. This DHT protocol was designed specifically with the
with the purpose of enabling a distributed SIP registrar in mind. purpose of enabling a distributed SIP registrar in mind. While
While designing the protocol other applications were considered, and designing the protocol other applications were considered, and when
when possible design decisions were made that allow RELOAD to be used possible design decisions were made that allow RELOAD to be used in
in other instances where a DHT is desirable, but only when making other instances where a DHT is desirable, but only when making such
such decisions did not add undue complexity to the RELOAD protocol. decisions did not add undue complexity to the RELOAD protocol. The
The RELOAD sip draft [I-D.ietf-p2psip-sip] specifies how RELOAD is RELOAD sip draft [I-D.ietf-p2psip-sip] specifies how RELOAD is used
used with the SIP protocol to enable a distributed, server-less SIP with the SIP protocol to enable a distributed, server-less SIP
solution. solution.
3. High-Level Description 2. High-Level Description
A P2PSIP Overlay is a collection of nodes organized in a peer-to-peer A P2PSIP Overlay is a collection of nodes organized in a peer-to-peer
fashion for the purpose of enabling real-time communication using the fashion for the purpose of enabling real-time communication using the
Session Initiation Protocol (SIP). Collectively, the nodes in the Session Initiation Protocol (SIP). Collectively, the nodes in the
overlay provide a distributed mechanism for mapping names to overlay overlay provide a distributed mechanism for mapping names to overlay
locations. This provides for the mapping of Addresses of Record locations. This provides for the mapping of Addresses of Record
(AoRs) to Contact URIs, thereby providing the "location server" (AoRs) to Contact URIs, thereby providing the "location server"
function of [RFC3261]. An Overlay also provides a transport function function of [RFC3261]. An Overlay also provides a transport function
by which SIP messages can be transported between any two nodes in the by which SIP messages can be transported between any two nodes in the
overlay. overlay.
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that the loss of a node does not result in the loss of the data item that the loss of a node does not result in the loss of the data item
to the overlay. to the overlay.
One use of this distributed database is to store the information One use of this distributed database is to store the information
required to provide the mapping between AoRs and Contact URIs for the required to provide the mapping between AoRs and Contact URIs for the
distributed location function. This provides a location function distributed location function. This provides a location function
within each overlay that is an alternative to the location functions within each overlay that is an alternative to the location functions
described in [RFC3263]. However, the model of [RFC3263] is used described in [RFC3263]. However, the model of [RFC3263] is used
between overlays. between overlays.
3.1. Services 2.1. Services
The nature of peer-to-peer computing is that each peer offers The nature of peer-to-peer computing is that each peer offers
services to other peers to allow the overlay to collectively provide services to other peers to allow the overlay to collectively provide
larger functions. In P2PSIP, peers offer both distributed storage larger functions. In P2PSIP, peers offer both distributed storage
and distributed message routing services, allowing these functions to and distributed message routing services, allowing these functions to
be implemented across the overlay. Additionally, the RELOAD protocol be implemented across the overlay. Additionally, the RELOAD protocol
offers a simplistic discovery mechanism specific to the TURN offers a simplistic discovery mechanism specific to the TURN
[RFC5766] protocol used for NAT traversal. Individual peers may also [RFC5766] protocol used for NAT traversal. Individual peers may also
offer other services as an enhancement to P2PSIP functionality (for offer other services as an enhancement to P2PSIP functionality (for
example to support voicemail) or to support other applications beyond example to support voicemail) or to support other applications beyond
SIP. To support these additional services, peers may need to store SIP. To support these additional services, peers may need to store
additional information in the overlay. additional information in the overlay. [RFC7374] describes the
[I-D.ietf-p2psip-service-discovery] describes the mechanism used in mechanism used in P2PSIP for resource discovery.
P2PSIP for resource discovery.
3.2. Clients 2.2. Clients
An overlay may or may not also include one or more nodes called An overlay may or may not also include one or more nodes called
clients. Clients are supported in the RELOAD protocol as peers that clients. Clients are supported in the RELOAD protocol as peers that
have not joined the overlay, and therefore do not route messages or have not joined the overlay, and therefore do not route messages or
store information. Clients access the services of the RELOAD store information. Clients access the services of the RELOAD
protocol by connecting to a peer which performs operations on the protocol by connecting to a peer which performs operations on the
behalf of the client. Note that in RELOAD there is no distinct behalf of the client. Note that in RELOAD there is no distinct
client protocol. Instead, a client connects using the same protocol, client protocol. Instead, a client connects using the same protocol,
but never joins the overlay as a peer. For more information, see but never joins the overlay as a peer. For more information, see
[RFC6940]. [RFC6940].
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Note that in the context of P2PSIP, there is an additional entity Note that in the context of P2PSIP, there is an additional entity
that is sometimes referred to as a client. A special peer may be a that is sometimes referred to as a client. A special peer may be a
member of the in the P2PSIP overlay and may present the functionality member of the in the P2PSIP overlay and may present the functionality
of one or all of a SIP registrar, proxy or redirect server to of one or all of a SIP registrar, proxy or redirect server to
conventional SIP devices (SIP clients). In this way, existing, non- conventional SIP devices (SIP clients). In this way, existing, non-
modified SIP clients may connect to the network. These unmodified modified SIP clients may connect to the network. These unmodified
SIP devices do not speak the RELOAD protocol, and this is a distinct SIP devices do not speak the RELOAD protocol, and this is a distinct
concept from the notion of client discussed in the previous concept from the notion of client discussed in the previous
paragraph. paragraph.
3.3. Relationship Between P2PSIP and RELOAD 2.3. Relationship Between P2PSIP and RELOAD
The RELOAD protocol defined by the P2PSIP working group implements a The RELOAD protocol defined by the P2PSIP working group implements a
DHT primarily for use by server-less, peer-to-peer SIP deployments. DHT primarily for use by server-less, peer-to-peer SIP deployments.
However, the RELOAD protocol could be used for other applications as However, the RELOAD protocol could be used for other applications as
well. As such, a "P2PSIP" deployment is generally assumed to be a well. As such, a "P2PSIP" deployment is generally assumed to be a
use of RELOAD to implement distributed SIP, but it is possible that use of RELOAD to implement distributed SIP, but it is possible that
RELOAD is used as a mechanism to distribute other applications, RELOAD is used as a mechanism to distribute other applications,
completely unrelated to SIP. completely unrelated to SIP.
3.4. Relationship Between P2PSIP and SIP 2.4. Relationship Between P2PSIP and SIP
Since P2PSIP is about peer-to-peer networks for real-time Since P2PSIP is about peer-to-peer networks for real-time
communication, it is expected that most peers and clients will be communication, it is expected that most peers and clients will be
coupled with SIP entities (although RELOAD may be used for other coupled with SIP entities (although RELOAD may be used for other
applications than P2PSIP). For example, one peer might be coupled applications than P2PSIP). For example, one peer might be coupled
with a SIP UA, another might be coupled with a SIP proxy, while a with a SIP UA, another might be coupled with a SIP proxy, while a
third might be coupled with a SIP-to-PSTN gateway. For such nodes, third might be coupled with a SIP-to-PSTN gateway. For such nodes,
the peer or client portion of the node is logically distinct from the the peer or client portion of the node is logically distinct from the
SIP entity portion. However, there is no hard requirement that every SIP entity portion. However, there is no hard requirement that every
P2PSIP node (peer or client) be coupled to a SIP entity. As an P2PSIP node (peer or client) be coupled to a SIP entity. As an
example, additional peers could be placed in the overlay to provide example, additional peers could be placed in the overlay to provide
additional storage or redundancy for the RELOAD overlay, but might additional storage or redundancy for the RELOAD overlay, but might
not have any direct SIP capabilities. not have any direct SIP capabilities.
3.5. Relationship Between P2PSIP and Other AoR Dereferencing Approaches 2.5. Relationship Between P2PSIP and Other AoR Dereferencing Approaches
OPEN ISSUE: Many of the "decisions" made have been moved out of the
main document. This one, however, seems to point out a difference.
Should this section be moved or removed?
As noted above, the fundamental task of P2PSIP is turning an AoR into As noted above, the fundamental task of P2PSIP is turning an AoR into
a Contact. This task might be approached using zeroconf techniques a Contact. This task might be approached using zeroconf techniques
such as multicast DNS and DNS Service Discovery (as in Apple's such as multicast DNS and DNS Service Discovery [RFC6762][RFC6763],
Bonjour protocol), link-local multicast name resolution [RFC4795], link-local multicast name resolution [RFC4795], and dynamic DNS
and dynamic DNS [RFC2136]. [RFC2136].
These alternatives were discussed in the P2PSIP Working Group, and These alternatives were discussed in the P2PSIP Working Group, and
not pursued as a general solution for a number of reasons related to not pursued as a general solution for a number of reasons related to
scalability, the ability to work in a disconnected state, partition scalability, the ability to work in a disconnected state, partition
recovery, and so on. However, there does seem to be some continuing recovery, and so on. However, there does seem to be some continuing
interest in the possibility of using DNS-SD and mDNS for interest in the possibility of using DNS-SD and mDNS for
bootstrapping of P2PSIP overlays. bootstrapping of P2PSIP overlays.
3.6. NAT Issues 2.6. NAT Issues
Network Address Translators (NATs) are impediments to establishing Network Address Translators (NATs) are impediments to establishing
and maintaining peer-to-peer networks, since NATs hinder direct and maintaining peer-to-peer networks, since NATs hinder direct
communication between nodes. Some peer-to-peer network architectures communication between nodes. Some peer-to-peer network architectures
avoid this problem by insisting that all nodes exist in the same avoid this problem by insisting that all nodes exist in the same
address space. However, RELOAD provides capabilities that allow address space. However, RELOAD provides capabilities that allow
nodes to be located in multiple address spaces interconnected by nodes to be located in multiple address spaces interconnected by
NATs, to allow RELOAD messages to traverse NATs, and to assist in NATs, to allow RELOAD messages to traverse NATs, and to assist in
transmitting application-level messages (for example SIP messages) transmitting application-level messages (for example SIP messages)
across NATs. across NATs.
4. Reference Model 3. Reference Model
The following diagram shows a P2PSIP Overlay consisting of a number The following diagram shows a P2PSIP Overlay consisting of a number
of Peers, one Client, and an ordinary SIP UA. It illustrates a of Peers, one Client, and an ordinary SIP UA. It illustrates a
typical P2PSIP overlay but does not limit other compositions or typical P2PSIP overlay but does not limit other compositions or
variations; for example, Proxy Peer P might also talk to a ordinary variations; for example, Proxy Peer P might also talk to a ordinary
SIP proxy as well. The figure is not intended to cover all possible SIP proxy as well. The figure is not intended to cover all possible
architecture variations, but simply to show a deployment with many architecture variations, but simply to show a deployment with many
common P2PSIP elements. common P2PSIP elements.
--->PSTN --->PSTN
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resolves the next-hop by using the P2PSIP protocol to interact with resolves the next-hop by using the P2PSIP protocol to interact with
the routing knowledge of the Overlay, then processes the SIP requests the routing knowledge of the Overlay, then processes the SIP requests
as appropriate (proxying or redirecting towards the next-hop). Note as appropriate (proxying or redirecting towards the next-hop). Note
that proxy operation is bidirectional - the proxy may be forwarding a that proxy operation is bidirectional - the proxy may be forwarding a
request from an ordinary SIP device to the Overlay, or from the request from an ordinary SIP device to the Overlay, or from the
P2PSIP overlay to an ordinary SIP device. P2PSIP overlay to an ordinary SIP device.
The PSTN Gateway at peer "G" provides a similar sort of adaptation to The PSTN Gateway at peer "G" provides a similar sort of adaptation to
and from the public switched telephone network (PSTN). and from the public switched telephone network (PSTN).
5. Definitions 4. Definitions
This section defines a number of concepts that are key to This section defines a number of concepts that are key to
understanding the P2PSIP work. understanding the P2PSIP work.
Overlay Network: An overlay network is a computer network which is Overlay Network: An overlay network is a computer network which is
built on top of another network. Nodes in the overlay can be built on top of another network. Nodes in the overlay can be
thought of as being connected by virtual or logical links, each of thought of as being connected by virtual or logical links, each of
which corresponds to a path, perhaps through many physical links, which corresponds to a path, perhaps through many physical links,
in the underlying network. For example, many peer-to-peer in the underlying network. For example, many peer-to-peer
networks are overlay networks because they run on top of the networks are overlay networks because they run on top of the
Internet. Dial-up Internet is an overlay upon the telephone Internet. Dial-up Internet is an overlay upon the telephone
network. <http://en.wikipedia.org/wiki/P2P_overlay> network.
P2P Network: A peer-to-peer (or P2P) computer network is a network P2P Network: A peer-to-peer (or P2P) computer network is a network
that relies primarily on the computing power and bandwidth of the that relies primarily on the computing power and bandwidth of the
participants in the network rather than concentrating it in a participants in the network rather than concentrating it in a
relatively low number of servers. P2P networks are typically used relatively low number of servers. P2P networks are typically used
for connecting nodes via largely ad hoc connections. Such for connecting nodes via largely ad hoc connections. Such
networks are useful for many purposes. Sharing content files (see networks are useful for many purposes. Sharing content files
<http://en.wikipedia.org/wiki/File_sharing>) containing audio, containing audio, video, data or anything in digital format is
video, data or anything in digital format is very common, and very common, and real-time data, such as telephony traffic, is
real-time data, such as telephony traffic, is also exchanged using also exchanged using P2P technology. A P2P Network may also be
P2P technology. <http://en.wikipedia.org/wiki/Peer-to-peer>. A called a "P2P Overlay" or "P2P Overlay Network" or "P2P Network
P2P Network may also be called a "P2P Overlay" or "P2P Overlay Overlay", since its organization is not at the physical layer, but
Network" or "P2P Network Overlay", since its organization is not is instead "on top of" an existing Internet Protocol network.
at the physical layer, but is instead "on top of" an existing
Internet Protocol network.
P2PSIP: A suite of communications protocols related to the Session P2PSIP: A suite of communications protocols related to the Session
Initiation Protocol (SIP) [RFC3261] that enable SIP to use peer- Initiation Protocol (SIP) [RFC3261] that enable SIP to use peer-
to-peer techniques for resolving the targets of SIP requests, to-peer techniques for resolving the targets of SIP requests,
providing SIP message transport, and providing other SIP-related providing SIP message transport, and providing other SIP-related
functions. At present, these protocols include [RFC6940], functions. At present, these protocols include [RFC6940],
[I-D.ietf-p2psip-sip], [I-D.ietf-p2psip-diagnostics], [I-D.ietf-p2psip-sip], [I-D.ietf-p2psip-diagnostics], [RFC7374]
[I-D.ietf-p2psip-service-discovery] and and [RFC7363].
[I-D.ietf-p2psip-self-tuning].
User: A human that interacts with the overlay through SIP UAs User: A human that interacts with the overlay through SIP UAs
located on peers and clients (and perhaps other ways). located on peers and clients (and perhaps other ways).
The following terms are defined here only within the scope of The following terms are defined here only within the scope of
P2PSIP. These terms may have conflicting definitions in other P2PSIP. These terms may have conflicting definitions in other
bodies of literature. Some earlier versions of this document bodies of literature. Some earlier versions of this document
prefixed each term with "P2PSIP" to clarify the term's scope. prefixed each term with "P2PSIP" to clarify the term's scope.
This prefixing has been eliminated from the text; however the This prefixing has been eliminated from the text; however the
scoping still applies. scoping still applies.
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Peer Protocol: The protocol spoken between P2PSIP Overlay peers to Peer Protocol: The protocol spoken between P2PSIP Overlay peers to
share information and organize the P2PSIP Overlay Network. In share information and organize the P2PSIP Overlay Network. In
P2PSIP, this is implemented using the RELOAD [RFC6940] protocol. P2PSIP, this is implemented using the RELOAD [RFC6940] protocol.
Client Protocol: The protocol spoken between Clients and Peers. In Client Protocol: The protocol spoken between Clients and Peers. In
P2PSIP and RELOAD, this is the same protocol syntactically as the P2PSIP and RELOAD, this is the same protocol syntactically as the
Peer Protocol. The only difference is that Clients are not Peer Protocol. The only difference is that Clients are not
routing messages or routing information, and have not (or can not) routing messages or routing information, and have not (or can not)
insert themselves into the overlay. insert themselves into the overlay.
Peer Protocol Connection / P2PSIP Client Protocol Connection: The Peer Protocol Connection / P2PSIP Client Protocol Connection:
TLS, DTLS, TCP, UDP or other transport layer protocol connection The TLS, DTLS, TCP, UDP or other transport layer protocol
over which the RELOAD Peer Protocol messages are transported. connection over which the RELOAD Peer Protocol messages are
transported.
Neighbors: The set of P2PSIP Peers that a Peer or Client know of Neighbors: The set of P2PSIP Peers that a Peer or Client know of
directly and can reach without further lookups. directly and can reach without further lookups.
Joining Peer: A node that is attempting to become a Peer in a Joining Peer: A node that is attempting to become a Peer in a
particular Overlay. particular Overlay.
Bootstrap Peer: A Peer in the Overlay that is the first point of Bootstrap Peer: A Peer in the Overlay that is the first point of
contact for a Joining Peer. It selects the peer that will serve contact for a Joining Peer. It selects the peer that will serve
as the Admitting Peer and helps the joining peer contact the as the Admitting Peer and helps the joining peer contact the
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the joining peer is a fully-functional peer of the overlay. the joining peer is a fully-functional peer of the overlay.
During the admission process, the joining peer may need to present During the admission process, the joining peer may need to present
credentials to prove that it has sufficient authority to join the credentials to prove that it has sufficient authority to join the
overlay. overlay.
Resource Record Insertion: The act of inserting a P2PSIP Resource Resource Record Insertion: The act of inserting a P2PSIP Resource
Record into the distributed database. Following insertion, the Record into the distributed database. Following insertion, the
data will be stored at one or more peers. The data can be data will be stored at one or more peers. The data can be
retrieved or updated using the Resource-ID as a key. retrieved or updated using the Resource-ID as a key.
6. Discussion 5. Discussion
6.1. The Distributed Database Function 5.1. The Distributed Database Function
A P2PSIP Overlay functions as a distributed database. The database A P2PSIP Overlay functions as a distributed database. The database
serves as a way to store information about Resources. A piece of serves as a way to store information about Resources. A piece of
information, called a Resource Record, can be stored by and retrieved information, called a Resource Record, can be stored by and retrieved
from the database using a key associated with the Resource Record from the database using a key associated with the Resource Record
called its Resource-ID. Each Resource must have a unique called its Resource-ID. Each Resource must have a unique Resource-
Resource-ID. In addition to uniquely identifying the Resource, the ID. In addition to uniquely identifying the Resource, the Resource-
Resource-ID is also used by the distributed database algorithm to ID is also used by the distributed database algorithm to determine
determine the peer or peers that store the Resource Record in the the peer or peers that store the Resource Record in the overlay.
overlay.
Users are humans that can use the overlay to do things like making Users are humans that can use the overlay to do things like making
and receiving calls. Information stored in the resource record and receiving calls. Information stored in the resource record
associated with a user can include things like the full name of the associated with a user can include things like the full name of the
user and the location of the UAs that the user is using (the users user and the location of the UAs that the user is using (the users
SIP AoR). Full details of how this is implemented using RELOAD are SIP AoR). Full details of how this is implemented using RELOAD are
provided in [I-D.ietf-p2psip-sip] provided in [I-D.ietf-p2psip-sip]
Before information about a user can be stored in the overlay, a user Before information about a user can be stored in the overlay, a user
needs a User Name. The User Name is a human-friendly identifier that needs a User Name. The User Name is a human-friendly identifier that
skipping to change at page 14, line 13 skipping to change at page 12, line 46
certificates, identify the User Name as well as a certain number of certificates, identify the User Name as well as a certain number of
Resource-IDs where the user may store their information. For more Resource-IDs where the user may store their information. For more
information, see [RFC6940]. information, see [RFC6940].
The P2PSIP suite of protocols also standardizes information about how The P2PSIP suite of protocols also standardizes information about how
to locate services. Services represent actions that a peer (and to locate services. Services represent actions that a peer (and
perhaps a client) can do to benefit other peers and clients in the perhaps a client) can do to benefit other peers and clients in the
overlay. Information that might be stored in the resource record overlay. Information that might be stored in the resource record
associated with a service might include the peers (and perhaps associated with a service might include the peers (and perhaps
clients) offering the service. Service discovery for P2PSIP is clients) offering the service. Service discovery for P2PSIP is
defined in [I-D.ietf-p2psip-service-discovery]. defined in [RFC7374].
Each service has a human-friendly Service Name that uniquely Each service has a human-friendly Service Name that uniquely
identifies the service. Like User Names, the Service Name is not a identifies the service. Like User Names, the Service Name is not a
resource-id, rather the resource-id is derived from the service name resource-id, rather the resource-id is derived from the service name
using some function defined by the distributed database algorithm using some function defined by the distributed database algorithm
used by the overlay. used by the overlay.
A class of algorithms known as Distributed Hash Tables A class of algorithms known as Distributed Hash Tables are one way to
<http://en.wikipedia.org/wiki/P2P_overlay> are one way to implement implement the Distributed Database. The RELOAD protocol is
the Distributed Database. The RELOAD protocol is extensible and extensible and allows many different DHTs to be implemented, but
allows many different DHTs to be implemented, but specifies a specifies a mandatory to implement DHT in the form of a modified
mandatory to implement DHT in the form of a modified Chord DHT. For Chord DHT. For more information, see [Chord]
more information, see [Chord]
6.2. Using the Distributed Database Function 5.2. Using the Distributed Database Function
While there are a number of ways the distributed database described While there are a number of ways the distributed database described
in the previous section can be used to establish multimedia sessions in the previous section can be used to establish multimedia sessions
using SIP, the basic mechanism defined in the RELOAD base draft and using SIP, the basic mechanism defined in the RELOAD protocol and SIP
SIP usage is summarized below. This is a very simplistic overview. usage is summarized below. This is a very simplistic overview. For
For more detailed information, please see the RELOAD base draft. more detailed information, please see the RELOAD protocol document.
Contact information for a user is stored in the resource record for Contact information for a user is stored in the resource record for
that user. Assume that a user is using a device, here called peer A, that user. Assume that a user is using a device, here called peer A,
which serves as the contact point for this user. The user adds which serves as the contact point for this user. The user adds
contact information to this resource record, as authorized by the contact information to this resource record, as authorized by the
RELOAD certificate mechanism. The resource record itself is stored RELOAD certificate mechanism. The resource record itself is stored
with peer Z in the network, where peer Z is chosen by the particular with peer Z in the network, where peer Z is chosen by the particular
distributed database algorithm in use by the overlay. distributed database algorithm in use by the overlay.
When the SIP entity coupled with peer B has an INVITE message When the SIP entity coupled with peer B has an INVITE message
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appropriate NAT traversal (the details of which are not shown). appropriate NAT traversal (the details of which are not shown).
Note that RELOAD is used only to establish the connection. Once the Note that RELOAD is used only to establish the connection. Once the
connection is established, messages between the peers are sent using connection is established, messages between the peers are sent using
ordinary SIP. ordinary SIP.
This exchange is illustrated in the following figure. The notation This exchange is illustrated in the following figure. The notation
"Store(U@A)" is used to show the distributed database operation of "Store(U@A)" is used to show the distributed database operation of
updating the resource record for user U with the contract A, and updating the resource record for user U with the contract A, and
"Fetch(U)" illustrates the distributed database operation of "Fetch(U)" illustrates the distributed database operation of
retrieving the resource record for user U. Note that the messages retrieving the resource record for user U. Note that the messages
between the peers A, B and Z may actually travel via intermediate between the peers A, B and Z may actually travel via intermediate
peers (not shown) as part of the distributed lookup process or so as peers (not shown) as part of the distributed lookup process or so as
to traverse intervening NATs. to traverse intervening NATs.
Peer B Peer Z Peer A Peer B Peer Z Peer A
| | | | | |
| | Store(U@Y)| | | Store(U@Y)|
| |<------------------| | |<------------------|
| |Store-Resp(OK) | | |Store-Resp(OK) |
| |------------------>| | |------------------>|
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|------------------->| | |------------------->| |
| Fetch-Resp(U@Y)| | | Fetch-Resp(U@Y)| |
|<-------------------| | |<-------------------| |
| | | | | |
(RELOAD IS USED TO ESTABLISH CONNECTION) (RELOAD IS USED TO ESTABLISH CONNECTION)
| | | | | |
| SIP INVITE(To:U) | | | SIP INVITE(To:U) | |
|--------------------------------------->| |--------------------------------------->|
| | | | | |
6.3. NAT Traversal 5.3. NAT Traversal
NAT Traversal in P2PSIP using RELOAD treats all peers as equal and NAT Traversal in P2PSIP using RELOAD treats all peers as equal and
establishes a partial mesh of connections between them. Messages establishes a partial mesh of connections between them. Messages
from one peer to another are routed along the edges in the mesh of from one peer to another are routed along the edges in the mesh of
connections until they reach their destination. To make the routing connections until they reach their destination. To make the routing
efficient and to avoid the use of standard Internet routing efficient and to avoid the use of standard Internet routing
protocols, the partial mesh is organized in a structured manner. If protocols, the partial mesh is organized in a structured manner. If
the structure is based on any one of a number of common DHT the structure is based on any one of a number of common DHT
algorithms, then the maximum number of hops between any two peers is algorithms, then the maximum number of hops between any two peers is
log N, where N is the number of peers in the overlay. Existing log N, where N is the number of peers in the overlay. Existing
connections, along with the ICE NAT traversal techniques [RFC5245], connections, along with the ICE NAT traversal techniques [RFC5245],
are used to establish new connections between peers, and also to are used to establish new connections between peers, and also to
allow the applications running on peers to establish a connection to allow the applications running on peers to establish a connection to
communicate with one another. communicate with one another.
6.4. Locating and Joining an Overlay 5.4. Locating and Joining an Overlay
Before a peer can attempt to join a P2PSIP overlay, it must first Before a peer can attempt to join a P2PSIP overlay, it must first
obtain a Node-ID, configuration information, and optionally a set of obtain a Node-ID, configuration information, and optionally a set of
credentials. The Node-ID is an identifier that will uniquely credentials. The Node-ID is an identifier that will uniquely
identify the peer within the overlay, while the credentials show that identify the peer within the overlay, while the credentials show that
the peer is allowed to join the overlay. the peer is allowed to join the overlay.
The P2PSIP WG does not impose a particular mechanism for how the The P2PSIP WG does not impose a particular mechanism for how the
peer-ID and the credentials are obtained, but the RELOAD base draft peer-ID and the credentials are obtained, but the RELOAD protocol
does specify the format for the configuration information, and does specify the format for the configuration information, and
specifies how this information may be obtained, along with specifies how this information may be obtained, along with
credentials and a Node-ID, from an offline enrollment server. credentials and a Node-ID, from an offline enrollment server.
Once the configuration information is obtained, the RELOAD base draft Once the configuration information is obtained, RELOAD specifies a
specifies a mechanism whereby a peer may obtain a multicast-bootstrap mechanism whereby a peer may obtain a multicast-bootstrap address in
address in the configuration file, and can broadcast to this address the configuration file, and can broadcast to this address to attempt
to attempt to locate a bootstrap peer. Additionally, the peer may to locate a bootstrap peer. Additionally, the peer may store
store previous peers it has seen and attempt to use these as previous peers it has seen and attempt to use these as bootstrap
bootstrap peers, or may obtain an address for a bootstrap peer by peers, or may obtain an address for a bootstrap peer by some other
some other mechanism. For more information, see the RELOAD base mechanism. For more information, see the RELOAD protocol.
draft.
The job of the bootstrap peer is simple: refer the joining peer to a The job of the bootstrap peer is simple: refer the joining peer to a
peer (called the "admitting peer") that will help the joining peer peer (called the "admitting peer") that will help the joining peer
join the network. The choice of admitting peer will often depend on join the network. The choice of admitting peer will often depend on
the joining node - for example, the admitting peer may be a peer that the joining node - for example, the admitting peer may be a peer that
will become a neighbor of the joining peer in the overlay. It is will become a neighbor of the joining peer in the overlay. It is
possible that the bootstrap peer might also serve as the admitting possible that the bootstrap peer might also serve as the admitting
peer. peer.
The admitting peer will help the joining peer learn about other peers The admitting peer will help the joining peer learn about other peers
skipping to change at page 16, line 49 skipping to change at page 15, line 34
whatever else is required to help the joining peer become a fully- whatever else is required to help the joining peer become a fully-
functional peer. The details of how this is done will depend on the functional peer. The details of how this is done will depend on the
distributed database algorithm used by the overlay. distributed database algorithm used by the overlay.
At various stages in this process, the joining peer may be asked to At various stages in this process, the joining peer may be asked to
present its credentials to show that it is authorized to join the present its credentials to show that it is authorized to join the
overlay. Similarly, the various peers contacted may be asked to overlay. Similarly, the various peers contacted may be asked to
present their credentials so the joining peer can verify that it is present their credentials so the joining peer can verify that it is
really joining the overlay it wants to. really joining the overlay it wants to.
6.5. Clients and Connecting Unmodified SIP Devices 5.5. Clients and Connecting Unmodified SIP Devices
As mentioned above, in RELOAD, from the perspective of the protocol, As mentioned above, in RELOAD, from the perspective of the protocol,
clients are simply peers that do not store information, do not route clients are simply peers that do not store information, do not route
messages, and which have not inserted themselves into the overlay. messages, and which have not inserted themselves into the overlay.
The same protocol is used for the actual message exchanged. Note The same protocol is used for the actual message exchanged. Note
that while the protocol is the same, the client need not implement that while the protocol is the same, the client need not implement
all the capabilities of a peer. If, for example, it never routes all the capabilities of a peer. If, for example, it never routes
messages, it will not need to be capable of processing such messages, messages, it will not need to be capable of processing such messages,
or understanding a DHT. or understanding a DHT.
For SIP devices, another way to realize this functionality is for a For SIP devices, another way to realize this functionality is for a
Peer to behave as a [RFC3261] proxy/registrar. SIP devices then use Peer to behave as a [RFC3261] proxy/registrar. SIP devices then use
standard SIP mechanisms to add, update, and remove registrations and standard SIP mechanisms to add, update, and remove registrations and
to send SIP messages to peers and other clients. The authors here to send SIP messages to peers and other clients. The authors here
refer to these devices simply as a "SIP UA", not a "P2PSIP Client", refer to these devices simply as a "SIP UA", not a "P2PSIP Client",
to distinguish it from the concept described above. to distinguish it from the concept described above.
6.6. Architecture 5.6. Architecture
The architecture adopted by RELOAD to implement P2PSIP is shown The architecture adopted by RELOAD to implement P2PSIP is shown
below. An application, for example SIP (or another application using below. An application, for example SIP (or another application using
RELOAD) uses RELOAD to locate other peers and (optionally) to RELOAD) uses RELOAD to locate other peers and (optionally) to
establish connections to those peers, potentially across NATs. establish connections to those peers, potentially across NATs.
Messages may still be exchanged directly between the peers. The Messages may still be exchanged directly between the peers. The
overall block diagram for the architecture is as follows: overall block diagram for the architecture is as follows:
__________________________ __________________________
| | | |
| SIP, other apps... | | SIP, other apps... |
| ___________________| | ___________________|
| | RELOAD Layer | | | RELOAD Layer |
|______|___________________| |______|___________________|
| Transport Layer | | Transport Layer |
|__________________________| |__________________________|
7. Open Issues 6. Security Considerations
OPEN ISSUE: The initial wording in the high-level description about
proving AoR to contact mapping reflects a very long and contentious
debate about the role of the protocol, and reflected a pretense that
this was an overlay only for P2PSIP. That is not really true in base
anymore (see last paragraph of introduction) and the language has
been very much genericized in base. Should we make this text more
abstract and then use AoR->contact mapping as an example of the
(original) use? On a related note, see the last paragraph of the
Background section -- do we want to reword this?
At this point, the editors believe these additional two issues are This specification is an overview of existing specifications and does
settled, but are left here for final debate on the document before not introduce any security considerations on its own. Please refer
publication. to the security considerations of the respective specifications,
particularly the RELOAD protocol specification ([RFC6940]) for
further details.
OPEN ISSUE: Should we include a section that documents previous 7. IANA Considerations
decisions made, to preserve the historical debate and prevent past
issues from being raised in the future, or simply rely on the mailing
list to address these concerns? (consensus seemed to be no)
OPEN ISSUE: Should we include the use cases from This document has no actions for IANA.
draft-bryan-p2psip-app-scenarios-00 (now long expired)? (consensus
seemed to be no)
8. Informative References 8. Informative References
[Chord] Singh, K., Stoica, I., Morris, R., Karger, D., Kaashock, [Chord] Singh, K., Stoica, I., Morris, R., Karger, D., Kaashock,
M., Dabek, F., and H. Balakrishman, "Chord: A scalable M., Dabek, F., and H. Balakrishman, "Chord: A scalable
peer-to-peer lookup protocol for internet applications", peer-to-peer lookup protocol for internet applications",
IEEE/ACM Transactions on Neworking Volume 11 Issue 1, pp. IEEE/ACM Transactions on Neworking Volume 11 Issue 1, pp.
17-32, Feb. 2003. 17-32, Feb. 2003, August 2001.
Copy available at Copy available at http://pdos.csail.mit.edu/chord/papers/
http://pdos.csail.mit.edu/chord/papers/paper-ton.pdf paper-ton.pdf
[I-D.ietf-p2psip-diagnostics] [I-D.ietf-p2psip-diagnostics]
Song, H., Jiang, X., Even, R., Bryan, D., and Y. Sun, "P2P Song, H., Xingfeng, J., Even, R., Bryan, D., and Y. Sun,
Overlay Diagnostics", draft-ietf-p2psip-diagnostics-14 "P2P Overlay Diagnostics", draft-ietf-p2psip-
(work in progress), February 2014. diagnostics-19 (work in progress), November 2015.
[I-D.ietf-p2psip-self-tuning]
Maenpaa, J. and G. Camarillo, "Self-tuning Distributed
Hash Table (DHT) for REsource LOcation And Discovery
(RELOAD)", draft-ietf-p2psip-self-tuning-12 (work in
progress), June 2014.
[I-D.ietf-p2psip-service-discovery]
Maenpaa, J. and G. Camarillo, "Service Discovery Usage for
REsource LOcation And Discovery (RELOAD)",
draft-ietf-p2psip-service-discovery-12 (work in progress),
June 2014.
[I-D.ietf-p2psip-sip] [I-D.ietf-p2psip-sip]
Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., Jennings, C., Lowekamp, B., Rescorla, E., Baset, S.,
Schulzrinne, H., and T. Schmidt, "A SIP Usage for RELOAD", Schulzrinne, H., and T. Schmidt, "A SIP Usage for RELOAD",
draft-ietf-p2psip-sip-12 (work in progress), January 2014. draft-ietf-p2psip-sip-16 (work in progress), December
2015.
[RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound, [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)", "Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, April 1997. RFC 2136, DOI 10.17487/RFC2136, April 1997,
<http://www.rfc-editor.org/info/rfc2136>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002. DOI 10.17487/RFC3261, June 2002,
<http://www.rfc-editor.org/info/rfc3261>.
[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation [RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation
Protocol (SIP): Locating SIP Servers", RFC 3263, Protocol (SIP): Locating SIP Servers", RFC 3263,
June 2002. DOI 10.17487/RFC3263, June 2002,
<http://www.rfc-editor.org/info/rfc3263>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005. RFC 3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC4795] Aboba, B., Thaler, D., and L. Esibov, "Link-local [RFC4795] Aboba, B., Thaler, D., and L. Esibov, "Link-local
Multicast Name Resolution (LLMNR)", RFC 4795, Multicast Name Resolution (LLMNR)", RFC 4795,
January 2007. DOI 10.17487/RFC4795, January 2007,
<http://www.rfc-editor.org/info/rfc4795>.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment [RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT) (ICE): A Protocol for Network Address Translator (NAT)
Traversal for Offer/Answer Protocols", RFC 5245, Traversal for Offer/Answer Protocols", RFC 5245,
April 2010. DOI 10.17487/RFC5245, April 2010,
<http://www.rfc-editor.org/info/rfc5245>.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using [RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session Relays around NAT (TURN): Relay Extensions to Session
Traversal Utilities for NAT (STUN)", RFC 5766, April 2010. Traversal Utilities for NAT (STUN)", RFC 5766,
DOI 10.17487/RFC5766, April 2010,
<http://www.rfc-editor.org/info/rfc5766>.
[RFC6940] Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., and [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
H. Schulzrinne, "REsource LOcation And Discovery (RELOAD) DOI 10.17487/RFC6762, February 2013,
Base Protocol", RFC 6940, January 2014. <http://www.rfc-editor.org/info/rfc6762>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<http://www.rfc-editor.org/info/rfc6763>.
[RFC6940] Jennings, C., Lowekamp, B., Ed., Rescorla, E., Baset, S.,
and H. Schulzrinne, "REsource LOcation And Discovery
(RELOAD) Base Protocol", RFC 6940, DOI 10.17487/RFC6940,
January 2014, <http://www.rfc-editor.org/info/rfc6940>.
[RFC7363] Maenpaa, J. and G. Camarillo, "Self-Tuning Distributed
Hash Table (DHT) for REsource LOcation And Discovery
(RELOAD)", RFC 7363, DOI 10.17487/RFC7363, September 2014,
<http://www.rfc-editor.org/info/rfc7363>.
[RFC7374] Maenpaa, J. and G. Camarillo, "Service Discovery Usage for
REsource LOcation And Discovery (RELOAD)", RFC 7374,
DOI 10.17487/RFC7374, October 2014,
<http://www.rfc-editor.org/info/rfc7374>.
Authors' Addresses Authors' Addresses
David A. Bryan David A. Bryan
Cogent Force, LLC Cogent Force, LLC
Cedar Park, TX, Texas Cedar Park, TX, Texas
USA USA
Email: dbryan@ethernot.org Email: dbryan@ethernot.org
Philip Matthews Philip Matthews
Alcatel-Lucent Alcatel-Lucent
600 March Road 600 March Road
Ottawa, Ontario K2K 2E6 Ottawa, Ontario K2K 2E6
Canada Canada
Phone: +1 613 784 3139 Phone: +1 613 784 3139
Email: philip_matthews@magma.ca Email: philip_matthews@magma.ca
Eunsoo Shim Eunsoo Shim
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