Network Working Group K. Inamdar
Internet-Draft Unaffiliated
Intended status: Standards Track S. Narayanan
Expires: 28 September 2022 D. Engi
G. Salgueiro
Cisco
March 2022
The 'sipTrunkingCapability' Link Relation Type
draft-engi-siptrunkingcapability-link-00
Abstract
This specification defines the 'sipTrunkingCapabilities' link
relation type that may be used for the retrieval of capabilities and
configuration requirements from Internet Telephony Service Providers
(ITSPs). A Session Initiation Protocol (SIP) trunking capability set
is defined to allow the transfer of technical requirements needed for
seamless peering between SIP-based enterprise telephony networks and
ITSPs where an exchange of parameters and configuration information
is required.
Status of This Memo
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This Internet-Draft will expire on 2 September 2022.
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This document is subject to BCP 78 and the IETF Trust's Legal
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. The 'sipTrunkingCapability' Link Relation Type . . . . . . . 3
4. Example Usage . . . . . . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. Informative Reference . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
RFC 8288 [RFC8288] defined a way of indicating relationships between
resources on the Web. This document specifies the
'sipTrunkingCapability' link relation type according to the rules of
RFC 8288 [RFC8288]. Links with this relationship type can be used to
exchange capability information between potential peer devices. In
the event that systems require additional parameters and
configuration to negotiate communication, a well-known URI can be
utilized to deliver information to potential peers including machine-
readable instructions and parameters needed for peering.
The 'sipTrunkingCapability' link relation type may be used on web
resources hosted by Internet Telephony Service Providers (ITSPs) to
provide a structured and detailed capability set document. The
capability set document encapsulates a set of characteristics of an
ITSP, which when retrieved by enterprise telephony network devices
allows for automated establishment of Session Initiation Protocol
(SIP) trunking between the two telephony networks.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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3. The 'sipTrunkingCapability' Link Relation Type
A capability set document is hosted via web resources by the ITSP.
The document describes the configuration parameters required to
successfully establish SIP trunking between an enterprise and service
provider SIP telephony network. The capability set document SHOULD
be comprised of structured and machine-readable parameters that could
be easily converted into configuration data to meet the communication
requirements of the service provider.
4. Example Usage
This section provides an example of possible use of the
'sipTrunkingCapability' relation type. The need for an enterprise
telephony network to obtain a capability set document from an
Internet Telephony Service Provider (ITSP) is documented in Automatic
Peering for SIP Trunks [I-D.ietf-asap-sip-auto-peer]. The
'sipTrunkingCapability' link relation type allows an enterprise
telephony network to specifically request the capability set document
from a web server hosted in the ITSP network.
The enterprise network device solicits the location of the capability
document from the well-known URI hosted by the SIP service provider
using the WebFinger protocol [RFC7033].
GET /.well-known/webfinger?
resource=http%3A%2F%2Fssp1.example.com
rel=sipTrunkingCapability
HTTP/1.1
Host: ssp1.example.com
The capability set location is returned to the source device
referencing the URI that contains parameters for peering.
HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Content-Type: application/jrd+json
{
"subject" : "http://ssp1.example.com",
"links" :
[
{
"rel" : "sipTrunkingCapability",
"href" :"https://capserver.ssp1.com/capserver/capdoc.json"
},
]
}
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The ITSP may use an authentication framework such as Oauth2 to
determine the identity of the enterprise telephony network and
provide the appropriate capability set document.
5. IANA Considerations
IANA has registered the sipTrunkingCapability link relation under the
"Link Relation Types" Registry, with a reference to this document,
using the following template:
Relation Name: sipTrunkingCapability
Description: A capability document that defines parameters or
configuration requirements for automated peering and communication
channel negotiation of the Session Initiation Protocol (SIP).
Reference: RFCXXXX
[[NOTE TO RFC EDITOR: Please change XXXX to the number assigned to
this specification, and remove this paragraph on publication.]]
6. Security Considerations
The 'sipTrunkingCapability' relation type is not known to introduce
any new security issues not already discussed in RFC 8288 [RFC8288]
for generic use of web linking mechanisms. However, it is
recommended to exercise caution when publishing potentially sensitive
capability information over unencrypted or unauthenticated channels.
7. Acknowledgements
This document resulted from the discussions in the ASAP working
group, especially the detailed and thoughtful comments of Cullen
Jennings, Jonathan Rosenberg, Jon Peterson and Chris Wendt.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8288] Nottingham, M., "Web Linking", RFC 8288,
DOI 10.17487/RFC8288, October 2017,
<https://www.rfc-editor.org/info/rfc8288>.
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8.2. Informative Reference
[I-D.ietf-asap-sip-auto-peer]
Inamdar, K., Narayanan, S., and C. Jennings, "Automatic
Peering for SIP Trunks", October 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-asap-
sip-auto-peer-04>.
[RFC7033] Jones, P., Salgueiro, G., Jones, M., and J. Smarr,
"WebFinger", RFC 7033, DOI 10.17487/RFC7033, September
2013, <https://www.rfc-editor.org/info/rfc7033>.
Authors' Addresses
Kaustubh Inamdar
Unaffiliated
Email: kaustubh.ietf@gmail.com
Sreekanth Narayanan
Cisco
Email: sreenara@cisco.com
Derek Engi
Cisco
Ann Arbor, MI
US
Phone: +1 919 392 7966
Email: deengi@cisco.com
Gonzalo Salgueiro
Cisco
7200-12 Kit Creek Rd.
Research Triangle Park, NC 27709
US
Phone: +1 919 392 3266
Email: gsalguei@cisco.com
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