Mapping RTP streams to CLUE Media Captures
draft-ietf-clue-rtp-mapping-12
The information below is for an old version of the document.
Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 8849.
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Authors | Roni Even , Jonathan Lennox | ||
Last updated | 2017-01-19 (Latest revision 2017-01-14) | ||
RFC stream | Internet Engineering Task Force (IETF) | ||
Formats | |||
Reviews |
GENART Last Call review
(of
-10)
by Vijay Gurbani
Ready w/nits
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Additional resources | Mailing list discussion | ||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Paul Kyzivat | ||
Shepherd write-up | Show Last changed 2016-12-16 | ||
IESG | IESG state | Became RFC 8849 (Proposed Standard) | |
Consensus boilerplate | Yes | ||
Telechat date |
(None)
Needs a YES. Needs 10 more YES or NO OBJECTION positions to pass. |
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Responsible AD | Alissa Cooper | ||
Send notices to | "Paul Kyzivat" <pkyzivat@alum.mit.edu> | ||
IANA | IANA review state | IANA - Not OK |
draft-ietf-clue-rtp-mapping-12
TEAS Working Group J. Dong Internet-Draft Huawei Intended status: Informational S. Bryant Expires: 27 June 2024 University of Surrey Z. Li China Mobile T. Miyasaka KDDI Corporation Y. Lee Samsung 25 December 2023 A Framework for NRP-based Enhanced Virtual Private Network draft-ietf-teas-enhanced-vpn-17 Abstract This document describes the framework for NRP-based Enhanced Virtual Private Networks (VPNs) to support the needs of applications with specific traffic performance requirements (e.g., low latency, bounded jitter). NRP-based Enhanced VPNs leverage the VPN and Traffic Engineering (TE) technologies and adds characteristics that specific services require beyond those provided by conventional VPNs. Typically, an NRP-based enhanced VPN will be used to underpin network slicing, but could also be of use in its own right providing enhanced connectivity services between customer sites. This document also provides an overview of relevant technologies in different network layers, and identifies some areas for potential new work. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 27 June 2024. Dong, et al. Expires 27 June 2024 [Page 1] Internet-Draft Enhanced VPN Framework December 2023 Copyright Notice Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Overview of the Requirements . . . . . . . . . . . . . . . . 7 3.1. Performance Guarantees . . . . . . . . . . . . . . . . . 7 3.2. Interaction between Enhanced VPN Services . . . . . . . . 9 3.2.1. Requirements on Traffic Isolation . . . . . . . . . . 9 3.2.2. Limited Interaction with Other Services . . . . . . . 10 3.2.3. Realization of Limited Interaction Between Enhanced VPN Services . . . . . . . . . . . . . . . . . . . . . . 11 3.3. Integration with Network Resources and Service Functions . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3.1. Abstraction . . . . . . . . . . . . . . . . . . . . . 12 3.4. Dynamic Changes . . . . . . . . . . . . . . . . . . . . . 12 3.5. Customized Control . . . . . . . . . . . . . . . . . . . 13 3.6. Applicability to Overlay Technologies . . . . . . . . . . 14 3.7. Inter-Domain and Inter-Layer Network . . . . . . . . . . 14 4. The Architecture of NRP-based Enhanced VPNs . . . . . . . . . 14 4.1. Layered Architecture . . . . . . . . . . . . . . . . . . 16 4.2. Connectivity Types . . . . . . . . . . . . . . . . . . . 19 4.3. Application-Specific Data Types . . . . . . . . . . . . . 19 4.4. Scalable Service Mapping . . . . . . . . . . . . . . . . 20 5. Candidate Technologies . . . . . . . . . . . . . . . . . . . 20 5.1. Forwarding Resource Partitioning . . . . . . . . . . . . 21 5.1.1. Flexible Ethernet . . . . . . . . . . . . . . . . . . 21 5.1.2. Dedicated Queues . . . . . . . . . . . . . . . . . . 21 5.1.3. Time Sensitive Networking . . . . . . . . . . . . . . 22 5.2. Data Plane Encapsulation and Forwarding . . . . . . . . . 22 5.2.1. Deterministic Networking . . . . . . . . . . . . . . 22 5.2.2. MPLS Traffic Engineering (MPLS-TE) . . . . . . . . . 23 5.2.3. Segment Routing . . . . . . . . . . . . . . . . . . . 23 5.2.4. New Encapsulation Extensions . . . . . . . . . . . . 24 5.3. Non-Packet Data Plane . . . . . . . . . . . . . . . . . . 24 Dong, et al. Expires 27 June 2024 [Page 2] Internet-Draft Enhanced VPN Framework December 2023 5.4. Control Plane . . . . . . . . . . . . . . . . . . . . . . 24 5.5. Management Plane . . . . . . . . . . . . . . . . . . . . 26 5.6. Applicability of Service Data Models to Enhanced VPNs . . 27 6. Applicability in Network Slice Realization . . . . . . . . . 28 6.1. NRP Planning . . . . . . . . . . . . . . . . . . . . . . 28 6.2. NRP Creation . . . . . . . . . . . . . . . . . . . . . . 29 6.3. Network Slice Service Provisioning . . . . . . . . . . . 29 6.4. Network Slice Traffic Steering and Forwarding . . . . . . 29 7. Scalability Considerations . . . . . . . . . . . . . . . . . 30 7.1. Maximum Stack Depth of SR . . . . . . . . . . . . . . . . 31 7.2. RSVP-TE Scalability . . . . . . . . . . . . . . . . . . . 31 7.3. SDN Scaling . . . . . . . . . . . . . . . . . . . . . . . 31 8. Manageability Considerations . . . . . . . . . . . . . . . . 31 8.1. OAM Considerations . . . . . . . . . . . . . . . . . . . 32 8.2. Telemetry Considerations . . . . . . . . . . . . . . . . 32 9. Enhanced Resiliency . . . . . . . . . . . . . . . . . . . . . 32 10. Operational Considerations . . . . . . . . . . . . . . . . . 34 11. Security Considerations . . . . . . . . . . . . . . . . . . . 34 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 35 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 35 15. Informative References . . . . . . . . . . . . . . . . . . . 36 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42 1. Introduction RFC Editor Note: Please replace "RFC XXXX" in this document with the RFC number assigned to [I-D.ietf-teas-ietf-network-slices], and remove this note. Virtual Private Networks (VPNs) have served the industry well as a means of providing different groups of users with logically isolated connectivity over a common network. The common (base) network that is used to provide the VPNs is often referred to as the underlay, and the VPN is often called an overlay. Customers of a network operator may request connectivity services with advanced characteristics, such as low latency guarantees, bounded jitter, or isolation from other services or customers so that changes in some other services (e.g., changes in network load, or events such as congestion or outages) have no or only acceptable effect on the observed throughput or latency of the services delivered to the customer. These services are referred to as "enhanced VPNs", as they are similar to VPN services providing the customer with the required connectivity, but in addition they also provide enhanced characteristics. Dong, et al. Expires 27 June 2024 [Page 3] Internet-Draft Enhanced VPN Framework December 2023Even & Lennox Expires July 18, 2017 [Page 7] Internet-Draft RTP mapping to CLUE January 2017 Note to the RFC Editor: Please replace RFCXXXX with this RFC number. 9. Security Considerations The security considerations of the RTP specification, the RTP/SAVPF profile, and the various RTP/RTCP extensions and RTP payload formats that form the complete protocol suite described in this memo apply. It is not believed there are any new security considerations resulting from the combination of these various protocol extensions. The Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback [RFC5124] (RTP/SAVPF) provides handling of fundamental issues by offering confidentiality, integrity and partial source authentication. CLUE endpoints MUST support RTP/ SAVPF and DTLS-SRTP keying [RFC5764]. RTCP packets convey a Canonical Name (CNAME) identifier that is used to associate RTP packet streams that need to be synchronised across related RTP sessions. Inappropriate choice of CNAME values can be a privacy concern, since long-term persistent CNAME identifiers can be used to track users across multiple calls. CLUE endpoint MUST generate short-term persistent RTCP CNAMES, as specified in RFC7022 [RFC7022], resulting in untraceable CNAME values that alleviate this risk. Some potential denial of service attacks exist if the RTCP reporting interval is configured to an inappropriate value. This could be done by configuring the RTCP bandwidth fraction to an excessively large or small value using the SDP "b=RR:" or "b=RS:" lines [RFC3556], or some similar mechanism, or by choosing an excessively large or small value for the RTP/AVPF minimal receiver report interval (if using SDP, this is the "a=rtcp-fb:... trr-int" parameter) [RFC4585] The risks are as follows: 1. the RTCP bandwidth could be configured to make the regular reporting interval so large that effective congestion control cannot be maintained, potentially leading to denial of service due to congestion caused by the media traffic; 2. the RTCP interval could be configured to a very small value, causing endpoints to generate high rate RTCP traffic, potentially leading to denial of service due to the non-congestion controlled RTCP traffic; and 3. RTCP parameters could be configured differently for each endpoint, with some of the endpoints using a large reporting interval and some using a smaller interval, leading to denial of service due to premature participant timeouts due to mismatched Even & Lennox Expires July 18, 2017 [Page 8] Internet-Draft RTP mapping to CLUE January 2017 timeout periods which are based on the reporting interval (this is a particular concern if endpoints use a small but non-zero value for the RTP/AVPF minimal receiver report interval (trr-int) [RFC4585], as discussed in [I-D.ietf-avtcore-rtp-multi-stream]). Premature participant timeout can be avoided by using the fixed (non- reduced) minimum interval when calculating the participant timeout ([I-D.ietf-avtcore-rtp-multi-stream]). To address the other concerns, endpoints SHOULD ignore parameters that configure the RTCP reporting interval to be significantly longer than the default five second interval specified in [RFC3550] (unless the media data rate is so low that the longer reporting interval roughly corresponds to 5% of the media data rate), or that configure the RTCP reporting interval small enough that the RTCP bandwidth would exceed the media bandwidth. The guidelines in [RFC6562] apply when using variable bit rate (VBR) audio codecs such as Opus. The use of the encryption of the header extensions are RECOMMENDED, unless there are known reasons, like RTP middleboxes performing voice activity based source selection or third party monitoring that will greatly benefit from the information, and this has been expressed using API or signalling. If further evidence are produced to show that information leakage is significant from audio level indications, then use of encryption needs to be mandated at that time. In multi-party communication scenarios using RTP Middleboxes; this middleboxes are trusted to preserve the sessions' security. The middlebox SHOULD maintain the confidentiality, integrity and perform source authentication. The middlebox MAY perform checks that prevents any endpoint participating in a conference to impersonate another. Some additional security considerations regarding multi- party topologies can be found in [RFC7667] The CaptureID is created as part of the CLUE protocol. The CaptId SDES item is used to convey the same CaptureID value in the SDES item. When sending the SDES item the security considertion specied in the security section of [RFC7941] are applicable and this SDES item MUST use similar security as the CLUE protocol messages carried in the CLUE data channel. 10. References 10.1. Normative References Even & Lennox Expires July 18, 2017 [Page 9] Internet-Draft RTP mapping to CLUE January 2017 [I-D.ietf-clue-data-model-schema] Presta, R. and S. Romano, "An XML Schema for the CLUE data model", draft-ietf-clue-data-model-schema-17 (work in progress), August 2016. [I-D.ietf-clue-framework] Duckworth, M., Pepperell, A., and S. Wenger, "Framework for Telepresence Multi-Streams", draft-ietf-clue- framework-25 (work in progress), January 2016. [I-D.ietf-mmusic-sdp-bundle-negotiation] Holmberg, C., Alvestrand, H., and C. Jennings, "Negotiating Media Multiplexing Using the Session Description Protocol (SDP)", draft-ietf-mmusic-sdp-bundle- negotiation-36 (work in progress), October 2016. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>. [RFC7941] Westerlund, M., Burman, B., Even, R., and M. Zanaty, "RTP Header Extension for the RTP Control Protocol (RTCP) Source Description Items", RFC 7941, DOI 10.17487/RFC7941, August 2016, <http://www.rfc-editor.org/info/rfc7941>. 10.2. Informative References [I-D.ietf-avtcore-rtp-multi-stream] Lennox, J., Westerlund, M., Wu, W., and C. Perkins, "Sending Multiple Media Streams in a Single RTP Session", draft-ietf-avtcore-rtp-multi-stream-11 (work in progress), December 2015. [I-D.ietf-clue-signaling] Kyzivat, P., Xiao, L., Groves, C., and R. Hansen, "CLUE Signaling", draft-ietf-clue-signaling-10 (work in progress), January 2017. [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with Session Description Protocol (SDP)", RFC 3264, DOI 10.17487/RFC3264, June 2002, <http://www.rfc-editor.org/info/rfc3264>. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550, July 2003, <http://www.rfc-editor.org/info/rfc3550>. Even & Lennox Expires July 18, 2017 [Page 10] Internet-Draft RTP mapping to CLUE January 2017 [RFC3556] Casner, S., "Session Description Protocol (SDP) Bandwidth Modifiers for RTP Control Protocol (RTCP) Bandwidth", RFC 3556, DOI 10.17487/RFC3556, July 2003, <http://www.rfc-editor.org/info/rfc3556>. [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, DOI 10.17487/RFC4566, July 2006, <http://www.rfc-editor.org/info/rfc4566>. [RFC4575] Rosenberg, J., Schulzrinne, H., and O. Levin, Ed., "A Session Initiation Protocol (SIP) Event Package for Conference State", RFC 4575, DOI 10.17487/RFC4575, August 2006, <http://www.rfc-editor.org/info/rfc4575>. [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, "Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, DOI 10.17487/RFC4585, July 2006, <http://www.rfc-editor.org/info/rfc4585>. [RFC4796] Hautakorpi, J. and G. Camarillo, "The Session Description Protocol (SDP) Content Attribute", RFC 4796, DOI 10.17487/RFC4796, February 2007, <http://www.rfc-editor.org/info/rfc4796>. [RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)", RFC 5124, DOI 10.17487/RFC5124, February 2008, <http://www.rfc-editor.org/info/rfc5124>. [RFC5285] Singer, D. and H. Desineni, "A General Mechanism for RTP Header Extensions", RFC 5285, DOI 10.17487/RFC5285, July 2008, <http://www.rfc-editor.org/info/rfc5285>. [RFC5506] Johansson, I. and M. Westerlund, "Support for Reduced-Size Real-Time Transport Control Protocol (RTCP): Opportunities and Consequences", RFC 5506, DOI 10.17487/RFC5506, April 2009, <http://www.rfc-editor.org/info/rfc5506>. [RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer Security (DTLS) Extension to Establish Keys for the Secure Real-time Transport Protocol (SRTP)", RFC 5764, DOI 10.17487/RFC5764, May 2010, <http://www.rfc-editor.org/info/rfc5764>. This document describes a framework for delivering VPN services with enhanced characteristics, such as guaranteed resources, latency, jitter, etc. This is not a closed list. It is expected that other enhanced features may be added to VPN over time, and it is expected this framework will support these additions with necessary changes or enhancements in some network layers and network planes. The concept of network slicing has gained traction driven largely by needs surfacing from 5G [NGMN-NS-Concept] [TS23501] [TS28530]. According to [TS28530], a 5G end-to-end network slice consists of three major types of network segments: Radio Access Network (RAN), Transport Network (TN), and Mobile Core Network (CN). The transport network provides the connectivity between different entities in RAN and CN segments of a 5G end-to-end network slice, with specific performance commitments. [I-D.ietf-teas-ietf-network-slices] discusses the general framework, the components, and interfaces for requesting and operating network slices using IETF technologies. These network slices may be referred to as RFC XXXX Network Slices, but in this document (which is solely about IETF technologies) we simply use the term "network slice" to refer to this concept. A network slice service enables connectivity between a set of Service Demarcation Points (SDPs) with specific Service Level Objectives (SLOs) and Service Level Expectations (SLEs) over a common underlay network. A network slice can be realized as a logical network connecting a number of endpoints and is associated with a set of shared or dedicated network resources that are used to satisfy the SLOs and SLEs requirements. A network slice is considered as one target use case of enhanced VPNs. [I-D.ietf-teas-ietf-network-slices] also introduces the concept of the Network Resource Partition (NRP), which is a subset of the buffer/queuing/scheduling resources and associated policies on each of a connected set of links in the underlay network. An NRP can be associated with a dedicated or shared network topology to select or specify the set of links and nodes involved. The requirements of enhanced VPN services cannot simply be met by overlay networks, as enhanced VPN services require tighter coordination and integration between the overlay and the underlay networks. In the overlay network, the VPN has been defined as the network construct to provide the required connectivity for different services or customers. Multiple VPN flavors can be considered to create that construct [RFC4026]. In the underlay network, the concept of a Network Resource Partition (NRP) as defined in [I-D.ietf-teas-ietf-network-slices] is used to represent a subset of Dong, et al. Expires 27 June 2024 [Page 4] Internet-Draft Enhanced VPN Framework December 2023 the buffer/queuing/scheduling resources and associated policies in the underlay network. An NRP can be associated with a dedicated or shared network topology to select or specify the set of links and nodes involved. An enhanced VPN service can be realized by integrating a VPN in the overlay and an NRP in the underlay. This is called an NRP-based enhanced VPN. In doing so, an enhanced VPN service can provide enhanced properties, such as guaranteed resources and assured or predictable performance. An enhanced VPN service may also involve a set of service functions (Section 1.4 of [RFC7665]). The techniques for delivering an NRP-based enhanced VPN can be used to instantiate a network slice service, and they can also be of use in general cases to provide enhanced connectivity services between customer sites or service endpoints. This document describes a framework for using existing, modified, and potential new technologies as components to provide NRP-based enhanced VPN services. Specifically, this document provides: * The functional requirements and service characteristics of an enhanced VPN service. * The design of the data plane for NRP-based enhanced VPNs. * The necessary control and management protocols in both the underlay and the overlay of enhanced VPNs. * The mechanisms to achieve integration between the overlay network and the underlay network. * The necessary Operation, Administration, and Management (OAM) methods to instrument an enhanced VPN to make sure that the required Service Level Agreement (SLA) between the customer and the network operator is met, and to take any corrective action (such as switching traffic to an alternate path) to avoid SLA violation. The required layered network structure to achieve these objectives is shown in Section 4.1. It is not envisaged that enhanced VPN services will replace conventional VPN services. VPN services will continue to be delivered using existing mechanisms and can co-exist with enhanced VPN services. Whether enhanced VPN features are added to an active VPN service is deployment specific. Dong, et al. Expires 27 June 2024 [Page 5] Internet-Draft Enhanced VPN Framework December 2023 2. Terminology In this document, the relationship of the four terms "VPN", "enhanced VPN", "NRP", and "Network Slice" are as follows: * A Virtual Private Network (VPN) refers to the overlay network service that provides connectivity between different customer sites, and that maintains traffic separation between different customers. Examples of technologies to provide VPN services are: IPVPN [RFC2764], L2VPN [RFC4664], L3VPN [RFC4364], and EVPN [RFC7432]. * An enhanced VPN service is an evolution of the VPN service that makes additional service-specific commitments. An NRP-based enhanced VPN is made by integrating a VPN with a set of network resources allocated in the underlay network (i.e. an NRP). * A Network Resource Partition (NRP) is a subset of the buffer/queuing/scheduling resources and associated policies on each of a connected set of links in the underlay network. An NRP can be associated with a dedicated or shared network topology to select or specify the set of links and nodes involved. An NRP is designed to meet the network resources and performance characteristics required by the enhanced VPN services. * A network slice service could be delivered by provisioning one or more NRP-based enhanced VPN in the network. Other mechanisms for realizing network slices may exist but are not in scope for this document. The term "tenant" is used in this document to refer to a customer of the enhanced VPN services. The following terms, defined in other documents, are also used in this document. SLA: Service Level Agreement. See [I-D.ietf-teas-ietf-network-slices]. SLO: Service Level Objective. See [I-D.ietf-teas-ietf-network-slices]. SLE: Service Level Expectation. See [I-D.ietf-teas-ietf-network-slices]. NRP: Network Resource Partition. See [I-D.ietf-teas-ietf-network-slices] Dong, et al. Expires 27 June 2024 [Page 6] Internet-Draft Enhanced VPN Framework December 2023 ACTN: Abstraction and Control of Traffic Engineered Networks [RFC8453]. DetNet: Deterministic Networking. See [RFC8655]. FlexE: Flexible Ethernet [FLEXE]. TSN: Time Sensitive Networking [TSN]. VN: Virtual Network. See [RFC8453]. 3. Overview of the Requirements This section provides an overview of the requirements of an enhanced VPN service. 3.1. Performance Guarantees Performance guarantees are committed by network operators to their customers in relation to the services delivered to the customers. They are usually expressed in SLAs as a set of SLOs. There are several kinds of performance guarantees, including guaranteed maximum packet loss, guaranteed maximum delay, and guaranteed delay variation. Note that these guarantees apply to conformance traffic; out-of-profile traffic will be handled according to a separate agreement with the customer (see, for example, Section 3.6 of [RFC7297]). Guaranteed maximum packet loss is usually addressed by setting packet priorities, queues size, and discard policy. However, this becomes more difficult when the requirement is combined with latency requirements. The limiting case is zero congestion loss, and that is the goal of Deterministic Networking (DetNet) [RFC8655] and Time- Sensitive Networking (TSN) [TSN]. In modern optical networks, loss due to transmission errors already approaches zero, but there is the possibility of failure of the interface or the fiber itself. This type of fault can be addressed by some form of signal duplication and transmission over diverse paths. Guaranteed maximum latency is required by a number of applications, particularly real-time control applications and some types of augumented reality and virtual reality (AR/VR) applications. DetNet techniques may be considered [RFC8655], however additional methods of enhancing the underlay to better support the delay guarantees may be needed, and these methods will need to be integrated with the overall service provisioning mechanisms. Dong, et al. Expires 27 June 2024 [Page 7] Internet-Draft Enhanced VPN Framework December 2023Even & Lennox Expires July 18, 2017 [Page 11] Internet-Draft RTP mapping to CLUE January 2017 [RFC6562] Perkins, C. and JM. Valin, "Guidelines for the Use of Variable Bit Rate Audio with Secure RTP", RFC 6562, DOI 10.17487/RFC6562, March 2012, <http://www.rfc-editor.org/info/rfc6562>. [RFC7022] Begen, A., Perkins, C., Wing, D., and E. Rescorla, "Guidelines for Choosing RTP Control Protocol (RTCP) Canonical Names (CNAMEs)", RFC 7022, DOI 10.17487/RFC7022, September 2013, <http://www.rfc-editor.org/info/rfc7022>. [RFC7205] Romanow, A., Botzko, S., Duckworth, M., and R. Even, Ed., "Use Cases for Telepresence Multistreams", RFC 7205, DOI 10.17487/RFC7205, April 2014, <http://www.rfc-editor.org/info/rfc7205>. [RFC7667] Westerlund, M. and S. Wenger, "RTP Topologies", RFC 7667, DOI 10.17487/RFC7667, November 2015, <http://www.rfc-editor.org/info/rfc7667>. Authors' Addresses Roni Even Huawei Technologies Tel Aviv Israel Email: roni.even@huawei.com Jonathan Lennox Vidyo, Inc. 433 Hackensack Avenue Seventh Floor Hackensack, NJ 07601 US Email: jonathan@vidyo.com Even & Lennox Expires July 18, 2017 [Page 12]