Mboned J. Holland Internet-Draft Akamai Technologies, Inc. Intended status: Standards Track September 26, 2019 Expires: March 29, 2020 Discovery Of Restconf Metadata for Source-specific multicast draft-jholland-mboned-dorms-01 Abstract This document defines DORMS (Discovery Of Restconf Metadata for Source-specific multicast), a method to discover and retrieve extensible metadata about source-specific multicast channels using RESTCONF. The reverse IP DNS zone for a multicast sender's IP address is configured to use SRV resource records to advertise the hostname of a RESTCONF server that publishes metadata according to a new YANG module with support for extensions. A new service name and the new YANG module are defined. 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 March 29, 2020. Copyright Notice Copyright (c) 2019 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 Holland Expires March 29, 2020 [Page 1] Internet-Draft DORMS September 2019 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Background . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. Discovery and Metdata Retrieval . . . . . . . . . . . . . . . 4 2.1. DNS Bootstrap . . . . . . . . . . . . . . . . . . . . . . 4 2.2. RESTCONF Bootstrap . . . . . . . . . . . . . . . . . . . 5 2.2.1. Root Resource Discovery . . . . . . . . . . . . . . . 5 2.2.2. Yang Library Version . . . . . . . . . . . . . . . . 6 2.2.3. Yang Library Contents . . . . . . . . . . . . . . . . 6 2.2.4. Metadata Retrieval . . . . . . . . . . . . . . . . . 7 2.2.5. Cross Origin Resource Sharing (CORS) . . . . . . . . 8 3. Scalability Considerations . . . . . . . . . . . . . . . . . 9 3.1. Provisioning . . . . . . . . . . . . . . . . . . . . . . 9 3.2. Data Scoping . . . . . . . . . . . . . . . . . . . . . . 9 4. YANG Model . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.1. Yang Tree . . . . . . . . . . . . . . . . . . . . . . . . 10 4.2. Yang Module . . . . . . . . . . . . . . . . . . . . . . . 10 5. Privacy Considerations . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6.1. The YANG Module Names Registry . . . . . . . . . . . . . 12 6.2. The Service Name and Transport Protocol Port Number Registry . . . . . . . . . . . . . . . . . . . . . . . . 13 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7.1. Secure Communications . . . . . . . . . . . . . . . . . . 13 7.2. Exposure of Metadata . . . . . . . . . . . . . . . . . . 13 7.3. DNS Bootstrapping . . . . . . . . . . . . . . . . . . . . 14 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . 15 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17 1. Introduction This document defines DORMS (Discovery Of Restconf Metadata for Source-specific multicast). A DORMS service is a RESTCONF [RFC8040] service that provides read access to data in the "ietf-dorms" YANG [RFC7950] model defined in Section 4. This model, along with optional extensions defined in other documents, provide an extensible set of information about multicast data streams. Holland Expires March 29, 2020 [Page 2] Internet-Draft DORMS September 2019 This document defines the "dorms" service name for use with the SRV DNS Resource Record (RR) type [RFC2782]. A sender offering a DORMS service to publish metadata SHOULD configure at least one SRV RR for the "_dorms._tcp" subdomain in the reverse IP DNS zone for the source IP of its multicast channel to advertise a hostname for a DORMS server that can provide metadata for the sender's source-specific multicast traffic. Doing so enables receivers and middleboxes to discover and query a DORMS server as described in Section 2. The goal is to provide an extensible framework for attaching information necessary for the correct processing of multicast data channels, both for middle boxes forwarding the traffic, and for receivers subscribing to traffic (hereafter called "clients"). 1.1. Background The reader is assumed to be familiar with the basic DNS concepts described in [RFC1034], [RFC1035], and the subsequent documents that update them, as well as the use of the SRV Resource Record type as described in [RFC2782]. The reader is also assumed to be familiar with the concepts and terminology regarding source-specific multicast as described in [RFC4607] and the use of IGMPv3 [RFC3376] and MLDv2 [RFC3810] for group management of source-specific multicast channels, as described in [RFC4604]. The reader is also assumed to be familiar with the concepts and terminology for RESTCONF [RFC8040] and YANG [RFC7950]. 1.2. Terminology +--------+----------------------------------------------------------+ | Term | Definition | +--------+----------------------------------------------------------+ | (S,G) | A source-specific multicast channel, as described in | | | [RFC4607]. A pair of IP addresses with a source host IP | | | and destination group IP. | | | | | RR | A DNS Resource Record, as described in [RFC1034] | | | | | RRType | A DNS Resource Record Type, as described in [RFC1034] | | | | | SSM | Source-specific multicast, as described in [RFC4607] | +--------+----------------------------------------------------------+ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and Holland Expires March 29, 2020 [Page 3] Internet-Draft DORMS September 2019 "OPTIONAL" in this document are to be interpreted as described in [RFC2119] and [RFC8174] when, and only when, they appear in all capitals, as shown here. 2. Discovery and Metdata Retrieval A client that needs metadata about a (S,G) MAY attempt to discover metadata for the (S,G) using the mechanisms defined here, and MAY use the metadata received to manage the forwarding or processing of the packets in the channel. 2.1. DNS Bootstrap The DNS Bootstrap step is how a client discovers an appropriate RESTCONF server, given the source address of an (S,G). Use of the DNS Bootstrap is OPTIONAL for clients with an alternate method of obtaining a RESTCONF hostname for a DORMS server with metadata for an (S,G). This mechanism only works for source-specific multicast (SSM) channels. The source address of the (S,G) is reversed and used as an index into one of the reverse mapping trees (in-addr.arpa for IPv4, as described in Section 3.5 of [RFC1035], or ip6.arpa for IPv6, as described in Section 2.5 of [RFC3596]). When a receiver or middle box needs metadata for an (S,G), for example when handling a new join for that (S,G) and looking up authentication methods available, a receiver or middlebox can issue a DNS query for a SRV RR using the "dorms" service name with the domain from the reverse mapping tree, combining them as described in [RFC2782]. For example, while handling a join for (203.0.113.15, 232.1.1.1), a receiver would perform a DNS query for the SRV RRType for the domain: _dorms._tcp.15.113.0.203.in-addr.arpa. The DNS response for this domain might return a record such as: SRV 0 1 443 dorms-restconf.example.com. This response informs the receiver that a DORMS server SHOULD be reachable at dorms-restconf.example.com on port 443. Multiple SRV records are handled as described by [RFC2782]. A sender providing DORMS discovery SHOULD publish at least one SRV record in the reverse DNS zone for each source address of the multicast channels it is sending, in order to advertise the hostname Holland Expires March 29, 2020 [Page 4] Internet-Draft DORMS September 2019 of the DORMS server to receivers and middle boxes. The DORMS servers advertised SHOULD be configured with metadata for all the groups sent from the same source IP address that have metadata published with DORMS. 2.2. RESTCONF Bootstrap Once a DORMS host has been chosen (whether via an SRV RR from a DNS response or via some other method), RESTCONF provides all the information necessary to determine the versions and url paths for metadata from the server. A walkthrough is provided here for a sequence of example requests and responses from a receiver connecting to a new DORMS server. 2.2.1. Root Resource Discovery As described in Section 3.1 of [RFC8040] and [RFC6415], the RESTCONF server provides the link to the RESTCONF api entry point via the "/.well-known/host-meta" or "/.well-known/host-meta.json" resource. Example: The receiver might send: GET /.well-known/host-meta.json HTTP/1.1 Host: dorms-restconf.example.com Accept: application/json The server might respond as follows: HTTP/1.1 200 OK Date: Tue, 27 Aug 2019 20:56:00 GMT Server: example-server Cache-Control: no-cache Content-Type: application/json { "links":[ { "rel":"restconf", "href":"/top/restconf" } ] } Holland Expires March 29, 2020 [Page 5] Internet-Draft DORMS September 2019 2.2.2. Yang Library Version As described in Section 3.3.3 of [RFC8040], the yang-library-version leaf is required by RESTCONF, and can be used to determine the schema of the ietf-yang-library module: Example: The receiver might send: GET /top/restconf/yang-library-version HTTP/1.1 Host: dorms-restconf.example.com Accept: application/yang-data+json The server might respond as follows: HTTP/1.1 200 OK Date: Tue, 27 Aug 2019 20:56:01 GMT Server: example-server Cache-Control: no-cache Content-Type: application/yang-data+json { "ietf-restconf:yang-library-version": "2016-06-21" } TBD: We might need a method for learning a specific restconf server or resource path that supports a version the client knows how to use, in the case the client is older than the server after a new yang- library version is released... Can this be just retry with a hold- down on specific hostnames, so that you can find a lower priority older server from the SRV records, or is signaling that can find or negotiate an explicit version as part of the lookup going to be necessary? -jake 2019-08-26 2.2.3. Yang Library Contents After checking that the version of the yang-library module will be understood by the receiver, the client can check that the desired metadata module is available on the DORMS server by fetching the module-state resource from the ietf-yang-library module. Example: The receiver might send: Holland Expires March 29, 2020 [Page 6] Internet-Draft DORMS September 2019 GET /top/restconf/data/ietf-yang-library:modules-state/\ module=ietf-dorms,2016-08-15 Host: dorms-restconf.example.com Accept: application/yang-data+json The server might respond as follows: HTTP/1.1 200 OK Date: Tue, 27 Aug 2019 20:56:02 GMT Server: example-server Cache-Control: no-cache Content-Type: application/yang-data+json { "ietf-yang-library:module": [ { "conformance-type": "implement", "name": "ietf-dorms", "namespace": "urn:ietf:params:xml:ns:yang:ietf-dorms", "revision": "2019-08-25", "schema": "https://example.com/yang/ietf-dorms@2019-08-25.yang" } ] } Other modules required or desired by the client also can be checked in a similar way, or the full set of available modules can be retrieved by not providing a key for the "module" list. 2.2.4. Metadata Retrieval Once the expected DORMS version is confirmed, the client can retrieve the metadata specific to the desired (S,G). Example: The receiver might send: GET /top/restconf/data/ietf-dorms:metadata/\ sender=203.0.113.15/group=232.1.1.1 Host: dorms-restconf.example.com Accept: application/yang-data+json The server might respond as follows: Holland Expires March 29, 2020 [Page 7] Internet-Draft DORMS September 2019 HTTP/1.1 200 OK Date: Tue, 27 Aug 2019 20:56:02 GMT Server: example-server Cache-Control: no-cache Content-Type: application/yang-data+json { "ietf-dorms:group": [ { "group-address":"232.1.1.1", "udp-stream":[ { "port":"5001" } ] } ] } Note that when other modules are installed on the DORMS server that extend the ietf-dorms module, other fields MAY appear inside the response. This is the primary mechanism for providing extensible metadata for an (S,G), so clients SHOULD ignore fields they do not understand. As mentioned in Section 3.2, most clients SHOULD use data resource identifiers in the request URI as in the above example, in order to retrieve metadata for only the targeted (S,G)s. 2.2.5. Cross Origin Resource Sharing (CORS) It is RECOMMENDED that DORMS servers use the Access-Control-Allow- Origin header field, as specified by [W3C.REC-cors-20140116], and that they respond appropriately to Preflight requests. Providing '*' for the allowed origins exposes the DORMS-based metadata to all web pages. When access to the metadata is used as a prerequisite to permitting the joining of the multicast flows, this would permit scripts from arbitrary web pages to issue joins for the multicast flows, which could allow e.g. malicious advertisements to participate in overjoining attacks (see Appendix A of [I-D.draft-jholland-cb-assisted-cc-01]) using multicast flows not controlled by the ad's senders. Therefore the use of '*' for allowed origins is NOT RECOMMENDED. (TBD: this probably deserves a security considerations section.) Holland Expires March 29, 2020 [Page 8] Internet-Draft DORMS September 2019 3. Scalability Considerations 3.1. Provisioning In contrast to many common RESTCONF deployments that are intended to provide configuration management for a service to a narrow set of authenticated administrators, DORMS servers often provide read-only metadata for public access, or for a very large set of end receivers, since it provides metadata in support of multicast data streams and multicast can scale to very large audiences. Operators are advised to provision the DORMS service in a way that will scale appropriately to the size of the expected audience. Specific advice on such scaling is out of scope for this document, but some of the mechanisms outlined in [RFC3040] or other online resources might be useful, depending on the expected number of receivers. 3.2. Data Scoping In the absence of contextual information, clients SHOULD issue narrowed requests for DORMS resources by following the format from Section 3.5.3 of [RFC8040] to encode data resource identifiers in the request URI. This avoids downloading excessive data, since the DORMS server may provide metadata for many (S,G)s, possibly from many different senders. However, clients MAY use heuristics or out of band information about the service to issue requests for (S,G) metadata narrowed only by the source-address, or not narrowed at all. Depending on the request patterns and the contents of the data store, this may result in fewer round trips or less overhead, and can therefore be helpful behavior for scaling purposes. Servers MAY restrict or throttle client access based on the client certificate presented (if any), or based on heuristics that take note of client request patterns. A complete description of the heuristics for clients and servers to meet their scalability goals is out of scope for this document. 4. YANG Model The primary purpose of the YANG model defined here is to serve as a scaffold for the more useful metadata that will extend it. Currently known use cases include providing authentication information and bit- rate information for use by receivers and middle boxes, but more use cases are anticipated. Holland Expires March 29, 2020 [Page 9] Internet-Draft DORMS September 2019 4.1. Yang Tree module: ietf-dorms +--rw metadata +--rw sender* [source-address] +--rw source-address inet:ip-address +--rw group* [group-address] +--rw group-address rt-types:ip-multicast-group-address +--rw udp-stream* [port] +--rw port inet:port-number DORMS Tree Diagram 4.2. Yang Module file ietf-dorms@2019-09-26.yang module ietf-dorms { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-dorms"; prefix "dorms"; import ietf-inet-types { prefix "inet"; reference "RFC 6991 Section 4"; } import ietf-routing-types { prefix "rt-types"; reference "RFC 8294"; } organization "IETF"; contact "Author: Jake Holland "; description "Copyright (c) 2019 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Holland Expires March 29, 2020 [Page 10] Internet-Draft DORMS September 2019 Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices. The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document are to be interpreted as described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here. This module contains the definition for the DORMS data type. It provides out of band metadata about SSM channels."; revision 2019-08-25 { description "Initial revision."; reference ""; // "I-D.draft-jholland-mboned-dorms"; } container metadata { description "Metadata scaffold for source-specific multicast channels."; list sender { key source-address; description "Sender for DORMS"; leaf source-address { type inet:ip-address; mandatory true; description "The source IP address of a multicast sender."; } list group { key group-address; description "Metadata for a DORMS (S,G)."; leaf group-address { type rt-types:ip-multicast-group-address; mandatory true; description "The group IP address for an (S,G)."; } list udp-stream { Holland Expires March 29, 2020 [Page 11] Internet-Draft DORMS September 2019 key "port"; description "Metadata for UDP traffic on a specific port."; leaf port { type inet:port-number; mandatory true; description "The UDP port of a data stream in an (S,G)."; } } } } } } 5. Privacy Considerations In the typical case, the mechanisms defined in this document provide a standardized way to discover information that is already available in other ways. However, depending on the metadata provided by the server, observers may be able to more easily associate traffic from an (S,G) with the content contained within the (S,G). At the subscriber edge of a multicast-capable network, where the network operator has the capability to localize a IGMP [RFC3376] or MLD [RFC3810] channel subscription to a specific user or location by MAC address or source IP address, the structured publishing of metadata may make it easier to automate collection of data about the content a receiver is consuming. RESTCONF communication will expose to the controller of the RESTCONF server information about the consumers of content that is not otherwise available from multicast subscription to a channel, such as the remote IP address and timing information. 6. IANA Considerations 6.1. The YANG Module Names Registry This document adds one YANG module to the "YANG Module Names" registry maintained at . The following registrations are made, per the format in Section 14 of [RFC6020]: Holland Expires March 29, 2020 [Page 12] Internet-Draft DORMS September 2019 name: ietf-dorms namespace: urn:ietf:params:xml:ns:yang:ietf-dorms prefix: dorms reference: I-D.draft-jholland-mboned-dorms 6.2. The Service Name and Transport Protocol Port Number Registry This document adds one service name to the "Service Name and Transport Protocol Port Number Registry" maintained at . The following registrations are made, per the format in Section 8.1.1 of [RFC6335]: Service Name: dorms Transport Protocol(s): TCP Assignee: IESG Contact: IETF Chair Description: This service name is used to construct the SRV service label "_dorms" for discovering DORMS servers. Reference: I-D.draft-jholland-mboned-dorms Port Number: N/A Service Code: N/A Known Unauthorized Uses: N/A Assignment Notes: This protocol uses HTTPS as a substrate. 7. Security Considerations 7.1. Secure Communications It is intended that security related metadata about the SSM channels will be delivered over the RESTCONF connection, and that information available from this connection can be used as a trust anchor. The provisions of Section 2 of [RFC8040] provide secure communication requirements that are already required of DORMS servers, since they are RESTCONF servers. All RESTCONF requirements and security considerations remain in force for DORMS servers. 7.2. Exposure of Metadata Although some DORMS servers MAY restrict access based on client identity, as described in Section 2.5 of [RFC8040], many DORMS servers will use the ietf-dorms YANG model to publish information without restriction, and even DORMS servers requiring client authentication will inherently, because of the purpose of DORMS, be providing the DORMS metadata to potentially many receivers. Holland Expires March 29, 2020 [Page 13] Internet-Draft DORMS September 2019 Accordingly, future YANG modules that augment data paths under "ietf- dorms:metadata" MUST NOT include any sensitive data unsuitable for public dissemination in those data paths. Because of the possibility that scalable read-only access might be necessary to fulfill the scalability goals for a DORMS server, data under these paths MAY be cached or replicated by numerous external entities, so owners of such data SHOULD NOT assume it can be kept secret when provided by DORMS servers anywhere under the "ietf-dorms:metadata" path, even if they are authenticating clients. 7.3. DNS Bootstrapping The DNS bootstrap phase relies on DNS for the reverse IP tree. When using DNS to discover a DORMS server's domain name, there must be a trust relationship between the end consumer of this resource record and the DNS server. This relationship may be end-to-end DNSSEC validation, a TSIG [RFC2845] or SIG(0) [RFC2931] channel to another secure source, a secure local channel on the host, DNS over TLS [RFC7858] or HTTPS [RFC8484], or some other secure mechanism. If the SRV Resource Record cannot be authenticated, it may be possible for an attacker who can spoof the resource record to perform a denial of service for the receiver by providing wrong or missing authentication metadata. An attacker who can also inject traffic for (S,G)s, would also be able to provide false content in the data stream, so an attacker who can perform both could provide authenticated false content by authenticating with a trust anchor from an attacker-controlled DORMS server. Clients MAY use other secure methods to explicitly associate an (S,G) with a set of DORMS server hostnames, such as a configured mapping or an alternative trusted lookup service. 8. Acknowledgements Thanks to Christian Worm Mortensen for some very helpful comments and review. 9. References 9.1. 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, . Holland Expires March 29, 2020 [Page 14] Internet-Draft DORMS September 2019 [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2782, DOI 10.17487/RFC2782, February 2000, . [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, "DNS Extensions to Support IP Version 6", STD 88, RFC 3596, DOI 10.17487/RFC3596, October 2003, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8294] Liu, X., Qu, Y., Lindem, A., Hopps, C., and L. Berger, "Common YANG Data Types for the Routing Area", RFC 8294, DOI 10.17487/RFC8294, December 2017, . [W3C.REC-cors-20140116] Kesteren, A., "Cross-Origin Resource Sharing", World Wide Web Consortium Recommendation REC-cors-20140116, January 2014, . 9.2. Informative References [I-D.draft-jholland-cb-assisted-cc-01] Holland, J., "Circuit Breaker Assisted Congestion Control (CBACC): Protocol Specification", draft-jholland-cb- assisted-cc-01 (work in progress), April 2017. [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, . Holland Expires March 29, 2020 [Page 15] Internet-Draft DORMS September 2019 [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, November 1987, . [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. Wellington, "Secret Key Transaction Authentication for DNS (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, . [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September 2000, . [RFC3040] Cooper, I., Melve, I., and G. Tomlinson, "Internet Web Replication and Caching Taxonomy", RFC 3040, DOI 10.17487/RFC3040, January 2001, . [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. Thyagarajan, "Internet Group Management Protocol, Version 3", RFC 3376, DOI 10.17487/RFC3376, October 2002, . [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, DOI 10.17487/RFC3810, June 2004, . [RFC4604] Holbrook, H., Cain, B., and B. Haberman, "Using Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Protocol Version 2 (MLDv2) for Source- Specific Multicast", RFC 4604, DOI 10.17487/RFC4604, August 2006, . [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for IP", RFC 4607, DOI 10.17487/RFC4607, August 2006, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . Holland Expires March 29, 2020 [Page 16] Internet-Draft DORMS September 2019 [RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. Cheshire, "Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry", BCP 165, RFC 6335, DOI 10.17487/RFC6335, August 2011, . [RFC6415] Hammer-Lahav, E., Ed. and B. Cook, "Web Host Metadata", RFC 6415, DOI 10.17487/RFC6415, October 2011, . [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., and P. Hoffman, "Specification for DNS over Transport Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 2016, . [RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, . [whatwg-fetch] Kesteren, A., "WHATWG Fetch Living Standard", August 2019, . Author's Address Jake Holland Akamai Technologies, Inc. 150 Broadway Cambridge, MA 02144 United States of America Email: jakeholland.net@gmail.com Holland Expires March 29, 2020 [Page 17]