DNS Reverse IP Automatic Multicast Tunneling (AMT) Discovery
RFC 8777
Document | Type |
RFC - Proposed Standard
(April 2020; Errata)
Updates RFC 7450
|
|
---|---|---|---|
Author | Jake Holland | ||
Last updated | 2020-07-18 | ||
Replaces | draft-jholland-mboned-driad-amt-discovery | ||
Stream | IETF | ||
Formats | plain text html xml pdf htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Tim Chown | ||
Shepherd write-up | Show (last changed 2019-09-24) | ||
IESG | IESG state | RFC 8777 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Warren Kumari | ||
Send notices to | Tim Chown <tim.chown@jisc.ac.uk> | ||
IANA | IANA review state | IANA OK - Actions Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) J. Holland Request for Comments: 8777 Akamai Technologies, Inc. Updates: 7450 April 2020 Category: Standards Track ISSN: 2070-1721 DNS Reverse IP Automatic Multicast Tunneling (AMT) Discovery Abstract This document updates RFC 7450, "Automatic Multicast Tunneling" (or AMT), by modifying the relay discovery process. A new DNS resource record named AMTRELAY is defined for publishing AMT relays for source-specific multicast channels. The reverse IP DNS zone for a multicast sender's IP address is configured to use AMTRELAY resource records to advertise a set of AMT relays that can receive and forward multicast traffic from that sender over an AMT tunnel. Other extensions and clarifications to the relay discovery process are also defined. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8777. Copyright Notice Copyright (c) 2020 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 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 1.1. Background 1.2. Terminology 1.2.1. Relays and Gateways 1.2.2. Definitions 1.2.3. Requirements Language 2. Relay Discovery Overview 2.1. Basic Mechanics 2.2. Signaling and Discovery 2.3. Example Deployments 2.3.1. Example Receiving Networks 2.3.2. Example Sending Networks 3. Relay Discovery Operation 3.1. Optimal Relay Selection 3.1.1. Overview 3.1.2. Preference Ordering 3.1.3. Connecting to Multiple Relays 3.2. Happy Eyeballs 3.2.1. Overview 3.2.2. Algorithm Guidelines 3.2.3. Connection Definition 3.3. Guidelines for Restarting Discovery 3.3.1. Overview 3.3.2. Updates to Restarting Events 3.3.3. Tunnel Stability 3.3.4. Traffic Health 3.3.5. Relay Loaded or Shutting Down 3.3.6. Relay Discovery Messages vs. Restarting Discovery 3.3.7. Independent Discovery per Traffic Source 3.4. DNS Configuration 3.5. Waiting for DNS Resolution 4. AMTRELAY Resource Record Definition 4.1. AMTRELAY RRType 4.2. AMTRELAY RData Format 4.2.1. RData Format - Precedence 4.2.2. RData Format - Discovery Optional (D-bit) 4.2.3. RData Format - Type 4.2.4. RData Format - Relay 4.3. AMTRELAY Record Presentation Format 4.3.1. Representation of AMTRELAY RRs 4.3.2. Examples 5. IANA Considerations 6. Security Considerations 6.1. Use of AMT 6.2. Record-Spoofing 6.3. Congestion 7. References 7.1. Normative References 7.2. Informative References Appendix A. Unknown RRType Construction Acknowledgements Author's Address 1. Introduction This document defines DNS Reverse IP AMT Discovery (DRIAD), a mechanism for AMT gateways to discover AMT relays that are capable of forwarding multicast traffic from a known source IP address. AMT (Automatic Multicast Tunneling) is defined in [RFC7450] and provides a method to transport multicast traffic over a unicast tunnel in order to traverse network segments that are not multicast capable. Section 4.1.5 of [RFC7450] explains that the relay selection process for AMT is intended to be more flexible than the particular discovery method described in that document. That section further explains that the selection process might need to depend on the source of the multicast traffic in some deployments, since a relay must be able to receive multicast traffic from the desired source in order to forward it. Section 4.1.5 of [RFC7450] goes on to suggest DNS-based queries as a possible solution: DRIAD is DNS based. This solution also addressesShow full document text