draft-ietf-mboned-driad-amt-discovery-04.txt		draft-ietf-mboned-driad-amt-discovery-05.txt
	Mboned J. Holland		Mboned J. Holland
	Internet-Draft Akamai Technologies, Inc.		Internet-Draft Akamai Technologies, Inc.
	Updates: 7450 (if approved) April 22, 2019		Updates: 7450 (if approved) April 25, 2019
	Intended status: Standards Track		Intended status: Standards Track
	Expires: October 24, 2019		Expires: October 27, 2019
	DNS Reverse IP AMT Discovery		DNS Reverse IP AMT Discovery
	draft-ietf-mboned-driad-amt-discovery-04		draft-ietf-mboned-driad-amt-discovery-05
	Abstract		Abstract
	This document updates RFC 7450 (Automatic Multicast Tunneling, or		This document updates RFC 7450 (Automatic Multicast Tunneling, or
	AMT) by extending the relay discovery process to use a new DNS		AMT) by extending the relay discovery process to use a new DNS
	resource record named AMTRELAY when discovering AMT relays for		resource record named AMTRELAY when discovering AMT relays for
	source-specific multicast channels. The reverse IP DNS zone for a		source-specific multicast channels. The reverse IP DNS zone for a
	multicast sender's IP address is configured to use AMTRELAY resource		multicast sender's IP address is configured to use AMTRELAY resource
	records to advertise a set of AMT relays that can receive and forward		records to advertise a set of AMT relays that can receive and forward
	multicast traffic from that sender over an AMT tunnel.		multicast traffic from that sender over an AMT tunnel.
	skipping to change at page 1, line 37 ¶		skipping to change at page 1, line 37 ¶
	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 https://datatracker.ietf.org/drafts/current/.		Drafts is at https://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 October 24, 2019.		This Internet-Draft will expire on October 27, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 9, line 31 ¶		skipping to change at page 9, line 31 ¶
	Eyeballs algorithm is a useful one, and so this section provides the		Eyeballs algorithm is a useful one, and so this section provides the
	following normative definition:		following normative definition:
	o An AMT connection is completed successfully when the gateway		o An AMT connection is completed successfully when the gateway
	receives from a newly discovered relay a valid Membership Query		receives from a newly discovered relay a valid Membership Query
	message (Section 5.1.4 of [RFC7450]) that does not have the L flag		message (Section 5.1.4 of [RFC7450]) that does not have the L flag
	set.		set.
	See Section 2.5.5 of this document for further information about the		See Section 2.5.5 of this document for further information about the
	relevance of the L flag to the establishment of a Happy Eyeballs		relevance of the L flag to the establishment of a Happy Eyeballs
	connection.		connection. See Section 2.5.4 for an overview of how to respond if
			the connection does not provide multicast connectivity to the source.
	2.4. Optimal Relay Selection		2.4. Optimal Relay Selection
	2.4.1. Overview		2.4.1. Overview
	The reverse source IP DNS query of an AMTRELAY RR is a good way for a		The reverse source IP DNS query of an AMTRELAY RR is a good way for a
	gateway to discover a relay that is known to the sender.		gateway to discover a relay that is known to the sender.
	However, it is NOT necessarily a good way to discover the best relay		However, it is NOT necessarily a good way to discover the best relay
	for that gateway to use, because the RR will only provide information		for that gateway to use, because the RR will only provide information
	skipping to change at page 12, line 38 ¶		skipping to change at page 12, line 38 ¶
	above, a Happy Eyeballs algorithm for AMT MUST use the Destination		above, a Happy Eyeballs algorithm for AMT MUST use the Destination
	Address Selection defined in Section 6 of [RFC6724], as required by		Address Selection defined in Section 6 of [RFC6724], as required by
	[RFC8305].		[RFC8305].
	Among relay addresses that still have an equivalent preference after		Among relay addresses that still have an equivalent preference after
	the above orderings, a gateway MUST make a non-deterministic choice		the above orderings, a gateway MUST make a non-deterministic choice
	for relay preference ordering, in order to support load balancing by		for relay preference ordering, in order to support load balancing by
	DNS configurations that provide many relay options.		DNS configurations that provide many relay options.
	The gateway MAY introduce a bias in the non-deterministic choice		The gateway MAY introduce a bias in the non-deterministic choice
	according to network topology or timing information obtained out of		according to information obtained out of band or from a historical
	band or from a historical record. The collection of this information		record about network topology, timing information, or the response to
	is out of scope for this document, but a gateway in possession of		a probing mechanism, that indicates some expected benefits from
	such information MAY use it to prefer topologically closer relays.		selecting some relays in preference to others. Details about the
			structure and collection of this information is out of scope for this
			document, but a gateway in possession of such information MAY use it
			to prefer topologically closer relays.
	Note also that certain relay addresses may be excluded from		Note also that certain relay addresses may be excluded from
	consideration by the hold-down timers described in Section 2.5.4.1 or		consideration by the hold-down timers described in Section 2.5.4.1 or
	Section 2.5.5. These relays constitute "unusable destinations" under		Section 2.5.5. These relays constitute "unusable destinations" under
	Rule 1 of the Destination Address Selection, and are also not part of		Rule 1 of the Destination Address Selection, and are also not part of
	the superseding considerations described above.		the superseding considerations described above.
	The discovery and connection process for the relay addresses in the		The discovery and connection process for the relay addresses in the
	above described ordering MAY operate in parallel, subject to delays		above described ordering MAY operate in parallel, subject to delays
	prescribed by the Happy Eyeballs requirements described in Section 5		prescribed by the Happy Eyeballs requirements described in Section 5
End of changes. 6 change blocks.
	9 lines changed or deleted		13 lines changed or added
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