rfc9893v4.txt		rfc9893.txt
	Internet Engineering Task Force (IETF) B. Cheng		Internet Engineering Task Force (IETF) B. Cheng
	Request for Comments: 9893 MIT Lincoln Laboratory		Request for Comments: 9893 MIT Lincoln Laboratory
	Category: Standards Track D. Wiggins		Category: Standards Track D. Wiggins
	ISSN: 2070-1721		ISSN: 2070-1721
	S. Ratliff		S. Ratliff
	L. Berger		L. Berger
	E. Kinzie, Ed.		E. Kinzie, Ed.
	LabN Consulting, L.L.C.		LabN Consulting, L.L.C.
	December 2025		January 2026
	Dynamic Link Exchange Protocol (DLEP) Credit-Based Flow Control Messages		Dynamic Link Exchange Protocol (DLEP) Credit-Based Flow Control Messages
	and Data Items		and Data Items
	Abstract		Abstract
	This document defines new Dynamic Link Exchange Protocol (DLEP) Data		This document defines new Dynamic Link Exchange Protocol (DLEP) Data
	Items that are used to support credit-based flow control. Credit		Items that are used to support credit-based flow control. Credit
	window flow control is used to regulate when data may be sent to an		window flow control is used to regulate when data may be sent to an
	associated virtual or physical queue. These Data Items are		associated virtual or physical queue. These Data Items are
	skipping to change at line 43 ¶		skipping to change at line 43 ¶
	received public review and has been approved for publication by the		received public review and has been approved for publication by the
	Internet Engineering Steering Group (IESG). Further information on		Internet Engineering Steering Group (IESG). Further information on
	Internet Standards is available in Section 2 of RFC 7841.		Internet Standards is available in Section 2 of RFC 7841.
	Information about the current status of this document, any errata,		Information about the current status of this document, any errata,
	and how to provide feedback on it may be obtained at		and how to provide feedback on it may be obtained at
	https://www.rfc-editor.org/info/rfc9893.		https://www.rfc-editor.org/info/rfc9893.
	Copyright Notice		Copyright Notice
	Copyright (c) 2025 IETF Trust and the persons identified as the		Copyright (c) 2026 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
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Revised BSD License text as described in Section 4.e of the		include Revised BSD License text as described in Section 4.e of the
	Trust Legal Provisions and are provided without warranty as described		Trust Legal Provisions and are provided without warranty as described
	skipping to change at line 211 ¶		skipping to change at line 211 ¶
	data when an extension requiring the use of credit window flow		data when an extension requiring the use of credit window flow
	control is used. Note that Traffic Classification Identifier (TID)		control is used. Note that Traffic Classification Identifier (TID)
	values and FID values are significant only to the issuing modem.		values and FID values are significant only to the issuing modem.
	There is no relationship implied by the same TID or FID value being		There is no relationship implied by the same TID or FID value being
	issued by more than one modem. In addition to the traffic		issued by more than one modem. In addition to the traffic
	classification information associated with a FID, modems provide an		classification information associated with a FID, modems provide an
	initial credit window size, as well as the maximum size of the		initial credit window size, as well as the maximum size of the
	logical queue associated with each credit window. The maximum size		logical queue associated with each credit window. The maximum size
	is included for informative and potential future uses.		is included for informative and potential future uses.
	Modems provide an initial credit window size at the time of "Credit		Modems provide an initial credit window size at the time of credit
	Window Initialization". Such initialization can take place during		window initialization. Such initialization can take place during
	session initiation or any point thereafter. It can also take place		session initiation or any point thereafter. It can also take place
	when rate information changes. An increment to a credit window size,		when rate information changes. An increment to a credit window size,
	specified in a Credit Window Grant Data Item, is provided in a		specified in a Credit Window Grant Data Item, is provided in a
	Destination Up Message (Section 2.3.2) or Credit Control Message		Destination Up Message (Section 2.3.2) or Credit Control Message
	(Section 2.2.1). A router provides its view of the credit window,		(Section 2.2.1). A router provides its view of the credit window,
	which is known as "Status", in Destination Up Response Messages		which is known as "Status", in Destination Up Response Messages
	(Section 2.3.3) and Credit Control Response Messages (Section 2.2.2).		(Section 2.3.3) and Credit Control Response Messages (Section 2.2.2).
	Routers can also request credits using the Credit Control Message.		Routers can also request credits using the Credit Control Message.
	When modems provide credits to a router, they will need to take into		When modems provide credits to a router, they will need to take into
	skipping to change at line 876 ¶		skipping to change at line 876 ¶
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[RFC8175] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B.		[RFC8175] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B.
	Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175,		Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175,
	DOI 10.17487/RFC8175, June 2017,		DOI 10.17487/RFC8175, June 2017,
	<https://www.rfc-editor.org/info/rfc8175>.		<https://www.rfc-editor.org/info/rfc8175>.
	[RFC9892] Cheng, B., Wiggins, D., Berger, L., and D. Fedyk, Ed.,		[RFC9892] Cheng, B., Wiggins, D., Berger, L., and D. Fedyk, Ed.,
	"Dynamic Link Exchange Protocol (DLEP) Traffic		"Dynamic Link Exchange Protocol (DLEP) Traffic
	Classification Data Item", RFC 9892, DOI 10.17487/RFC9892,		Classification Data Item", RFC 9892, DOI 10.17487/RFC9892,
	December 2025, <https://www.rfc-editor.org/info/rfc9892>.		January 2026, <https://www.rfc-editor.org/info/rfc9892>.
	6.2. Informative References		6.2. Informative References
	[BCP195] Best Current Practice 195,		[BCP195] Best Current Practice 195,
	<https://www.rfc-editor.org/info/bcp195>.		<https://www.rfc-editor.org/info/bcp195>.
	At the time of writing, this BCP comprises the following:		At the time of writing, this BCP comprises the following:
	Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS		Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS
	1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021,		1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021,
	<https://www.rfc-editor.org/info/rfc8996>.		<https://www.rfc-editor.org/info/rfc8996>.
	skipping to change at line 935 ¶		skipping to change at line 935 ¶
	<https://www.rfc-editor.org/info/rfc8126>.		<https://www.rfc-editor.org/info/rfc8126>.
	[RFC8651] Cheng, B., Wiggins, D., and L. Berger, Ed., "Dynamic Link		[RFC8651] Cheng, B., Wiggins, D., and L. Berger, Ed., "Dynamic Link
	Exchange Protocol (DLEP) Control-Plane-Based Pause		Exchange Protocol (DLEP) Control-Plane-Based Pause
	Extension", RFC 8651, DOI 10.17487/RFC8651, October 2019,		Extension", RFC 8651, DOI 10.17487/RFC8651, October 2019,
	<https://www.rfc-editor.org/info/rfc8651>.		<https://www.rfc-editor.org/info/rfc8651>.
	[RFC9894] Cheng, B., Wiggins, D., Berger, L., and D. Eastlake 3rd,		[RFC9894] Cheng, B., Wiggins, D., Berger, L., and D. Eastlake 3rd,
	Ed., "Dynamic Link Exchange Protocol (DLEP) Diffserv Aware		Ed., "Dynamic Link Exchange Protocol (DLEP) Diffserv Aware
	Credit Window Extension", RFC 9894, DOI 10.17487/RFC9894,		Credit Window Extension", RFC 9894, DOI 10.17487/RFC9894,
	December 2025, <https://www.rfc-editor.org/info/rfc9894>.		January 2026, <https://www.rfc-editor.org/info/rfc9894>.
	[RFC9895] Wiggins, D., Berger, L., and D. Eastlake 3rd, Ed.,		[RFC9895] Wiggins, D., Berger, L., and D. Eastlake 3rd, Ed.,
	"Dynamic Link Exchange Protocol (DLEP) IEEE 802.1Q Aware		"Dynamic Link Exchange Protocol (DLEP) IEEE 802.1Q Aware
	Credit Window Extension", RFC 9895, DOI 10.17487/RFC9895,		Credit Window Extension", RFC 9895, DOI 10.17487/RFC9895,
	December 2025, <https://www.rfc-editor.org/info/rfc9895>.		January 2026, <https://www.rfc-editor.org/info/rfc9895>.
	Appendix A. Example DLEP Credit Flow Control and Traffic Classification		Appendix A. Example DLEP Credit Flow Control and Traffic Classification
	Data Item Exchange		Data Item Exchange
	Figure 2 illustrates a credit flow control and traffic classification		Figure 2 illustrates a credit flow control and traffic classification
	exchange between a router and a modem. The modem will initialize a		exchange between a router and a modem. The modem will initialize a
	number of queues with Credit Window Initialization Data Items, Credit		number of queues with Credit Window Initialization Data Items, Credit
	Window Association Data Item(s), and Traffic Classification Data		Window Association Data Item(s), and Traffic Classification Data
	Item(s) included in DLEP messages as outlined in this document. If		Item(s) included in DLEP messages as outlined in this document. If
	the Data Items are successfully validated, traffic is mapped to the		the Data Items are successfully validated, traffic is mapped to the
End of changes. 6 change blocks.
	7 lines changed or deleted		7 lines changed or added
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