Dynamic Link Exchange Protocol (DLEP) Control-Plane-Based Pause Extension
RFC 8651
Internet Engineering Task Force (IETF) B. Cheng
Request for Comments: 8651 D. Wiggins
Category: Standards Track MIT Lincoln Laboratory
ISSN: 2070-1721 L. Berger, Ed.
LabN Consulting, L.L.C.
October 2019
Dynamic Link Exchange Protocol (DLEP)
Control-Plane-Based Pause Extension
Abstract
This document defines an extension to the Dynamic Link Exchange
Protocol (DLEP) that enables a modem to use DLEP messages to pause
and resume data traffic coming from its peer router.
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/rfc8651.
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
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Table of Contents
1. Introduction
1.1. Key Words
2. Extension Usage and Identification
3. Extension Data Items
3.1. Queue Parameters
3.1.1. Queue Parameter Sub-Data Item
3.2. Pause
3.3. Restart
4. Security Considerations
5. IANA Considerations
5.1. Extension Type Value
5.2. Data Item Values
5.3. Queue Parameter Sub-Data Item Values
6. References
6.1. Normative References
6.2. Informative References
Acknowledgments
Authors' Addresses
1. Introduction
The Dynamic Link Exchange Protocol (DLEP) is defined in [RFC8175].
It provides the exchange of link-related control information between
a modem and a router. DLEP defines a base set of mechanisms as well
as support for possible extensions. This document defines one such
extension.
The base DLEP specification does not include any data-plane
flow-control capability. The extension defined in this document
supports flow control of data traffic based on explicit messages sent
via DLEP by a modem to indicate when a router should hold off sending
traffic and when it should resume. This functionality parallels the
flow-control mechanism found in PPP over Ethernet (PPPoE) per
[RFC5578]. The extension also optionally supports DSCP-aware flow
control ("DSCP" stands for "Differentiated Services Code Point") for
use by Diffserv-aware modems. (For general background on
Differentiated Services, see [RFC2475].) This functionality is very
similar to that provided by Ethernet priority-based flow control; see
[IEEE.802.1Q_2014]. The extension defined in this document is
referred to as "Control-Plane-Based Pause". Other flow-control
methods are possible with DLEP; for example, see [DLEP-DIFFSERV] and
[DLEP-CREDIT].
Note that this mechanism only applies to traffic that is to be
transmitted on the modem's attached data channel and not to DLEP
control messages themselves. Furthermore, it applies only to the
single subnetwork that is used to connect a modem and a router, and
for traffic sent from a router to a modem.
This document defines a new DLEP Extension Type Value that is used to
indicate the use of the extension; see Section 2. Three new DLEP
Data Items are defined in Section 3.
1.1. Key Words
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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. Extension Usage and Identification
The use of the Control-Plane-Based Pause Extension SHOULD be
configurable. To indicate that the implementation supports the use
of the Control-Plane-Based Pause Extension, an implementation MUST
include the Control-Plane-Based Pause Extension Type Value in the
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