< draft-ietf-manet-dlep-pause-extension-06.txt   draft-ietf-manet-dlep-pause-extension-07.txt >
Network Working Group B. Cheng Network Working Group B. Cheng
Internet-Draft D. Wiggins Internet-Draft D. Wiggins
Intended status: Standards Track MIT Lincoln Laboratory Intended status: Standards Track MIT Lincoln Laboratory
Expires: October 5, 2019 L. Berger, Ed. Expires: November 7, 2019 L. Berger, Ed.
LabN Consulting, L.L.C. LabN Consulting, L.L.C.
April 3, 2019 May 6, 2019
DLEP Control Plane Based Pause Extension DLEP Control Plane Based Pause Extension
draft-ietf-manet-dlep-pause-extension-06 draft-ietf-manet-dlep-pause-extension-07
Abstract Abstract
This document defines an extension to the Dynamic Link Exchange This document defines an extension to the Dynamic Link Exchange
Protocol (DLEP) that enables a modem to use DLEP messages to pause Protocol (DLEP) that enables a modem to use DLEP messages to pause
and resume data traffic coming from its peer router. and resume data traffic coming from its peer router.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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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 5, 2019. This Internet-Draft will expire on November 7, 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
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Extension Usage and Identification . . . . . . . . . . . . . 3 2. Extension Usage and Identification . . . . . . . . . . . . . 3
3. Extension Data Items . . . . . . . . . . . . . . . . . . . . 3 3. Extension Data Items . . . . . . . . . . . . . . . . . . . . 3
3.1. Queue Parameters . . . . . . . . . . . . . . . . . . . . 3 3.1. Queue Parameters . . . . . . . . . . . . . . . . . . . . 3
3.1.1. Queue Parameter Sub Data Item . . . . . . . . . . . . 5 3.1.1. Queue Parameter Sub Data Item . . . . . . . . . . . . 5
3.2. Pause . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2. Pause . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. Restart . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3. Restart . . . . . . . . . . . . . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
5.1. Extension Type Value . . . . . . . . . . . . . . . . . . 9 5.1. Extension Type Value . . . . . . . . . . . . . . . . . . 9
5.2. Data Item Values . . . . . . . . . . . . . . . . . . . . 9 5.2. Data Item Values . . . . . . . . . . . . . . . . . . . . 10
5.3. Queue Parameters Sub Data Item Values . . . . . . . . . . 10 5.3. Queue Parameters Sub Data Item Values . . . . . . . . . . 10
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.1. Normative References . . . . . . . . . . . . . . . . . . 10 6.1. Normative References . . . . . . . . . . . . . . . . . . 11
6.2. Informative References . . . . . . . . . . . . . . . . . 11 6.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 11 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction 1. Introduction
The Dynamic Link Exchange Protocol (DLEP) is defined in [RFC8175]. The Dynamic Link Exchange Protocol (DLEP) is defined in [RFC8175].
It provides the exchange of link related control information between It provides the exchange of link related control information between
DLEP peers. DLEP peers are comprised of a modem and a router. DLEP a modem and a router. DLEP defines a base set of mechanisms as well
defines a base set of mechanisms as well as support for possible as support for possible extensions. This document defines one such
extensions. This document defines one such extension. extension.
The base DLEP specification does not include any data plane flow The base DLEP specification does not include any data plane flow
control capability. Various flow control methods are possible, e.g., control capability. The extension defined in this document supports
see [I-D.ietf-manet-dlep-da-credit-extension]. The extension defined flow control of data traffic based on explicit messages sent via DLEP
in this document supports flow control of data traffic based on by a modem to indicate when a router should hold off sending traffic,
explicit messages sent via DLEP by a modem to indicate when a router and when it should resume. This functionality parallels the flow
should hold off sending traffic, and when it should resume. The control mechanism found in PPP over Ethernet (PPPoE) per [RFC5578].
extension also optionally supports DSCP (differentiated services The extension also optionally supports DSCP (differentiated services
codepoint) aware flow control. For general background on codepoint) aware flow control for use by DiffServ-aware modems. (For
Differentiated Services see [RFC2475]. The extension defined in this general background on Differentiated Services see [RFC2475].) This
document is referred to as "Control Plane Based Pause". Note that functionality is very similar to that provided by Ethernet Priority
this mechanism only applies to traffic that is to be transmitted on flow control, see [IEEE.802.1Q_2014]. The extension defined in this
the modem's attached data channel and not to DLEP control messages document is referred to as "Control Plane Based Pause". Other flow
themselves. control methods are possible with DLEP, e.g., see
[I-D.ietf-manet-dlep-da-credit-extension] and
[I-D.ietf-manet-dlep-credit-flow-control].
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 sub-network 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 in Section 2 This document defines a new DLEP Extension Type Value in Section 2
which is used to indicate the use of the extension, and three new which is used to indicate the use of the extension, and three new
DLEP Data Items in Section 3. DLEP Data Items in Section 3.
1.1. Key Words 1.1. Key Words
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
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Three data items are defined by this extension. The Queue Parameters Three data items are defined by this extension. The Queue Parameters
Data Item is used by a modem to provide information about the DSCPs Data Item is used by a modem to provide information about the DSCPs
it uses in forwarding. The Pause Data Item is used by a modem to it uses in forwarding. The Pause Data Item is used by a modem to
indicate when a router should cease sending packets and the Restart indicate when a router should cease sending packets and the Restart
Data Item is used by a modem to indicate when a router can resume Data Item is used by a modem to indicate when a router can resume
sending packets. sending packets.
3.1. Queue Parameters 3.1. Queue Parameters
The Queue Parameters Data Item is used by a modem to indicate DSCP The Queue Parameters Data Item is sent by a modem to to a router to
values that may be independently paused. This data item MUST be indicate DSCP values that may be independently paused. This data
included in a Session Initialization Response Message that also item MUST be included in a Session Initialization Response Message
contains the Control Plane Based Pause Extension Type Value in the that also contains the Control Plane Based Pause Extension Type Value
Extensions Supported Data Item. Updates to these parameters MAY be in the Extensions Supported Data Item. Updates to these parameters
sent by a modem by including the data item in Session Update MAY be sent by a modem by including the data item in Session Update
Messages. Messages.
The Queue Parameters Data Item groups DSCPs into logical queues, each The Queue Parameters Data Item groups DSCPs into logical queues, each
of which is identified by a "Queue Index". The number of logical of which is identified by a "Queue Index". The number of logical
queues, or queue indexes, is variable as is the number of DSCPs queues, or queue indexes, is variable as is the number of DSCPs
associated with each queue. A queue size (in bytes) is provided for associated with each queue. A queue size (in bytes) is provided for
informational purposes. Queue Indexes are numbered sequentially from informational purposes. Queue Indexes are numbered sequentially from
zero, where queue index zero is a special case covering DSCPs which zero, where queue index zero is a special case covering DSCPs which
are not otherwise associated with Queue Index. are not otherwise associated with a Queue Index.
An implementation that does not support DSCPs would indicate 1 queue An implementation that does not support DSCPs would indicate 1 queue
with 0 DSCPs, and the number of bytes that may be in its associated with 0 DSCPs, and the number of bytes that may be in its associated
link transmit queue. Additional logical queues are represented in a link transmit queue. Additional logical queues are represented in a
variable series of Queue Parameter sub data items. variable series of Queue Parameter sub data items.
The format of the Queue Parameters Data Item is: The format of the Queue Parameters Data Item is:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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Num Queues: Num Queues:
An 8-bit unsigned integer indicating the number of queues An 8-bit unsigned integer indicating the number of queues
represented in the data item. This field MUST contain a value of represented in the data item. This field MUST contain a value of
at least one (1), and is equal to one greater than the number of at least one (1), and is equal to one greater than the number of
included Queue Parameter Sub Data Items. included Queue Parameter Sub Data Items.
Scale: Scale:
An 4-bit unsigned integer indicating the scale used in the Queue A 4-bit unsigned integer indicating the scale used in the Queue
Size fields. The valid values are: Size fields. The valid values are:
Value Scale Value Scale
------------ ------------
0 B - Bytes (Octets) 0 B - Bytes (Octets)
1 KiB - Kilobytes (1024 B) 1 KiB - Kilobytes (1024 B)
2 MiB - Megabytes (1024 KiB) 2 MiB - Megabytes (1024 KiB)
3 GiB - Gigabytes (1024 MiB) 3 GiB - Gigabytes (1024 MiB)
Reserved: Reserved:
MUST be set to zero by the sender (a modem) and ignored by the A 20-bit field that MUST be set to zero by the sender (a modem)
receiver (a router). and ignored by the receiver (a router).
3.1.1. Queue Parameter Sub Data Item 3.1.1. Queue Parameter Sub Data Item
Queue Parameter Sub Data Items are an unordered list composed of sub Queue Parameter Sub Data Items are an unordered list composed of sub
data items with a common format. The format of the Queue Parameter data items with a common format. The format of the Queue Parameter
Sub Data Item is patterned after the standard DLEP data item format, Sub Data Item is patterned after the standard DLEP data item format,
see [RFC8175] Section 11.3. Any errors or inconsistencies see [RFC8175] Section 11.3. Any errors or inconsistencies
encountered in parsing Sub Data Items are handled in the same fashion encountered in parsing Sub Data Items are handled in the same fashion
as any other Data Item parsing error encountered in DLEP. as any other Data Item parsing error encountered in DLEP. In
particular, the receiving implementation MUST issue a Session
Termination Message containing a Status Data Item with status code
set to 130 'Invalid Data' and transition to the Session Termination
state.
The format of the Queue Parameter Sub Data Item is: The format of the Queue Parameter Sub Data Item is:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub Data Item Type (1) | Length | | Sub Data Item Type (1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value... | | Value... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
| DSCP | CU | | DSCP | CU |
+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
DSCP: differentiated services codepoint DSCP: differentiated services codepoint
CU: currently unused, MUST be zero CU: currently unused, MUST be zero
3.2. Pause 3.2. Pause
The Pause Data Item is used by a modem to indicate to its peer that The Pause Data Item is sent by a modem to a router to indicate to its
traffic is to be suppressed. The motivating use case is for this peer that traffic is to be suppressed, i.e., paused. The motivating
data item is when a modem's internal queue length exceeds a use case for this data item is when a modem's internal queue length
particular threshold. Other use cases are possible, e.g., when there exceeds a particular threshold. Other use cases are possible, e.g.,
a non queue related congestion points within a modem, but such are when there are non queue related congestion points within a modem.
not explicitly described in this document. Such cases are not explicitly described in this document.
A modem can indicate that traffic is to be suppressed on a device- A modem can indicate that traffic is to be suppressed on a device-
wide or destination-specific basis. An example of when a modem might wide or destination-specific basis. An example of when a modem might
use device wide indications is when output queues are shared across use device wide indications is when output queues are shared across
all destinations, and destination specific might be used when per all destinations, and destination specific might be used when per
destination queuing is used. To indicate that suppression applies to destination queuing is used. To indicate that suppression applies to
all destinations, a modem MUST send the Pause Data Item in a Session all destinations, a modem MUST send the Pause Data Item in a Session
Update Message. To indicate that suppression applies to a particular Update Message. To indicate that suppression applies to a particular
destination a modem MUST send the Pause Data Item in a Destination destination a modem MUST send the Pause Data Item in a Destination
Update Message. Update Message.
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traffic identified by DSCPs. The special value of 255 is used to traffic identified by DSCPs. The special value of 255 is used to
indicate that all traffic is to be suppressed. indicate that all traffic is to be suppressed.
While there is no restriction on the number of Messages containing While there is no restriction on the number of Messages containing
Pause Data Item that may be sent by a modem, a modem SHOULD include Pause Data Item that may be sent by a modem, a modem SHOULD include
multiple queue indexes in the same message when possible. multiple queue indexes in the same message when possible.
A router which receives the Pause Data Item MUST cease sending the A router which receives the Pause Data Item MUST cease sending the
identified traffic to the modem. This may of course translate into identified traffic to the modem. This may of course translate into
the router's queues exceeding their own thresholds. If a received the router's queues exceeding their own thresholds. If a received
Pause Data Item contains a Queue Index value other than 255, or a Pause Data Item contains a Queue Index value other than 255 or a
queue index established by a Session Initialization or Session Update queue index established by a Session Initialization or Session Update
Message, the router MUST terminate the session with a Status Data Message, the router MUST terminate the session with a Status Data
Item indicating Invalid Data. Item indicating Invalid Data.
The format of the Pause Data Item is: The format of the Pause Data Item is:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Item Type | Length | | Data Item Type | Length |
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One or more 8-bit fields used to indicate a queue index defined by One or more 8-bit fields used to indicate a queue index defined by
a Queue Parameters Data Item. The special value of 255 indicates a Queue Parameters Data Item. The special value of 255 indicates
all traffic is to be suppressed to the modem, when the data item all traffic is to be suppressed to the modem, when the data item
is carried in a Session Update Message, or is to be suppressed to is carried in a Session Update Message, or is to be suppressed to
a destination, when the data item is carried in Destination Update a destination, when the data item is carried in Destination Update
Message. Message.
3.3. Restart 3.3. Restart
The Restart Data Item is used by a modem to indicate to its peer that The Restart Data Item is sent by a modem to a router to indicate to
transmission of previously suppressed traffic may be resumed. An its peer that transmission of previously suppressed traffic may be
example of when a modem might send this data item is when an internal resumed. An example of when a modem might send this data item is
queue length drops below a particular threshold. when an internal queue length drops below a particular threshold.
The sending of this data item parallels the Pause Data Item, see the The sending of this data item parallels the Pause Data Item, see the
previous section, and follows the same rules. As above, to indicate previous section, and follows the same rules. As above, to indicate
that transmission can resume to all destinations, a modem MUST send that transmission can resume to all destinations, a modem MUST send
the Restart Data Item in a Session Update Message. It also includes the Restart Data Item in a Session Update Message. It also includes
that to indicate that transmission can resume to a particular that to indicate that transmission can resume to a particular
destination a modem MUST send the Pause Restart Item in a Destination destination a modem MUST send the Pause Restart Item in a Destination
Update Message. Finally, queue indexes are interpreted in the same Update Message. Finally, queue indexes are interpreted in the same
way as in the Pause Data Item.. way as in the Pause Data Item..
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Queue Index: See Section 3.2. Queue Index: See Section 3.2.
4. Security Considerations 4. Security Considerations
The extension introduces a new mechanism for flow control between a The extension introduces a new mechanism for flow control between a
router and modem using DLEP. The extension does not inherently router and modem using DLEP. The extension does not inherently
introduce any additional vulnerabilities above those documented in introduce any additional vulnerabilities above those documented in
[RFC8175]. The approach taken to Security in that document applies [RFC8175]. The approach taken to Security in that document applies
equally when running the extension defined in this document. equally when running the extension defined in this document.
Implementations of the extension defined in this document MUST
support configuration of TLS usage, as describe in [RFC8175], in
order to protect configurations where injection attacks are possible,
i.e., when the link between a modem and router is not otherwise
protected.
Note that this extension does allow a compromised or impersonating Note that this extension does allow a compromised or impersonating
modem to suppress transmission by the router, but this is not a modem to suppress transmission by the router or a switch that
substantively different attack by such a compromised modem simply interconnects the modem and router. Similar attacks are generally
dropping all traffic destined to, or sent by a router. [RFC8175] possible base DLEP, for example an impersonating modem may cause a
defines the use of TLS to protect against the impersonating attacker. session reset or a compromised modem simply can drop all traffic
destined to, or sent by a router. [RFC8175] defines the use of TLS
to protect against the impersonating attacker.
5. IANA Considerations 5. IANA Considerations
This document requests the assignment of 4 values by IANA. All This document requests the assignment of 4 values by IANA. All
assignments are to registries defined by [RFC8175]. assignments are to registries defined by [RFC8175].
5.1. Extension Type Value 5.1. Extension Type Value
This document requests 1 new assignment to the DLEP Extensions This document requests 1 new assignment to the DLEP Extensions
Registry named "Extension Type Values" in the range with the Registry named "Extension Type Values" in the range with the
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2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
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>.
6.2. Informative References 6.2. Informative References
[I-D.ietf-manet-dlep-credit-flow-control]
Cheng, B., Wiggins, D., Berger, L., and S. Ratliff, "DLEP
Credit-Based Flow Control Messages and Data Items", draft-
ietf-manet-dlep-credit-flow-control-04 (work in progress),
March 2019.
[I-D.ietf-manet-dlep-da-credit-extension] [I-D.ietf-manet-dlep-da-credit-extension]
Cheng, B., Wiggins, D., and L. Berger, "DLEP DiffServ Cheng, B., Wiggins, D., and L. Berger, "DLEP DiffServ
Aware Credit Window Extension", draft-ietf-manet-dlep-da- Aware Credit Window Extension", draft-ietf-manet-dlep-da-
credit-extension-07 (work in progress), March 2019. credit-extension-07 (work in progress), March 2019.
[IEEE.802.1Q_2014]
IEEE, "IEEE Standard for Local and metropolitan area
networks--Bridges and Bridged Networks", IEEE 802.1Q-2014,
DOI 10.1109/ieeestd.2014.6991462, December 2014,
<http://ieeexplore.ieee.org/servlet/
opac?punumber=6991460>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS "Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474, Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998, DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>. <https://www.rfc-editor.org/info/rfc2474>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998, Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<https://www.rfc-editor.org/info/rfc2475>. <https://www.rfc-editor.org/info/rfc2475>.
[RFC5578] Berry, B., Ed., Ratliff, S., Paradise, E., Kaiser, T., and
M. Adams, "PPP over Ethernet (PPPoE) Extensions for Credit
Flow and Link Metrics", RFC 5578, DOI 10.17487/RFC5578,
February 2010, <https://www.rfc-editor.org/info/rfc5578>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
Appendix A. Acknowledgments Appendix A. Acknowledgments
The sub data item format was inspired by Rick Taylor's "Data Item The sub data item format was inspired by Rick Taylor's "Data Item
Containers" idea. Containers" idea.
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