IGP Extensions for Deterministic Traffic Engineering
draft-peng-lsr-deterministic-traffic-engineering-02
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draft-peng-lsr-deterministic-traffic-engineering-02
LSR Shaofu. Peng
Internet-Draft ZTE
Intended status: Standards Track 24 June 2024
Expires: 26 December 2024
IGP Extensions for Deterministic Traffic Engineering
draft-peng-lsr-deterministic-traffic-engineering-02
Abstract
This document describes IGP extensions to support Traffic Engineering
(TE) of deterministic routing, by specifying new information that a
router can place in the advertisement of neighbors. This information
describes additional details regarding the state of the network that
are useful for deterministic traffic engineering path computations.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 26 December 2024.
Copyright Notice
Copyright (c) 2024 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 Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Scheduling Resources . . . . . . . . . . . . . . . . . . . . 4
4. ISIS Advertisement of Link Scheduling Capability . . . . . . 5
5. ISIS Advertisement of DetNet Maximum Reservable Bandwidth . . 8
6. ISIS Advertisement of DetNet Unreserved Bandwidth . . . . . . 10
7. ISIS Advertisement of DetNet Maximum Reservable Burst . . . . 12
8. ISIS Advertisement of DetNet Unreserved Burst . . . . . . . . 13
9. OSPF Advertisement of Link Deterministic Resource . . . . . . 15
10. Announcement Suppression . . . . . . . . . . . . . . . . . . 15
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
12. Security Considerations . . . . . . . . . . . . . . . . . . . 15
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
14.1. Normative References . . . . . . . . . . . . . . . . . . 16
14.2. Informative References . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
[RFC8655] describes the architecture of a deterministic networking
(DetNet) and defines the QoS goals of deterministic forwarding: 1)
Minimum and maximum end-to-end latency from source to destination,
timely delivery, and bounded jitter (packet delay variation); 2) A
bounded packet loss ratio under various assumptions about the
operational states of the nodes and links; 3) An upper bound on out-
of-order packet delivery.
In order to achieve these goals, DetNet use resource reservation,
explicit routing, and service protection, as well as other means. A
deterministic forwarding path is typically (but not necessarily) an
explicit route so that it does not suffer temporary interruptions
caused by the convergence of routing or bridging protocols.
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The IEEE 802.1 WG has specified a set of queuing, shaping, and
scheduling algorithms that may be used by DetNet, such as ATS
([IEEE802.1Qcr]), CBS ([IEEE802.1Qav]), CQF ([IEEE802.1Qch]), ECQF
([IEEE802.1Qdv]). There are also some enhanced data plane queueing
mechanisms under discussion in DetNet to meet large scaling
requirements, such as C-SCORE
[I-D.joung-detnet-stateless-fair-queuing], EDF
[I-D.peng-detnet-deadline-based-forwarding], TQF
[I-D.peng-detnet-packet-timeslot-mechanism], gLBF
[I-D.eckert-detnet-glbf]. These queueing mechanisms may be roughly
classified into two categories: rate based and latency based. For
example, ATS, CBS, C-SCORE, gLBF are rate based mechanisms, while
CQF, EDF, TQF are latency based mechanisms. Some mechanisms may have
mixed characteristics of these two categories.
* The delay performance provided by rate based mechanisms is
generally inversely proportional to the service rate of the flow
or traffic class, and their worst-case delay evaluation is
relatively overestimated.
* The delay performance provided by latency based mechanism is
related to the time resources occupied by the flow by accurately
planning the scheduling orders (e.g., rank, deadline), and their
worst-case delay evaluation is basically a preset precise value.
In order to provide deterministic forwarding QoS, each queueing
mechanism not only discusses the implementation on the data plane,
but also has clear requirements for resource reservation on the
control plane, involving resource types and parameters from strict
mathematical proof.
This document describes IGP extensions to advertise resource
information related with deterministic queueing mechanism in the
network, which may be used for the deterministic traffic engineering
path computations.
2. Requirements Language
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.
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3. Scheduling Resources
One or more queueing mechanisms may be enabled on the same link, each
of which may support single or multiple instances (or considered as
multiple capability levels), and each instance has dedicated
deterministic forwarding resources. For example, the traditional
Strict Priority (SP) queueing mechanism may support 8 traffic classes
and each has the Maximum Reservable Bandwidth resource. Here, we are
not concerned about the challenges that SP faces when guaranteeing
DetNet QoS. For any queueing mechanism that can guarantee DetNet
QoS, it is similar to support multiple instances, but the
deterministic forwarding resources involved can be summarized into
two types:
* Bandwidth
* Burst
For ATS ([IEEE802.1Qcr]), CBS ([IEEE802.1Qav]), gLBF
[I-D.eckert-detnet-glbf], they may support multiple instances (such
as 8 traffic classes ), and each instance has dedicated Maximum
Reservable Bandwidth (MRBan) and Maximum Reservable Burst (MRBur).
DetNet flows mapped to a certain instance will consume the resources
of that instance. The MRBan and MRBur corresponding to a certain
instance are the dominator factors for the worst-case per-hop delay
for that instance.
For C-SCORE [I-D.joung-detnet-stateless-fair-queuing], it may be
considered to support a single instance, and have Maximum Reservable
Bandwidth (MRBan) and Maximum Reservable Burst (MRBur). DetNet flows
mapped to C-SCORE will consume the resources of this instance. The
Maximum Reservable Burst resource provided by C-SCORE is actually
determined by the physical size of the used sorted-queue, which
stores all concurrent incoming bursts. However, the MRBan and MRBur
of C-SCORE are only used for admitting condition check, and the
worst-case per-hop delay for each flow is only determined by flow's
rate and burst size.
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For CQF ([IEEE802.1Qch]), ECQF ([IEEE802.1Qdv]), they may support
multiple instances each with specific cycle duration (e.g., 10us).
Each instance has dedicated Maximum Reservable Bandwidth (MRBan) and
Maximum Reservable Burst (MRBur), where MRBur = MRBan * cycle
duration. Note that MRBur represents the resources of the entire
instance, not the resources of a specific cycle under the instance
(e.g., a instance may have cycle a, b, c). DetNet flows mapped to a
certain instance will consume the resources of that instance.
However, the MRBan and MRBur of CQF/ECQF are only used for admitting
condition check, and the worst-case per-hop delay is determined by
the cycle duration.
For EDF [I-D.peng-detnet-deadline-based-forwarding], it may support
multiple instances each with specific delay level (e.g., 10us). Each
instance has dedicated Maximum Reservable Bandwidth (MRBan) and
Maximum Reservable Burst (MRBur). The MRBan and MRBur of all
instances meet the shcedulability condition. DetNet flows mapped to
a certain instance will consume the resources of that instance.
However, the MRBan and MRBur of EDF are only used for admitting
condition check, and the worst-case per-hop delay is determined by
the delay level.
For TQF [I-D.peng-detnet-packet-timeslot-mechanism], it may support
multiple instances each with specific orchestration period (e.g.,
1ms) that containing N timeslots. Each instance has dedicated
Maximum Reservable Bandwidth (MRBan) and Maximum Reservable Burst
(MRBur), where MRBur = MRBan * timeslot length. Note that MRBur
represents resources for individual timeslot, and in general all
timeslots have the same MRBur value. DetNet flows mapped to a
certain instance will consume the resources of that instance.
However, the MRBan and MRBur of TQF are only used for admitting
condition check, and the worst-case per-hop delay is determined by
the the timeslot length and forwarding timeslot mapping.
The link should also maintain the unused resources of each capability
level based on the reservation result, i.e., Unused Bandwidth and
Unused Burst. Initially, unused resources are equal to the maximum
available reservable resources, and only the maximum available
reservable resources need to be advertised by IGP if there is no
consumption of resources.
4. ISIS Advertisement of Link Scheduling Capability
A new IS-IS sub-TLV is defined: the DetNet Scheduling Capability Sub-
TLV, which is advertised within TLV-22, 222, 23, 223, 141, 25. For
each link, multiple DetNet Scheduling Capability Sub-TLVs can be
included, depending on how many scheduling mechanisms are enabled on
the link.
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The following format is defined for the DetNet Scheduling Capability
Sub-TLV:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | ST | Flags |I|O|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scheduling Capability Info (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
where:
Type: TBD.
Length: variable, depending on size of the Scheduling Capability
Info field.
ST(Scheduling Type): 1 byte, represents the type of scheduling
mechanism supported by the link, as below.
0: Reserved for default or unspecified scheduling mechanisms,
such as SP (strict priority) that is widely used in the
network. It is not recommended to explicitly advertise the
detailed capability information of default scheduling
mechanisms through the DetNet Scheduling Capability Sub-TLV.
1: ATS ([IEEE802.1Qcr]).
2: CBS ([IEEE802.1Qav]).
3: ATS+CBS ([ATSplusCBS]).
4: CQF ([IEEE802.1Qch]).
5: ECQF ([IEEE802.1Qdv]).
6: EDF ([I-D.peng-detnet-deadline-based-forwarding]).
7: TQF ([I-D.peng-detnet-packet-timeslot-mechanism]).
8: C-SCORE ([I-D.joung-detnet-stateless-fair-queuing]).
9: gLBF ([I-D.eckert-detnet-glbf]).
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10~255: To be defined in the future.
Flags: 1 byte, currently two flags are defined as below:
I (In-time mode): Indicates whether the scheduling mechanism
supports in-time scheduling mode. When this flag is set, it
indicates support, and when this flag is unset, it indicates
not support. In-time scheduling mode can be understood as
sending the packet as soon as possible before its bounded
latency.
O (On-time mode): Indicates whether the scheduling mechanism
supports on-time scheduling mode. When this flag is set, it
indicates support, and when this flag is unset, it indicates
not support. On-time scheduling mode can be understood as
sending the packet on time at its bounded latency.
Scheduling Capability Info: Includes capability level information
corresponding to the specific scheduling mechanism type with
variable size, depending on the ST.
- If ST is one of ATS ([IEEE802.1Qcr]), CBS ([IEEE802.1Qav]),
ATS+CBS ([ATSplusCBS]), gLBF ([I-D.eckert-detnet-glbf]), the
field size is 1 byte, and it contains the number (i.e., n) of
traffic classes supported by the scheduling mechanism. Let the
first traffic class be 0, the last traffic class be n-1, with
ascending priority order from traffic class 0 to traffic class
n.
- If ST is one of CQF ([IEEE802.1Qch]), ECQF ([IEEE802.1Qdv]),
the field size is n*2 bytes, and it contains n cycle durations
supported by the scheduling mechanism, with each cycle duration
accounting for 2 bytes, in unit of microseconds. For example,
the cycle duration may be 10 us, or 20 us, and so on.
- If ST is EDF ([I-D.peng-detnet-deadline-based-forwarding]), the
field size is 6 bytes, and it contains the minimum delay level
(2 bytes, with unit us), maximum delay level (2 bytes, with
unit us), and delay level interval (2 bytes, with unit us)
supported by the EDF scheduling mechanism. The number of
supported delay levels can be deduced by n = (maximum delay
level - minimum delay level) / delay level interval + 1. For
example, the minimum delay level may be 10 us, the maximum
delay level may be 100 us, and the delay level interval may be
10 us.
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- If ST is TQF ([I-D.peng-detnet-packet-timeslot-mechanism]), the
field size is n*8 bytes, and it contains n TQF instances
supported by the TQF scheduling mechanism, with each TQF
instance accounting for 8 bytes. These 8 bytes specifically
include the Orchestration Period Length (4 bytes, with unit
us), the number of time slots N (2 bytes) included in the
Orchestration Period, and the number of time slots M (2 bytes)
included in the Scheduling Period. The timeslot length can be
deduced by Orchestration Period Length / N. For example, the
Orchestration Period Length may be 1000 us, the Orchestration
Period may contain 100 timeslots, and the Scheduling Period may
contain fewer timeslots, such as 10.
- If ST is C-SCORE ([I-D.joung-detnet-stateless-fair-queuing]),
the field size is zero, and there is no need to specify
capability level information. It can be considered to support
a single unified instance.
For each scheduling mechanism enabled on the link, the DetNet
Scheduling Capability Sub-TLV SHOULD be advertised once at most. A
router receiving multiple DetNet Scheduling Capability Sub-TLVs for
the same link and same scheduling mechanism, SHOULD select the first
advertisement in the lowest-numbered LSP.
5. ISIS Advertisement of DetNet Maximum Reservable Bandwidth
A new IS-IS sub-TLV is defined: the DetNet Maximum Reservable
Bandwidth Sub-TLV, which is advertised within TLV-22, 222, 23, 223,
141, 25. For each link, multiple DetNet Maximum Reservable Bandwidth
Sub-TLVs can be included, depending on how many scheduling mechanisms
are enabled on the link.
This sub-TLV contains the maximum amount of bandwidth that can be
reserved in the link with the direction from this node to the
neighbor, for each instance of a specific scheduling mechanism. Note
that oversubscription is prohibited, so this must be less than the
bandwidth of the link.
The following format is defined for the DetNet Maximum Reservable
Bandwidth Sub-TLV:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | ST |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Reservable Bandwidth (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
where:
Type: TBD.
Length: variable, depending on size of the Maximum Reservable
Bandwidth field.
ST(Scheduling Type): 1 byte, represents the type of scheduling
mechanism supported by the link, as defined in Section 4).
Maximum Reservable Bandwidth: Includes the maximum reservable
bandwidth (MRBan) corresponding to the specific scheduling
mechanism type with variable size, depending on the ST.
- If ST is one of ATS ([IEEE802.1Qcr]), CBS ([IEEE802.1Qav]),
ATS+CBS ([ATSplusCBS]), gLBF ([I-D.eckert-detnet-glbf]), the
field size is n*4 bytes, and it contains the MRBan per traffic
class (4 bytes, in the unit of bytes per second in IEEE
floating point format), from traffic class 0 to traffic class
n-1.
- If ST is one of CQF ([IEEE802.1Qch]), ECQF ([IEEE802.1Qdv]),
the field size is n*6 bytes, and it contains n tuple <cycle
duration(2B), MRBan(4B)>, where, cycle duration in the unit of
microseconds, and MRBan in the unit of bytes per second in IEEE
floating point format.
- If ST is EDF ([I-D.peng-detnet-deadline-based-forwarding]), the
field size is n*6 bytes, and it contains n tuple <delay
level(2B), MRBan(4B)>, where, delay level in the unit of
microseconds, and MRBan in the unit of bytes per second in IEEE
floating point format. Note that all delay levels' maximum
reservable bandwidth must meet the schedulability condition
equation.
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- If ST is TQF ([I-D.peng-detnet-packet-timeslot-mechanism]), the
field size is n*8 bytes, and it contains n tuple <OPL(4B),
MRBan(4B)>, where, OPL (Orchestration Period Length) in the
unit of microseconds, and MRBan in the unit of bytes per second
in IEEE floating point format.
- If ST is C-SCORE ([I-D.joung-detnet-stateless-fair-queuing]),
the field size is 4 bytes, and it contains the MRBan in the
unit of bytes per second in IEEE floating point format.
For each scheduling mechanism enabled on the link, the DetNet Maximum
Reservable Bandwidth Sub-TLV SHOULD be advertised once at most. A
router receiving multiple DetNet Maximum Reservable Bandwidth Sub-
TLVs for the same link and same scheduling mechanism, SHOULD select
the first advertisement in the lowest-numbered LSP.
Note that oversubscription is prohibited, so that the sum of MRBan of
all scheduling mechanisms must be less than the bandwidth of the
link.
6. ISIS Advertisement of DetNet Unreserved Bandwidth
A new IS-IS sub-TLV is defined: the DetNet Unreserved Bandwidth Sub-
TLV, which is advertised within TLV-22, 222, 23, 223, 141, 25. For
each link, multiple DetNet Unreserved Bandwidth Sub-TLVs can be
included, depending on how many scheduling mechanisms are enabled on
the link.
This sub-TLV contains the amount of bandwidth reservable in the link
with the direction from this node to the neighbor, for each instance
of a specific scheduling mechanism. Initially, the unreserved
bandwidth equals to the maximum reservable bandwidth.
The following format is defined for the DetNet Unreserved Bandwidth
Sub-TLV:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | ST |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unreserved Bandwidth (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3
where:
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Type: TBD.
Length: variable, depending on size of the Unreserved Bandwidth
field.
ST(Scheduling Type): 1 byte, represents the type of scheduling
mechanism supported by the link, as defined in Section 4).
Unreserved Bandwidth: Includes the unreserved bandwidth (UBan)
corresponding to the specific scheduling mechanism type with
variable size, depending on the ST.
- If ST is one of ATS ([IEEE802.1Qcr]), CBS ([IEEE802.1Qav]),
ATS+CBS ([ATSplusCBS]), gLBF ([I-D.eckert-detnet-glbf]), the
field size is n*4 bytes, and it contains the UBan per traffic
class (4 bytes, in the unit of bytes per second in IEEE
floating point format), from traffic class 0 to traffic class
n-1.
- If ST is one of CQF ([IEEE802.1Qch]), ECQF ([IEEE802.1Qdv]),
the field size is n*6 bytes, and it contains n tuple <cycle
duration(2B), UBan(4B)>, where, cycle duration in the unit of
microseconds, and UBan in the unit of bytes per second in IEEE
floating point format.
- If ST is EDF ([I-D.peng-detnet-deadline-based-forwarding]), the
field size is n*6 bytes, and it contains n tuple <delay
level(2B), UBan(4B)>, where, delay level in the unit of
microseconds, and UBan in the unit of bytes per second in IEEE
floating point format.
- If ST is TQF ([I-D.peng-detnet-packet-timeslot-mechanism]), the
field size is n*8 bytes, and it contains n tuple <OPL(4B),
UBan(4B)>, where, OPL (Orchestration Period Length) in the unit
of microseconds, and UBan in the unit of bytes per second in
IEEE floating point format.
- If ST is C-SCORE ([I-D.joung-detnet-stateless-fair-queuing]),
the field size is 4 bytes, and it contains the UBan in the unit
of bytes per second in IEEE floating point format.
For each scheduling mechanism enabled on the link, the DetNet
Unreserved Bandwidth Sub-TLV SHOULD be advertised once at most. A
router receiving multiple DetNet Unreserved Bandwidth Sub-TLVs for
the same link and same scheduling mechanism, SHOULD select the first
advertisement in the lowest-numbered LSP.
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7. ISIS Advertisement of DetNet Maximum Reservable Burst
A new IS-IS sub-TLV is defined: the DetNet Maximum Reservable Burst
Sub-TLV, which is advertised within TLV-22, 222, 23, 223, 141, 25.
For each link, multiple DetNet Maximum Reservable Burst Sub-TLVs can
be included, depending on how many scheduling mechanisms are enabled
on the link.
The following format is defined for the DetNet Maximum Reservable
Burst Sub-TLV:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | ST |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Reservable Burst (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4
where:
Type: TBD.
Length: variable, depending on size of the Maximum Reservable
Burst field.
ST(Scheduling Type): 1 byte, represents the type of scheduling
mechanism supported by the link, as defined in Section 4).
Maximum Reservable Burst: Includes the maximum reservable burst
(MRBur) corresponding to the specific scheduling mechanism type
with variable size, depending on the ST.
- If ST is one of ATS ([IEEE802.1Qcr]), CBS ([IEEE802.1Qav]),
ATS+CBS ([ATSplusCBS]), gLBF ([I-D.eckert-detnet-glbf]), the
field size is n*4 bytes, and it contains the MRBur per traffic
class (4 bytes, in the unit of bytes), from traffic class 0 to
traffic class n-1.
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- If ST is one of CQF ([IEEE802.1Qch]), ECQF ([IEEE802.1Qdv]),
the field size is n*6 bytes, and it contains n tuple <cycle
duration(2B), MRBur(4B)>, where, cycle duration in the unit of
microseconds, and MRBur in the unit of bytes. Note that MRBur
represents the resources of the entire CQF instance, not the
resources of a specific cycle under the instance (e.g., a
instance may have cycle a, b, c).
- If ST is EDF ([I-D.peng-detnet-deadline-based-forwarding]), the
field size is n*6 bytes, and it contains n tuple <delay
level(2B), MRBur(4B)>, where, delay level in the unit of
microseconds, and MRBur in the unit of bytes. Note that all
delay levels' maximum reservable burst must meet the
schedulability condition equation.
- If ST is TQF ([I-D.peng-detnet-packet-timeslot-mechanism]), the
field size is n*8 bytes, and it contains n tuple <OPL(4B),
MRBur(4B)>, where, OPL (Orchestration Period Length) in the
unit of microseconds, and MRBur in the unit of bytes. Note
that MRBur represents resources for individual timeslot, and in
general all timeslots have the same MRBur value.
- If ST is C-SCORE ([I-D.joung-detnet-stateless-fair-queuing]),
the field size is 4 bytes, and it contains the MRBur in the
unit of bytes.
For each scheduling mechanism enabled on the link, the DetNet Maximum
Reservable Burst Sub-TLV SHOULD be advertised once at most. A router
receiving multiple DetNet Maximum Reservable Burst Sub-TLVs for the
same link and same scheduling mechanism, SHOULD select the first
advertisement in the lowest-numbered LSP.
8. ISIS Advertisement of DetNet Unreserved Burst
A new IS-IS sub-TLV is defined: the DetNet Unreserved Burst Sub-TLV,
which is advertised within TLV-22, 222, 23, 223, 141, 25. For each
link, multiple DetNet Unreserved Burst Sub-TLVs can be included,
depending on how many scheduling mechanisms are enabled on the link.
The following format is defined for the DetNet Unreserved Burst Sub-
TLV:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | ST |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unreserved Burst (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5
where:
Type: TBD.
Length: variable, depending on size of the Unreserved Burst field.
ST(Scheduling Type): 1 byte, represents the type of scheduling
mechanism supported by the link, as defined in Section 4).
Unreserved Burst: Includes the unreserved burst (UBur)
corresponding to the specific scheduling mechanism type with
variable size, depending on the ST.
- If ST is one of ATS ([IEEE802.1Qcr]), CBS ([IEEE802.1Qav]),
ATS+CBS ([ATSplusCBS]), gLBF ([I-D.eckert-detnet-glbf]), the
field size is n*4 bytes, and it contains the UBur per traffic
class (4 bytes, in the unit of bytes), from traffic class 0 to
traffic class n-1.
- If ST is one of CQF ([IEEE802.1Qch]), ECQF ([IEEE802.1Qdv]),
the field size is n*6 bytes, and it contains n tuple <cycle
duration(2B), UBur(4B)>, where, cycle duration in the unit of
microseconds, and UBur in the unit of bytes. Note that UBur
represents the resources of the entire CQF instance, not the
resources of a specific cycle under the instance (e.g., a
instance may have cycle a, b, c).
- If ST is EDF ([I-D.peng-detnet-deadline-based-forwarding]), the
field size is n*6 bytes, and it contains n tuple <delay
level(2B), UBur(4B)>, where, delay level in the unit of
microseconds, and UBur in the unit of bytes.
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- If ST is TQF ([I-D.peng-detnet-packet-timeslot-mechanism]), the
field size is 4+k*6 bytes, and it contains OPL(4B) and k (k <=
N) tuple <timeslot id(2B), UBur(4B)>, where, OPL (Orchestration
Period Length) in the unit of microseconds, and UBur in the
unit of bytes. Note that UBur represents resources for
individual timeslot.
- If ST is C-SCORE ([I-D.joung-detnet-stateless-fair-queuing]),
the field size is 4 bytes, and it contains the UBur in the unit
of bytes.
For each scheduling mechanism enabled on the link, the DetNet
Unreserved Burst Sub-TLV SHOULD be advertised once at most, except
that TQF may advertise multiple DetNet Unreserved Burst Sub-TLVs each
for a set of timeslots. A router receiving multiple DetNet
Unreserved Burst Sub-TLVs for the same link and same scheduling
mechanism (and same timeslot id in the case of TQF scheduling type),
SHOULD select the first advertisement in the lowest-numbered LSP.
9. OSPF Advertisement of Link Deterministic Resource
Provided in next versions.
10. Announcement Suppression
To prevent oscillations and unnecessary advertisements,
implementations MUST comply with the requirements found in sections 5
and 6 of [RFC8570] regarding announcement thresholds, filters, and
suppression.
11. IANA Considerations
TBD
12. Security Considerations
This document introduces no new security issues. Security of routing
within a domain is already addressed as part of the routing protocols
themselves. This document proposes no changes to those security
architectures.
The authentication methods described in [RFC5304] and [RFC5310] for
IS-IS, [RFC2328] and [RFC7474] for OSPFv2 and [RFC5340] and [RFC4552]
for OSPFv3 SHOULD be used to prevent attacks on the IGPs.
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13. Acknowledgements
TBD.
14. References
14.1. Normative References
[I-D.eckert-detnet-glbf]
Eckert, T. T., Clemm, A., Bryant, S., and S. Hommes,
"Deterministic Networking (DetNet) Data Plane - guaranteed
Latency Based Forwarding (gLBF) for bounded latency with
low jitter and asynchronous forwarding in Deterministic
Networks", Work in Progress, Internet-Draft, draft-eckert-
detnet-glbf-02, 5 January 2024,
<https://datatracker.ietf.org/doc/html/draft-eckert-
detnet-glbf-02>.
[I-D.joung-detnet-stateless-fair-queuing]
Joung, J., Ryoo, J., Cheung, T., Li, Y., and P. Liu,
"Latency Guarantee with Stateless Fair Queuing", Work in
Progress, Internet-Draft, draft-joung-detnet-stateless-
fair-queuing-02, 29 February 2024,
<https://datatracker.ietf.org/doc/html/draft-joung-detnet-
stateless-fair-queuing-02>.
[I-D.peng-detnet-deadline-based-forwarding]
Peng, S., Du, Z., Basu, K., cheng, Yang, D., and C. Liu,
"Deadline Based Deterministic Forwarding", Work in
Progress, Internet-Draft, draft-peng-detnet-deadline-
based-forwarding-09, 1 March 2024,
<https://datatracker.ietf.org/doc/html/draft-peng-detnet-
deadline-based-forwarding-09>.
[I-D.peng-detnet-packet-timeslot-mechanism]
Peng, S., Liu, P., Basu, K., Liu, A., Yang, D., and G.
Peng, "Timeslot Queueing and Forwarding Mechanism", Work
in Progress, Internet-Draft, draft-peng-detnet-packet-
timeslot-mechanism-06, 4 March 2024,
<https://datatracker.ietf.org/doc/html/draft-peng-detnet-
packet-timeslot-mechanism-06>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality
for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006,
<https://www.rfc-editor.org/info/rfc4552>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, DOI 10.17487/RFC5310, February
2009, <https://www.rfc-editor.org/info/rfc5310>.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008,
<https://www.rfc-editor.org/info/rfc5340>.
[RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed.,
"Security Extension for OSPFv2 When Using Manual Key
Management", RFC 7474, DOI 10.17487/RFC7474, April 2015,
<https://www.rfc-editor.org/info/rfc7474>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March
2019, <https://www.rfc-editor.org/info/rfc8570>.
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>.
14.2. Informative References
[ATSplusCBS]
"Latency and Backlog Bounds in Time-Sensitive Networking
with Credit Based Shapers and Asynchronous Traffic
Shaping", 2018,
<https://ieeexplore.ieee.org/document/8493026>.
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[IEEE802.1Qav]
"IEEE Standard for Local and metropolitan area networks --
Virtual Bridged Local Area Networks - Amendment 12:
Forwarding and Queuing Enhancements for Time-Sensitive
Streams", 2010,
<https://ieeexplore.ieee.org/document/8684664>.
[IEEE802.1Qch]
"IEEE Standard for Local and metropolitan area networks --
Bridges and Bridged Networks - Amendment 29: Cyclic
Queuing and Forwarding", 2017,
<https://ieeexplore.ieee.org/document/7961303>.
[IEEE802.1Qcr]
"IEEE Standard for Local and Metropolitan Area Networks--
Bridges and Bridged Networks Amendment 34:Asynchronous
Traffic Shaping", 2020,
<https://ieeexplore.ieee.org/document/9253013>.
[IEEE802.1Qdv]
"Draft Standard for Local and metropolitan area networks--
Enhancements to Cyclic Queuing and Forwarding", 2023,
<https://1.ieee802.org/tsn/802-1qdv/>.
Author's Address
Shaofu Peng
ZTE
China
Email: peng.shaofu@zte.com.cn
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