LSR Shaofu. Peng
Internet-Draft ZTE
Intended status: Standards Track 24 December 2024
Expires: 27 June 2025
IGP Extensions for Deterministic Traffic Engineering
draft-peng-lsr-deterministic-traffic-engineering-03
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
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provisions of BCP 78 and BCP 79.
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Deterministic Forwarding Resources . . . . . . . . . . . . . 4
4. ISIS Advertisement of Link Scheduling Capability . . . . . . 6
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 . . . . 11
8. ISIS Advertisement of DetNet Unreserved Burst . . . . . . . . 13
9. OSPF Advertisement of Link Deterministic Resource . . . . . . 14
10. Announcement Suppression . . . . . . . . . . . . . . . . . . 14
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
12. Security Considerations . . . . . . . . . . . . . . . . . . . 14
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
14.1. Normative References . . . . . . . . . . . . . . . . . . 15
14.2. Informative References . . . . . . . . . . . . . . . . . 16
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17
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.
The IEEE 802.1 WG has specified a set of queuing, shaping, and
scheduling algorithms that are mainly used for L2 networks, such as
ATS [IEEE802.1Qcr], CBS [IEEE802.1Qav], and CQF/ECQF [IEEE802.1Qch]
[IEEE802.1Qdv]. There are some challenges in applying these
mechanisms to IP/MPLS network, mainly due to the cost of per flow
state, or limited service scale. There are also some enhanced data
plane (EDP) queueing mechanisms under discussion in DetNet working
group 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]. According to [Net-Calculus], queueing
mechanisms may be roughly classified into two categories: rate based,
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and delay based. For example, ATS, CBS, C-SCORE, and gLBF are rate
based mechanisms, while CQF/ECQF, EDF, and TQF are delay based
mechanisms. It can also be classified from other dimensions, such as
work-conserving or non work-conserving. One mechanism may correspond
to multiple categories simultaneously.
The latency bound provided by rate based mechanisms is generally
inversely proportional to the service rate of the flow or flow
aggregate, and overestimated. While the latency bound provided by
delay based mechanisms is related to the time resources consumed by
the flow by accurately planning the scheduling orders (e.g., slot,
deadline), and is an accurate preset value.
In order to provide DetNet QoS, queueing mechanisms not only specify
scheduling techniques on the data plane, but also quantify forwarding
resources to provide a foundation for admission control of service
flows. Generally, the successful operation of a DetNet queueing
mechanism relies on admission control of the data volume and data
rate allowed to be released into the network, and avoiding burst
accumulation at intermediate nodes. The deterministic forwarding
resources will be designed around two factors: data volume and data
rate. Note that in L4S architecture [RFC9330], the endpoint of
transport layer also dynamically control these two factors in
response to network congestion indications to get low latency target,
however, it rely on heuristics that can either undershoot or
overshoot the bottleneck bandwidth, and latency bound cannot be
guaranteed.
This document describes IGP extensions to advertise forwarding
resources related with deterministic queueing mechanisms in the
network, which may be used for the deterministic traffic engineering
path computation.
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. Deterministic Forwarding 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) mechanism may support 8 traffic classes and each
has the Maximum Reservable Bandwidth resource. It is known that SP
faces challenges in providing DetNet QoS. For any queueing mechanism
that can guarantee DetNet QoS, it is similar to support multiple
instances, especially the deterministic forwarding resources involved
can be summarized into two types:
* Bandwidth: refers to the share of link capacity allocated by an
instance. In some contexts, bandwidth is also replaced by terms
such as service rate or data rate.
* Burst: refers to the data volume that an instance is allowed to
send during a busy period of scheduling.
For ATS, CBS, or 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 latency for that
instance.
For C-SCORE, 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 latency for each flow is
only determined by flow's service rate and burst size.
For CQF/ECQF, 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.
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For EDF, 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, 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 timeslot length, as well as the mapping
relationship between the incoming and outgoing timeslots.
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. The utilized resources are equal to the
maximum resources minus the unused resources.
The rate based queueing mechanisms can always use MRBan and MRBur to
calculate latency bound, as long as the reserved bandwidth and burst
resources consumed by admitted flows do not exceed MRBan and MRBur,
respectively. Alternatively, it may also use the utilized bandwidth
and bursts to calculate latency bound, which however will change with
the dynamic admission and release of flows.
EDF mechanism can always use MRBan and MRBur to check the
schedulability condition, as long as the reserved bandwidth and burst
resources consumed by admitted flows do not exceed MRBan and MRBur,
respectively. Alternatively, whenever a new flow is admitted, it
uses the utilized bandwidth and bursts to check the schedulability
condition.
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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.
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 by the DetNet Scheduling Capability Sub-TLV.
1: ATS [IEEE802.1Qcr].
2: CBS [IEEE802.1Qav].
3: ATS+CBS [ATSplusCBS].
4: CQF/ECQF [IEEE802.1Qch] [IEEE802.1Qdv].
5: EDF [I-D.peng-detnet-deadline-based-forwarding].
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6: TQF [I-D.peng-detnet-packet-timeslot-mechanism].
7: C-SCORE [I-D.joung-detnet-stateless-fair-queuing].
8: gLBF [I-D.eckert-detnet-glbf].
9~255: 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. Support if set, otherwise
not support. In-time scheduling mode can be understood as
sending the packet as soon as possible before its bounded
latency per-hop.
O (On-time mode): indicates whether the scheduling mechanism
supports on-time scheduling mode. Support if set, otherwise
not support. On-time scheduling mode can be understood as
sending the packet as close as possible to its bounded latency
per-hop.
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, CBS, ATS+CBS, or 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 CQF/ECQF, the field size is n*2 bytes, and it contains
n cycle durations, each with 2 bytes, in unit of microseconds.
For example, the cycle duration may be 10 us, or 20 us, and so
on. Different cycle durations represent different CQF
instances.
- If ST is EDF, the field size is 6 bytes, and it contains the
minimum delay level (2 bytes, in unit of microseconds), maximum
delay level (2 bytes, in unit of microseconds), and delay level
interval (2 bytes, in unit of microseconds) 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, the field size is n*8 bytes, and it contains n
TQF instances, each with 8 bytes. These 8 bytes specifically
include the Orchestration Period Length (4 bytes, in unit of
microseconds), the amount of timeslots N (2 bytes) within the
Orchestration Period, and the amount of timeslots M (2 bytes)
within the Scheduling Period. The timeslot length can be
deduced by Orchestration Period Length / N. For example, the
Orchestration Period Length may be 1000 us, containing 100
timeslots, and the Scheduling Period may contain fewer
timeslots, such as 10.
- If ST is C-SCORE, 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:
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
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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, CBS, ATS+CBS, or 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 CQF/ECQF, 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, 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.
- If ST is TQF, 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, 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 link capacity.
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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:
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, CBS, ATS+CBS, or 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.
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- If ST is CQF/ECQF, 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, 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, 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, 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.
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:
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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, CBS, ATS+CBS, or 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.
- If ST is CQF/ECQF, 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 (or bin) under
that instance (e.g., a CQF instance may configure 3-bin mode,
with bin a, b, c).
- If ST is EDF, 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, 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 within the Orchestration Period, and in general all
timeslots have the same MRBur value.
- If ST is C-SCORE, 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.
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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:
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, CBS, ATS+CBS, or 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 CQF/ECQF, 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 (or bin) under
that instance (e.g., a CQF instance may configure 3-bin mode,
with bin a, b, c).
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- If ST is EDF, 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.
- If ST is TQF, 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 within the
Orchestration Period.
- If ST is C-SCORE, 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
[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>.
[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>.
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[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>.
[RFC9330] Briscoe, B., Ed., De Schepper, K., Bagnulo, M., and G.
White, "Low Latency, Low Loss, and Scalable Throughput
(L4S) Internet Service: Architecture", RFC 9330,
DOI 10.17487/RFC9330, January 2023,
<https://www.rfc-editor.org/info/rfc9330>.
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>.
[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-03, 5 July 2024,
<https://datatracker.ietf.org/doc/html/draft-eckert-
detnet-glbf-03>.
[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-03, 2 July 2024,
<https://datatracker.ietf.org/doc/html/draft-joung-detnet-
stateless-fair-queuing-03>.
[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-13, 19 November 2024,
<https://datatracker.ietf.org/doc/html/draft-peng-detnet-
deadline-based-forwarding-13>.
[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
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in Progress, Internet-Draft, draft-peng-detnet-packet-
timeslot-mechanism-10, 27 November 2024,
<https://datatracker.ietf.org/doc/html/draft-peng-detnet-
packet-timeslot-mechanism-10>.
[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/>.
[Net-Calculus]
"Network Calculus: A Theory of Deterministic Queuing
Systems for the Internet", 2001,
<https://leboudec.github.io/netcal/latex/netCalBook.pdf>.
Author's Address
Shaofu Peng
ZTE
China
Email: peng.shaofu@zte.com.cn
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