Internet DRAFT - draft-xiong-lsr-detnet-deterministic-links
draft-xiong-lsr-detnet-deterministic-links
LSR Q. Xiong
Internet-Draft X. Qian
Intended status: Standards Track ZTE Corporation
Expires: 25 April 2024 23 October 2023
IGP Extensions for DetNet Deterministic Links
draft-xiong-lsr-detnet-deterministic-links-00
Abstract
This document proposes the deterministic links to provide a one-
dimensional deterministic metric to guarantee the deterministic
forwarding capabilities at different levels and proposes the
deterministic links distribution by IGP extensions.
Status of This Memo
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This Internet-Draft will expire on 25 April 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Deterministic Links . . . . . . . . . . . . . . . . . . . . . 3
3.1. Deterministic Links Model . . . . . . . . . . . . . . . . 3
3.2. Classfication of deterministic Links . . . . . . . . . . 4
3.3. Deterministic Links Resources . . . . . . . . . . . . . . 5
4. ISIS Extensions of Deterministic Links . . . . . . . . . . . 5
4.1. Deterministic Link Sub-TLV . . . . . . . . . . . . . . . 5
4.1.1. Deterministic Link Maximum Reservble Bandwidth
Sub-sub-TLV . . . . . . . . . . . . . . . . . . . . . 6
4.1.2. Deterministic Link Available Bandwidth Sub-sub-TLV . 7
4.1.3. Deterministic Link Delay Sub-sub-TLV . . . . . . . . 7
5. OSPF Extensions of Deterministic Links . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
According to [RFC8655], Deterministic Networking (DetNet) operates at
the IP layer and delivers service which provides extremely low data
loss rates and bounded latency within a network domain. The bounded
latency indicates the minimum and maximum end-to-end latency from
source to destination and bounded jitter (packet delay variation).
[I-D.ietf-detnet-scaling-requirements]has described the enhanced
requirements for DetNet enhanced data plane including the
deterministic latency guarantees.
[I-D.xiong-detnet-large-scale-enhancements] has proposed the packet
treatment which should support new functions such as queuing
mechanisms to ensure the deterministic latency. As per
[I-D.ietf-detnet-controller-plane-framework], network nodes collects
topology information and DetNet capabilities through IGP.
The computing method of end-to-end delay bounds is defined in
[RFC9320]. It is the sum of the six delays in DetNet bounded latency
model. It is the sum of non-queuing delay bound and queuing delay
bound in DetNet bounded latency model. The upper bounds of queuing
delay depends on the queuing mechanisms deployed along the path. For
example, a link with a queuing mechanism that does not guarantee a
bounded delay a non-determinisitc link and a link with a queuing
mechanism that can provide deterministic delay is called a
deterministic link. The delay of a a deterministic link is consist
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of the propagation delay of the packet on the link and the queuing
delay of the packet at the node. A deterministic link can be a sub-
network that provides deterministic transmission or a Point-to-Point
(P2P) link.
This document proposes the deterministic links to provide a one-
dimensional deterministic metric to guarantee the deterministic
forwarding capabilities at different levels and proposes the
deterministic links distribution by IGP extensions.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Terminology
The terminology is defined as [RFC8655] and [RFC9320].
3. Deterministic Links
This document proposes the deterministic links to provide a one-
dimensional deterministic metric to guarantee the deterministic
forwarding capabilities at different levels. The deterministic links
can shield the differences from underlying forwarding and queuing
mechanisms.
3.1. Deterministic Links Model
As per [RFC9320], six types of delays are defined in timing Model of
DetNet. And the DetNet domain can also be modeling as deterministic
links and nodes as shown in Figure 1. The deterministic node delay
is constant while the deterministic link delay is variable within
bounded latency. The end-to-end bounded latency depends on the sum
of the deterministic link delay.
* Deterministic Link Delay = Regulation delay + Queuing subsystem
delay + Output delay + Link delay + Frame preemption delay
* Deterministic Node Delay = Processing delay
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DetNet transit node A DetNet transit node B
+-------------------------+ +------------------------+
| Queuing | | Queuing |
| Regulator subsystem | | Regulator subsystem |
| +-+-+-+-+ +-+-+-+-+ | | +-+-+-+-+ +-+-+-+-+ |
-->+ | | | | | | | | | + +------------>+ | | | | | | | | | + +--->
| +-+-+-+-+ +-+-+-+-+ | | +-+-+-+-+ +-+-+-+-+ |
| | | |
+-------------------------+ +------------------------+
|-->|------->|------->|-->|------------>|-->|------->|------>|-->|-->|
2,3 4 5 6 1 2,3 4 5 6 1 2,3
|---- Deterministic Link Delay ---->|
Deterministic Links Deterministic Node
| A |---------------------------------->| B |----------------------->|
Figure 1: Deterministic Links Model
3.2. Classfication of deterministic Links
There are a number of deterministic links between deterministic
nodes. And each deterministic link provides different level of
deterministic forwarding capabilities indicated by Deterministic
Class-Type (DT).
Deterministic Class-Type (DT): indicate the set of Traffic Trunks
crossing a deterministic link that is governed by a specific set of
bounded latency constraints. DT is used for the purposes of
deterministic link resource planning, reservation and allocation,
deterministic link resource constraint-based routing and admission
control. A given Traffic Trunk belongs to the same DT on all links.
For example, three deterministic links with guaranteed jitter are
supported between the Node A and Node B as following shown.
* deterministic link 1, DT=1 (Jitter Guarantee, queuing type=CSQF),
bandwidth=20Mbit/s, jitter=10us.
* deterministic link 2, DT=2 (Jitter Guarantee, queuing type=TCQF),
bandwidth=30Mbit/s, jitter=20us.
* deterministic link 3, DT=3 (Jitter Guarantee, queuing type=TQF),
bandwidth=40Mbit/s, jitter=30us.
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3.3. Deterministic Links Resources
The traditional resource reservation method only considers the
bandwidth availability of the BE (Best Effort) flow, which means that
the reserved bandwidth meets the peak information rate (PIR) of the
business flow at the macro level. As per
[I-D.ietf-detnet-scaling-requirements], the enhanced DetNet need to
support multiple queuing mechanisms to provide deterministic latency.
For such scheduling mechanisms, even the bandwidth resources meet the
transmission requirements at the macro level, there may not be enough
resources in a specific timeslot, cycle or authorization time zone,
so bounded delay and jitter cannot be guaranteed. So it is required
to provide provisioning of fine-grained reservation for time-based
resources.
Time-based Resources Container (TRC): the entity which is used for
deterministic link to provide the time-based resources with
deterministic capabilities by resolving resource conflicts between
different levels. The container indicates the maximum transmitting
bits per scheduling timeslot and it contains the corresponding
scheduling resources reserved to guarantee the capability of
deterministic link such as queuing, buffer and bandwidth.
4. ISIS Extensions of Deterministic Links
This document defines new IS-IS TE sub-TLVs to distribute the
deterministic links attributes at TE link and it can be announced in
TLVs 22, 23, 141, 222, and 223" registry.
4.1. Deterministic Link Sub-TLV
A new IS-IS Deterministic Link Sub-TLV is defined and the format is
as shown in the following figure.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DT | Link Scheduling Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sub-sub-TLV ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 2: Deterministic Link Sub-TLV
where:
* Type: Set to TBD1.
* Length: Contains the total length of the subobject in octets. The
Length MUST be at least 8 and MUST be a multiple of 4.
* DT: the value of DT to indicates the set of Traffic Trunks
crossing the deterministic linke that is governed by a specific
set of bounded latency constraints.
* Link Scheduling Type: indicates the type of the queuing or
scheduling mechanisms on this deterministic link.
* Sub-sub-TLV: indicates the optional sub-sub-TLV carried in this
sub-TLV.
4.1.1. Deterministic Link Maximum Reservble Bandwidth Sub-sub-TLV
A new IS-IS Deterministic Link Maximum Reservble Bandwidth Sub-sub-
TLV is defined and the format is as shown in the following figure.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Maximum Reserved Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Deterministic Link Maximum Reservble Bandwidth sub-sub-TLV
where:
* Type: Set to TBD2.
* Length: Contains the total length of the subobject in octets. The
Length MUST be at least 8 and MUST be a multiple of 4.
* Maximum Reserved Bandwidth: indicates the maximum reservble
bandwidth for this deterministic link.
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4.1.2. Deterministic Link Available Bandwidth Sub-sub-TLV
A new IS-IS Deterministic Link Available Bandwidth Sub-sub-TLV is
defined and the format is as shown in the following figure.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Deterministic Link Available Bandwidth sub-sub-TLV
where:
* Type: Set to TBD3.
* Length: Contains the total length of the subobject in octets. The
Length MUST be at least 8 and MUST be a multiple of 4.
* Available Bandwidth: indicates the available bandwidth of this
deterministic link.
4.1.3. Deterministic Link Delay Sub-sub-TLV
A new IS-IS Deterministic Link Delay Sub-sub-TLV is defined and the
format is as shown in the following figure.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| Reserved | Maximum Deterministic Link Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Minimum Deterministic Link Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | Maximum Deterministic Link Delay Variation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 5: Deterministic Link Delay sub-sub-TLV
where:
* Type: Set to TBD4.
* Length: Contains the total length of the subobject in octets. The
Length MUST be at least 8 and MUST be a multiple of 4.
* A: The A bit represents the Anomalous (A) bit. The A bit is set
when the measured value of this parameter exceeds its configured
maximum threshold.
* Maximum Deterministic Link Delay: indicates the maximum
deterministic link delay value (in microseconds) over a
configurable interval, encoded as an integer value.
* Minimum Deterministic Link Delay: indicates the minimum
deterministic link delay value (in microseconds) over a
configurable interval, encoded as an integer value.
* Maximum Deterministic Link Delay Variation: indicates the maximum
deterministic link delay variation value over a configurable
interval in microseconds, encoded as an integer value.
5. OSPF Extensions of Deterministic Links
TBA
6. Security Considerations
TBA
7. IANA Considerations
IANA is requested to register the following sub-TLVs in the "Sub-TLVs
for TLVs 22, 23, 141, 222,and 223" registry:
Type Description
------------------------------------
TBD1 Deterministic Link Sub-TLV
TBD2 Deterministic Link Maximum Reservble Bandwidth Sub-sub-TLV
TBD3 Deterministic Link Available Bandwidth Sub-sub-TLV
TBD4 Deterministic Link Delay Sub-sub-TLV
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8. Acknowledgements
TBA
9. References
9.1. Normative References
[I-D.ietf-detnet-controller-plane-framework]
Malis, A. G., Geng, X., Chen, M., Qin, F., Varga, B., and
C. J. Bernardos, "Deterministic Networking (DetNet)
Controller Plane Framework", Work in Progress, Internet-
Draft, draft-ietf-detnet-controller-plane-framework-05, 26
September 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-detnet-controller-plane-framework-05>.
[I-D.ietf-detnet-scaling-requirements]
Liu, P., Li, Y., Eckert, T. T., Xiong, Q., Ryoo, J.,
zhushiyin, and X. Geng, "Requirements for Scaling
Deterministic Networks", Work in Progress, Internet-Draft,
draft-ietf-detnet-scaling-requirements-04, 18 October
2023, <https://datatracker.ietf.org/doc/html/draft-ietf-
detnet-scaling-requirements-04>.
[I-D.xiong-detnet-large-scale-enhancements]
Xiong, Q., Du, Z., Zhao, J., and D. Yang, "Enhanced DetNet
Data Plane (EDP) Framework for Scaling Deterministic
Networks", Work in Progress, Internet-Draft, draft-xiong-
detnet-large-scale-enhancements-03, 10 July 2023,
<https://datatracker.ietf.org/doc/html/draft-xiong-detnet-
large-scale-enhancements-03>.
[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>.
[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>.
[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>.
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[RFC8664] Sivabalan, S., Filsfils, C., Tantsura, J., Henderickx, W.,
and J. Hardwick, "Path Computation Element Communication
Protocol (PCEP) Extensions for Segment Routing", RFC 8664,
DOI 10.17487/RFC8664, December 2019,
<https://www.rfc-editor.org/info/rfc8664>.
[RFC9320] Finn, N., Le Boudec, J.-Y., Mohammadpour, E., Zhang, J.,
and B. Varga, "Deterministic Networking (DetNet) Bounded
Latency", RFC 9320, DOI 10.17487/RFC9320, November 2022,
<https://www.rfc-editor.org/info/rfc9320>.
Authors' Addresses
Quan Xiong
ZTE Corporation
China
Email: xiong.quan@zte.com.cn
Xiaocong Qian
ZTE Corporation
China
Email: qian.xiaocong@zte.com.cn
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