BGP Flow Specification Extensions for Scheduling
draft-zzd-idr-flowspec-scheduling-02
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Li Zhang , Tianran Zhou , Zhenqiang Li , Jie Dong | ||
| Last updated | 2024-11-03 | ||
| Replaces | draft-zzd-idr-flowspec-path-scheduling | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
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| Send notices to | (None) |
draft-zzd-idr-flowspec-scheduling-02
IDR L. Zhang, Ed.
Internet-Draft T. Zhou
Intended status: Standards Track Huawei
Expires: 7 May 2025 Z. Li
China Mobile
J. Dong
Huawei
3 November 2024
BGP Flow Specification Extensions for Scheduling
draft-zzd-idr-flowspec-scheduling-02
Abstract
BGP Flow Specification allows conveying flow specifications and
traffic Action/Rules associated to perform different actions based on
the traffic features. One of the applications is to steer one
specific flow into its specific path. However, in some scenarios,
the traffic forwarding paths are not constant and change over time.
This document extends BGP Flow Specification with scheduling time
information to identify the packets arrived at different time slot.
Based on that, the headend can perform different actions at different
time for the same traffic.
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
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and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 7 May 2025.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Scheduling Time Information in FlowSpecv1 . . . . . . . . . . 3
4. Scheduling time information in FlowSpecv2 . . . . . . . . . . 3
5. Scheduling Time Information . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
[RFC8955] and [RFC8956] define the BGP [RFC4271] Flow Specification
(FlowSpec) that allows conveying flow specifications and traffic
Action/Rules associated. BGP Flow specifications are encoded within
the MP_REACH_NLRI and MP_UNREACH_NLRI attributes [RFC4760]. Rules
(Actions associated) are encoded in Extended Community attribute
[RFC4360].
The existing traffic filter rules and actions in FlowSpec are always
effective and will steer specific traffic into one path once been
delivered to the headend. However, there are many scenarios that
need to schedule routing paths in the network.
[RFC9657] introduces a set of use cases where the topology of the
network changes predictably. The topology change may cause some of
the paths invalid, and lead to path reselection or even
recalculation. However, the reselection or recalculation takes a
period of time, which will affect packet forwarding and cause
problems such as packet disorder and packet loss. However, on a
network with predictable topology changes, the ingress node knows
future topology changes, it can schedule the forwarding paths in
advance, and steer flows to different set of paths based on time to
prevent packet forwarding from being affected by topology changes.
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This document extends BGP Flow Specification with scheduling time
information to identify the packets arrived at different time slot.
Based on that, the headend can perform different actions at different
time for the same traffic.
1.1. 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.
2. Motivation
[RFC9657] introduces the time variant network use cases, the tidal
network is one of the typical time variant network scenarios. In the
tidal network, the traffic volume varies greatly at different time.
In order to reduce the power consumption, some of the links and nodes
may be shut down when the traffic is at a low level.
In this scenario, the controller can generate a FlowSpec with
scheduling time rule to identify the packets arriving time and
corresponding paths. The headend doesn't need to wait for the
advertisement of topology change and just steer traffic in to
different paths based on the flowSpec with scheduling time
information, the affection of topology change is minimized.
3. Scheduling Time Information in FlowSpecv1
[RFC8955] defines 12 Components to identify different traffics.
Based on [RFC8955], this document defines a new Component to identify
the arrival time of packets and perform different actions.
Encoding: <type (1 octet, TBD1), length (1 octet), scheduling time
information (variable)+>
Defines the time information that matches the arrival time of
packets. This component matches if the arrival time of an IP packet
in the scope of scheduling time information.
4. Scheduling time information in FlowSpecv2
[I-D.ietf-idr-flowspec-v2] specifies BGP flow specification v2(FSv2)
to address the issues detected during the deployment of BGP flow
specification v1. It defines that the traffic filters are described
in the format of sub-TLV and different traffic type have different
filter sub-TLVs.
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For the IP and VPN IP filters, FSv2 reused the components defined in
[RFC8955], [RFC8956], and [I-D.ietf-idr-flowspec-srv6]. Therefore,
the new component defined for FlowSpecv1 in Section 3 is also
applicable for FlowSpecv2
For L2 Traffic, this document defines a new sub-TLV for L2 filters
defined in Section 3 of [I-D.ietf-idr-flowspec-v2] to identify the
arrival time of packets and perform different actions. The format of
Scheduling Time sub-TLV is shown as follows:
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 | Reserved |Schedule Number|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
/ Scheduling Time Information /
| |
Figure 1: Scheduling Time Sub-TLV
Type: TBD2
Length: the size of the value field in octets, variable.
Schedule Number: indicates the number of schedules.
Schedules Time information: one or more schedules, each schedule
indicates when one or more time slots.
5. Scheduling Time Information
The format of Scheduling time information sub-TLV is shown as
follows:
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Schedule-id | Priority | Reserved | Flags |P|S|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End Time (Duration) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End Time (Duration) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Frequency (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Recurrence count(Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Schedule of SR Policy
Schedule-id: 8-bit value, the unique identifier to distinguish each
schedule within a FlowSpec, this value is allocated by the FlowSpec
generator.
Priority: 8-bit value, this field is used when there are multiple
schedules valid at the same point. The higher value indicates higher
priority and the default Preference value is 10.
Flags: 8 bits, currently only 2 bits are used, the other bits are
reserved.
P (Period format): one-bit flag to indicate the format of a period.
if P=1, then the period is described by a start time filed and an end
time field; If P =0, then the period is described by a start time
field and a duration time field.
S (Schedule type): one-bit flag to indicate the type of a schedule.
If S=0, it indicates the schedule only has one instance, the
Frequency and Recurrence count field should not be included in the
sub-TLV; If S=1, it indicates the schedule has multiple instances,
the Frequency and Recurrence count field should be included.
Start Time: 64-bit value, the number of seconds since the epoch, it
indicates when the FlowSpec start to take effect.
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End Time (Duration): 64-bit value, if the flag P=1, then it is the
number of seconds since the epoch, it indicates when the FlowSpec
becomes ineffective. If the flag P=0, then it is the number of
seconds since the Start Time, it indicates how long the FlowSpec take
effect.
Frequency(optional): 32-bit value, it is the numbers of seconds since
the Start Time of an instance to the Start Time of next instance.
This field indicates the recurrence frequency for all the instance of
this schedule. This field should not be included if S=0.
Recurrence Count(optional): 32-bit value, it indicates the number of
occurrences. For example, if it is set to 2, then the schedule will
repeat twice with the specified Frequency. This field should not be
included if P=0.
6. Security Considerations
These extensions to BGP FlowSpec do not add any new security issues
to the existing protocol.
7. IANA Considerations
IANA is requested to allocate a new type value for "Scheduling Time
Information" Component in "Flow Spec Component Types" registry:
+=======+=============================+===============+
| Value | Description | Reference |
+=======+=============================+===============+
| TBD1 | Scheduling Time Information | This document |
+-------+-----------------------------+---------------+
Table 1
IANA is requested to allocate a new type value for "Scheduling Time
sub-TLV" in "L2 Flow Specification Component Types"
registry[I-D.ietf-idr-flowspec-l2vpn]:
+=======+=========================+===============+
| Value | Description | Reference |
+=======+=========================+===============+
| TBD2 | Scheduling Time sub-TLV | This document |
+-------+-------------------------+---------------+
Table 2
8. References
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8.1. Normative References
[RFC8955] Loibl, C., Hares, S., Raszuk, R., McPherson, D., and M.
Bacher, "Dissemination of Flow Specification Rules",
RFC 8955, DOI 10.17487/RFC8955, December 2020,
<https://www.rfc-editor.org/info/rfc8955>.
[RFC8956] Loibl, C., Ed., Raszuk, R., Ed., and S. Hares, Ed.,
"Dissemination of Flow Specification Rules for IPv6",
RFC 8956, DOI 10.17487/RFC8956, December 2020,
<https://www.rfc-editor.org/info/rfc8956>.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007,
<https://www.rfc-editor.org/info/rfc4760>.
[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>.
8.2. Informative References
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
February 2006, <https://www.rfc-editor.org/info/rfc4360>.
[RFC9657] Birrane III, E., Kuhn, N., Qu, Y., Taylor, R., and L.
Zhang, "Time-Variant Routing (TVR) Use Cases", RFC 9657,
DOI 10.17487/RFC9657, October 2024,
<https://www.rfc-editor.org/info/rfc9657>.
[I-D.ietf-idr-flowspec-v2]
Hares, S., Eastlake, D. E., Yadlapalli, C., and S.
Maduschke, "BGP Flow Specification Version 2", Work in
Progress, Internet-Draft, draft-ietf-idr-flowspec-v2-04,
28 April 2024, <https://datatracker.ietf.org/doc/html/
draft-ietf-idr-flowspec-v2-04>.
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[I-D.ietf-idr-flowspec-srv6]
Li, Z., Chen, H., Loibl, C., Mishra, G. S., Fan, Y., Zhu,
Y., Liu, L., Liu, X., and S. Zhuang, "BGP Flow
Specification for SRv6", Work in Progress, Internet-Draft,
draft-ietf-idr-flowspec-srv6-06, 16 October 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-
flowspec-srv6-06>.
[I-D.ietf-idr-flowspec-l2vpn]
Weiguo, H., Eastlake, D. E., Litkowski, S., and S. Zhuang,
"BGP Dissemination of L2 Flow Specification Rules", Work
in Progress, Internet-Draft, draft-ietf-idr-flowspec-
l2vpn-24, 6 October 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-
flowspec-l2vpn-24>.
Authors' Addresses
Li Zhang (editor)
Huawei
Beiqing Road
Beijing
China
Email: zhangli344@huawei.com
Tianran Zhou
Huawei
Email: zhoutianran@huawei.com
Zhenqiang Li
China Mobile
Email: lizhenqiang@chinamobile.com
Jie Dong
Huawei
Email: jie.dong@huawei.com
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