Distribution of Service Metadata in BGP FlowSpec
draft-yi-idr-bgp-fs-edge-service-metadata-04
This document is an Internet-Draft (I-D).
Anyone may submit an I-D to the IETF.
This I-D is not endorsed by the IETF and has no formal standing in the
IETF standards process.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Xinxin Yi , Tao He , Cheng Li , Hang Shi , Xiangfeng Ding , Haibo Wang , Zicheng Wang | ||
| Last updated | 2025-05-15 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Additional resources |
Github Repo
|
||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-yi-idr-bgp-fs-edge-service-metadata-04
Inter-Domain Routing X. Yi, Ed.
Internet-Draft T. He, Ed.
Intended status: Standards Track China Unicom
Expires: 16 November 2025 C. Li, Ed.
H. Shi
X. Ding
H. Wang
Huawei Technologies
Z. Wang
Inspur
15 May 2025
Distribution of Service Metadata in BGP FlowSpec
draft-yi-idr-bgp-fs-edge-service-metadata-04
Abstract
In edge computing, a service may be deployed on multiple instances
within one or more sites, called edge service. The edge service is
associated with an ANYCAST IP address. Its routes along with service
metadata can be collected by a central controller. The controller
may process the metadata and distribute the result to ingress routers
using BGP FlowSpec. The service metadata can be used by ingress
routers to make path selections not only based on the routing cost
but also on the running environment of the edge services. This
document describes a mechanism to distribute the information of the
service routes and related service metadata using BGP FlowSpec.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the Inter-Domain Routing
Working Group mailing list (idr@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/idr/.
Source for this draft and an issue tracker can be found at
https://github.com/VMatrix1900/draft-bgp-fs-edge-service-metadata.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Yi, et al. Expires 16 November 2025 [Page 1]
Internet-Draft Service Metadata in BGP FlowSpec May 2025
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
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 16 November 2025.
Copyright Notice
Copyright (c) 2025 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. BGP FlowSpec Extension for Service Metadata . . . . . . . . . 3
2.1. Metadata Path Attribute TLV . . . . . . . . . . . . . . . 4
2.2. Aggregated Metric Path Attribute TLV . . . . . . . . . . 4
3. Security Considerations . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Many modern services deploy their service instances in multiple sites
to get better response time and resource utilization. These sites
are often geographically distributed to serve the user demand. For
some services such as VR/AR and intelligent transportation, the QoE
will depend on both the network metrics and the compute metrics. For
example, if the nearest site is overloaded due to the demand
fluctuation, then steering the user traffic to another light-loaded
Yi, et al. Expires 16 November 2025 [Page 2]
Internet-Draft Service Metadata in BGP FlowSpec May 2025
site may improve the QoE. To steer the traffic to the best site, the
computing metadata of the site needs to be collected.
[I-D.ietf-idr-5g-edge-service-metadata] describes the BGP extension
of distributing service routes with network and computing-related
metrics. The router connected to the site will receive the service
routes and service metadata sent from devices inside the edge site,
and then generate the corresponding routes and distribute them to
ingress routers. However, the route with service metadata on the
router connected to the site can be also collected by a central
controller using BGP LS. Then the central controller may process the
metadata and distribute the result to the ingress router using BGP
FlowSpec.
This document defines an extension of BGP FlowSpec to carry the
service metadata along with the service route which is received from
the controller. Using the service metadata and the service route,
the ingress router can calculate the best site for the traffic,
giving each user the best QoE.
1.1. Terminology
1.2. 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.
2. BGP FlowSpec Extension for Service Metadata
The goal of the BGP FlowSpec extension is to distribute the
information of the service route and metadata. A service is
identified by a prefix and this information is carried using the
existing Destination Prefix Component specified in [RFC8955] and
[RFC8956]. [I-D.ietf-idr-ts-flowspec-srv6-policy] defines that the
Color Extended Community and BGP Prefix-SID attribute is carried in
the context of the FlowSpec NLRI.
In addition to that, this document proposes to carry the service
metadata attribute(See Figure 1). The ingress router can compare the
compute metric of different sites and steer the traffic into the best
one using the SR policy. The metadata can be original values defined
in [I-D.ietf-idr-5g-edge-service-metadata] or an aggregated one
calculated using original values.
Yi, et al. Expires 16 November 2025 [Page 3]
Internet-Draft Service Metadata in BGP FlowSpec May 2025
+------------+
| BGP FS |
| Controller |
+------------+
| FlowSpec route to Ingress:
| NLRI: Destination Prefix
| Redirect to IPv6 Nexthop: Egress's Address
| Policy Color: C1
| PrefixSID: End.X1
| Service Metadata: Compute metric
| .-----.
| ( )
V .--( )--.
+-------+ ( ) +------+ +---------+
| |_( SRv6 Core Network )_| | (End.X1) | |
|Ingress| ( ================> ) |Egress|----------| Site |
+-------+ (SR List<S1,S2,S3>) +------+ +---------+
'--( )--'
( )
'-----'
Figure 1: Example of using BGP FlowSpec to distribute the service
route and metadata
2.1. Metadata Path Attribute TLV
The Metadata Path Attribute TLV is the same as defined in
[I-D.ietf-idr-5g-edge-service-metadata], including the following
three sub-TLVs:
1. Site Preference Index sub-TLV indicates the preference to choose
the site.
2. Capacity Index sub-TLV indicates the capability of a site. One
Edge Site can be at full capacity, reduced capacity, or
completely out of service.
3. Load Measurement sub-TLV indicates the load level of the site.
2.2. Aggregated Metric Path Attribute TLV
The Aggregated Metric Path Attribute is a newly defined TLV(See
Figure 2). It contains a single aggregated value which is calculated
by the controller using the original metrics such as site preference,
capacity, and load measurement.
Yi, et al. Expires 16 November 2025 [Page 4]
Internet-Draft Service Metadata in BGP FlowSpec May 2025
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Aggregated Metadata Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Aggregated Metric Value (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Aggregated Metric Path Attribute TLV format
* Type: identify the Aggregated Metadata Attribute, to be assigned
by IANA.
* Length: the total number of the octets of the value field.
* Value: the value of Aggregated Computing metric.
3. Security Considerations
TBD
4. IANA Considerations
This document requires IANA to assign the following code points from
the registry called "BGP Path Attributes":
+=======+==========================+=============+
| Value | Description | Reference |
+=======+==========================+=============+
| TBD1 | Aggregated Metadata Type | Section 2.2 |
+-------+--------------------------+-------------+
Table 1
5. 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>.
Yi, et al. Expires 16 November 2025 [Page 5]
Internet-Draft Service Metadata in BGP FlowSpec May 2025
[I-D.ietf-idr-5g-edge-service-metadata]
Dunbar, L., Majumdar, K., Li, C., Mishra, G. S., and Z.
Du, "BGP Extension for 5G Edge Service Metadata", Work in
Progress, Internet-Draft, draft-ietf-idr-5g-edge-service-
metadata-29, 28 April 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-5g-
edge-service-metadata-29>.
[I-D.ietf-idr-ts-flowspec-srv6-policy]
Wenying, J., Liu, Y., Zhuang, S., Mishra, G. S., and S.
Chen, "Traffic Steering using BGP FlowSpec with SR
Policy", Work in Progress, Internet-Draft, draft-ietf-idr-
ts-flowspec-srv6-policy-05, 6 January 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-idr-ts-
flowspec-srv6-policy-05>.
[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>.
Authors' Addresses
Xinxin Yi (editor)
China Unicom
Beijing
China
Email: yixx3@chinaunicom.cn
Tao He (editor)
China Unicom
Beijing
China
Email: het21@chinaunicom.cn
Cheng Li (editor)
Huawei Technologies
China
Email: c.l@huawei.com
Yi, et al. Expires 16 November 2025 [Page 6]
Internet-Draft Service Metadata in BGP FlowSpec May 2025
Hang Shi
Huawei Technologies
Beijing
China
Email: shihang9@huawei.com
Xiangfeng Ding
Huawei Technologies
Beijing
China
Email: dingxiangfeng@huawei.com
Haibo Wang
Huawei Technologies
Beijing
China
Email: rainsword.wang@huawei.com
Zicheng Wang
Inspur
Beijing
China
Email: wangzicheng01@inspur.com
Yi, et al. Expires 16 November 2025 [Page 7]