Network Working Group W. Li
Internet-Draft H. Wang
Intended status: Standards Track J. Dong
Expires: 27 April 2022 Huawei Technologies
24 October 2021
Extension of Link Bandwidth Extended Community
draft-li-idr-link-bandwidth-ext-00
Abstract
[I-D.ietf-idr-link-bandwidth] defines a BGP link bandwidth extended
community attribute, which can enable devices to implement unequal-
cost load-balancing. However, the bandwidth value encapsulated by
the extended community attribute is of the floating-point type, which
is inconvenient to use. In this document, a set of new types of link
bandwidth extended community are introduced to facilitate the
configuration and calculation of link bandwidth.
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].
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
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 27 April 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
Li, et al. Expires 27 April 2022 [Page 1]
Internet-Draft Abbreviated-Title October 2021
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 Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Link Bandwidth Extended Community . . . . . . . . . . . . . . 3
3. Deployment Considerations . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. References . . . . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
In [I-D.ietf-idr-link-bandwidth], the link bandwidth extended
community attribute is added to implement unequal-cost load balancing
based on the bandwidth on a path. As defined in the draft, the
bandwidth of a link is expressed in 4-octets in IEEE floating-point
format.
In practice, the use of this floating-point format may result errors
in configuration and computation. When an operator needs to manually
specify the bandwidth, you also need to consider the conversion from
the bandwidth value to the floating-point number. This mode is not
user-friendly, especially when the routing policy is used for
bandwidth matching.
This document introduce a more intuitive expression of link bandwidth
in BGP. The combination of unit type and unsigned integer value is
used to describe the link bandwidth value. This is easier for
operators to use and understand, and can avoid configuration and
computation errors.
Li, et al. Expires 27 April 2022 [Page 2]
Internet-Draft Abbreviated-Title October 2021
2. Link Bandwidth Extended Community
The type of Link Bandwidth Extended Community is 0x40, and the
subtype is 0x04. In the attribute value, the global administrator
subfield is set to the AS number of the route to which the Link
Bandwidth attribute is added. In the local administrator subfield,
the link bandwidth value [I-D.ietf-idr-link-bandwidth] is set to the
IEEE floating-point type.
This document retains the basic format of Link Bandwidth Extended
Community, uses several special subtypes to identify different
bandwidth units, and uses a combination of units and integers to
accurately represent a specific bandwidth value.
* bps Link Bandwidth, subtype is TBD. The value of bandwidth in the
Local Administrator subfield is an unsigned integer. The unit of
this type of link bandwidth is bps.
* Kbps Link Bandwidth, subtype is TBD. The value of bandwidth in
the Local Administrator subfield is an unsigned integer. The unit
of this type of link bandwidth is Kbps.
* Mbps Link Bandwidth, subtype is TBD. The value of bandwidth in
the Local Administrator subfield is an unsigned integer. The unit
of this type of link bandwidth is Mbps.
* Gbps Link Bandwidth, subtype is TBD. The value of bandwidth in
the Local Administrator subfield is an unsigned integer. The unit
of this type of link bandwidth is Gbps.
* Tbps Link Bandwidth, subtype is TBD. The value of bandwidth in
the Local Administrator subfield is an unsigned integer. The unit
of this type of link bandwidth is Tbps.
We can use different unit bandwidth values to identify the required
bandwidth.
The subtypes defined here can be used for both optional transitive
and non-transitive extended community attributes.
3. Deployment Considerations
In network deployment, a routing policy may be used to match the link
bandwidth advertised by BGP link bandwidth extended community, based
on the mechanisms of this document, the operator can specify the
bandwidth in different units as required, so that exact value
matching can be achieved.
Li, et al. Expires 27 April 2022 [Page 3]
Internet-Draft Abbreviated-Title October 2021
Bandwidths of different units may be used together. For example, an
link bandwidth extended community with the type Gbps and value 1, and
another link bandwidth extended community with the type Mbps and
value 500 may be used to represent 1.500 Gbps. However, it is
RECOMMENDED to use a single link bandwidth extended community with
the type Mbps and value 1500 Mbps to achieve the same purpose.
4. IANA Considerations
This document defines a specific application of the two-octet AS
specific extended community. IANA is requested to assign new sub-
types for both non-transitive and transitive extended communities.
SubType Description
------- -------------------------------
TBD Link Bandwidth EC in bps unit
TBD Link Bandwidth EC in Kbps unit
TBD Link Bandwidth EC in Mbps unit
TBD Link Bandwidth EC in Gbps unit
TBD Link Bandwidth EC in Tbps unit
5. Security Considerations
There are no additional security risks introduced by this design.
6. Acknowledgements
7. References
7.1. 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>.
7.2. References
[I-D.ietf-idr-link-bandwidth]
Mohapatra, P. and R. Fernando, "BGP Link Bandwidth
Extended Community", Work in Progress, Internet-Draft,
draft-ietf-idr-link-bandwidth-07, 5 March 2018,
<https://www.ietf.org/archive/id/draft-ietf-idr-link-
bandwidth-07.txt>.
Authors' Addresses
Li, et al. Expires 27 April 2022 [Page 4]
Internet-Draft Abbreviated-Title October 2021
Wenyan Li
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing
100095
China
Email: liwenyan@huawei.com
Haibo Wang
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing
100095
China
Email: rainsword.wang@huawei.com
Jie Dong
Huawei Technologies
Huawei Campus, No. 156 Beiqing Road
Beijing
100095
China
Email: jie.dong@huawei.com
Li, et al. Expires 27 April 2022 [Page 5]