Internet DRAFT - draft-li-idr-link-bandwidth-ext
draft-li-idr-link-bandwidth-ext
Network Working Group W. Li
Internet-Draft H. Wang
Intended status: Standards Track J. Dong
Expires: 6 September 2022 Huawei Technologies
5 March 2022
Extension of Link Bandwidth Extended Community
draft-li-idr-link-bandwidth-ext-01
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
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This Internet-Draft will expire on 6 September 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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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. It uses an unsigned long integer value to describe the link
bandwidth value. This is easier for operators to use and understand,
and can avoid configuration and computation errors.
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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.
A new type of IPv6 Address Specific Extended Community[RFC5701] is
added in this document. The ASN field of this attribute is set to
the AS number of the route to which the link bandwidth attribute is
added. The Link Bandwidth value field (8 bytes) is set to the link
bandwidth. The following extended contents are added:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x03 or 0x43 | Sub-Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 8 bytes Link Bandwidth value (cont.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 8 bytes Link Bandwidth value (cont.) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 4 bytes ASN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* The value of the high-order octet of the extended Type, refer to
[RFC4360], It is recommended that 0x03 and 0x43 be used.
* New Link Bandwidth, subtype is TBD. The value of the Link
Bandwidth subfield is an unsigned long integer, in bytes per
second.
The subtypes defined here can be used for both optional transitive
and non-transitive extended community attributes.
3. Deployment Considerations
The extended link bandwidth extended community attribute in this
document should not be used together with the standard link bandwidth
extended community attribute. If a route carries both the standard
link bandwidth extended community attribute and the unit link
bandwidth extended community attribute, the standard link bandwidth
extended community attribute is ignored.
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In actual deployment, if a routing policy is used to match link
bandwidth attributes, you can directly perform exact value matching.
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 bytes per second
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>.
[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>.
[RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community
Attribute", RFC 5701, DOI 10.17487/RFC5701, November 2009,
<https://www.rfc-editor.org/info/rfc5701>.
Authors' Addresses
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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
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