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.




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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
   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.









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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.

   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.




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   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




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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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