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OSPF extension for priority allocation support in the PCE discovery
draft-wu-pce-discovery-priority-allocation-00

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This is an older version of an Internet-Draft whose latest revision state is "Expired".
Author Qin Wu
Last updated 2013-07-15
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draft-wu-pce-discovery-priority-allocation-00
PCE working group                                                  Q. Wu
Internet-Draft                                                    Huawei
Intended status: Standards Track                           July 15, 2013
Expires: January 16, 2014

  OSPF extension for priority allocation support in the PCE discovery
             draft-wu-pce-discovery-priority-allocation-00

Abstract

   Each network domain may contain multiple PCE servers.  It provides
   redundancy to the PCCs in the event of a server failure.  However
   load balance decision is made by PCC,it doesn't enable real load
   balance across the PCE servers if PCC still tries PCE one by one and
   PCE doesn't indicate the load status to the PCC.

   This document proposes new PCE discovery sub-TLV that can be
   announced as attribute in the OSPF advertisement (defined in [RFC5088
   ]) to distribute priority information.

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 http://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 January 16, 2014.

Copyright Notice

   Copyright (c) 2013 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
   (http://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

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   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  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Conventions used in this document . . . . . . . . . . . . . . . 4
   3.  PCE-ALLOCATION-PRIORITY Sub-TLV for PCE Load Balancing  . . . . 5
     3.1.  Use of PCE-ALLOCATION-PRIORITY sub-TLV for PCE
           discovery . . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 9

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1.  Introduction

   Usually a single PCE server sits per domain in the nework.  The PCE
   server disseminates its address in the network using OSPF [RFC5088]
   or ISIS [RFC5089] and the PCCs connect to it automatically.  However
   in some cases, each network domain may contain multiple PCE servers.
   It provides redundancy to the PCCs in the event of a server failure.

   However load balance decision is made by PCC,it doesn't enable real
   load balance across the PCE servers if PCC still tries PCE one by one
   and PCE doesn't indicate the load status to the PCC (e.g., the number
   of incoming requests that have already targeted to the PCE).

   This document proposes new PCE discovery TLV that can be announced as
   attribute in the OSPF advertisement (defined in [RFC5088 ]) to
   distribute priority information.

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2.  Conventions used in this document

   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 RFC2119 [RFC2119].

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3.  PCE-ALLOCATION-PRIORITY Sub-TLV for PCE Load Balancing

   The PCE-Allocated-Priority sub-TLV is an optional sub-TLV used to
   indicate allocated priority of each PCE.  The format of the sub-TLVs
   is identical to the TLV format used by the Traffic Engineering
   Extensions to OSPF [RFC3630].  It MAY be present within the PCED TLV.
   It MUST NOT be present more than once.  If it appears more than once,
   only the first occurrence is processed and any others MUST be
   ignored.

   The value field of the PCE-ALLOCATED-PRIORITY sub-TLV is expressed as
   32-bit unsigned integer value..

   The format of the PCE-ALLOCATED-PRIORITY sub-TLV is 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 = TBD         |            Length           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Allocated Priority                         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Type:     TBD
         Length:   4 octets
         Value:    This contains allocated priority value for each PCE
                   server. The priority value can be allocated based
                   on PCE load or incoming request to the PCE server.

3.1.  Use of PCE-ALLOCATION-PRIORITY sub-TLV for PCE discovery

   Multiple servers can be present in a single network for redundancy in
   which case each PCE server is allocated with a priority value.  The
   priority can be allocated based on PCE load (e.g., incoming request
   to the PCE server) announced as attribute in the OSPF advertisement.
   The PCC can be configured to use the highest priority PCE server that
   is available or specify the priority of a computation request when
   multiple PCEs has already been found using OSPF[RFC5088].

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4.  Security Considerations

   This document raises no new security issues beyond those described in
   [RFC5088].

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5.  IANA Considerations

   IANA maintains the registry for the TLVs.  PCE-allocated-priority
   sub-TLV will require one new type code per sub-TLV defined in this
   document.

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6.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", March 1997.

   [RFC5088]  Le Roux, JL., "OSPF Protocol Extensions for Path
              Computation Element (PCE) Discovery", RFC 5088,
              January 2008.

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Author's Address

   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: sunseawq@huawei.com

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