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Versions: 00 01 02                                                      
Network Working Group                                              Z. Li
Internet-Draft                                                  L. Zhang
Intended status: Standards Track                     Huawei Technologies
Expires: January 4, 2015                                         G. Yang
                                                           China Telecom
                                                            July 3, 2014


        RSVP-TE Extensions for Bit Error Rate (BER) Measurement
                draft-zhang-ccamp-rsvpte-ber-measure-02

Abstract

   In the mobile backhaul network, the mobile service is sensitive to
   Bit Error Rate (BER).  When the BER value of the service exceeds the
   threshold, the cell site equipments will stop working and the mobile
   terminal users cannot obtain voice and data services anymore.  Now
   the mobile backhaul tends to be IP/MPLS network and MPLS TE LSP is
   used to bear the mobile service which may be encapsulated in PW or
   L3VPN end to end.  Then the ingress Label Switched Router (LSR) of
   the MPLS TE LSP needs to get information on BER along the path of the
   LSP.  This document proposes new extensions of RSVP-TE to advertise
   the BER measurement requirement of the specific LSP to all of the
   transit LSRs and the egress LSR, and to report the BER measurement
   result from any transit or egress LSR towards the ingress LSR.

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 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 4, 2015.



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Copyright Notice

   Copyright (c) 2014 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
   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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  BER_REQUEST TLV . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Format of BER_REQUEST . . . . . . . . . . . . . . . . . .   3
     3.2.  Procedures for BER_REQUEST TLV  . . . . . . . . . . . . .   5
   4.  BER Measurement Result Report . . . . . . . . . . . . . . . .   5
     4.1.  Error Code for BER measurement report . . . . . . . . . .   5
     4.2.  Procedures for BER Error Code . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Bit Error Rate (BER) is a significant parameter for the mobile
   service, which can cause the cell site equipment to stop working when
   its value exceeds the threshold that the mobile service can tolerate.
   In IP/MPLS based mobile backhaul network, PW and L3VPN are adopted to
   bear the mobile service, and MPLS TE LSP is adopted as the transport
   tunnel for which Hot-standby (MPLS TE HSB) or fast reroute (MPLS TE
   FRR) technologies is used to meet the SLA(Service Level Agreement).
   There are different kinds of failure detection methods, such as
   BFD[RFC5884] or MPLS OAM[RFC4378], to trigger fast traffic switch
   when failure happens.  But as to BER, even if the BER value exceeds
   the threshold, the detection mechanisms may be not able to detect the
   failure to trigger traffic switch to the backup path.  In order to
   solve the issue, RSVP-TE extensions can be introduced to notify the
   ingress LSR of the BER measurement result when a specific LSR along



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   the LSP detects that the BER value exceeds the threshold or restores
   to the normal value below the threshold.  When the ingress LSP
   receives the BER measurement result, it can switch the traffic
   between the primary path and the backup path which is policy specific
   and out of scope of the document.

   This document defines new extensions of RSVP-TE for BER measurement:
   One extension is to advertise the BER measurement requirement to all
   of the transit LSRs and the egress LSR, then these LSRs along the
   path will start BER measurement for the LSP.  The other extension is
   to report the BER measurement result from any transit LSR or the
   egress LSR towards the ingress LSR.

2.  Terminology

   BER: Bit Error Rate

   RAN: Radio Access Network

   LSR: Label Switch Router

   LSP: Label Switch Path

3.  BER_REQUEST TLV

3.1.  Format of BER_REQUEST

   Path Message of RSVP-TE is used to signal the BER measurement
   requirement of the LSP, and the LSP_ATTRIBUTES object will be
   included in the Path Message.  The LSP_ATTRIBUTES object which is
   defined in [RFC5420] is used to signal attributes required in support
   of an LSP, or to indicate the nature or use of an LSP.  The
   LSP_ATTRIBUTES object format is as below (refer to[RFC5420]):

      LSP_ATTRIBUTES class = 197, C-Type = 1

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //                       Attributes TLVs                       //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 1: LSP_ATTRIBUTES object

   The LSP_ATTRIBUTES object class is 197 of the form 11bbbbbb.  This
   C-Num value (see [RFC2205], Section 3.10) ensures that LSRs that do



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   not recognize the object pass it on transparently.  One C-Type is
   defined, C-Type = 1 for LSP Attributes.

   The Attributes TLVs are encoded as below:

       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              |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //                            Value                            //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    Figure 2: Attributes TLVs format

   Here we define the BER_REQUEST TLV which is a new type of Attribute
   TLV to indicate the BER measurement requirement of the LSP.  The
   format of BER_REQUEST TLV is as below:

                 LSP_ATTRIBUTES Class=197, C-Type=1
                 Type=TBD, BER_REQ TLV
     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 = BER_REQ TLV(TBD)     |          Length               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                        BER threshold                          |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                    Figure 3:BER_REQUEST TLV

   Type

   The identifier of the BER_REQUEST TLV which should be allocated by
   IANA.

   Length

   Indicates the total length of the TLV in two octets.

   Value

   The BER threshold for the service.  It is a 32-bit IEEE floating
   point number.  The format of IEEE floating-point numbers is further
   summarized in [RFC1832].





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3.2.  Procedures for BER_REQUEST TLV

   BER_REQUEST TLV is one type of attribute TLVs of the LSP_ATTRIBUTE
   object.  It is optional and MAY be placed in Path messages to
   advertise the BER measurement requirement of the LSP.  The process of
   the LSP_ATTRIBUTE object can refer to section 4.2 in [RFC5420].

   When a RSVP-TE LSP requires the BER measurement of the path, the
   ingress LSR MUST send a Path Message with BER_REQUEST TLV in which
   the BER threshold value is set according to the service requirement.

   When an LSR receives a Path Message with the BER_REQUEST TLV, the LSR
   SHOULD start the BER measurement for the LSP.  The LSR MUST pass the
   Path Message with BER_REQUEST TLV unchanged to the next LSR.  If the
   measured BER value exceeds the BER threshold value set in the
   BER_REQUEST TLV, the LSR MUST report the bit error result towards the
   ingress LSR of the LSP.

   If an LSR cannot support the BER_REQUEST TLV, the LSR SHOULD ignore
   this TLV and pass the Path Message with BER_REQUEST TLV unchanged to
   the next LSR.

   For an LSR which has started the BER measurement on receiving the
   Path Message with the BER_REQUEST UEST TLV, if the LSR receives the
   updated Path Message without BER_REQUEST TLV, it MUST stop the BER
   measurement for this LSP and pass the Path Message unchanged to the
   next LSR.

4.  BER Measurement Result Report

   For an LSR that starts the BER measurement, When the BER measurement
   value exceeds the threshold for the service, the LSR MUST report the
   indication of bit error towards the ingress LSR of the LSP.  If the
   LSR has already reported the indication of bit error, it MUST report
   the elimination of bit error towards the ingress LSR when it measures
   that the BER is blow the specified threshold.  A new type of Error
   Code and its Error Value of the ERROR_SPEC object are defined to
   report the BER measurement result within PathErr Message.

4.1.  Error Code for BER measurement report

   The ERROR_SPEC object is defined in [RFC2205] and [RFC3209].  The BER
   Error Code and its Error Values are defined as below:

      Error Code      Error Value           Description
   -----------------------------------------------------------------
      TBD                 0              Bit Error Elimination
                          1              Bit Error Indication



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4.2.  Procedures for BER Error Code

   The BER measurement result is reported through a new Error Code and
   the corresponding Error Value of the ERROR_SPEC object which is
   placed in PathErr Message.

   For a LSR which has started the BER measurement for the specific LSP,
   if the BER measurement value exceeds the threshold of the service, a
   PathErr Message MUST be sent towards the ingress LSR of this LSP.
   The PathErr Message MUST include an ERROR_SPEC object with the BER
   Error code and Error Value 1 for Bit Error Indication.  When the BER
   measurement value becomes less than the BER threshold value after
   report the Bit Error Indication, the LSR MUST send a PathErr Message
   including an ERROR_SPEC object with the BER Error Code and Error
   Value 0 for Bit Error Elimination.

5.  IANA Considerations

   IANA should allocate the type value of the BER_REQUEST TLV and the
   BER Error Code which are defined in this document.

6.  Security Considerations

   The extensions of RSVP TE for BER in this document do not introduce
   any new security issues, and the reader is referred to the security
   considerations expressed in [RFC2205], [RFC3209], and [RFC5420].

7.  References

7.1.  Normative References

   [RFC1832]  Srinivasan, R., "XDR: External Data Representation
              Standard", RFC 1832, August 1995.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2205]  Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, September 1997.

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, December 2001.







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   [RFC5420]  Farrel, A., Papadimitriou, D., Vasseur, JP., and A.
              Ayyangarps, "Encoding of Attributes for MPLS LSP
              Establishment Using Resource Reservation Protocol Traffic
              Engineering (RSVP-TE)", RFC 5420, February 2009.

7.2.  Informative References

   [RFC4378]  Allan, D. and T. Nadeau, "A Framework for Multi-Protocol
              Label Switching (MPLS) Operations and Management (OAM)",
              RFC 4378, February 2006.

   [RFC5884]  Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
              "Bidirectional Forwarding Detection (BFD) for MPLS Label
              Switched Paths (LSPs)", RFC 5884, June 2010.

Authors' Addresses

   Zhenbin Li
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: lizhenbin@huawei.com


   Li Zhang
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: monica.zhangli@huawei.com


   Guangming Yang
   China Telecom
   No. 109, Zhongshan Road West, Tianhe District
   Guangzhou  510630
   China

   Email: yanggm@gsta.com









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