Network Working Group                                              Z. Li
Internet-Draft                                                  L. Zhang
Intended status: Standards Track                     Huawei Technologies
Expires: July 20, 2014                                  January 16, 2014


        RSVP-TE Extensions for Bit Error Rate (BER) Measurement
                draft-zhang-ccamp-rsvpte-ber-measure-01

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 Base Station will stop working and the User Equipments
   (UEs) 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
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   This Internet-Draft will expire on July 20, 2014.





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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
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   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.  Operations for BER_REQUEST TLV  . . . . . . . . . . . . .   5
   4.  Bit Error Indication Report . . . . . . . . . . . . . . . . .   5
     4.1.  Error Code for BER measurement report . . . . . . . . . .   5
     4.2.  Operations for BER Error Code . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Bit Error Rate (BER) is a significant parameter for the mobile
   service, which can cause the Base Station to stop working when its
   value exceeds the threshold of the service.  In IP/MPLS based mobile
   backhaul network, PW and L3VPN are adopted to bear the mobile service
   end-to-end, 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 or MPLS
   OAM, to trigger MPLS TE HSB or FRR to switch traffic fast when
   failure happens.  But as to BER, even if the BER value exceeds the
   threshold, the detection mechanisms cannot detect the failure to
   trigger traffic switch to the backup path.  In this document, we
   propose new extensions of RSVP-TE to advertise the BER measurement
   requirement of the LSP to its transit LSRs and the egress LSR, and to
   report the BER measurement result from any transit LSR or the egress
   LSR towards the ingress LSR.



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   There are two types of BER measurement requirements: one is the
   single-point BER measurement and the other is the multi-point BER
   measurement.  The first one is to measure if the BER value of one
   point of the LSP path has exceeded the threshold of the service.  The
   second one is to measure if the sum of BER value of multiple points
   of the LSP exceeds the threshold of the service.  In this document,
   we just focus on the single-point BER measurement . The multi-point
   BER measurement will be described in the future version.

   For the single-point BER measurement, there are two new extensions of
   RSVP-TE protocol.  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



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   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
   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_REQ 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 of the service, which is a 32-bit IEEE floating
   point number.  Positive infinity is represented as an IEEE single-
   precision floating-point number with an exponent of all ones (255)



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   and a sign and mantissa of all zeros.  The format of IEEE floating-
   point numbers is further summarized in [RFC1832]

3.2.  Operations for BER_REQUEST TLV

   BER_REQUEST TLV is one type of attribute TLVs of the LSP_ATTRIBUTE
   object, which 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.

   When a 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 a 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 a 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 to next LSRs
   unchanged.

4.  Bit Error Indication Report

   For the single-point BER measurement, the LSR should report the BER
   measurement result towards the ingress LSR of the LSP when the BER
   measurement value exceeds the threshold of the service.  This
   document we propose a new type of Error Code and its Error Value of
   the ERROR_SPEC object, which is defined in [RFC2205] and [RFC3209],
   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].  Here we
   define a new BER Error Code as below (The Error Code for "BER
   measurement report" is to be defined) :






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      Error code      Error value           Description
   -----------------------------------------------------------------
      TBD                 0              Bit Error Elimination
                          1              Bit Error Indication

4.2.  Operations for BER Error Code

   The BER measurement result is reported through a new Error Code and
   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 trigged to send towards the ingress LSR of
   this LSP.  The PathErr Message MUST include BER Error code with Error
   Value 1 for Bit Error Indication.  When the BER measurement value
   becomes less than the BER threshold value, the LSR MUST send a
   PathErr Message with a value of 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.  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.

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




























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