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Versions: 00 01 02 draft-ietf-mpls-pm-udp-return

MPLS                                                           S. Bryant
Internet-Draft                                              S. Sivabalan
Intended status: Standards Track                                 S. Soni
Expires: November 22, 2014                                 Cisco Systems
                                                            May 21, 2014


              MPLS Performance Measurement UDP Return Path
                  draft-bryant-mpls-oam-udp-return-01

Abstract

   This document specifies the proceedure to be used by the Packet Loss
   and Delay Measurement for MPLS Networks protocol defined in RFC6374
   when sending and processing MPLS performance management out-of-band
   responses for delay and loss measurements over an IP/UDP return path.

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 November 22, 2014.

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
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   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.



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1.  Introduction

   The Packet Loss and Delay Measurement for MPLS Networks protocol
   (MPLS-PLDM) defined in[RFC6374] does not define how an MPLS-PLDM out-
   of-band response delivered over IP will be transmitted to the
   Querier.

   In a highly scaled system some MPLS-PLDM sessions may be off-loaded
   to a specific node within a the distributed system that comprises the
   LSR as a whole.  In such systems the response may arrive via any
   interface in the LSR and need to internally forwarded to the
   processor tasked with handling the particular MPLS-PLDM measurement.
   Currently the MPLS-PLDM protocol does not have any mechanism to
   deliver the PLDM Response message to particular node within a multi-
   CPU LSR.

   The procedure described in this specification describes how the
   queryer requests delivery of the MPLS-PLDM response over IP to a
   dynamic UDP port.  It makes no other changes to the protocol and thus
   does not affect the case where the reponse is delivered over a MPLS
   Associated Channel [RFC5586].


2.  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 [RFC2119].


3.  Solution Overview

   This document specifies that, unless configured otherwise, the
   Addressing Object defined in [RFC6374] SHALL be sent in MPLS-PLDM
   query messages to tell the responder the IP return address to be
   used.  This document also defines Return UDP Port object which,
   unless configured otherwise SHALL be used to the return UDP port.
   The Addressing Object and the Return UDP PORT object carried in the
   MPLS-PLDM query message are used to specify to the Responder how to
   return the response message.

   The procedures defined in this document may be applied to both
   unidirectional tunnels and Bidirectional LSPs.  In this document, the
   term bidirectional LSP includes the co-routed Bidirectional LSP
   defined in [RFC3945] and the associated bidirectional LSP that is
   constructed from a pair of unidirectional LSPs (one for each
   direction) that are associated with one another at the LSP's ingress/
   egress points [RFC5654].  The mechanisms defined in this document can



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   apply to both IP/MPLS and the MPLS Transport Profile (MPLS-TP).

3.1.  Return UDP Port Object

   The format of the Return UDP Port Object 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | UDP TLV Type  |   Length = 2  |    UDP Destination Port       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   The Return UDP Port Object TLV Type (UDP TLV Type) has a value of
   <TBD>.

   The Return UDP Port Object MUST NOT appear in a response.


4.  Theory of Operation

   This document defines the Return UDP Port Object and uses the
   Addressing Object to enable the MPLS-PLDM Querier to specify the
   return path for the MPLS-PLDM reply using IP/UDP encapsulation.

   When the MPLS-PLDM Response is requested out-of-band by setting
   Control Code of the MPLS-PLDM Query to "Out-of-band Response
   Requested", the responder SHOULD send the response back to Querier on
   the specified destination UDP port at the specified destination IP
   address as received in the Return UDP Port Object and Return Address
   Object respectively.

   If either the Return Address Object or Return UDP Port Object is not
   present in Query message and an MPLS-PLDM Response is requested out-
   of-band, the Query message MUST NOT be processed further.  If
   received over a bidirectional LSP, the control code of the Response
   message MUST be set to "Error - Missing TLV" and a Response SHOULD be
   sent over the reverse LSP.  The receipt of such a mal-formed request
   SHOULD be notified to the operator through the management system,
   taking the normal precautions with respect to the prevention of
   overload of the error reporting system.

4.1.  Missing TLV

   The control code "Missing TLV", which is classified as an Error
   response code, indicates that the operation failed because one or
   more required TLV Objects was not sent in the query message.




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4.2.  Sending an MPLS-PM Query

   When sending an MPLS-PLDM Query message, in addition to the rules and
   procedures defined in [RFC6374]; the Control Code of the MPLS-PLDM
   Query MUST be set to "Out-of-band Response Requested", and a "Return
   UDP Port TLV" along with "Return Address TLV" MUST be carried in the
   MPLS-PLDM Query message.

   Since the Querier uses the UDP port to de-multiplex response for
   different measurement type, there SHOULD be a different UDP port for
   each measurement type (Delay, loss and delay-loss combined).

   An implementation MAY use multiple UDP ports for same measurement
   type to direct the response to the correct management process in the
   LSR.

4.3.  Receiving an MPLS PM Query Request

   The processing of MPLS-PLDM query messages as defined in [RFC6374]
   applies in this document.  In addition, when an MPLS-PLDM Query
   request is received, with the Control Code of the MPLS-PLDM Query set
   to "Out-of-band Response Requested" with a Return address TLV and
   Return UDP TLV is present, then the Responder SHOULD use that IP
   address and UDP port to send MPLS-PLDM response back to Querier.

   If an Out-of-band response is requested and either the Return Address
   TLV or the Return UDP port TLV is missing, the Query SHOULD be
   dropped in the case of unidirectional LSP.  If either of these TLVs
   is missing on a bidirectional LSP, the control code of Response
   message should set to "Invalid Message" and the response SHOULD be
   sent over the reverse LSP.  In either case the receipt of such a mal-
   formed request SHOULD be notified to the operator through the
   management system, taking the normal precautions with respect to the
   prevention of overload of the error reporting system.

4.4.  Sending an MPLS-PM Response

   As specified in [RFC6374] the MPLS-PLDM Response can be sent over
   either the reverse MPLS LSP for a bidirectional LSP or over an IP
   path.  It MUST NOT be sent other than in response to an MPLS-PLDM
   Query message.

   When the requested return path is an IP forwarding path and this
   method is in use, the destination IP address and UDP port SHOULD be
   copied from the Return Address TLV and the Return UDP TLV
   respectively.  The source IP address and the source UDP port of
   Response packet is left to discretion of the Responder subject to the
   normal management and security considerations.  The packet format for



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   the MPLS-PLDM response after the UDP header is as specified in
   [RFC6374].  As shown in Figure 1 the Associate Channel Header (ACH)
   [RFC5586] is not incuded.  The information provided by the ACH is not
   needed since the correct binding between the Querry and Response
   messages is achieved though the UDP Port and the Session Indentifier
   contained in the RFC6374 message.

   As noted in
       +----------------------------------------------------------+
       |  IP Header                                               |
       .    Source Address = Responders IP Address                |
       .    Destination Addess = Return Address TLV.Address       |
       .    Protocol = UDP                                        .
       .                                                          .
       +----------------------------------------------------------+
       | UDP Header                                               |
       .   Source Port = As chosen by Responder                   .
       .   Destination Port = Return UDP Port TLV.UDP Dest Port   .
       .                                                          .
       +----------------------------------------------------------+
       | Message as specified in RFC6374                          |
       .                                                          .
       +----------------------------------------------------------+


                     Figure 1: Response packet Format

   If the return path is IP path, only one-way delay or one-way loss
   measurement can be carried out.  In this case timestamps 3 and 4 MUST
   be zero as specified in [RFC6374].

4.5.  Receiving an MPLS-PM Response

   If the response was received over UDP/IP and an out-of-band response
   was expected, the Response message SHOULD be directed to the
   appropriate measurement process as determined by the destination UDP
   Port, and processed using the corresponding measurement type
   procedure specified in [RFC6374].

   If the Response was received over UDP/IP and an out-of-band response
   was not requested, that response should be dropped and the event
   SHOULD be notified to the operator through the management system,
   taking the normal precautions with respect to the prevention of
   overload of the error reporting system.







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5.  Manageability Considerations

   The manageability considerations described in Section 7 of [RFC6374]
   are applicable to this specification.  Additional manageability
   considerations are noted within the elements of procedure of this
   document.

   Nothing in this document precludes the use of a configured UDP/IP
   return path in a deployment in which configuration is preferred to
   signalling.  In these circumstances the address and UDP port TLVs MAY
   be omitted from the MPLS-PLDM messages.


6.  Security Considerations

   The MPLS-PLDM system is not intended to be deployed on the public
   Internet.  It is intended for deployment in well manages private and
   service provider networks.  The security considerations described in
   Section 8 of [RFC6374] are applicable to this specification and the
   reader's attention is drawn to the last two paragraphs.
   Cryptographic measures may be enhanced by the correct configuration
   of access control lists and firewalls.

   There is no additional exposure of information to pervasive
   monitoring systems observing LSPs that are being monitored.


7.  IANA Considerations

   IANA is requested to assign a new Optional TLV type from MPLS Loss/
   Delay Measurement TLV Object Registry contained within the g-ach-
   parameters registry set.
      Code              Description            Reference
       TBD     Return UDP Port                 [This]

   The TLV 131 is recommended.

   IANA is requested to assign a new response code in the MPLS Loss/
   Delay Measurement Control Code Registry contained within the g-ach-
   parameters registry set.
      Code              Description            Reference
       TBD     Missing TLV                     [This]

   The response code 0x1E is recommended.







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8.  Acknowledgements

   We acknowledge the contribution of Joseph Chin and Rakesh Gandhi,
   both with Cisco Systems.  We thank Loa Andersson for his review
   comments.

   We thank all who have reviewed this text and provided feedback.


9.  Normative References

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

   [RFC3945]  Mannie, E., "Generalized Multi-Protocol Label Switching
              (GMPLS) Architecture", RFC 3945, October 2004.

   [RFC5586]  Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
              Associated Channel", RFC 5586, June 2009.

   [RFC5654]  Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
              and S. Ueno, "Requirements of an MPLS Transport Profile",
              RFC 5654, September 2009.

   [RFC6374]  Frost, D. and S. Bryant, "Packet Loss and Delay
              Measurement for MPLS Networks", RFC 6374, September 2011.


Authors' Addresses

   Stewart Bryant
   Cisco Systems

   Email: stbryant@cisco.com


   Siva Sivabalan
   Cisco Systems


   Phone:
   Fax:
   Email: msiva@cisco.com
   URI:







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   Sagar Soni
   Cisco Systems


   Phone:
   Fax:
   Email: sagsoni@cisco.com
   URI:











































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