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Versions: (draft-wu-idr-te-pm-bgp) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18

IDR Working Group                                                  Q. Wu
Internet-Draft                                                    Huawei
Intended status: Standards Track                              S. Previdi
Expires: July 8, 2015                                              Cisco
                                                              H. Gredler
                                                                 Juniper
                                                                  S. Ray
                                                                   Cisco
                                                             J. Tantsura
                                                                Ericsson
                                                         January 4, 2015


 BGP attribute for North-Bound Distribution of Traffic Engineering (TE)
                          performance Metrics
                      draft-ietf-idr-te-pm-bgp-02

Abstract

   In order to populate network performance information like link
   latency, latency variation, packet loss and bandwidth into Traffic
   Engineering Database(TED) and ALTO server, this document describes
   extensions to BGP protocol, that can be used to distribute network
   performance information (such as link delay, delay variation, packet
   loss, residual bandwidth, available bandwidth and utilized bandwidth
   ).

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 July 8, 2015.








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Copyright Notice

   Copyright (c) 2015 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.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  MPLS-TE with H-PCE  . . . . . . . . . . . . . . . . . . .   3
     3.2.  ALTO Server Network API . . . . . . . . . . . . . . . . .   4
   4.  Carrying TE Performance information in BGP  . . . . . . . . .   5
   5.  Attribute TLV Details . . . . . . . . . . . . . . . . . . . .   6
   6.  Manageability Considerations  . . . . . . . . . . . . . . . .   7
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .   9
     A.1.  draft-ietf-idr-te-pm-bgp-00 . . . . . . . . . . . . . . .   9
     A.2.  draft-ietf-idr-te-pm-bgp-02 . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   As specified in [RFC4655],a Path Computation Element (PCE) is an
   entity that is capable of computing a network path or route based on
   a network graph, and of applying computational constraints during the
   computation.  In order to compute an end to end path, the PCE needs
   to have a unified view of the overall topology[I-D.ietf-pce-pcep-
   service-aware].  [I.D-ietf-idr-ls-distribution] describes a mechanism
   by which links state and traffic engineering information can be
   collected from networks and shared with external components using the
   BGP routing protocol.  This mechanism can be used by both PCE and
   ALTO server to gather information about the topologies and
   capabilities of the network.



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   With the growth of network virtualization technology, the Network
   performance or QoS requirements such as latency, limited bandwidth,
   packet loss, and jitter, for real traffic are all critical factors
   that must be taken into account in the end to end path computation
   and selection ([I-D.ietf-pce-pcep-service-aware])which enable
   optimizing resource usage and degrading gracefully during period of
   heavy load .

   In order to populate network performance information like link
   latency, latency variation, packet loss and bandwidth into TED and
   ALTO server, this document describes extensions to BGP protocol, that
   can be used to distribute network performance information (such as
   link delay, delay variation, packet loss, residual bandwidth,
   available bandwidth, and utilized bandwidth).  The network
   performance information can be distributed in the same way as link
   state information distribution,i.e., either directly or via a peer
   BGP speaker (see figure 1 of [I.D-ietf-idr-ls-distribution]).

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].

3.  Use Cases

3.1.  MPLS-TE with H-PCE

   For inter-AS path computation the Hierarchical PCE (H-PCE) [RFC6805]
   may be used to compute the optimal sequence of domains.  Within the
   H-PCE architecture, the child PCE communicates domain connectivity
   information to the parent PCE, and the parent PCE will use this
   information to compute a multi-domain path based on the optimal TE
   links between domains [I.D-ietf-pce-hierarchy-extensions] for the
   end-to-end path.

   The following figure demonstrates how a parent PCE may obtain TE
   performance information beyond that contained in the LINK_STATE
   attributes [I.D-ietf-idr-ls-distribution] using the mechanism
   described in this document.











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                  +----------+                           +---------+
                  |  -----   |                           |   BGP   |
                  | | TED |<-+-------------------------->| Speaker |
                  |  -----   |   TED synchronization     |         |
                  |    |     |        mechanism:         +---------+
                  |    |     | BGP with TE performance
                  |    v     |        NLRI
                  |  -----   |
                  | | PCE |  |
                  |  -----   |
                  +----------+
                       ^
                       | Request/
                       | Response
                       v
         Service  +----------+   Signaling  +----------+
         Request  | Head-End |   Protocol   | Adjacent |
         -------->|  Node    |<------------>|   Node   |
                  +----------+              +----------+

       Figure 1: External PCE node using a TED synchronization mechanism

3.2.  ALTO Server Network API

   The ALTO Server can aggregate information from multiple systems to
   provide an abstract and unified view that can be more useful to
   applications.

   The following figure shows how an ALTO Server can get TE performance
   information from the underlying network beyond that contained in the
   LINK_STATE attributes [I.D-ietf-idr-ls-distribution] using the
   mechanism described in this document.

   +--------+
   | Client |<--+
   +--------+   |
                |    ALTO    +--------+     BGP with    +---------+
   +--------+   |  Protocol  |  ALTO  |  TE Performance |   BGP   |
   | Client |<--+------------| Server |<----------------| Speaker |
   +--------+   |            |        |      NLR        |         |
                |            +--------+                 +---------+
   +--------+   |
   | Client |<--+
   +--------+
     Figure 2: ALTO Server using network performance information






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4.  Carrying TE Performance information in BGP

   This document proposes new BGP TE performance TLVs that can be
   announced as attribute in the BGP-LS attribute (defined in [I.D-ietf-
   idr-ls-distribution]) to distribute network performance information.
   The extensions in this document build on the ones provided in BGP-LS
   [I.D-ietf-idr-ls-distribution] and BGP-4 [RFC4271].

   BGP-LS attribute defined in [I.D-ietf-idr-ls-distribution] has nested
   TLVs which allow the BGP-LS attribute to be readily extended.  This
   document proposes seven additional TLVs as its attributes:

      Type            Value

      TBD1        Unidirectional Link Delay

      TBD2        Min/Max Unidirectional Link Delay

      TBD3        Unidirectional Delay Variation

      TBD4        Unidirectional Packet Loss

      TBD5        Unidirectional Residual Bandwidth

      TBD6        Unidirectional Available Bandwidth

      TBD7        Unidirectional Utilized Bandwidth


   As can be seen in the list above, the TLVs described in this document
   carry different types of network performance information.  Some of
   these TLVs include a bit called the Anomalous (or "A") bit at the
   left-most bit after length field of each TLV defined in figure 4 of
   [[I.D-ietf-idr-ls-distribution]].  The other bits in the first octets
   after length field of each TLV is reserved for future use.  When the
   A bit is clear (or when the TLV does not include an A bit), the TLV
   describes steady state link performance.  This information could
   conceivably be used to construct a steady state performance topology
   for initial tunnel path computation, or to verify alternative
   failover paths.

   When network performance downgrades and exceeds configurable maximum
   thresholds, a TLV with the A bit set is advertised.  These TLVs could
   be used by the receiving BGP peer to determine whether to redirect
   failing traffic to a backup path, or whether to calculate an entirely
   new path.  If link performance improves later and falls below a
   configurable value, that TLV can be re- advertised with the Anomalous
   bit cleared.  In this case, a receiving BGP peer can conceivably do



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   whatever re-optimization (or failback) it wishes to do (including
   nothing).

   Note that when a TLV does not include the A bit, that TLV cannot be
   used for failover purposes.  The A bit was intentionally omitted from
   some TLVs to help mitigate oscillations.

   Consistent with existing ISIS TE specifications [ISIS-TE-METRIC], the
   bandwidth advertisements, the delay and delay variation
   advertisements, packet loss defined in this document MUST be encoded
   in the same unit as one defined in IS-IS Extended IS Reachability
   sub-TLVs [ISIS-TE-METRIC].  All values (except residual bandwidth)
   MUST be obtained by a filter that is reasonably representative of an
   average or calculated as rolling averages where the averaging period
   MUST be a configurable period of time.  The measurement interval, any
   filter coefficients, and any advertisement intervals MUST be
   configurable per sub-TLV in the same way as ones defined in section 5
   of [ISIS-TE-METRIC].

5.  Attribute TLV Details

   Link attribute TLVs defined in section 3.2.2 of [I-D.ietf-idr-ls-
   distribution]are TLVs that may be encoded in the BGP-LS attribute
   with a link NLRI.  Each 'Link Attribute' is a Type/Length/ Value
   (TLV) triplet formatted as defined in Section 3.1 of [I-D.ietf-idr-
   ls-distribution].  The format and semantics of the 'value' fields in
   'Link Attribute' TLVs correspond to the format and semantics of value
   fields in IS-IS Extended IS Reachability sub-TLVs, defined in
   [RFC5305].  Although the encodings for 'Link Attribute' TLVs were
   originally defined for IS-IS, the TLVs can carry data sourced either
   by IS-IS or OSPF.

   The following 'Link Attribute' TLVs are valid in the LINK_STATE
   attribute:

















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   +------------+---------------------+--------------+-----------------+
   |  TLV Code  | Description         |     IS-IS    | Defined in:     |
   |    Point   |                     |  TLV/Sub-TLV |                 |
   +------------+---------------------+--------------+-----------------+
   |    xxxx    | Unidirectional      |    22/xx     | [ISIS-TE-       |
   |            | Link Delay          |              | METRIC]/4.1     |
   |            |                     |              |                 |
   |    xxxx    | Min/Max Unidirection|    22/xx     | [ISIS-TE-       |
   |            | Link Delay          |              | METRIC]/4.2     |
   |            |                     |              |                 |
   |    xxxx    | Unidirectional      |    22/xx     | [ISIS-TE-       |
   |            | Delay Variation     |              | METRIC]/4.3     |
   |            |                     |              |                 |
   |    xxxx    | Unidirectional      |    22/xx     | [ISIS-TE-       |
   |            | Link Loss           |              | METRIC]/4.4     |
   |            |                     |              |                 |
   |    xxxx    | Unidirectional      |    22/xx     | [ISIS-TE-       |
   |            |Residual Bandwidth   |              | METRIC]/4.5     |
   |            |                     |              |                 |
   |    xxxx    | Unidirectional      |    22/xx     | [ISIS-TE-       |
   |            |Available Bandwidth  |              | METRIC]/4.6     |
   |            |                     |              |                 |
   |    xxxx    | Unidirectional      |    22/xx     | [ISIS-TE-       |
   |            |Utilized Bandwidth   |              | METRIC]/4.7     |
   +------------+---------------------+--------------+-----------------+

                        Table 1: Link Attribute TLVs


6.  Manageability Considerations

   Manageability Considerations described in section 6.2 of [I-D.ietf-
   idr-ls-distribution] can be applied to Traffic Engineering (TE)
   performance Metrics as well.

7.  Security Considerations

   This document does not introduce security issues beyond those
   discussed in [I.D-ietf-idr-ls-distribution] and [RFC4271].

8.  IANA Considerations

   IANA maintains the registry for the TLVs.  BGP TE Performance TLV
   will require one new type code per TLV defined in this document.







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9.  References

9.1.  Normative References

   [I-D.ietf-idr-ls-distribution]
              Gredler, H., "North-Bound Distribution of Link-State and
              TE Information using BGP", ID draft-ietf-idr-ls-
              distribution-07, November 2014.

   [I-D.ietf-pce-pcep-service-aware]
              Dhruv, D., "Extensions to the Path Computation Element
              Communication Protocol (PCEP) to compute service aware
              Label Switched Path (LSP)", ID draft-ietf-pce-pcep-
              service-aware-06, December 2014.

   [ISIS-TE-METRIC]
              Giacalone, S., "ISIS Traffic Engineering (TE) Metric
              Extensions", ID draft-ietf-isis-te-metric-extensions-04,
              October 2014.

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

   [RFC4271]  Rekhter, Y., "A Border Gateway Protocol 4 (BGP-4)", RFC
              4271, January 2006.

   [RFC5305]  Li, T., "IS-IS Extensions for Traffic Engineering", RFC
              5305, October 2008.

9.2.  Informative References

   [ALTO]     Yang, Y., "ALTO Protocol", ID
              http://tools.ietf.org/html/draft-ietf-alto-protocol-16,
              May 2013.

   [I.D-ietf-pce-hierarchy-extensions]
              Zhang, F., Zhao, Q., Gonzalez de Dios, O., Casellas, R.,
              and D. King, "Extensions to Path Computation Element
              Communication Protocol (PCEP) for Hierarchical Path
              Computation Elements (PCE)", ID draft-ietf-pce-hierarchy-
              extensions-01, February 2014.

   [RFC4655]  Farrel, A., "A Path Computation Element (PCE)-Based
              Architecture", RFC 4655, August 2006.







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Appendix A.  Change Log

   Note to the RFC-Editor: please remove this section prior to
   publication as an RFC.

A.1.  draft-ietf-idr-te-pm-bgp-00

   The following are the major changes compared to previous version
   draft-wu-idr-te-pm-bgp-03:


   o  Update PCE case in section 3.1.

   o  Add some texts in section 1 and section 4 to clarify from where to
      distribute pm info and measurement interval and method.

A.2.  draft-ietf-idr-te-pm-bgp-02

   The following are the major changes compared to previous version
   draft-wu-idr-te-pm-bgp-03:


   o  Some Editorial changes.

Authors' Addresses

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

   Email: bill.wu@huawei.com


   Stefano Previdi
   Cisco Systems, Inc.
   Via Del Serafico 200
   Rome  00191
   Italy

   Email: sprevidi@cisco.com









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   Hannes Gredler
   Juniper Networks, Inc.
   1194 N. Mathilda Ave.
   Sunnyvale, CA  94089
   US

   Email: hannes@juniper.net


   Saikat Ray
   Cisco Systems, Inc.
   170, West Tasman Drive
   San Jose, CA  95134
   US

   Email: sairay@cisco.com


   Jeff Tantsura
   Ericsson
   300 Holger Way
   San Jose, CA  95134
   US

   Email: jeff.tantsura@ericsson.com


























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