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Versions: 00 01 02 draft-ietf-idr-bgp-flowspec-label

Idr Working Group                                               Q. Liang
Internet-Draft                                                  S. Hares
Intended status: Standards Track                                  J. You
Expires: September 22, 2016                                       Huawei
                                                               R. Raszuk
                                                                  Nozomi
                                                                   D. Ma
                                                           Cisco Systems
                                                          March 21, 2016


              Carrying Label Information for BGP FlowSpec
                 draft-liang-idr-bgp-flowspec-label-02

Abstract

   This document specifies a method in which the label mapping
   information for a particular FlowSpec rule is piggybacked in the same
   Border Gateway Protocol (BGP) Update message that is used to
   distribute the FlowSpec rule.  Based on the proposed method, the
   Label Switching Routers (LSRs) (except the ingress LSR) on the Label
   Switched Path (LSP) can use label to indentify the traffic matching a
   particular FlowSpec rule; this facilitates monitoring and traffic
   statistics for FlowSpec rules.

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].

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 September 22, 2016.




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Copyright Notice

   Copyright (c) 2016 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
     1.1.  Background  . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  MPLS Flow Specification Deployment  . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Overview of Proposal  . . . . . . . . . . . . . . . . . . . .   3
   4.  Protocol Extensions . . . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   6.  Security considerations . . . . . . . . . . . . . . . . . . .   7
   7.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   This section provides the background for proposing a new action for
   BGP Flow specification that push/pops MPLS or swaps MPLS tags.  For
   those familiar with BGP Flow specification ([RFC5575], [RFC7674],
   [I-D.ietf-idr-flow-spec-v6], [I-D.ietf-idr-flowspec-l2vpn],
   [I-D.ietf-idr-bgp-flowspec-oid] and MPLS ([RFC3107]) can skip this
   background section.

1.1.  Background

   [RFC5575] defines the flow specification (FlowSpec) that is an
   n-tuple consisting of several matching criteria that can be applied
   to IP traffic.  The matching criteria can include elements such as
   source and destination address prefixes, IP protocol, and transport
   protocol port numbers.  A given IP packet is said to match the
   defined flow if it matches all the specified criteria.  [RFC5575]



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   also defines a set of filtering actions, such as rate limit,
   redirect, marking, associated with each flow specification.  A new
   Border Gateway Protocol Network Layer Reachability Information (BGP
   NLRI) (AFI/SAFI: 1/133 for IPv4, AFI/SAFI: 1/134 for VPNv4) encoding
   format is used to distribute traffic flow specifications.

   [RFC3107] specifies the way in which the label mapping information
   for a particular route is piggybacked in the same Border Gateway
   Protocol Update message that is used to distribute the route itself.
   Label mapping information is carried as part of the Network Layer
   Reachability Information (NLRI) in the Multiprotocol Extensions
   attributes.  The Network Layer Reachability Information is encoded as
   one or more triples of the form <length, label, prefix>.  The NLRI
   contains a label is indicated by using Subsequent Address Family
   Identifier (SAFI) value 4.

   [RFC4364] describes a method in which each route within a Virtual
   Private Network (VPN) is assigned a Multiprotocol Label Switching
   (MPLS) label.  If the Address Family Identifier (AFI) field is set to
   1, and the SAFI field is set to 128, the NLRI is an MPLS-labeled VPN-
   IPv4 address.

1.2.  MPLS Flow Specification Deployment

   In BGP VPN/MPLS networks when flow specification policy rules exist
   on multiple forwarding devices in the network bound with labels from
   one or more LSPs, only the ingress LSR (Label Switching Router) needs
   to identify a particular traffic flow based on the matching criteria
   for flow.  Once the flow is match by the ingress LSR, the ingress LSR
   steers the packet to a corresponding LSP (Label Switched Path).
   Other LSRs of the LSP just need to forward the packet according to
   the label carried in it.

2.  Terminology

   This section contains definitions of terms used in this document.

      Flow Specification (FlowSpec): A flow specification is an n-tuple
      consisting of several matching criteria that can be applied to IP
      traffic, including filters and actions.  Each FlowSpec consists of
      a set of filters and a set of actions.

3.  Overview of Proposal

   This document proposes adding a BGP-FS action in an extended
   community alters the label switch path associated with a matched
   flow.  If the match does not have a label switch path, this action is
   skipped.



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   The BGP flow specification (BGP-FS) policy rule could match on the
   destination prefix and then utilize a BGP-FS action to adjust the
   label path associated with it (push/pop/swap tags.)  Or a BGP-FS
   policy rule could match on any set of BGP-FS match conditions
   associated with a BGP-FS action that adjust the label switch path
   (push/pop/swap).

   [I-D.yong-idr-flowspec-mpls-match] provides a match BGP-FS that may
   be used with this action to match and direct MPLS packets.

   Example of Use:

   Forwarding information for the traffic from IP1 to IP2 in the
   Routers:

          PE1:   in(<IP2,IP1>) --> out(Label2)
          ASBR1: in(Label2) --> out(Label3)
          ASBR2: in(Label3) --> out(Label4)
          PE2:   in(Label4) --> out(--)

   Labels allocated by flow policy process:

          Label4 allocated by PE2
          Label3 allocated by ASBR2
          Label2 allocated by ASBR1

              |<------AS1----->|    |<------AS2----->|
              +-----+    +-----+    +-----+    +-----+
   VPN 1,IP1..| PE1 |====|ASBR1|----|ASBR2|====| PE2 |..VPN1,IP2
              +-----+    +-----+    +-----+    +-----+
                | LDP LSP1 |          | LDP LSP2 |
                | -------> |          | -------> |
                |-------BGP VPN Flowspec LSP---->|
             (Label1)    (Label2)   (Label3)   (Label4)

                 Figure 1: Usage of FlowSpec with Label

   BGP-FS rule1 (locally configured):

          Filters:
             destination ip prefix:IP2/32
             source ip prefix:IP1/32

          Actions: Extended Communities
             traffic-marking: 1
             MPLS POP

   Note:



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   The following Extended Communities are added/deleted

          [rule-1a] BGP-FS action MPLS POP [used on PE2]
          [rule-1b] BGP-FS action SWAP 4   [used on ASBR-2]
          [rule-1c] BGP-FS action SWAP 3   [used on ASBR-1]
          [rule-1d] BGP-FS action push 2   [used on PE1]

   PE-2 Changes BGP-FS rule-1a to rule-1b prior to sending
        Clears Extended Community: BGP-FS action MPLS POP
        Adds   Extended Community: BGP-FS action MPLS SWAP 4

   ASBR-2 receives BGP-FS rule-1b (NRLI + 2 Extended Community)
          Installs the BGP-FS rule-1b (MPLS SWAP 4, traffic-marking)
          Changes BGP-FS rule-1b to rule-1c prior to sending to ASBR1
          Clear Extended Community: BGP-FS action MPLS SWAP 4
          Adds  Extended Community: BGP-FS action MPLS SWAP 3

   ASBR-1 Receives BGP-FS rule-1c (NLRI + 2 Extended Community)
          Installs the BGP-FS rule-1c (MPLS SWAP 3, traffic-marking
          Changes BGP-FS rule-1c to rule-1d prior to sending to PE-2
          Clear Extended Community: BGP-FS action MPLS SWAP 3
          Adds  Extended Community: BGP-FS action MPLS SWAP 2

   PE-1 Receives BGP-FS rule-1d (NLRI + 2 Extended Communities)
        Installs BGP-FS rule-1d action [MPLS SWAP 2, traffic-marking]

4.  Protocol Extensions

   In this document, BGP is used to distribute the FlowSpec rule bound
   with label(s).  A new label-action is defined as BGP extended
   community value based on Section 7 of [RFC5575].

        +--------+--------------------+--------------------------+
        | type   | extended community | encoding                 |
        +--------+--------------------+--------------------------+
        | TBD1   | label-action       | MPLS tag                 |
        +--------+--------------------+--------------------------+

   Label-action is described 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  (TBD1              | OpCode|Reserve| order         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Label
 |                Label                  | Exp |S|       TTL     | Stack
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Entry




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   The use and the meaning of these fields are as follows:

      Type: the same as defined in [RFC4360]

      OpCode: Operation code

   +------+------------------------------------------------------------+
   |OpCode| Function                                                   |
   +------+------------------------------------------------------------+
   |  0   | Push the MPLS tag                                          |
   +------+------------------------------------------------------------+
   |  1   | Pop the outermost MPLS tag in the packet                   |
   +------+------------------------------------------------------------+
   |  2   | Swap the MPLS tag with the outermost MPLS tag in the packet|
   +------+------------------------------------------------------------+
   | 3~15 | Reserved                                                   |
   +------+------------------------------------------------------------+

         When the Opcode field is set to 0, the label stack entry Should
         be pushed on the MPLS label stack.

         When the OpCode field is set to 1, the label stack entry is
         invalid, and the router SHOULD pop the existing outermost MPLS
         tag in the packet.

         When the OpCode field is set to 2, the router SHOULD swap the
         label stack entry with the existing outermost MPLS tag in the
         packet.  If the packet has no MPLS tag, it just pushes the
         label stack entry.

         The OpCode 0 or 1 may be used in some SDN networks, such as the
         scenario described in
         [I-D.filsfils-spring-segment-routing-central-epe].

         The OpCode 2 can be used in traditional BGP MPLS/VPN networks.

      Reserved: all zeros.

      Order: A FlowSpec rule MAY include one or more ordering label-
      action(s).  If multiple label action extended communities are
      associated with a BGP-FS Rule, this gives the order of this in the
      list.  The Last action received for an order will be used.

      Label: the same as defined in [RFC3032].

      Bottom of Stack (S): the same as defined in [RFC3032].  It SHOULD
      be invalid, and set to zero by default.  It MAY be modified by the
      forwarding router locally.



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      Time to Live (TTL): the same as defined in[RFC3032].  It MAY be
      modified by the forwarding router locally.

      Experimental Use (Exp): the same as defined in [RFC3032].  It MAY
      be modified by the forwarding router according to the local
      routing policy.

5.  IANA Considerations

   For the purpose of this work, IANA should allocate the following
   Extended community:

      TBD1 for label-action

6.  Security considerations

   This extension to BGP does not change the underlying security issues
   inherent in the existing BGP.

7.  Acknowledgement

   The authors would like to thank Shunwan Zhuang, Zhenbin Li, Peng Zhou
   and Jeff Haas for their comments.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, DOI 10.17487/RFC3032, January 2001,
              <http://www.rfc-editor.org/info/rfc3032>.

   [RFC3107]  Rekhter, Y. and E. Rosen, "Carrying Label Information in
              BGP-4", RFC 3107, DOI 10.17487/RFC3107, May 2001,
              <http://www.rfc-editor.org/info/rfc3107>.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
              February 2006, <http://www.rfc-editor.org/info/rfc4360>.






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   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <http://www.rfc-editor.org/info/rfc4364>.

   [RFC5575]  Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
              and D. McPherson, "Dissemination of Flow Specification
              Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
              <http://www.rfc-editor.org/info/rfc5575>.

   [RFC7674]  Haas, J., Ed., "Clarification of the Flowspec Redirect
              Extended Community", RFC 7674, DOI 10.17487/RFC7674,
              October 2015, <http://www.rfc-editor.org/info/rfc7674>.

8.2.  Informative References

   [I-D.filsfils-spring-segment-routing-central-epe]
              Filsfils, C., Previdi, S., Patel, K., Shaw, S., Ginsburg,
              D., and D. Afanasiev, "Segment Routing Centralized Egress
              Peer Engineering", draft-filsfils-spring-segment-routing-
              central-epe-05 (work in progress), August 2015.

   [I-D.ietf-idr-bgp-flowspec-oid]
              Uttaro, J., Filsfils, C., Smith, D., Alcaide, J., and P.
              Mohapatra, "Revised Validation Procedure for BGP Flow
              Specifications", draft-ietf-idr-bgp-flowspec-oid-02 (work
              in progress), January 2014.

   [I-D.ietf-idr-flow-spec-v6]
              McPherson, D., Raszuk, R., Pithawala, B., Andy, A., and S.
              Hares, "Dissemination of Flow Specification Rules for
              IPv6", draft-ietf-idr-flow-spec-v6-07 (work in progress),
              March 2016.

   [I-D.ietf-idr-flowspec-l2vpn]
              Weiguo, H., Litkowski, S., and S. Zhuang, "Dissemination
              of Flow Specification Rules for L2 VPN", draft-ietf-idr-
              flowspec-l2vpn-03 (work in progress), November 2015.

   [I-D.yong-idr-flowspec-mpls-match]
              Yong , L., Liang , Q., and J. You , "Dissemination of Flow
              Specification Rules for MPLS Label", March 2016.

Authors' Addresses








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   Qiandeng Liang
   Huawei
   101 Software Avenue, Yuhuatai District
   Nanjing,  210012
   China

   Email: liangqiandeng@huawei.com


   Susan Hares
   Huawei
   7453 Hickory Hill
   Saline, MI  48176
   USA

   Email: shares@ndzh.com


   Jianjie You
   Huawei
   101 Software Avenue, Yuhuatai District
   Nanjing,  210012
   China

   Email: youjianjie@huawei.com


   Robert Raszuk
   Nozomi

   Email: robert@raszuk.net


   Dan Ma
   Cisco Systems

   Email: danma@cisco.com














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