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Versions: (draft-hao-idr-flowspec-evpn) 00 01 02 03 04 05

IDR                                                              W. Hao
                                                               Q. Liang
Internet Draft                                                   Huawei
Intended status: Standards Track                             Jim Uttaro
                                                                   AT&T
                                                           S. Litkowski
                                                Orange Business Service
                                                              S. Zhuang
                                                                 Huawei
Expires: June 2017                                    December 30, 2016



            Dissemination of Flow Specification Rules for L2 VPN
                   draft-ietf-idr-flowspec-l2vpn-05.txt

Abstract

   This document defines BGP flow-spec extension for Ethernet traffic
   filtering in L2 VPN network. SAFI=134 in [RFC5575] is redefined for
   dissemination traffic filtering information in an L2VPN environment.
   A new subset of component types and extended community also are
   defined.

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
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Copyright Notice


   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors. All rights reserved.



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   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. Layer 2 Flow Specification encoding in BGP................... 3
   3. Ethernet Flow Specification encoding in BGP.................. 4
      3.1. Order of Traffic Filtering Rules........................ 6
   4. Ethernet Flow Specification Traffic Actions.................. 7
   5. Security Considerations..................................... 10
   6. IANA Considerations ........................................ 10
      6.1. Normative References................................... 12
      6.2. Informative References................................. 12
   7. Acknowledgments ............................................ 12

1. Introduction

   BGP Flow-spec is an extension to BGP that allows for the
   dissemination of traffic flow specification rules.  It leverages the
   BGP Control Plane to simplify the distribution of ACLs, new filter
   rules can be injected to all BGP peers simultaneously without
   changing router configuration. The typical application of BGP Flow-
   spec is to automate the distribution of traffic filter lists to
   routers for DDOS mitigation, access control, etc.

   RFC5575 defines a new BGP Network Layer Reachability Information
   (NLRI) format used to distribute traffic flow specification rules.
   NLRI (AFI=1, SAFI=133) is for IPv4 unicast filtering. NLRI (AFI=1,
   SAFI=134)is for BGP/MPLS VPN filtering. The Flow specification match
   part only includes L3/L4 information like source/destination prefix,
   protocol, ports, and etc, so traffic flows can only be selectively
   filtered based on L3/L4 information.

   Layer 2 Virtual Private Networks  L2VPNs have already been deployed
   in an increasing number of networks today. In L2VPN network, we also
   have requirement to deploy BGP Flow-spec to mitigate DDoS attack


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   traffic. Within L2VPN network, both IP and non-IP Ethernet traffic
   maybe exist. For IP traffic filtering, the Flow specification rules
   defined in [RFC5575] which include match criteria and actions can
   still be used, flow specification rules received via new NLRI format
   apply only to traffic that belongs to the VPN instance(s) in which
   it is imported. For non-IP Ethernet traffic filtering, Layer 2
   related information like source/destination MAC and VLAN should be
   considered. But the flow specification match criteria defined in
   RFC5575 only include layer 3 and layer 4 IP information, layer 2
   Ethernet information haven't been included.

   There are different kinds of L2VPN networks like EVPN [EVPN], BGP
   VPLS [RFC4761], LDP VPLS [RFC4762] and border gateway protocol (BGP)
   auto discovery [RFC 6074]. Because the flow-spec feature relies on
   BGP protocol to distribute traffic filtering rules, so it can only
   be incrementally deployed in those L2VPN networks where BGP has
   already been used for auto discovery and/or signaling purposes such
   as BGP-based VPLS [4761], EVPN and LDP-based VPLS [4762] with BGP
   auto-discovery [6074].

   This draft proposes a new subset of component types and extended
   community to support L2VPN flow-spec application. The flow-spec
   rules can be enforced on all border routers or on some interface
   sets of the border routers. SAFI=134 in [RFC5575] is redefined for
   dissemination traffic filtering information in an L2VPN environment.

2. Layer 2 Flow Specification encoding in BGP

   The [RFC5575] defines SAFI 133 and SAFI 134 for "dissemination of
   IPv4 flow specification rules" and "dissemination of VPNv4 flow
   specification rules" respectively. [draft-ietf-idr-flow-spec-v6-06]
   redefines the [RFC5575] SAFIs in order to make them applicable to
   both IPv4 and IPv6 applications. This document will further redefine
   the SAFI 134 in order to make them applicable to L2VPN applications.

   The following changes are defined:

   "SAFI 134 for dissemination of L3VPN flow specification rules" to
   now be defined as "SAFI 134 for dissemination of VPN flow
   specification rules"

   For SAFI 134 the indication to which address family it is referring
   to will be recognized by AFI value (AFI=1 for VPNv4, AFI=2 VPNv6 and
   AFI=25 for L2VPN). Such modification is fully backwards compatible
   with existing implementation and production deployments.




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3. Ethernet Flow Specification encoding in BGP

   The NLRI format for this address family consists of a fixed-length
   Route Distinguisher field (8 bytes) followed by a flow specification,
   following the encoding defined in this document.  The NLRI length
   field shall include both the 8 bytes of the Route Distinguisher as
   well as the subsequent flow specification.

   Flow specification rules received via this NLRI apply only to
   traffic that belongs to the VPN instance(s) in which it is imported.
   Flow rules are accepted by default, when received from remote PE
   routers.

   Besides the component types defined in [RFC5575] and [draft-ietf-
   idr-flow-spec-v6-06], this document proposes the following
   additional component types for L2VPN Ethernet traffic filtering:

   Type 14 - Ethernet Type

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match two-octet
   field. Values are encoded as 2-byte quantities. Ethernet II framing
   defines the two-octet Ethernet Type field in an Ethernet frame,
   preceded by destination and source MAC addresses, that identifies an
   upper layer protocol encapsulating the frame data.

   Type 15 - Source MAC

   Encoding: <type (1 octet), MAC Address length (1 octet), MAC Address>

   Defines the source MAC Address to match.

   Type 16 - Destination MAC

   Encoding: <type (1 octet), MAC Address length (1 octet), MAC Address>

   Defines the destination MAC Address to match.

   Type 17 - DSAP(Destination Service Access Point) in LLC

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match 1-octet
   DSAP in the 802.2 LLC(Logical Link Control Header). Values are
   encoded as 1-byte quantities. The operation field is encoded as
   'Numeric operator' defined in [RFC5575].


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   Type 18 - SSAP(Source Service Access Point) in LLC

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match 1-octet
   SSAP in the 802.2 LLC. Values are encoded as 1-byte quantities.

   Type 19 - Control field in LLC

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match 1-octet
   control field in the 802.2 LLC. Values are encoded as 1-byte
   quantities.

   Type 20 - SNAP

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match 5-octet
   SNAP(Sub-Network Access Protocol) field. Values are encoded as 5-
   byte quantities.



   Type 21 - VLAN ID

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match VLAN ID.
   Values are encoded as 2-byte quantities, where the four most
   significant bits are zero and the 12 least significant bits contain
   the VLAN value.

   In virtual local-area network (VLAN) stacking case, the VLAN ID is
   outer VLAN ID.

   Type 22 - VLAN COS

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match 3-bit VLAN
   COS fields [802.1p]. Values are encoded using a single byte, where
   the five most significant bits are zero and the three least
   significant bits contain the VLAN COS value.




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   In virtual local-area network (VLAN) stacking case, the VLAN COS is
   outer VLAN COS.

   Type 23 - Inner VLAN ID

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match inner VLAN
   ID using for virtual local-area network (VLAN) stacking or Q in Q
   case. Values are encoded as 2-byte quantities, where the four most
   significant bits are zero and the 12 least significant bits contain
   the VLAN value.

   In single VLAN case, the component type MUST not be used.

   Type 24 - Inner VLAN COS

   Encoding: <type (1 octet), [op, value]+>

   Defines a list of {operation, value} pairs used to match 3-bit inner
   VLAN COS fields [802.1p] using for virtual local-area network (VLAN)
   stacking or Q in Q case. Values are encoded using a single byte,
   where the five most significant bits are zero and the three least
   significant bits contain the VLAN COS value.

   In single VLAN case, the component type MUST not be used.

3.1. Order of Traffic Filtering Rules

   The original definition for the order of traffic filtering rules can
   be reused with new consideration for the MAC Address offset. As long
   as the offsets are equal, the comparison is the same, retaining
   longest-prefix-match semantics.  If the offsets are not equal, the
   lowest offset has precedence, as this flow matches the most
   significant bit.













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   Pseudocode:
   flow_rule_L2_cmp (a, b)
      {
          comp1 = next_component(a);
          comp2 = next_component(b);
          while (comp1 || comp2) {
              // component_type returns infinity on end-of-list
              if (component_type(comp1) < component_type(comp2)) {
                  return A_HAS_PRECEDENCE;
              }
              if (component_type(comp1) > component_type(comp2)) {
                  return B_HAS_PRECEDENCE;
              }

              if (component_type(comp1) == MAC_DESTINATION || MAC_SOURCE) {
                  common = MIN(MAC Address length (comp1),
                        MAC Address length (comp2));
                  cmp = MAC Address compare(comp1, comp2, common);
                  // not equal, lowest value has precedence
                  // equal, longest match has precedence
              } else {
                  common =
                     MIN(component_length(comp1), component_length(comp2));
                  cmp = memcmp(data(comp1), data(comp2), common);
                  // not equal, lowest value has precedence
                  // equal, longest string has precedence
              }
          }
          return EQUAL;
      }

4. Ethernet Flow Specification Traffic Actions

   The default action for a layer 2 traffic filtering flow
   specification is to accept traffic that matches that particular rule.
   The following extended community values per RFC5575 can be used to
   specify particular actions in L2VPN network:











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   +--------+--------------------+--------------------------+
   |  type  | extended community |        encoding          |
   +--------+--------------------+--------------------------+
   | 0x8006 | traffic-rate       | 2-byte as#, 4-byte float |
   | 0x8007 | traffic-action     | bitmask                  |
   | 0x8008 | redirect           | 6-byte Route Target      |
   | 0x8009 | traffic-marking    | DSCP value               |
   +--------+--------------------+--------------------------+
   Redirect: The action should be redefined to allow the traffic to be
   redirected to a MAC or IP VRF routing instance that lists the
   specified route-target in its import policy.

   Besides the above extended communities, this document also proposes
   the following BGP extended communities specifications for Ethernet
   flow to extend [RFC5575]:

   +--------+------------------------+--------------------------+
   | type   | extended community     |   encoding               |
   +--------+------------------------+--------------------------+
   |  TBD1  | VLAN-action            |   bitmask                |
   |  TBD2  | TPID-action            |   bitmask                |
   +--------+------------------------+--------------------------+


   VLAN-action: The VLAN-action extended community consists of 6 bytes
   which include the fields of action Flags, two VLAN IDs and the
   associating COS value. The action Flags fields are further divided
   into two parts which correspond to the first action and the second
   action respectively, bit 0 to bit 7 belong to the first action part
   while bit 8 to bit 15 belong to the second part. The bits of PO, PU,
   SW, RI and RO in each part represent the action of Pop, Push, Swap,
   Rewrite inner VLAN and Rewrite outer VLAN respectively. Through this
   method, more complicated actions also can be represented in a single
   VLAN-action extend community, such as SwapPop, PushSwap, etc. For
   example, SwapPop action is the concatenation of two actions, the
   first action is Swap and the second action is Pop.












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   0                       7                       15
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   |PO1|PU1|SW1|RI1|RO1|...|PO2|PU2|SW2|RI2|RO2|...|
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   | VLAN ID1                          |COS1    |R1|
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   | VLAN ID2                          |COS2    |R2|
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+

   PO1: Pop action. If the PO1 flag is one it indicates the outmost
   VLAN should be removed.

   PU1: Push action. If PU1 is one it indicates VLAN ID1 will be added,
   the associated COS is COS1.

   SW1: Swap action. If the SW1 flag is one it indicates the outer VLAN
   and inner VLAN should be swapped.

   PO2: Pop action. If the PO2 flag is one it indicates the outmost
   VLAN should be removed.

   PU2: Push action. If PU2 is one it indicates VLAN ID2 will be added,
   the associated COS is COS2.

   SW2: Swap action. If the SW2 flag is one it indicates the outer VLAN
   and inner VLAN should be swapped.

   RI1 and RI2: Rewrite inner VLAN action. If the RI flag is one it
   indicates the inner VLAN should be replaced by a new VLAN, the new
   VLAN is VLAN ID1, the associated COS is COS1. If the VLAN ID1 is 0,
   the action is to only modify the COS value of inner VLAN.

   RO1 and RO2: Rewrite outer VLAN action. If the RO flag is one it
   indicates the outer VLAN should be replaced by a new VLAN, the new
   VLAN is VLAN ID2, the associated COS is COS2. If the VLAN ID2 is 0,
   the action is to only modify the COS value of outer VLAN.

   R1 and R2: Reserved for future use.

    Giving an example, if the action of PUSH Inner VLAN 10 with COS
    value 5 and Outer VLAN 20 with COS value 6 is needed, the format of
    the VLAN-action extended community is as follows:







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   0                       7                       15
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   |0 |1 |0 |0 |0 |0 |0 |0 |0 |1 |0 |0 |0 |0 |0 |0 |
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   | 10                                |1 |0 |1 |0 |
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   | 20                                |1 |1 |0 |0 |
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+


   TPID-action: The TPID-action extended community consists of 6 bytes
   which includes the fields of action Flags, TPID1 and TPID2.

   0                                              15
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   |TI|TO|                     Resv                |
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   |                    TP ID1                     |
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   |                    TP ID2                     |
   +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+


   TI: Mapping inner TP ID action. If the TI flag is one it indicates
   the inner TP ID should be replaced by a new TP ID, the new TP ID is
   TP ID1.

   TO: Mapping outer TP ID action. If the TO flag is one it indicates
   the outer TP ID should be replaced by a new TP ID, the new TP ID is
   TP ID2.

   Resv: Reserved for future use.


5. Security Considerations

   No new security issues are introduced to the BGP protocol by this
   specification.

6. IANA Considerations

   IANA is requested to rename currently defined SAFI 134 per [RFC5575]
   to read:

      134     VPN dissemination of flow specification rules




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   IANA is requested to create and maintain a new registry for "Flow
   spec L2VPN Component Types". For completeness, the types defined in
   [RFC5575] and [draft-ietf-idr-flow-spec-v6-06] also are listed here.

   +--------+-------------------------------+--------------------------+
   |  type  |         RFC or Draft          |       discription        |
   +--------+-------------------------------+--------------------------+
   |   1    |RFC5575                        | Destination Prefix       |
   |   1    |draft-ietf-idr-flow-spec-v6-06 | Destination IPv6 Prefix  |
   |   2    |RFC5575                        | Source Prefix            |
   |   2    |draft-ietf-idr-flow-spec-v6-06 | Source IPv6 Prefix       |
   |   3    |RFC5575                        | IP Protocol              |
   |   3    |draft-ietf-idr-flow-spec-v6-06 | Next Header              |
   |   4    |RFC5575                        | Port                     |
   |   5    |RFC5575                        | Destination port         |
   |   6    |RFC5575                        | Source port              |
   |   7    |RFC5575                        | ICMP type                |
   |   8    |RFC5575                        | ICMP code                |
   |   9    |RFC5575                        | TCP flags                |
   |   10   |RFC5575                        | Packet length            |
   |   11   |RFC5575                        | DSCP                     |
   |   12   |RFC5575                        | Fragment                 |
   |   13   |draft-ietf-idr-flow-spec-v6-06 | Flow Label               |
   |   14   |This draft                     | Ethernet Type            |
   |   15   |This draft                     | Source MAC               |
   |   16   |This draft                     | Destination MAC          |
   |   17   |This draft                     | DSAP in LLC              |
   |   18   |This draft                     | SSAP in LLC              |
   |   19   |This draft                     | Control field in LLC     |
   |   20   |This draft                     | SNAP                     |
   |   21   |This draft                     | VLAN ID                  |
   |   22   |This draft                     | VLAN COS                 |
   |   23   |This draft                     | Inner VLAN ID            |
   |   24   |This draft                     | Inner VLAN COS           |
   +--------+-------------------------------+--------------------------+
   IANA is requested to update the reference for the following
   assignment in the "BGP Extended Communities Type - extended,
   transitive" registry:

   Type value Name Reference

   ---------- ---------------------------------------- ---------

   0x080A Flow spec VLAN action [this document]

   0x080B Flow spec TPID action [this document]



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6.1. Normative References

   [1]  [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate

         Requirement Levels", BCP 14, RFC 2119, March 1997.

   [2]  [RFC5575] P. Marques, N. Sheth, R. Raszuk, B. Greene, J.Mauch,
         D. McPherson, "Dissemination of Flow Specification Rules", RFC
         5575, August 2009.

   [3]  [RFC4761] K. Kompella, Ed., Y. Rekhter, Ed., "Virtual Private
         LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling",
         RFC4761, January 2007.

   [4]  [RFC4762] M. Lasserre, Ed., V. Kompella, Ed., "Virtual Private
         LAN Service (VPLS) Using Label Distribution Protocol (LDP)
         Signaling", RFC4762, January 2007.

   [5]  [RFC6074] E. Rosen, B. Davie, V. Radoaca, "Provisioning, Auto-
         Discovery, and Signaling in Layer 2 Virtual Private Networks
         (L2VPNs)", RFC6074, January 2011.



6.2. Informative References

   [1]   [EVPN] Sajassi et al., "BGP MPLS Based Ethernet VPN", draft-
         ietf-l2vpn-evpn-07.txt, work in progress, May, 2014.

   [2]   [IEEE 802.1p] Javin, et.al. "IEEE 802.1p: LAN Layer 2 QoS/CoS
         Protocol for Traffic Prioritization", 2012-02-15

7. Acknowledgments

   The authors wish to acknowledge the important contributions of
   Hannes Gredler, Xiaohu Xu, Zhenbin Li and Lucy Yong.












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   Authors' Addresses

   Weiguo Hao
   Huawei Technologies
   101 Software Avenue,
   Nanjing 210012
   China
   Email: haoweiguo@huawei.com

   Qiandeng Liang
   Huawei Technologies
   101 Software Avenue,
   Nanjing 210012
   China
   Email: liangqiandeng@huawei.com


   James Uttaro
   AT&T
   Email: uttaro@att.com


   Stephane Litkowski
   Orange
   Email: stephane.litkowski@orange.com



   Shunwan Zhuang
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China
   Email: zhuangshunwan@huawei.com














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