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INTERNET-DRAFT                                                    W. Hao
Intended Status: Proposed Standard                   Huawei Technologies
                                                             D. Eastlake
                                                  Futurewei Technologies
                                                            S. Litkowski
                                                           Cisco Systems
                                                               S. Zhuang
                                                     Huawei Technologies
Expires: November 23, 2020                                  May 24, 2020


            BGP Dissemination of L2 Flow Specification Rules
                    draft-ietf-idr-flowspec-l2vpn-15



Abstract
   This document defines a Border Gateway Protocol (BGP) Flow
   Specification (flowspec) extension to disseminate Ethernet Layer 2
   (L2) and Layer 2 Virtual Private Network (L2VPN) traffic filtering
   rules either by themselves or in conjunction with L3 flowspecs.
   AFI/SAFI 6/133 and 25/134 are used for these purposes.  New component
   types and an extended community also are defined.


Status of This Document

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Distribution of this document is unlimited. Comments should be sent
   to the authors or the IDR Working Group mailing list <idr@ietf.org>.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft
   Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.








W. Hao, et al                                                   [Page 1]


INTERNET-DRAFT                                              L2 Flow Spec


Table of Contents

      1. Introduction............................................3
      1.1 Terminology............................................4

      2. Layer 2 Flow Specification Encoding.....................5
      2.1 L2 Component Types.....................................6
      2.1.1 Type 1 - Ethernet Type (EtherType)...................6
      2.1.2 Type 2 - Source MAC..................................7
      2.1.3 Type 3 - Destination MAC.............................7
      2.1.4 Type 4 - DSAP (Destination Service Access Point).....7
      2.1.5 Type 5 - SSAP (Source Service Access Point)..........7
      2.1.6 Type 6 - Control field in LLC........................8
      2.1.7 Type 7 - SNAP........................................8
      2.1.8 Type 8 - VLAN ID.....................................8
      2.1.9 Type 9 - VLAN PCP....................................8
      2.1.10 Type 10 - Inner VLAN ID.............................9
      2.1.11 Type 11 - Inner VLAN PCP............................9
      2.1.12 Type 12 - VLAN DEI..................................9
      2.1.13 Type 13 - Inner VLAN DEI...........................10
      2.1.14 Type 14 - Source MAC Special Bits..................10
      2.1.15 Type 15 - Destination MAC Special Bits.............10
      2.2 Order of Traffic Filtering Rules......................10

      3. L2VPN Flow Specification Encoding in BGP...............12
      3.1 Order of L2VPN Filtering Rules........................12

      4. Ethernet Flow Specification Traffic Actions............13
      4.1 VLAN-action...........................................13
      4.2 TPID-action...........................................15

      5. Flow Spec Validation...................................16

      6. IANA Considerations....................................17
      7. Security Considerations................................19

      8. Acknowledgements.......................................19
      9. Contributors...........................................19

      Normative References......................................20
      Informative References....................................21

      Authors' Addresses........................................22









W. Hao, et al                                                   [Page 2]


INTERNET-DRAFT                                              L2 Flow Spec


1. Introduction

   Border Gateway Protocol (BGP) Flow Specification [RFC5575bis]
   (flowspec) is an extension to BGP that supports the dissemination of
   traffic flow specification rules and actions to be taken on packets
   in a specified flow.  It leverages the BGP Control Plane to simplify
   the distribution of ACLs (Access Control Lists).  Using the Flow
   Specification extension new filter rules can be injected to all BGP
   peers simultaneously without changing router configuration.  A
   typical application is to automate the distribution of traffic filter
   lists to routers for DDoS (Distributed Denial of Service) mitigation,
   access control, and similar applications.

   BGP Flow Specification [RFC5575bis] defines a BGP Network Layer
   Reachability Information (NLRI) format used to distribute traffic
   flow specification rules.  The NLRI for (AFI=1, SAFI=133) specifies
   IPv4 unicast filtering.  The NLRI for (AFI=1, SAFI=134) specifies
   IPv4 BGP/MPLS VPN filtering [RFC7432].  The Flow Specification match
   part defined in [RFC5575bis] only includes L3/L4 information like
   IPv4 source/destination prefix, protocol, ports, and the like, so
   traffic flows can only be filtered based on L3/L4 information. This
   has been extended by [FlowSpecV6] to cover IPv6 (AFI=2) L3/L4.

   Layer 2 Virtual Private Networks (L2VPNs) have been deployed in an
   increasing number of networks.  Such networks also have requirements
   to deploy BGP Flow Specification to mitigate DDoS attack traffic.
   Within an L2VPN network, both IP and non-IP Ethernet traffic may
   exist.  For IP traffic filtering, the VPN Flow Specification rules
   defined in [RFC5575bis] and/or [FlowSpecV6], which include match
   criteria and actions, can still be used.  For non-IP Ethernet traffic
   filtering, Layer 2 related information like source/destination MAC
   and VLAN must be considered.

   There are different kinds of L2VPN networks like EVPN [RFC7432], BGP
   VPLS [RFC4761], LDP VPLS [RFC4762] and border gateway protocol (BGP)
   auto discovery [RFC6074].  Because the Flow Specification feature
   relies on the BGP protocol to distribute traffic filtering rules, 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 [RFC4761], EVPN, and LDP-based VPLS [RFC4762]
   with BGP auto-discovery [RFC6074].

   This document defines new flowspec component types and two new
   extended communities to support L2 and L2VPN flowspec applications.
   The flowspec rules can be enforced on all border routers or on some
   interface sets of the border routers.  SAFI=133 in [RFC5575bis] and
   [FlowSpecV6] is extended for AFI=6 as specified in Section 2 to cover
   L2 traffic filtering information and in Section 3 SAFI=134 is
   extended for AFI=25 to cover the L2VPN environment.



W. Hao, et al                                                   [Page 3]


INTERNET-DRAFT                                              L2 Flow Spec


1.1 Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   The following acronyms and terms are used in this document:

      AFI - Address Family Identifier

      ACL - Access Control List

      DDoS - Distributed Denial of Service

      DEI - Drop Eligible Indicator

      EVPN - Ethernet VPN [RFC7432]

      flowspec - BGP Flow Specification

      L2 - Layer 2

      L2VPN - Layer 2 VPN

      L3 - Layer 3

      L3VPN - Layer 3 VPN

      NLRI - Network Layer Reachability Information

      PCP - Priority Code Point [802.1Q]

      SAFI - Subsequent Address Family Identifier

      TPID - Tag Protocol ID, typically a VLAN ID

      VLAN - Virtual Local Area Network

      VPLS - Virtual Private Line Service [RFC4762]

      VPN - Virtual Private Network









W. Hao, et al                                                   [Page 4]


INTERNET-DRAFT                                              L2 Flow Spec


2. Layer 2 Flow Specification Encoding

   [RFC5575bis] defines SAFI 133 and SAFI 134, with AFI=1, for
   "dissemination of IPv4 flow specification rules" and "dissemination
   of VPNv4 flow specification rules", respectively.  [FlowSpecV6]]
   extends [RFC5575bis] to also allow AFI=2 thus making it applicable to
   both IPv4 and IPv6 applications.  This document further extends
   SAFI=133 for AFI=6 and SAFI=134 for AFI=25 to make them applicable to
   L2 and L2VPN applications. This document also provides for the
   optional combination of L3 flow specifications with these L2 flow
   specifications.

   This section specifies the L2 flowspec for AFI=6/SAFI=133. To
   simplify assignments, a new registry is used for L2 flowspec. Since
   it is frequently desirable to also filter on L3/L4 fields, provision
   is made for their inclusion along with an indication of the L3
   protocol involved (IPv4 or IPv6).

   The NLRI part of the MP_REACH_NLRI and MP_UNREACH_NLRI is encoded as
   a 1- or 2-octet total NLRI length field followed by several fields as
   described below.

            +-------------------------------+
            | total-length (0xnn or 0xfnnn) |  2 or 3 octets
            +-------------------------------+
            |             L3-AFI            |  2 octets
            +-------------------------------+
            |  L2-length (0xnn or 0xfnnn)   |  2 or 3 octets
            +-------------------------------+
            |           NLRI-value          |  variable
            +-------------------------------+

                 Figure 1: Flow Specification NLRI for L2

   The fields show in Figure 1 are further specified below:

      total-length: The length of the subsequent fields (L3 AFI,
         L2-length, and NRLI-value) encoded as provided in Section 4.1
         of [RFC5575bis]. If this field is less than 4, which is the
         minimum valid value, then the NLRI is malformed in which case a
         NOTIFICATION message is sent and the BGP connection closed as
         provided in Section 6.3 of [RFC4271].

      L3-AFI: If no L3/L4 filtering is desired, this two octet field
         MUST be zero which is a reserved AFI value. Otherwise L3-AFI
         indicates the L3 protocol involved by giving its AFI (0x0001
         for IPv4 or 0x0002 for IPv6). If the receiver does not
         understand the value of the L3-AFI field, the MP_REACH or
         MP_UNREACH attribute is ignored.



W. Hao, et al                                                   [Page 5]


INTERNET-DRAFT                                              L2 Flow Spec


      L2-length: The length of the L2 components at the beginning of the
         NLRI-value field encoded as provided in Section 4.1 of
         [RFC5575bis].  If the value of this field indicates that the L2
         components extend beyond the total-length, the NLRI is
         malformed in which case a NOTIFICATION message is sent and the
         BGP connection closed as provided in Section 6.3 of [RFC4271].
         N2-length MAY be zero although, in that case, it would have
         been more efficient to encode the attribute as an L3 Flow spec
         unless it is desired to apply an L2 action (see Section 4). A
         null L2 flowspec always matches.

      NLRI-value: This consists of the L2 flowspec, of length L2-length,
         followed by an optionally present L3 flowspec. The result can
         be treated in most ways as a single flowspec, matching the
         intersection (AND) of all the components except that the
         components in the initial L2 region are interpreted as L2
         components and the remainder as L3 components per the L3-AFI
         field. This is necessary because there are different registries
         for the L2, L3 IPv4, and L3 IPv6 component types. If the L3
         flowspec is null (length zero), it always matches.



2.1 L2 Component Types

   The L2 flowspec portion of the NLRI-value consists of flowspec
   components as in [RFC5575bis] but using L2 components and types as
   specified below. All components start with a type octet followed by a
   length octet followed by any additional information needed. The
   length octet give the length, in octets, of the information after the
   length octet.  This structure applies to all new components to be
   defined in the L2 Flow-spec Component Registry (see Section 6) and to
   all existing components except Types 2 and 3 where the length is in
   bits.



2.1.1 Type 1 - Ethernet Type (EtherType)

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

   Defines a list of {operation, value} pairs used to match the two-
   octet EtherType field.  op is encoded as specified in Section 4.2.1.1
   of [RFC5575bis]. Values are encoded as 2-octet quantities.  Ethernet
   II framing defines the two-octet Ethernet Type (EtherType) field in
   an Ethernet frame, preceded by destination and source MAC addresses,
   that identifies an upper layer protocol encapsulating the frame data.
   The match fails if LLC encoding is being used rather than EtherType
   encoding.



W. Hao, et al                                                   [Page 6]


INTERNET-DRAFT                                              L2 Flow Spec


2.1.2 Type 2 - Source MAC

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

   Defines the source MAC Address prefix to match encoded as in BGP
   UPDATE messages [RFC4271].  Prefix length is in bits and the MAC
   Prefix is fill out with from 1 to 7 padding bits so that it is an
   integer number of octets. These padding bits are ignored for matching
   purposes.



2.1.3 Type 3 - Destination MAC

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

   Defines the destination MAC Address to match encoded as in BGP UPDATE
   messages [RFC4271]. Prefix length is in bits and the MAC Prefix is
   fill out with from 1 to 7 padding bits so that it is an integer
   number of octets. These padding bits are ignored for matching
   purposes.



2.1.4 Type 4 - DSAP (Destination Service Access Point)

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

   Defines a list of {operation, value} pairs used to match the 1-octet
   DSAP in the IEEE 802.2 LLC (Logical Link Control Header).  Values are
   encoded as 1-octet quantities.  op is encoded as specified in Section
   4.2.1.1 of [RFC5575bis]. The match fails if EtherType L2 header
   encoding is being used rather than LLC encoding.



2.1.5 Type 5 - SSAP (Source Service Access Point)

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

   Defines a list of {operation, value} pairs used to match the 1-octet
   SSAP in the IEEE 802.2 LLC.  Values are encoded as 1-octet
   quantities. op is encoded as specified in Section 4.2.1.1 of
   [RFC5575bis].  The match fails if EtherType L2 header encoding is
   being used rather than LLC encoding.







W. Hao, et al                                                   [Page 7]


INTERNET-DRAFT                                              L2 Flow Spec


2.1.6 Type 6 - Control field in LLC

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

   Defines a list of {operation, value} pairs used to match the 1-octet
   control field in the IEEE 802.2 LLC.  Values are encoded as 1-octet
   quantities. op is encoded as specified in Section 4.2.1.1 of
   [RFC5575bis].  The match fails if EtherType L2 header encoding is
   being used rather than LLC encoding.



2.1.7 Type 7 - SNAP

   Encoding: <type (1 octet), length (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-octet
   quantities. op is encoded as specified in Section 4.2.1.1 of
   [RFC5575bis]. The match fails if EtherType L2 header encoding is
   being used rather than LLC encoding.



2.1.8 Type 8 - VLAN ID

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

   Defines a list of {operation, value} pairs used to match VLAN ID.
   Values are encoded as 2-octet quantities, where the four most
   significant bits are set to zero and ignored for matching and the 12
   least significant bits contain the VLAN value. op is encoded as
   specified in Section 4.2.1.1 of [RFC5575bis].

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



2.1.9 Type 9 - VLAN PCP

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

   Defines a list of {operation, value} pairs used to match 3-bit VLAN
   PCP (priority code point) fields [802.1Q].  Values are encoded using
   a single octet, where the five most significant bits are set to zero
   and ignored for matching and the three least significant bits contain
   the VLAN PCP value. op is encoded as specified in Section 4.2.1.1 of
   [RFC5575bis].



W. Hao, et al                                                   [Page 8]


INTERNET-DRAFT                                              L2 Flow Spec


   In the virtual local-area network (VLAN) stacking case, the VLAN PCP
   is part of the outer VLAN tag.



2.1.10 Type 10 - Inner VLAN ID

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

   Defines a list of {operation, value} pairs used to match the inner
   VLAN ID using for virtual local-area network (VLAN) stacking or Q-in-
   Q use.  Values are encoded as 2-octet quantities, where the four most
   significant bits are set to zero and ignored for matching and the 12
   least significant bits contain the VLAN value. op is encoded as
   specified in Section 4.2.1.1 of [RFC5575bis].

   In the single VLAN case, this component type MUST NOT be used. If it
   appears the match will fail.



2.1.11 Type 11 - Inner VLAN PCP

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

   Defines a list of {operation, value} pairs used to match 3-bit inner
   VLAN PCP fields [802.1Q] using for virtual local-area network (VLAN)
   stacking or Q in Q use.  Values are encoded using a single octet,
   where the five most significant bits are set to zero and ignored for
   matching and the three least significant bits contain the VLAN PCP
   value. op is encoded as specified in Section 4.2.1.1 of [RFC5575bis].

   In the single VLAN case, this component type MUST NOT be used. If it
   appears the match will fail.



2.1.12 Type 12 - VLAN DEI

   Encoding: <type (1 octet), length (1 octet), op (1 octet)>

   This type tests the DEI (Drop Eligible Indicator) bit in the VLAN
   tag. If op is zero, it matches if and only if the DEI bit is zero. If
   op is non-zero, it matches if and only if the DEI bit is one.

   In the virtual local-area network (VLAN) stacking case, the VLAN DEI
   is part of the outer VLAN tag.





W. Hao, et al                                                   [Page 9]


INTERNET-DRAFT                                              L2 Flow Spec


2.1.13 Type 13 - Inner VLAN DEI

   Encoding: <type (1 octet), length (1 octet), op (1 octet)>

   This type tests the DEI bit in the inner VLAN tag. If op is zero, it
   matches if and only if the DEI bit is zero. If op is non-zero, it
   matches if and only if the DEI bit is one.

   In the single VLAN case, this component type MUST NOT be used. If it
   appears the match will fail.



2.1.14 Type 14 - Source MAC Special Bits

   Encoding: <type (1 octet), length (1 octet), op (1 octet)>

   This type tests the bottom nibble of the top octet of the Source MAC
   address. The two low order bits of that nibble have long been the
   local bit (0x2) and the group addressed bit (0x1). However, recent
   changes in IEEE 802 have divided the local address space into 4
   quadrants specified by the next two bits (0x4 and 0x8) [RFC7042bis].
   This flowspec component permits testing, for example, that a MAC is
   group addressed or is a local address in a particular quadrant. The
   encoding is as given in Section 4.2.1.2 of [RFC5575bis].



2.1.15 Type 15 - Destination MAC Special Bits

   Encoding: <type (1 octet), length (1 octet), op (1 octet)>

   As discussed in Section 2.1.14 but for the Destination MAC Address.



2.2 Order of Traffic Filtering Rules

   The existing rules in Section 5.1 of [RFC5575bis] and in [FlowSpecV6]
   for the ordering of traffic filtering are extended as follows:

   L2 flowspecs (AFI = 6, 25) take precedence over L3 flowspecs (AFI =
   1, 2). Between two L2 flowspecs, precedence of the L2 portion is
   determined as specified in this section after this paragraph. If the
   L2 flowspec L2 portions are the same and the L3-AFI is nonzero, then
   the L3 portions are compared as specified in [RFC5575bis] or
   [FlowSpecV6] as appropriate. Note: if the L3-AFI fields are different
   between two L2 flowspecs, they will never match the same packet so it
   will not be necessary to prioritize two flowspecs with different
   L3-AFI values.


W. Hao, et al                                                  [Page 10]


INTERNET-DRAFT                                              L2 Flow Spec


   The original definition for the order of traffic filtering rules can
   be reused for L2 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.

   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;
   }















W. Hao, et al                                                  [Page 11]


INTERNET-DRAFT                                              L2 Flow Spec


3. L2VPN Flow Specification Encoding in BGP

   The NLRI format for AFI=25/SAFI=134 (L2VPN), as with the other VPN
   flowspec AFI/SAFI pairs, is the same as the non-VPN Flow-Spec but
   with the addition of a Route Distinguisher to identify the VPN to
   which the flowspec is to be applied.

   In addition, the IANA entry for SAFI 134 is slightly generalized as
   specified at the beginning of Section 6.

   The L2VPN NLRI format is as follows:

            +-------------------------------+
            | total-length (0xnn or 0xfnnn) |  2 or 3 octets
            +-------------------------------+
            |      Route Distinguisher      |  8 octets
            +-------------------------------+
            |            L3-AFI             |  2 octets
            +-------------------------------+
            |  L2-length (0xnn or 0xfnnn)   |  2 or 3 octets
            +-------------------------------+
            |           NLRI-value          |  variable
            +-------------------------------+

                Figure 2: Flow Specification NLRI for L2VPN

   The fields in Figure 2, other than the Route Distinguisher, are
   encoded as specified in Section 2 except that the minimum value for
   total-length is 12.

   Flow specification rules received via this NLRI apply only to traffic
   that belongs to the VPN instance(s) into which it is imported.  Flow
   rules are accepted as specified in Section 5.



3.1 Order of L2VPN Filtering Rules

   The order between L2VPN filtering rules is determined as specified in
   Section 2.2. Note that if the Route Distinguisher is different
   between two L2VPN filtering rules, they will never both match the
   same packet so they need not be prioritized.










W. Hao, et al                                                  [Page 12]


INTERNET-DRAFT                                              L2 Flow Spec


4. Ethernet Flow Specification Traffic Actions

   The default action for an L2 traffic filtering flowspec is to accept
   traffic that matches that particular rule.  The following extended
   community values per [RFC5575bis] can be used to specify particular
   actions in an L2 VPN network:

       +--------+--------------------+----------------------------+
       |  type  | extended community |          encoding          |
       +--------+--------------------+----------------------------+
       | 0x8006 | traffic-rate       | 2-octet as#, 4-octet float |
       | 0x8007 | traffic-action     | bitmask                    |
       | 0x8008 | redirect           | 6-octet 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 specifies
   the following BGP extended communities for Ethernet flows to extend
   [RFC5575bis]:

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



4.1 VLAN-action

   The VLAN-action extended community, as shown in the diagram below,
   consists of 6 octets that include action Flags, two VLAN IDs, and the
   associated PCP and DEI values.  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 give the first action
   while bit 8 to bit 15 give the second action.  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 extended community, such as SwapPop, PushSwap, etc.  For
   example, SwapPop action is the sequence of two actions, the first
   action is Swap and the second action is Pop.





W. Hao, et al                                                  [Page 13]


INTERNET-DRAFT                                              L2 Flow Spec


     0   1   2   3   4   5   6   7   8   9   10  11  12  13  14  15
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   |PO1|PU1|SW1|RI1|RO1| Resv      |PO2|PU2|SW2|RI2|RO2| Resv      |
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   | VLAN ID1                                      | PCP1      |DE1|
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
   | VLAN ID2                                      | PCP2      |DE2|
   +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+

   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 PCP and DEI are PCP1 and DE1.

   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 PCP and DEI are PCP2 and DE2.

   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 RIx flag is one
   (where "x" is "1" or "2"), it indicates the inner VLAN should be
   replaced by a new VLAN where the new VLAN is VLAN IDx and the
   associated PCP and DEI are PCPx and DEx.  If the VLAN IDx is 0, the
   action is to only modify the PCP and DEI value of the inner VLAN.

   RO1 and RO2: Rewrite outer VLAN action.  If the ROx flag is one
   (where "x" is "1" or "2"), it indicates the outer VLAN should be
   replaced by a new VLAN where the new VLAN is VLAN IDx and the
   associated PCP and DEI are PCPx and DEx.  If the VLAN IDx is 0, the
   action is to only modify the PCP and DEI value of the outer VLAN.

   Resv: Reserved for future use.  MUST be sent as zero and ignored on
   receipt.

   Giving an example below: if the action of PUSH Inner VLAN 10 with PCP
   value 5 and DEI value 0 and PUSH Outer VLAN 20 with PCP value 6 and
   DEI value 0 is needed, the format of the VLAN-action extended
   community is as follows:






W. Hao, et al                                                  [Page 14]


INTERNET-DRAFT                                              L2 Flow Spec


        0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 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 |
      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+



4.2 TPID-action

   The TPID-action extended community consists of 6 octets which
   includes the fields of action Flags, TP ID1 and TP ID2.

        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.  MUST be sent as zero and ignored on
   receipt.

















W. Hao, et al                                                  [Page 15]


INTERNET-DRAFT                                              L2 Flow Spec


5. Flow Spec Validation

   Flow Specifications received over AFI=25/SAFI=134 are validated
   against routing reachability received over AFI=25/SAFI=128 as
   modified to conform to [FlowSpecOID].















































W. Hao, et al                                                  [Page 16]


INTERNET-DRAFT                                              L2 Flow Spec


6. IANA Considerations

   IANA is requested to change the description for SAFI 134 [RFC5575bis]
   to read as follows and to change the reference for it to [this
   document]:

      134  VPN dissemination of flow specification rules

   IANA is requested to create an L2 Flow Specification Component Type
   registry on the Flow Spec Component Types registries web page as
   follows:

      Name:  L2 Flow Specification Component Types
      Reference: [this document]
      Registration Procedures:
                  0  Reserved
              1-127  Specification Required
            128-255  First Come First Served

   Initial contents:
      +------+-----------------------+------------------------------+
      | type |       Reference       |         description          |
      +------+-----------------------+------------------------------+
      |   0  |  [this document]      |  Reserved                    |
      |   1  |  [this document]      |  Ethernet Type               |
      |   2  |  [this document]      |  Source MAC                  |
      |   3  |  [this document]      |  Destination MAC             |
      |   4  |  [this document]      |  DSAP in LLC                 |
      |   5  |  [this document]      |  SSAP in LLC                 |
      |   6  |  [this document]      |  Control field in LLC        |
      |   7  |  [this document]      |  SNAP                        |
      |   8  |  [this document]      |  VLAN ID                     |
      |   9  |  [this document]      |  VLAN PCP                    |
      |  10  |  [this document]      |  Inner VLAN ID               |
      |  11  |  [this document]      |  Inner VLAN PCP              |
      |  12  |  [this document]      |  VLAN DEI                    |
      |  13  |  [this document]      |  Inner VLAN DEI              |
      |  14  |  [this document]      |  Source MAC Special Bits     |
      |  15  |  [this document]      |  Destination MAC Special Bits|
      |16-254|  [this document]      |  unassigned                  |
      | 255  |  [this document]      |  Reserved                    |
      +------+-----------------------+------------------------------+

   IANA is requested to assign two values from the "BGP Extended
   Communities Type - extended, transitive" registry [suggested value
   provided in square brackets]:






W. Hao, et al                                                  [Page 17]


INTERNET-DRAFT                                              L2 Flow Spec


       Type value      Name                      Reference
      ------------    ------------------------  ---------------
      TBD1[0x080A]    Flow spec VLAN action     [this document]
      TBD2[0x080B]    Flow spec TPID action     [this document]
















































W. Hao, et al                                                  [Page 18]


INTERNET-DRAFT                                              L2 Flow Spec


7. Security Considerations

   For General BGP Flow Specification Security Considerations, see
   [RFC5575bis].

   VLAN tagging identifies Layer 2 communities which are commonly
   expected to be isolated except when higher layer connection is
   provided, such as Layer 3 routing. Thus, the ability of the flowspec
   VLAN action to change the VLAN ID in a frame might compromise
   security.



8. Acknowledgements

   The authors wish to acknowledge the important contributions and
   suggestions of the following:

      Hannes Gredler, Xiaohu Xu, Zhenbin Li, Lucy Yong, and Feng Dong.



9. Contributors

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

   Email: liangqiandeng@huawei.com





















W. Hao, et al                                                  [Page 19]


INTERNET-DRAFT                                              L2 Flow Spec


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, <https://www.rfc-
             editor.org/info/rfc2119>.

   [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border
             Gateway Protocol 4 (BGP-4)", RFC 4271, DOI
             10.17487/RFC4271, January 2006, <https://www.rfc-
             editor.org/info/rfc4271>.

   [RFC4761] Kompella, K., Ed. and Y. Rekhter, Ed., "Virtual Private LAN
             Service (VPLS) Using BGP for Auto-Discovery and Signaling",
             RFC 4761, DOI 10.17487/RFC4761, January 2007,
             <https://www.rfc-editor.org/info/rfc4761>.

   [RFC4762] Lasserre, M., Ed. and V. Kompella, Ed., "Virtual Private
             LAN Service (VPLS) Using Label Distribution Protocol (LDP)
             Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
             <https://www.rfc-editor.org/info/rfc4762>.

   [RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo,
             "Provisioning, Auto-Discovery, and Signaling in Layer 2
             Virtual Private Networks (L2VPNs)", RFC 6074, DOI
             10.17487/RFC6074, January 2011, <https://www.rfc-
             editor.org/info/rfc6074>.

   [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119
             Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May
             2017, <https://www.rfc-editor.org/info/rfc8174>.

   [FlowSpecOID] Uttaro, J., Alcaide, J., Filsfils, C. Smith, D.,
             Mohapatra, P., draft-ietf-idr-bgp-flowspec-oid, work in
             progress.

   [FlowSpecV6] McPherson, D., Raszuk, R., Pithawala, B.,
             akarch@cisco.com, a., and S. Hares, "Dissemination of Flow
             Specification Rules for IPv6", draft-ietf-idr-flow-spec-
             v6-10. Work in progress.

   [RFC5575bis] Hares, S., Loibl, C., Raszuk, R., McPherson, D., Bacher,
             M., "Dissemination of Flow Specification Rules", draft-
             ietf-idr-rfc5575bis, Work in progress.








W. Hao, et al                                                  [Page 20]


INTERNET-DRAFT                                              L2 Flow Spec


Informative References

   [RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
             Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
             Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
             2015, <https://www.rfc-editor.org/info/rfc7432>.

   [RFC7042bis] Eastlake, D., and J. Abley, "IANA Considerations and
             IETF Protocol and Documentation Usage for IEEE 802
             Parameters", draft-eastlake-rfc7042bis, Work in progress.










































W. Hao, et al                                                  [Page 21]


INTERNET-DRAFT                                              L2 Flow Spec


Authors' Addresses

      Weiguo Hao
      Huawei Technologies
      101 Software Avenue,
      Nanjing  210012
      China

      Email: haoweiguo@huawei.com


      Donald E. Eastlake, 3rd
      Futurewei Technologies
      2386 Panoramic Circle
      Apopka, FL 32703
      USA

      Tel: +1-508-333-2270
      Email: d3e3e3@gmail.com


      Stephane Litkowski
      Cisco Systems, Inc.

      Email: slitkows.ietf@gmail.com


      Shunwan Zhuang
      Huawei Technologies
      Huawei Bld., No.156 Beiqing Rd.
      Beijing  100095
      China

      Email: zhuangshunwan@huawei.com


















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INTERNET-DRAFT                                              L2 Flow Spec


Copyright, Disclaimer, and Additional IPR Provisions

   Copyright (c) 2020 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.






































W. Hao, et al                                                  [Page 23]


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