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BESS Workgroup                                              P. Jain, Ed.
Internet-Draft                                                  S. Salam
Intended status: Standards Track                              A. Sajassi
Expires: July 7, 2018                                Cisco Systems, Inc.
                                                              S. Boutros
                                                            VmWare, Inc.
                                                               G. Mirsky
                                                        ZTE Corporation.
                                                         January 3, 2018


               LSP-Ping Mechanisms for EVPN and PBB-EVPN
                    draft-jain-bess-evpn-lsp-ping-06

Abstract

   LSP-Ping is a widely deployed Operation, Administration, and
   Maintenance (OAM) mechanism in MPLS networks.  This document
   describes mechanisms for detecting data-plane failures using LSP Ping
   in MPLS based EVPN and PBB-EVPN networks.

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 https://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 7, 2018.

Copyright Notice

   Copyright (c) 2018 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
   (https://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



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   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.  Specification of Requirements . . . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Proposed Target FEC Stack Sub-TLVs  . . . . . . . . . . . . .   3
     4.1.  EVPN MAC Sub-TLV  . . . . . . . . . . . . . . . . . . . .   4
     4.2.  EVPN Inclusive Multicast Sub-TLV  . . . . . . . . . . . .   5
     4.3.  EVPN Auto-Discovery Sub-TLV . . . . . . . . . . . . . . .   6
     4.4.  EVPN IP Prefix Sub-TLV  . . . . . . . . . . . . . . . . .   6
   5.  Encapsulation of OAM Ping Packets . . . . . . . . . . . . . .   7
   6.  Operations  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     6.1.  Unicast Data-plane connectivity checks  . . . . . . . . .   7
     6.2.  Inclusive Multicast Data-plane Connectivity Checks  . . .   9
       6.2.1.  Ingress Replication . . . . . . . . . . . . . . . . .   9
       6.2.2.  Using P2MP P-tree . . . . . . . . . . . . . . . . . .  10
       6.2.3.  Controlling Echo Responses when using P2MP P-tree . .  11
     6.3.  EVPN Aliasing Data-plane connectivity check . . . . . . .  11
     6.4.  EVPN IP Prefix (RT-5) Data-plane connectivity check . . .  11
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
     8.1.  Sub-TLV Type  . . . . . . . . . . . . . . . . . . . . . .  12
     8.2.  Proposed new Return Codes . . . . . . . . . . . . . . . .  12
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     10.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   [RFC7432] describes MPLS based Ethernet VPN (EVPN) technology.  An
   EVPN comprises CE(s) connected to PE(s).  The PEs provide layer 2
   EVPN among the CE(s) over the MPLS core infrastructure.  In EVPN
   networks, PEs advertise the MAC addresses learned from the locally
   connected CE(s), along with MPLS Label, to remote PE(s) in the
   control plane using multi-protocol BGP.  EVPN enables multi-homing of
   CE(s) connected to multiple PEs and load balancing of traffic to and
   from multi-homed CE(s).

   [RFC7623] describes the use of Provider Backbone Bridging [802.1ah]
   with EVPN.  PBB-EVPN maintains the C-MAC learning in data plane and




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   only advertises Provider Backbone MAC (B-MAC) addresses in control
   plane using BGP.

   Procedures for simple and efficient mechanisms to detect data-plane
   failures using LSP Ping in MPLS network are well defined in
   [RFC8029][RFC6425].  This document defines procedures to detect data-
   plane failures using LSP Ping in MPLS networks deploying EVPN and
   PBB-EVPN.  This draft defines 4 new Sub-TLVs for Target FEC Stack TLV
   with the purpose of identifying the FEC on the Peer PE.

2.  Specification of Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

3.  Terminology

   AD: Auto Discovery

   B-MAC: Backbone MAC Address

   CE: Customer Edge Device

   C-MAC: Customer MAC Address

   DF: Designated Forwarder

   ESI: Ethernet Segment Identifier

   EVI: EVPN Instance Identifier that globally identifies the EVPN
   Instance

   EVPN: Ethernet Virtual Private Network

   MPLS-OAM: MPLS Operations, Administration and Maintenance

   P2MP: Point-to-Multipoint

   PBB: Provider Backbone Bridge

   PE: Provider Edge Device

4.  Proposed Target FEC Stack Sub-TLVs

   This document introduces four new Target FEC Stack sub-TLVs that are
   included in the LSP-Ping Echo Request packet sent for detecting




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   faults in data-plane connectivity in EVPN and PBB-EVPN networks.
   These Target FEC Stack sub-TLVs are described next.

   All these TLVs contain 8 bytes EVI value which identifies the EVPN
   instance globally.

4.1.  EVPN MAC Sub-TLV

   The EVPN MAC sub-TLV is used to identify the MAC for an EVI under
   test at a peer PE.

   The EVPN MAC sub-TLV fields are derived from the MAC/IP advertisement
   route defined in [RFC7432] Section 7.2 and has the format as shown in
   Figure 1.  This TLV is included in the Echo Request sent to the Peer
   PE by the PE that is the originator of the request.

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Route Distinguisher                        |
       |                        (8 octets)                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                     Ethernet Tag ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       +                           EVI                                 +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |               Ethernet Segment Identifier                     |
       |                     (10 octets)                               |
       +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                               | must be zero  |  MAC Addr Len |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                MAC Address                                    |
       +                 (6 Octets)    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                               | Must be zero  |  IP Addr Len  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                IP Address (0, 4 or 16 Octets)                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                     Figure 1: EVPN MAC sub-TLV format

   The LSP Ping echo request is sent using the EVPN MPLS label(s)
   associated with the MAC route announced by a remote PE and the MPLS
   transport label(s) to reach the remote PE.





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4.2.  EVPN Inclusive Multicast Sub-TLV

   The EVPN Inclusive Multicast sub-TLV fields are based on the EVPN
   Inclusive Multicast route defined in [RFC7432] Section 7.3.

   The EVPN Inclusive Multicast sub-TLV has the format as shown in
   Figure 2.  This TLV is included in the echo request sent to the EVPN
   peer PE by the originator of request to verify the multicast
   connectivity state on the peer PE(s) in EVPN and PBB-EVPN.

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Route Distinguisher                        |
       |                        (8 octets)                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                     Ethernet Tag ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       +                           EVI                                 +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | IP Addr Len |                                                 |
       +-+-+-+-+-+-+-+                                                 |
       ~               Originating Router's IP Addr                    ~
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


             Figure 2: EVPN Inclusive Multicast sub-TLV format


   Broadcast, multicast and unknown unicast traffic can be sent using
   ingress replication or P2MP P-tree in EVPN and PBB-EVPN network.  In
   case of ingress replication, the Echo Request is sent using a label
   stack of [Transport label, Inclusive Multicast label] to each remote
   PE participating in EVPN or PBB-EVPN.  The inclusive multicast label
   is the downstream assigned label announced by the remote PE to which
   the Echo Request is being sent.  The Inclusive Multicast label is the
   inner label in the MPLS label stack.

   When using P2MP P-tree in EVPN or PBB-EVPN, the Echo Request is sent
   using P2MP P-tree transport label for inclusive P-tree arrangement or
   using a label stack of [P2MP P-tree transport label, upstream
   assigned EVPN Inclusive Multicast label] for aggregate inclusive P2MP
   P-tree arrangement as described in Section 6.





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   In case of EVPN, an additional, EVPN Auto-Discovery sub-TLV and ESI
   MPLS label as the bottom label, may also be included in the Echo
   Request as is described in Section 6.

4.3.  EVPN Auto-Discovery Sub-TLV

   The EVPN Auto-Discovery (AD) sub-TLV fields are based on the Ethernet
   AD route advertisement defined in [RFC7432] Section 7.1.  EVPN AD
   sub-TLV applies to only EVPN.

   The EVPN AD sub-TLV has the format shown in Figure 3.

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Route Distinguisher                        |
       |                        (8 octets)                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                     Ethernet Tag ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       +                           EVI                                 +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |               Ethernet Segment Identifier                     |
       |                     (10 octets)                               |
       +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                               |      must be zero             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                Figure 3: EVPN Auto-Discovery sub-TLV format


4.4.  EVPN IP Prefix Sub-TLV

   The EVPN IP Prefix sub-TLV is used to identify the IP Prefix for an
   EVI under test at a peer PE.

   The EVPN IP Prefix sub-TLV fields are derived from the IP Prefix
   Route (RT-5) advertisement defined in
   [I-D.ietf-bess-evpn-prefix-advertisement] and has the format as shown
   in Figure 4.  This TLV is included in the Echo Request sent to the
   Peer PE by the PE that is the originator of the request.







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        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Route Distinguisher                        |
       |                        (8 octets)                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                     Ethernet Tag ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       +                           EVI                                 +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |               Ethernet Segment Identifier                     |
       |                     (10 octets)                               |
       +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                               | must be zero  | IP Prefix Len |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                 IP Prefix  (4 or 16 Octets)                   ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                GW IP Address (4 or 16 Octets)                 ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                     Figure 4: EVPN IP Prefix sub-TLV format

   The LSP Ping echo request is sent using the EVPN MPLS label(s)
   associated with the IP Prefix route announced by a remote PE and the
   MPLS transport label(s) to reach the remote PE.

5.  Encapsulation of OAM Ping Packets

   The LSP Ping Echo request IPv4/UDP packets are encapsulated with the
   Transport and EVPN Label(s) followed by the Generic Associated
   Channel Label (GAL) [RFC6426] which is bottom most label.  The GAL
   label is followed by IPv4(0x0021) or IPv6(0x0057) Associated Channel
   Header (ACH) [RFC4385].

6.  Operations

6.1.  Unicast Data-plane connectivity checks

   Figure 5 is an example of a PBB-EVPN network.  CE1 is dual-homed to
   PE1 and PE2.  Assume, PE1 announced a MAC route with RD 1.1.1.1:00
   and B-MAC 00aa.00bb.00cc and with MPLS label 16001 for EVI 10.
   Similarly PE2 announced a MAC route with RD 2.2.2.2:00 and B-MAC
   00aa.00bb.00cc and with MPLS label 16002.





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   On PE3, when a operator performs a connectivity check for the B-MAC
   address 00aa.00bb.00cc on PE1, the operator initiates an LSP Ping
   request with the target FEC stack TLV containing EVPN MAC sub-TLV in
   the Echo Request packet.  The Echo Request packet is sent with the
   {Transport Label(s) to reach PE1 + EVPN Label = 16001 + GAL} MPLS
   label stack and IP ACH Channel header.  Once the echo request packet
   reaches PE1, PE1 will use the GAL label and the IP ACH Channel header
   to determine that the packet is IPv4 OAM Packet.  The PE1 will
   process the packet and perform checks for the EVPN MAC sub-TLV
   present in the Target FEC Stack TLV as described in Section 4.4 in
   [RFC8029] and respond according to [RFC8029] processing rules.



                      BEB  +-----------------+  BEB
                       ||  |                 |  ||
                       \/  |                 |  \/
         +----+ AC1  +-----+                 +-----+     +----+
         | CE1|------|     |                 | PE 3|-----| CE2|
         +----+\     | PE1 |     IP/MPLS     |     |     +----+
                \    +-----+     Network     +-----+
                 \         |                 |
               AC2\  +-----+                 |
                   \ |     |                 |
                    \| PE2 |                 |
                     +-----+                 |
                       /\  |                 |
                       ||  +-----------------+
                      BEB

        <-802.1Q->  <------PBB over MPLS------>   <-802.1Q->

                          Figure 5: PBB EVPN network



   Similarly, on PE3, when an operator performs a connectivity check for
   the B-MAC address 00aa.00bb.00cc on PE2, the operator initiates an
   LSP Ping request with the target FEC stack TLV containing EVPN MAC
   sub-TLV in the echo request packet.  The echo request packet is sent
   with the {MPLS transport Label(s) to reach PE2 + EVPN Label = 16002 +
   GAL} MPLS label stack and IP ACH Channel header.

   LSP Ping operation for unicast data-plane connectivity checks in E-
   VPN, are similar to those described above for PBB-EVPN except that
   the checks are for C-MAC addresses instead of B-MAC addresses.





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6.2.  Inclusive Multicast Data-plane Connectivity Checks

6.2.1.  Ingress Replication

   Assume PE1 announced an Inclusive Multicast route for EVI 10, with RD
   1.1.1.1:00, Ethernet Tag (ISID 10), PMSI tunnel attribute Tunnel type
   set to ingress replication and downstream assigned inclusive
   multicast MPLS label 17001.  Similarly PE2 announced an Inclusive
   Multicast route for EVI 10, with RD 2.2.2.2:00, Ethernet Tag (ISID
   10), PMSI tunnel attribute Tunnel type set to ingress replication and
   downstream assigned inclusive multicast MPLS label 17002.

   Given CE1 is dual homed to PE1 and PE2, assume that PE1 is the DF for
   ISID 10 for the port corresponding to the ESI 11aa.22bb.33cc.
   44dd.5500.

   When an operator at PE3 initiates a connectivity check for the
   inclusive multicast on PE1, the operator initiates an LSP Ping
   request with the target FEC stack TLV containing EVPN Inclusive
   Multicast sub-TLV in the Echo Request packet.  The Echo Request
   packet is sent with the {Transport Label(s) to reach PE1 + EVPN Incl.
   Multicast Label = 17001 + GAL} MPLS label stack and IP ACH Channel
   header.  Once the echo request packet reaches PE1, PE1 will use the
   GAL label and the IP ACH Channel header to determine that the packet
   is IPv4 OAM Packet.  The packet will have EVPN Inclusive multicast
   label.  PE1 will process the packet and perform checks for the EVPN
   Inclusive Multicast sub-TLV present in the Target FEC Stack TLV as
   described in Section 4.4 in [RFC8029] and respond according to
   [RFC8029] processing rules.

   Operator at PE3, may similarly also initiate an LSP Ping to PE2 with
   the target FEC stack TLV containing EVPN Inclusive Multicast sub- TLV
   in the echo request packet.  The echo request packet is sent with the
   {transport Label(s) to reach PE2 + EVPN Incl.  Multicast Label =
   17002 + GAL} MPLS label stack and IP ACH Channel header.  Once the
   echo request packet reaches PE2, PE2 will use the GAL label and the
   IP ACH Channel header to determine that the packet is IPv4 OAM
   Packet.  Since PE2 is not the DF for ISID 10 for the port
   corresponding to the ESI value in the Inclusive Multicast sub- TLV in
   the Echo Request, PE2 will reply with special code indicating that
   FEC exists on the router and the behavior is to drop the packet
   because of not DF as described in Section 8.

   In case of EVPN, in the Echo Request packet, an Ethernet AD sub-TLV
   and the associated MPLS Split Horizon Label above the GAL label in
   the MPLS label stack, may be added to emulate traffic coming from a
   MH site, this label is used by leaf PE(s) attached to the same MH
   site not to forward packets back to the MH site.  If the behavior on



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   a leaf PE is to drop the packet because of Split Horizon filtering,
   the PE2 will reply with special code indicating that FEC exists on
   the router and the behavior is to drop the packet because of Split
   Horizon Filtering as described in Section 8.

6.2.2.  Using P2MP P-tree

   Both inclusive P-Tree and aggregate inclusive P-tree can be used in
   EVPN or PBB-EVPN networks.

   When using an inclusive P-tree arrangement, p2mp p-tree transport
   label itself is used to identify the L2 service associated with the
   Inclusive Multicast Route, this L2 service could be a customer
   Bridge, or a Provider Backbone Bridge.

   For an Inclusive P-tree arrangement, when an operator performs a
   connectivity check for the multicast L2 service, the operator
   initiates an LSP Ping request with the target FEC stack TLV
   containing EVPN Inclusive Multicast sub-TLV in the echo request
   packet.  The echo request packet is sent over P2MP LSP with the {P2MP
   P-tree label, GAL} MPLS label stack and IP ACH Channel header.

   When using Aggregate Inclusive P-tree, a PE announces an upstream
   assigned MPLS label along with the P-tree ID, in that case both the
   p2mp p-tree MPLS transport label and the upstream MPLS label can be
   used to identify the L2 service.

   For an Aggregate Inclusive P-tree arrangement, when an operator
   performs a connectivity check for the multicast L2 service, the
   operator initiates an LSP Ping request with the target FEC stack TLV
   containing EVPN Inclusive Multicast sub-TLV in the echo request
   packet.  The echo request packet is sent over P2MP LSP using the IP-
   ACH Control channel with the {P2MP P-tree label, EVPN Upstream
   assigned Multicast Label, GAL} MPLS label stack and IP ACH Channel
   header.

   The Leaf PE(s) of the p2mp tree will process the packet and perform
   checks for the EVPN Inclusive Multicast sub-TLV present in the Target
   FEC Stack TLV as described in Section 4.4 in [RFC8029] and respond
   according to [RFC8029] processing rules.  A PE that is not the DF for
   the EVI on the ESI in the Inclusive Multicast sub-TLV, will reply
   with a special code indicating that FEC exists on the router and the
   behavior is to drop the packet because of not DF as described in
   Section 8.

   In case of EVPN, in the Echo Request packet, an Ethernet AD sub-TLV
   and the associated MPLS Split Horizon Label above the GAL Label in
   MPLS label stack, may be added to emulate traffic coming from a MH



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   site, this label is used by leaf PE(s) attached to the same MH site
   not to forward packets back to the MH site.  If the behavior on a
   leaf PE is to drop the packet because of Split Horizon filtering, the
   PE2 will reply with special code indicating that FEC exists on the
   router and the behavior is to drop the packet because of Split
   Horizon Filtering as described in Section 8.

6.2.3.  Controlling Echo Responses when using P2MP P-tree

   The procedures described in [RFC6425] for preventing congestion of
   Echo Responses (Echo Jitter TLV) and limiting the echo reply to a
   single egress node (Node Address P2MP Responder Identifier TLV) can
   be applied to LSP Ping in PBB EVPN and EVPN when using P2MP P-trees
   for broadcast, multicast and unknown unicast traffic.

6.3.  EVPN Aliasing Data-plane connectivity check

   Assume PE1 announced an Ethernet Auto discovery Route with the ESI
   set to CE1 system ID and MPLS label 19001, and PE2 an Ethernet Auto
   discovery Route with the ESI set to CE1 system ID and MPLS label
   19002.

   When an operator performs at PE3 a connectivity check for the
   aliasing aspect of the Ethernet AD route to PE1, the operator
   initiates an LSP Ping request with the target FEC stack TLV
   containing EVPN Ethernet AD sub-TLV in the echo request packet.  The
   echo request packet is sent with the {Transport label(s) to reach PE1
   + EVPN Ethernet AD Label 19001 + GAL} MPLS label stack and IP ACH
   Channel header.

   When PE1 receives the packet it will process the packet and perform
   checks for the EVPN Ethernet AD sub-TLV present in the Target FEC
   Stack TLV as described in Section 4.4 in [RFC8029] and respond
   according to [RFC8029] processing rules.

6.4.  EVPN IP Prefix (RT-5) Data-plane connectivity check

   Assume PE1 in Figure 5, announced an IP Prefix Route (RT-5) with an
   IP prefix reachable behind CE1 and MPLS label 20001.  When an
   operator on PE3 performs a connectivity check for the IP prefix on
   PE1, the operator initiates an LSP Ping request with the target FEC
   stack TLV containing EVPN IP Prefix sub-TLV in the echo request
   packet.  The echo request packet is sent with the {Transport label(s)
   to reach PE1 + EVPN IP Prefix Label 20001 } MPLS label stack.

   When PE1 receives the packet it will process the packet and perform
   checks for the EVPN IP Prefix sub-TLV present in the Target FEC Stack




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   TLV as described in Section 4.4 in [RFC8029] and respond according to
   [RFC8029] processing rules.

7.  Security Considerations

   The proposal introduced in this document does not introduce any new
   security considerations beyond that already apply to [RFC7432],
   [RFC7623] and [RFC6425].

8.  IANA Considerations

8.1.  Sub-TLV Type

   This document defines 4 new sub-TLV type to be included in Target FEC
   Stack TLV (TLV Type 1) [RFC8029] in LSP Ping.

   IANA is requested to assign a sub-TLV type value to the following
   sub-TLV from the "Multiprotocol Label Switching (MPLS) Label Switched
   Paths (LSPs) Parameters - TLVs" registry, "TLVs and sub- TLVs" sub-
   registry:

   o  EVPN MAC route sub-TLV

   o  EVPN Inclusive Multicast route sub-TLV

   o  EVPN Auto-Discovery Route sub-TLV

   o  EVPN IP Prefix Route sub-TLV

8.2.  Proposed new Return Codes

   [RFC8029] defines values for the Return Code field of Echo Reply.
   This document proposes two new Return Codes, which SHOULD be included
   in the Echo Reply message by a PE in response to LSP Ping Echo
   Request message:

   1.  The FEC exists on the PE and the behavior is to drop the packet
   because of not DF.

   2.  The FEC exists on the PE and the behavior is to drop the packet
   because of Split Horizon Filtering.

9.  Acknowledgments

   The authors would like to thank Patrice Brissette and Weiguo Hao for
   their comments.





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10.  References

10.1.  Normative References

   [I-D.ietf-bess-evpn-prefix-advertisement]
              Rabadan, J., Henderickx, W., Drake, J., Lin, W., and A.
              Sajassi, "IP Prefix Advertisement in EVPN", draft-ietf-
              bess-evpn-prefix-advertisement-09 (work in progress),
              November 2017.

   [RFC6425]  Saxena, S., Ed., Swallow, G., Ali, Z., Farrel, A.,
              Yasukawa, S., and T. Nadeau, "Detecting Data-Plane
              Failures in Point-to-Multipoint MPLS - Extensions to LSP
              Ping", RFC 6425, DOI 10.17487/RFC6425, November 2011,
              <https://www.rfc-editor.org/info/rfc6425>.

   [RFC6426]  Gray, E., Bahadur, N., Boutros, S., and R. Aggarwal, "MPLS
              On-Demand Connectivity Verification and Route Tracing",
              RFC 6426, DOI 10.17487/RFC6426, November 2011,
              <https://www.rfc-editor.org/info/rfc6426>.

   [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>.

   [RFC7623]  Sajassi, A., Ed., Salam, S., Bitar, N., Isaac, A., and W.
              Henderickx, "Provider Backbone Bridging Combined with
              Ethernet VPN (PBB-EVPN)", RFC 7623, DOI 10.17487/RFC7623,
              September 2015, <https://www.rfc-editor.org/info/rfc7623>.

   [RFC8029]  Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
              Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
              Switched (MPLS) Data-Plane Failures", RFC 8029,
              DOI 10.17487/RFC8029, March 2017,
              <https://www.rfc-editor.org/info/rfc8029>.

10.2.  Informative 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>.








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   [RFC4875]  Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
              Yasukawa, Ed., "Extensions to Resource Reservation
              Protocol - Traffic Engineering (RSVP-TE) for Point-to-
              Multipoint TE Label Switched Paths (LSPs)", RFC 4875,
              DOI 10.17487/RFC4875, May 2007,
              <https://www.rfc-editor.org/info/rfc4875>.

   [RFC5085]  Nadeau, T., Ed. and C. Pignataro, Ed., "Pseudowire Virtual
              Circuit Connectivity Verification (VCCV): A Control
              Channel for Pseudowires", RFC 5085, DOI 10.17487/RFC5085,
              December 2007, <https://www.rfc-editor.org/info/rfc5085>.

   [RFC6338]  Giralt, V. and R. McDuff, "Definition of a Uniform
              Resource Name (URN) Namespace for the Schema for Academia
              (SCHAC)", RFC 6338, DOI 10.17487/RFC6338, August 2011,
              <https://www.rfc-editor.org/info/rfc6338>.

Authors' Addresses

   Parag Jain (editor)
   Cisco Systems, Inc.
   2000 Innovation Drive
   Kanata, ON  K2K 3E8
   Canada

   Email: paragj@cisco.com


   Samer Salam
   Cisco Systems, Inc.
   595 Burrard Street, Suite 2123
   Vancouver, BC  V7X 1J1
   Canada

   Email: ssalam@cisco.com


   Ali Sajassi
   Cisco Systems, Inc.
   USA

   Email: sajassi@cisco.com









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   Sami Boutros
   VmWare, Inc.
   USA

   Email: sboutros@vmware.com


   Greg Mirsky
   ZTE Corporation.
   USA

   Email: gregmirsky@gmail.com>







































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