< draft-ietf-bess-evpn-vpws-11.txt   draft-ietf-bess-evpn-vpws-14.txt >
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INTERNET-DRAFT Sami Boutros INTERNET-DRAFT Sami Boutros
Intended Status: Standard Track VMware Intended Status: Standard Track VMware
Ali Sajassi Ali Sajassi
Samer Salam Samer Salam
Cisco Systems Cisco Systems
John Drake John Drake
Juniper Networks Juniper Networks
J. Rabadan J. Rabadan
Nokia Nokia
Expires: September 13, 2017 March 12, 2017 Expires: November 15, 2017 May 14, 2017
VPWS support in EVPN Virtual Private Wire Service support in Ethernet VPN
draft-ietf-bess-evpn-vpws-11.txt draft-ietf-bess-evpn-vpws-14.txt
Abstract Abstract
This document describes how EVPN can be used to support Virtual This document describes how Ethernet VPN (EVPN) can be used to
Private Wire Service (VPWS) in MPLS/IP networks. EVPN enables the support Virtual Private Wire Service (VPWS) in MPLS/IP networks. EVPN
following characteristics for VPWS: single-active as well as all- enables the following characteristics for VPWS: single-active as well
active multi-homing with flow-based load-balancing, eliminates the as all-active multi-homing with flow-based load-balancing, eliminates
need for traditional way of Pseudowire (PW) signaling, and provides the need for Pseudowire (PW) signaling, and provides fast protection
fast protection convergence upon node or link failure. convergence upon node or link failure.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as other groups may also distribute working documents as
Internet-Drafts. Internet-Drafts.
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carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Service interface . . . . . . . . . . . . . . . . . . . . . . . 5 2 Service interface . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 VLAN-Based Service Interface . . . . . . . . . . . . . . . . 5 2.1 VLAN-Based Service Interface . . . . . . . . . . . . . . . . 6
2.2 VLAN Bundle Service Interface . . . . . . . . . . . . . . . 6 2.2 VLAN Bundle Service Interface . . . . . . . . . . . . . . . 6
2.2.1 Port-Based Service Interface . . . . . . . . . . . . . . 6 2.2.1 Port-Based Service Interface . . . . . . . . . . . . . . 7
2.3 VLAN-Aware Bundle Service Interface . . . . . . . . . . . . 6 2.3 VLAN-Aware Bundle Service Interface . . . . . . . . . . . . 7
3. BGP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 6 3. BGP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 EVPN Layer 2 attributes extended community . . . . . . . . . 7 3.1 EVPN Layer 2 attributes extended community . . . . . . . . . 7
4 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5 EVPN Comparison to PW Signaling . . . . . . . . . . . . . . . . 10 5 EVPN Comparison to PW Signaling . . . . . . . . . . . . . . . . 11
6 Failure Scenarios . . . . . . . . . . . . . . . . . . . . . . . 11 6 Failure Scenarios . . . . . . . . . . . . . . . . . . . . . . . 11
6.1 Single-Homed CEs . . . . . . . . . . . . . . . . . . . . . . 11 6.1 Single-Homed CEs . . . . . . . . . . . . . . . . . . . . . . 11
6.2 Multi-Homed CEs . . . . . . . . . . . . . . . . . . . . . . 11 6.2 Multi-Homed CEs . . . . . . . . . . . . . . . . . . . . . . 12
7 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 11 7 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Security Considerations . . . . . . . . . . . . . . . . . . . . 11 8 Security Considerations . . . . . . . . . . . . . . . . . . . . 12
9 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 12 9 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 12
10 References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 10 References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
10.1 Normative References . . . . . . . . . . . . . . . . . . . 12 10.1 Normative References . . . . . . . . . . . . . . . . . . . 13
10.2 Informative References . . . . . . . . . . . . . . . . . . 13 10.2 Informative References . . . . . . . . . . . . . . . . . . 13
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
1 Introduction 1 Introduction
This document describes how EVPN can be used to support Virtual This document describes how EVPN can be used to support VPWS in
Private Wire Service (VPWS) in MPLS/IP networks. The use of EVPN MPLS/IP networks. The use of EVPN mechanisms for VPWS (EVPN-VPWS)
mechanisms for VPWS (EVPN-VPWS) brings the benefits of EVPN to P2P brings the benefits of EVPN to Point to Point (P2P) services. These
services. These benefits include single-active redundancy as well as benefits include single-active redundancy as well as all-active
all-active redundancy with flow-based load-balancing. Furthermore, redundancy with flow-based load-balancing. Furthermore, the use of
the use of EVPN for VPWS eliminates the need for traditional way of EVPN for VPWS eliminates the need for traditional way of PW signaling
PW signaling for P2P Ethernet services, as described in section 4. for P2P Ethernet services, as described in section 4.
[RFC7432] provides the ability to forward customer traffic to/from a [RFC7432] provides the ability to forward customer traffic to/from a
given customer Attachment Circuit (AC), without any MAC lookup. This given customer Attachment Circuit (AC), without any Media Access
capability is ideal in providing P2P services (aka VPWS services). Control (MAC) lookup. This capability is ideal in providing P2P
[MEF] defines Ethernet Virtual Private Line (EVPL) service as P2P services (aka VPWS services). [MEF] defines Ethernet Virtual Private
service between a pair of ACs (designated by VLANs) and Ethernet Line (EVPL) service as P2P service between a pair of ACs (designated
Private Line (EPL) service, in which all traffic flows are between a by VLANs) and Ethernet Private Line (EPL) service, in which all
single pair of ports, that in EVPN terminology would mean a single traffic flows are between a single pair of ports, that in EVPN
pair of Ethernet Segments ES(es). EVPL can be considered as a VPWS terminology would mean a single pair of Ethernet Segments ES(es).
with only two ACs. In delivering an EVPL service, the traffic EVPL can be considered as a VPWS with only two ACs. In delivering an
forwarding capability of EVPN is based on the exchange of a pair of EVPL service, the traffic forwarding capability of EVPN is based on
Ethernet Auto-discovery (A-D) routes; whereas, for more general VPWS the exchange of a pair of Ethernet Auto-discovery (A-D) routes;
as per [RFC4664], traffic forwarding capability of EVPN is based on whereas, for more general VPWS as per [RFC4664], traffic forwarding
the exchange of a group of Ethernet AD routes (one Ethernet AD route capability of EVPN is based on the exchange of a group of Ethernet AD
per AC/ES). In a VPWS service, the traffic from an originating routes (one Ethernet AD route per AC/ES). In a VPWS service, the
Ethernet Segment can be forwarded only to a single destination traffic from an originating Ethernet Segment can be forwarded only to
Ethernet Segment; hence, no MAC lookup is needed and the MPLS label a single destination Ethernet Segment; hence, no MAC lookup is needed
associated with the per EVPN instance (EVI) Ethernet A-D route can be and the MPLS label associated with the per EVPN instance (EVI)
used in forwarding user traffic to the destination AC. Ethernet A-D route can be used in forwarding user traffic to the
destination AC.
For both EPL and EVPL services, a specific VPWS service instance is For both EPL and EVPL services, a specific VPWS service instance is
identified by a pair of per-EVI Ethernet A-D routes which together identified by a pair of per-EVI Ethernet A-D routes which together
identify the VPWS service instance endpoints and the VPWS service identify the VPWS service instance endpoints and the VPWS service
instance. In the control plane the VPWS service instance is instance. In the control plane the VPWS service instance is
identified using the VPWS service instance identifiers advertised by identified using the VPWS service instance identifiers advertised by
each PE. In the data plane the value of the MPLS label advertised by each Provider Edge node (PE). In the data plane the value of the MPLS
one PE is used by the other PE to send traffic for that VPWS service label advertised by one PE is used by the other PE to send traffic
instance. As with the Ethernet Tag in standard EVPN, the VPWS service for that VPWS service instance. As with the Ethernet Tag in standard
instance identifier has uniqueness within an EVPN instance. EVPN, the VPWS service instance identifier has uniqueness within an
EVPN instance.
For EVPN routes, the Ethernet Tag IDs are set to zero for Port-based, For EVPN routes, the Ethernet Tag IDs are set to zero for Port-based,
VLAN-based, and VLAN-bundle interface mode and set to non-zero VLAN-based, and VLAN-bundle interface mode and set to non-zero
Ethernet Tag IDs for VLAN-aware bundle mode. Conversely, for EVPN- Ethernet Tag IDs for VLAN-aware bundle mode. Conversely, for EVPN-
VPWS, the Ethernet Tag ID in the Ethernet A-D route MUST be set to a VPWS, the Ethernet Tag ID in the Ethernet A-D route MUST be set to a
non-zero value for all four service interface types. non-zero value for all four service interface types.
In terms of route advertisement and MPLS label lookup behavior, EVPN- In terms of route advertisement and MPLS label lookup behavior, EVPN-
VPWS resembles the VLAN-aware bundle mode of [RFC7432] such that when VPWS resembles the VLAN-aware bundle mode of [RFC7432] such that when
a PE advertises per-EVI Ethernet A-D route, the VPWS service instance a PE advertises per-EVI Ethernet A-D route, the VPWS service instance
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label in this route represents both the EVI and the VPWS service label in this route represents both the EVI and the VPWS service
instance, so that upon receiving an MPLS encapsulated packet, the instance, so that upon receiving an MPLS encapsulated packet, the
disposition PE can identify the egress AC from the MPLS label and disposition PE can identify the egress AC from the MPLS label and
subsequently perform any required tag translation. For EVPL service, subsequently perform any required tag translation. For EVPL service,
the Ethernet frames transported over an MPLS/IP network SHOULD remain the Ethernet frames transported over an MPLS/IP network SHOULD remain
tagged with the originating VLAN-ID (VID) and any VID translation tagged with the originating VLAN-ID (VID) and any VID translation
MUST be performed at the disposition PE. For EPL service, the MUST be performed at the disposition PE. For EPL service, the
Ethernet frames are transported as is and the tags are not altered. Ethernet frames are transported as is and the tags are not altered.
The MPLS label value in the Ethernet A-D route can be set to the The MPLS label value in the Ethernet A-D route can be set to the
VXLAN Network Identifier (VNI) for VXLAN encap, and this VNI may have Virtual Extensible LAN (VXLAN) Network Identifier (VNI) for VXLAN
a global scope or local scope per PE and may also be equal to the encapsulation as per [RFC7348], and this VNI will have a local scope
VPWS service instance identifier set in the Ethernet A-D route. per PE and may also be equal to the VPWS service instance identifier
set in the Ethernet A-D route. When using VXLAN encap, the BGP
Encapsulation extended community is included in the Ethernet A-D
route as described in [ietf-evpn-overlay]. The VXLAN VNI like the
MPLS label that will be set in the tunnel header used to tunnel
Ethernet packets from all the service interface types defined in
section 2. The EVPN-VPWS techniques defined in this document has no
dependency on the tunneling technology.
The Ethernet Segment identifier encoded in the Ethernet A-D per-EVI The Ethernet Segment identifier encoded in the Ethernet A-D per-EVI
route is not used to identify the service. However it can be used for route is not used to identify the service. However it can be used for
flow-based load-balancing and mass withdraw functions as per the flow-based load-balancing and mass withdraw functions as per the
[RFC7432] baseline. [RFC7432] baseline.
As with standard EVPN, the Ethernet A-D per-ES route is used for fast As with standard EVPN, the Ethernet A-D per-ES route is used for fast
convergence upon link or node failure. The Ethernet Segment route is convergence upon link or node failure. The Ethernet Segment route is
used for auto-discovery of the PEs attached to a given multi-homed CE used for auto-discovery of the PEs attached to a given multi-homed
and to synchronize state between them. Customer Edge node (CE) and to synchronize state between them.
1.1 Terminology 1.1 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
EVPN: Ethernet VPN
MAC: Media Access Control MAC: Media Access Control
MPLS: Multi Protocol Label Switching. MPLS: Multi Protocol Label Switching.
OAM: Operations, Administration and Maintenance. OAM: Operations, Administration and Maintenance.
PE: Provide Edge Node. PE: Provide Edge Node.
ASBR: Autonomous System Border Router ASBR: Autonomous System Border Router
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S-VLAN: Service VLAN identifier. S-VLAN: Service VLAN identifier.
C-VLAN: Customer VLAN identifier. C-VLAN: Customer VLAN identifier.
VID: VLAN-ID. VID: VLAN-ID.
VPWS: Virtual Private Wire Service. VPWS: Virtual Private Wire Service.
EVI: EVPN Instance. EVI: EVPN Instance.
P2P: Point to Point.
VXLAN: Virtual Extensible LAN.
DF: Designated Forwarder.
L2: Layer 2.
MTU: Maximum Transmission Unit.
eBGP: Exterior Border Gateway Protocol.
iBGP: Internal Border Gateway Protocol.
ES: Ethernet Segment on a PE refers to the link attached to it, this ES: Ethernet Segment on a PE refers to the link attached to it, this
link can be part of a set of links attached to different PEs in multi link can be part of a set of links attached to different PEs in multi
homed cases, or could be a single link in single homed cases. homed cases, or could be a single link in single homed cases.
ESI: Ethernet Segment Identifier. ESI: Ethernet Segment Identifier.
Single-Active Mode: When a device or a network is multi-homed to two Single-Active Mode: When a device or a network is multi-homed to two
or more PEs and when only a single PE in such redundancy group can or more PEs and when only a single PE in such redundancy group can
forward traffic to/from the multi-homed device or network for a given forward traffic to/from the multi-homed device or network for a given
VLAN, then such multi-homing or redundancy is referred to as "Single- VLAN, then such multi-homing or redundancy is referred to as "Single-
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The Route-Target (RT) extended community with which the per-EVI The Route-Target (RT) extended community with which the per-EVI
Ethernet A-D route is tagged identifies the EVPN instance in which Ethernet A-D route is tagged identifies the EVPN instance in which
the VPWS service instance is configured. It is the operator's choice the VPWS service instance is configured. It is the operator's choice
as to how many and which VPWS service instances are configured in a as to how many and which VPWS service instances are configured in a
given EVPN instance. However, a given EVPN instance MUST NOT be given EVPN instance. However, a given EVPN instance MUST NOT be
configured with both VPWS service instances and standard EVPN multi- configured with both VPWS service instances and standard EVPN multi-
point services. point services.
3.1 EVPN Layer 2 attributes extended community 3.1 EVPN Layer 2 attributes extended community
This draft defines a new extended community [RFC4360], to be included This document defines a new extended community [RFC4360], to be
with per-EVI Ethernet A-D routes. This attribute is mandatory if included with per-EVI Ethernet A-D routes. This attribute is
multihoming is enabled. mandatory if multihoming is enabled.
+------------------------------------+ +------------------------------------+
| Type(0x06)/Sub-type(0x04)(2 octet)| | Type(0x06)/Sub-type(0x04)(2 octet)|
+------------------------------------+ +------------------------------------+
| Control Flags (2 octets) | | Control Flags (2 octets) |
+------------------------------------+ +------------------------------------+
| L2 MTU (2 octets) | | L2 MTU (2 octets) |
+------------------------------------+ +------------------------------------+
| Reserved (2 octets) | | Reserved (2 octets) |
+------------------------------------+ +------------------------------------+
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P If set to 1 in multihoming single-active scenarios, it P If set to 1 in multihoming single-active scenarios, it
indicates that the advertising PE is the Primary PE. indicates that the advertising PE is the Primary PE.
MUST be set to 1 for multihoming all-active scenarios by MUST be set to 1 for multihoming all-active scenarios by
all active PE(s). all active PE(s).
B If set to 1 in multihoming single-active scenarios, it B If set to 1 in multihoming single-active scenarios, it
indicates that the advertising PE is the Backup PE. indicates that the advertising PE is the Backup PE.
C If set to 1, a Control word [RFC4448] MUST be present C If set to 1, a Control word [RFC4448] MUST be present
when sending EVPN packets to this PE. when sending EVPN packets to this PE. It is recommended to
include the control word in the absence of Entropy Label.
L2 MTU (Maximum Transmission Unit) is a 2-octet value indicating the L2 MTU (Maximum Transmission Unit) is a 2-octet value indicating the
MTU in bytes. MTU in bytes.
A received L2 MTU of zero means no MTU checking against local MTU is A received L2 MTU of zero means no MTU checking against local MTU is
needed. A received non-zero MTU MUST be checked against local MTU and needed. A received non-zero MTU MUST be checked against local MTU and
if there is a mismatch, the local PE MUST NOT add the remote PE as if there is a mismatch, the local PE MUST NOT add the remote PE as
the EVPN destination for the corresponding VPWS service instance. the EVPN destination for the corresponding VPWS service instance.
The usage of the Per ES Ethernet A-D route is unchanged from its The usage of the Per ES Ethernet A-D route is unchanged from its
usage in [RFC7432], i.e., the "Single-Active" bit in the flags of the usage in [RFC7432], i.e., the "Single-Active" bit in the flags of the
ESI Label extended community will indicate if single-active or all- ESI Label extended community will indicate if single-active or all-
active redundancy is used for this ES. active redundancy is used for this ES.
In multihoming scenarios, both B and P flags MUST NOT be both set. A In multihoming scenarios, the B and P flags MUST be cleared. A PE
PE that receives an update with both B and P flags set MUST treat the that receives an update with both B and P flags set MUST treat the
route as a withdrawal. If the PE receives a route with both B and P route as a withdrawal. If the PE receives a route with both B and P
clear, it MUST treat the route as a withdrawal from the sender PE. clear, it MUST treat the route as a withdrawal from the sender PE.
In a multihoming all-active scenario, there is no DF election, and In a multihoming all-active scenario, there is no Designated
all the PEs in the ES that are active and ready to forward traffic Forwarder (DF) election, and all the PEs in the ES that are active
to/from the CE will set the P Flag. A remote PE will do per-flow and ready to forward traffic to/from the CE will set the P Flag. A
load-balancing to the PEs that set the P Flag for the same Ethernet remote PE will do per-flow load-balancing to the PEs that set the P
Tag and ESI. The B Flag in control flags SHOULD NOT be set in the Flag for the same Ethernet Tag and ESI. The B Flag in control flags
multihoming all-active scenario and MUST be ignored by receiving SHOULD NOT be set in the multihoming all-active scenario and MUST be
PE(s) if set. ignored by receiving PE(s) if set.
In multihoming single-active scenario for a given VPWS service In multihoming single-active scenario for a given VPWS service
instance, the DF election should result in the Primary-elected PE for instance, the DF election should result in the Primary-elected PE for
the VPWS service instance advertising the P Flag set and the B Flag the VPWS service instance advertising the P Flag set and the B Flag
clear, the Backup elected PE should advertise the P Flag clear and clear, the Backup elected PE should advertise the P Flag clear and
the B Flag set, and the rest of the PEs in the same ES should signal the B Flag set, and the rest of the PEs in the same ES should signal
both P and B Flags clear. When the primary PE/ES fails, the primary both P and B Flags clear. When the primary PE/ES fails, the primary
PE will withdraw the associated Ethernet A-D routes for the VPWS PE will withdraw the associated Ethernet A-D routes for the VPWS
service instance from the remote PE and the remote PEs should then service instance from the remote PE and the remote PEs should then
send traffic associated with the VPWS instance to the backup PE. DF send traffic associated with the VPWS instance to the backup PE. DF
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editor.org/info/rfc4271>. editor.org/info/rfc4271>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, February 2006, <http://www.rfc- Communities Attribute", RFC 4360, February 2006, <http://www.rfc-
editor.org/info/rfc4360>. editor.org/info/rfc4360>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008, IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>. <http://www.rfc-editor.org/info/rfc5226>.
[RFC7348] Mahalingam, M., et al, "VXLAN: A Framework for Overlaying
Virtualized Layer 2 Networks over Layer 3 Networks", RFC 7348, August
2014
10.2 Informative References 10.2 Informative References
[MEF] Metro Ethernet Forum, "Ethernet Services Definitions - Phase [MEF] Metro Ethernet Forum, "Ethernet Services Definitions - Phase
2", Technical Specification MEF 6.1, April 2008, 2", Technical Specification MEF 6.1, April 2008,
https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_6.1.pdf https://www.mef.net/Assets/Technical_Specifications/PDF/MEF_6.1.pdf
[RFC4664] Andersson, L., Ed., and E. Rosen, Ed., "Framework for [RFC4664] Andersson, L., Ed., and E. Rosen, Ed., "Framework for
Layer 2 Virtual Private Networks (L2VPNs)", RFC 4664, September 2006, Layer 2 Virtual Private Networks (L2VPNs)", RFC 4664, September 2006,
<http://www.rfc-editor.org/info/rfc4664>. <http://www.rfc-editor.org/info/rfc4664>.
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