draft-ietf-bess-evpn-vpws-13.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: November 5, 2017 May 4, 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-13.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 Pseudowire (PW) signaling, and provides fast protection the need for Pseudowire (PW) signaling, and provides 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
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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 . . . . . . . . . . . . . . . . . . . . . . . 6 2 Service interface . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 VLAN-Based Service Interface . . . . . . . . . . . . . . . . 6 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 . . . . . . . . . . . . . . . . . . . . . . . . 7 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 . . . . . . . . . . . . . . . . . . . . . . . . 12 7 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Security Considerations . . . . . . . . . . . . . . . . . . . . 12 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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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
Virtual Extensible LAN (VXLAN) Network Identifier (VNI) for VXLAN Virtual Extensible LAN (VXLAN) Network Identifier (VNI) for VXLAN
encap as per [RFC7348], and this VNI will have a local scope per PE encapsulation as per [RFC7348], and this VNI will have a local scope
and may also be equal to the VPWS service instance identifier set in per PE and may also be equal to the VPWS service instance identifier
the Ethernet A-D route. When using VXLAN encap, the BGP Encapsulation set in the Ethernet A-D route. When using VXLAN encap, the BGP
extended community is included in the Ethernet A-D route as described Encapsulation extended community is included in the Ethernet A-D
in [ietf-evpn-overlay]. The VXLAN VNI like the MPLS label that will route as described in [ietf-evpn-overlay]. The VXLAN VNI like the
be set in the tunnel header used to tunnel Ethernet packets from all MPLS label that will be set in the tunnel header used to tunnel
the service interface types defined in section 2. The EVPN-VPWS Ethernet packets from all the service interface types defined in
techniques defined in this document has no dependency on the section 2. The EVPN-VPWS techniques defined in this document has no
tunneling technology. 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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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. P2P: Point to Point.
VXLAN: Virtual Extensible LAN. 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 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, the B and P flags MUST be cleared. A PE In multihoming scenarios, the B and P flags MUST be cleared. A 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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