rfc9784v1.txt   rfc9784.txt 
Internet Engineering Task Force (IETF) A. Sajassi Internet Engineering Task Force (IETF) A. Sajassi
Request for Comments: 9784 P. Brissette Request for Comments: 9784 P. Brissette
Category: Standards Track Cisco Systems Category: Standards Track Cisco Systems
ISSN: 2070-1721 R. Schell ISSN: 2070-1721 R. Schell
Verizon
J. Drake J. Drake
Juniper Independent
J. Rabadan J. Rabadan
Nokia Nokia
May 2025 June 2025
EVPN Virtual Ethernet Segments Virtual Ethernet Segments for EVPN and Provider Backbone Bridge EVPN
Abstract Abstract
Ethernet VPN (EVPN) and Provider Backbone Bridge EVPN (PBB-EVPN) Ethernet VPN (EVPN) and Provider Backbone Bridge EVPN (PBB-EVPN)
introduce a comprehensive suite of solutions for delivering Ethernet introduce a comprehensive suite of solutions for delivering Ethernet
services over MPLS/IP networks. These solutions offer advanced services over MPLS/IP networks. These solutions offer advanced
multi-homing capabilities. Specifically, they support Single-Active multihoming capabilities. Specifically, they support Single-Active
and All-Active redundancy modes for an Ethernet Segment (ES), which and All-Active redundancy modes for an Ethernet Segment (ES), which
is defined as a collection of physical links connecting a multi-homed is defined as a collection of physical links connecting a multihomed
device or network to a set of Provider Edge (PE) devices. This device or network to a set of Provider Edge (PE) devices. This
document extends the concept of an Ethernet Segment by allowing an ES document extends the concept of an ES by allowing an ES to be
to be associated with a set of Ethernet Virtual Circuits (EVCs), such associated with a set of Ethernet Virtual Circuits (EVCs), such as
as VLANs, or other entities, including MPLS Label Switched Paths VLANs, or other entities, including MPLS Label Switched Paths (LSPs)
(LSPs) or pseudowires (PWs). This extended concept is referred to as or pseudowires (PWs). This extended concept is referred to as
virtual Ethernet Segments (vESes). This document lists the virtual Ethernet Segments (vESes). This document lists the
requirements and specifies the necessary extensions to support vES in requirements and specifies the necessary extensions to support vES in
both EVPN and PBB-EVPN. both EVPN and PBB-EVPN.
Status of This Memo Status of This Memo
This is an Internet Standards Track document. This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has (IETF). It represents the consensus of the IETF community. It has
skipping to change at line 69 skipping to change at line 68
in the Revised BSD License. in the Revised BSD License.
Table of Contents Table of Contents
1. Introduction 1. Introduction
1.1. Requirements Language 1.1. Requirements Language
1.2. vESes in Access Ethernet Networks 1.2. vESes in Access Ethernet Networks
1.3. vESes in Access MPLS Networks 1.3. vESes in Access MPLS Networks
2. Terminology 2. Terminology
3. Requirements 3. Requirements
3.1. Single-Homed and Multi-Homed vES 3.1. Single-Homed and Multihomed vES
3.2. Local Switching 3.2. Local Switching
3.3. EVC Service Types 3.3. EVC Service Types
3.4. Designated Forwarder (DF) Election 3.4. Designated Forwarder (DF) Election
3.5. EVC Monitoring 3.5. EVC Monitoring
3.6. Failure and Recovery 3.6. Failure and Recovery
3.7. Fast Convergence 3.7. Fast Convergence
4. Solution Overview 4. Solution Overview
4.1. EVPN DF Election for vES 4.1. EVPN DF Election for vES
4.2. Grouping and Route Coloring for vES 4.2. Grouping and Route Coloring for vES
4.2.1. EVPN Route Coloring for vES 4.2.1. EVPN Route Coloring for vES
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8.1. Normative References 8.1. Normative References
8.2. Informative References 8.2. Informative References
Acknowledgements Acknowledgements
Authors' Addresses Authors' Addresses
1. Introduction 1. Introduction
Ethernet VPN (EVPN) [RFC7432] and Provider Backbone Bridge EVPN (PBB- Ethernet VPN (EVPN) [RFC7432] and Provider Backbone Bridge EVPN (PBB-
EVPN) [RFC7623] introduce a comprehensive suite of solutions for EVPN) [RFC7623] introduce a comprehensive suite of solutions for
delivering Ethernet services over MPLS/IP networks. These solutions delivering Ethernet services over MPLS/IP networks. These solutions
offer advanced multi-homing capabilities. Specifically, they support offer advanced multihoming capabilities. Specifically, they support
Single-Active and All-Active redundancy modes for an Ethernet Segment Single-Active and All-Active redundancy modes for an Ethernet Segment
(ES). As defined in [RFC7432], an ES represents a collection of (ES). As defined in [RFC7432], an ES represents a collection of
Ethernet links that connect a customer site to one or more Provider Ethernet links that connect a customer site to one or more Provider
Edge (PE) devices. Edge (PE) devices.
This document extends the concept of an Ethernet Segment by allowing This document extends the concept of an ES by allowing an ES to be
an ES to be associated with a set of Ethernet Virtual Circuits (EVCs) associated with a set of Ethernet Virtual Circuits (EVCs) (such as
(such as VLANs) or other entities, including MPLS Label Switched VLANs) or other entities, including MPLS Label Switched Paths (LSPs)
Paths (LSPs) or pseudowires (PWs). This extended concept is referred or pseudowires (PWs). This extended concept is referred to as
to as virtual Ethernet Segments (vESes). This document lists the virtual Ethernet Segments (vESes). This document lists the
requirements and specifies the necessary extensions to support vES in requirements and specifies the necessary extensions to support vES in
both EVPN and PBB-EVPN. The scope of this document includes PBB-EVPN both EVPN and PBB-EVPN. The scope of this document includes PBB-EVPN
[RFC7623], EVPN over MPLS [RFC7432], and EVPN over IP [RFC8365]; [RFC7623], EVPN over MPLS [RFC7432], and EVPN over IP [RFC8365];
however, it excludes EVPN over SRv6 [RFC9252]. however, it excludes EVPN over SRv6 [RFC9252].
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
skipping to change at line 133 skipping to change at line 132
1.2. vESes in Access Ethernet Networks 1.2. vESes in Access Ethernet Networks
Some service providers (SPs) seek to extend the concept of physical Some service providers (SPs) seek to extend the concept of physical
Ethernet links in an ES to encompass EVCs, wherein multiple EVCs Ethernet links in an ES to encompass EVCs, wherein multiple EVCs
(such as VLANs) can be aggregated onto a single physical External (such as VLANs) can be aggregated onto a single physical External
Network-Network Interface (ENNI). An ES composed of a set of EVCs Network-Network Interface (ENNI). An ES composed of a set of EVCs
rather than physical links is referred to as a vES. Figure 1 rather than physical links is referred to as a vES. Figure 1
illustrates two PE devices (PE1 and PE2), each with an ENNI illustrates two PE devices (PE1 and PE2), each with an ENNI
aggregating several EVCs. Some of these EVCs on a given ENNI can be aggregating several EVCs. Some of these EVCs on a given ENNI can be
associated with vESes. For instance, the multi-homed vES depicted in associated with vESes. For instance, the multihomed vES depicted in
Figure 1 consists of EVC4 on ENNI1 and EVC5 on ENNI2. Figure 1 consists of EVC4 on ENNI1 and EVC5 on ENNI2.
Third-Party Third-Party
+-----+ EAP +-----+ EAP
| CE11|EVC1 +---------+ | CE11|EVC1 +---------+
+-----+ \ | | +---+ +-----+ \ | | +---+
Cust. A \-0=========0--ENNI1| | Cust. A \-0=========0--ENNI1| |
+-----+ | | ENNI1| | +-------+ +---+ +-----+ | | ENNI1| | +-------+ +---+
| CE12|EVC2--0=========0--ENNI1|PE1|---| | | | | CE12|EVC2--0=========0--ENNI1|PE1|---| | | |
+-----+ | | ENNI1| | |SP |---|PE3|- +-----+ | | ENNI1| | |SP |---|PE3|-
skipping to change at line 159 skipping to change at line 158
+-----+ -0=== ===0--ENNI2| | | |---|PE4|-/ +---+ +-----+ -0=== ===0--ENNI2| | | |---|PE4|-/ +---+
| CE3 |EVC4/ | | ENNI2|PE2|---| | | | | CE3 |EVC4/ | | ENNI2|PE2|---| | | |
| |EVC5--0=========0--ENNI2| | +-------+ +---+ | |EVC5--0=========0--ENNI2| | +-------+ +---+
+-----+ | | +---+ +-----+ | | +---+
Cust. C +---------+ /\ Cust. C +---------+ /\
/\ || /\ ||
|| ENNI || ENNI
EVCs Interface EVCs Interface
<--------802.1Q----------> <---- EVPN Network -----> <-802.1Q-> <--------802.1Q----------> <---- EVPN Network -----> <-802.1Q->
Figure 1: A Dual-Homed Device/Network (Both SA/AA) and SH on the Figure 1: Single-Homed Devices and a Dual-Homed Device/Network on
Same ENNI the Same ENNI
ENNIs are commonly used to reach remote customer sites via ENNIs are commonly used to reach remote customer sites via
independent Ethernet access networks or third-party Ethernet Access independent Ethernet access networks or third-party Ethernet Access
Providers (EAPs). ENNIs can aggregate traffic from many vESes (e.g., Providers (EAPs). ENNIs can aggregate traffic from many vESes (e.g.,
hundreds to thousands), where each vES is represented by its hundreds to thousands), where each vES is represented by its
associated EVC on that ENNI. As a result, ENNIs and their associated associated EVC on that ENNI. As a result, ENNIs and their associated
EVCs are key elements of SP external boundaries that are carefully EVCs are key elements of SP external boundaries that are carefully
designed and closely monitored. As a reminder, the ENNI is the designed and closely monitored. As a reminder, the ENNI is the
demarcation between the SP (IP/MPLS core network) and the third-party demarcation between the SP (IP/MPLS core network) and the third-party
Ethernet Access Provider. Ethernet Access Provider.
To meet customers' Service Level Agreements (SLAs), SPs build To meet customers' Service Level Agreements (SLAs), SPs build
redundancy via multiple EVPN PEs and across multiple ENNIs (as shown redundancy via multiple EVPN PEs and across multiple ENNIs (as shown
in Figure 1), where a given vES can be multi-homed to two or more in Figure 1), where a given vES can be multihomed to two or more EVPN
EVPN PE devices (on two or more ENNIs) via their associated EVCs. PE devices (on two or more ENNIs) via their associated EVCs. Just
Just like physical ESs in the solutions described in [RFC7432] and like physical ESs in the solutions described in [RFC7432] and
[RFC7623], these vESes can be single-homed or multi-homed ESs, and [RFC7623], these vESes can be single-homed or multihomed ESs, and
when multi-homed, they can operate in either Single-Active or All- when multihomed, they can operate in either Single-Active or All-
Active redundancy modes. In a typical SP external-boundary scenario Active redundancy modes. In a typical SP external-boundary scenario
(e.g., with an EAP), an ENNI can be associated with several thousands (e.g., with an EAP), an ENNI can be associated with several thousands
of single-homed vESes, several hundreds of Single-Active vESes, and of single-homed vESes, several hundreds of Single-Active vESes, and
tens or hundreds of All-Active vESes. The specific figures used tens or hundreds of All-Active vESes. The specific figures used
throughout this document reflect the relative quantities (hundreds, throughout this document reflect the relative quantities (hundreds,
thousands, etc.) of various elements as understood at the time of thousands, etc.) of various elements as understood at the time of
writing. writing.
1.3. vESes in Access MPLS Networks 1.3. vESes in Access MPLS Networks
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pairs between PE1 and AG2 and between PE2 and AG2, respectively. The pairs between PE1 and AG2 and between PE2 and AG2, respectively. The
vES consists of these two LSP pairs (LSP1 and LSP2), and each LSP vES consists of these two LSP pairs (LSP1 and LSP2), and each LSP
pair has two PWs. This vES will be shared by two separate EVPN pair has two PWs. This vES will be shared by two separate EVPN
instances (e.g., EVI-1 and EVI-2) in the EVPN network. PW3 and PW4 instances (e.g., EVI-1 and EVI-2) in the EVPN network. PW3 and PW4
are associated with EVI-1 and EVI-2, respectively, on PE1, and PW5 are associated with EVI-1 and EVI-2, respectively, on PE1, and PW5
and PW6 are associated with EVI-1 and EVI-2, respectively, on PE2. and PW6 are associated with EVI-1 and EVI-2, respectively, on PE2.
In some cases, the aggregation of PWs that share the same LSP pair In some cases, the aggregation of PWs that share the same LSP pair
may not be possible. For instance, if PW3 were terminated into a may not be possible. For instance, if PW3 were terminated into a
third PE, e.g., PE3, instead of PE1, the vES would need to be defined third PE, e.g., PE3, instead of PE1, the vES would need to be defined
on a per individual PW on each PE. on each PW on each PE.
For MPLS/IP access networks where a vES represents a set of LSP pairs For MPLS/IP access networks where a vES represents a set of LSP pairs
or a set of PWs, this document extends the Single-Active multi-homing or a set of PWs, this document extends the Single-Active multihoming
procedures defined in [RFC7432] and [RFC7623] to accommodate vES. procedures defined in [RFC7432] and [RFC7623] to accommodate vES.
The extension of vES to support All-Active multi-homing in MPLS/IP The extension of vES to support All-Active multihoming in MPLS/IP
access networks is beyond the scope of this document. access networks is beyond the scope of this document.
This document defines the concept of a vES and specifies the This document defines the concept of a vES and specifies the
additional extensions necessary to support a vES in accordance with additional extensions necessary to support a vES in accordance with
[RFC7432] and [RFC7623]. Section 3 enumerates the set of [RFC7432] and [RFC7623]. Section 3 enumerates the set of
requirements for a vES. Section 4 details the extensions for a vES requirements for a vES. Section 4 details the extensions for a vES
applicable to EVPN solutions, including those specified in [RFC7432] applicable to EVPN solutions, including those specified in [RFC7432]
and [RFC7209]. These extensions are designed to meet the and [RFC7209]. These extensions are designed to meet the
requirements listed in Section 3. Section 4 also provides an requirements listed in Section 3. Section 4 also provides an
overview of the solution, while Section 5 addresses failure handling, overview of the solution, while Section 5 addresses failure handling,
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PBB: Provider Backbone Bridge PBB: Provider Backbone Bridge
PBB-EVPN: Provider Backbone Bridge EVPN PBB-EVPN: Provider Backbone Bridge EVPN
PE: Provider Edge PE: Provider Edge
VPWS: Virtual Private Wire Service VPWS: Virtual Private Wire Service
Single-Active (SA) Redundancy Mode: When only a single PE, among a Single-Active (SA) Redundancy Mode: When only a single PE, among a
group of PEs attached to an Ethernet Segment, is allowed to group of PEs attached to an ES, is allowed to forward
forward traffic to/from that Ethernet Segment, the Ethernet traffic to/from that ES, the ES is defined as operating in
Segment is defined as operating in Single-Active redundancy Single-Active redundancy mode.
mode.
All-Active (AA) Redundancy Mode: When all PEs attached to an All-Active (AA) Redundancy Mode: When all PEs attached to an ES are
Ethernet Segment are allowed to forward traffic to/from allowed to forward traffic to/from that ES, the ES is
that Ethernet Segment, the Ethernet Segment is defined as defined as operating in All-Active redundancy mode.
operating in All-Active redundancy mode.
3. Requirements 3. Requirements
This section describes the requirements specific to vES for EVPN and This section describes the requirements specific to vES for EVPN and
PBB-EVPN solutions. These requirements are in addition to the ones PBB-EVPN solutions. These requirements are in addition to the ones
described in [RFC8214], [RFC7432], and [RFC7623]. described in [RFC8214], [RFC7432], and [RFC7623].
3.1. Single-Homed and Multi-Homed vES 3.1. Single-Homed and Multihomed vES
A PE device MUST support the following types of vESes: A PE device MUST support the following types of vESes:
(R1a) The PE MUST handle single-homed vESes on a single physical (R1a) The PE MUST handle single-homed vESes on a single physical
port, such as a single ENNI. port, such as a single ENNI.
(R1b) The PE MUST support a combination of single-homed vESes and (R1b) The PE MUST support a combination of single-homed vESes and
Single-Active multi-homed vESes simultaneously on a single Single-Active multihomed vESes simultaneously on a single
physical port, such as a single ENNI. Throughout this physical port, such as a single ENNI. Throughout this
document, Single-Active multi-homed vESes will be referred to document, Single-Active multihomed vESes will be referred to
as "Single-Active vESes". as "Single-Active vESes".
(R1c) The PE MAY support All-Active multi-homed vESes on a single (R1c) The PE MAY support All-Active multihomed vESes on a single
physical port. Throughout this document, All-Active multi- physical port. Throughout this document, All-Active
homed vESes will be referred to as "All-Active vESes". multihomed vESes will be referred to as "All-Active vESes".
(R1d) The PE MAY support a combination of All-Active vESes along (R1d) The PE MAY support a combination of All-Active vESes along
with other types of vESes on a single physical port. with other types of vESes on a single physical port.
(R1e) A multi-homed vES, whether Single-Active or All-Active, can (R1e) A multihomed vES, whether Single-Active or All-Active, can
span across two or more ENNIs on any two or more PEs. span across two or more ENNIs on any two or more PEs.
3.2. Local Switching 3.2. Local Switching
Many vESes of different types can be aggregated on a single physical Many vESes of different types can be aggregated on a single physical
port on a PE device and some of these vESes can belong to the same port on a PE device and some of these vESes can belong to the same
service instance (e.g., EVI). This translates into the need for service instance (e.g., EVI). This translates into the need for
supporting local switching among the vESes for the same service supporting local switching among the vESes for the same service
instance on the same physical port (e.g., ENNI) of the PE. instance on the same physical port (e.g., ENNI) of the PE.
(R3a) A PE device that supports the vES function MUST support local (R2a) A PE device that supports the vES function MUST support local
switching among different vESes associated with the same switching among different vESes associated with the same
service instance on a single physical port. For instance, in service instance on a single physical port. For instance, in
Figure 1, PE1 must support local switching between CE11 and Figure 1, PE1 must support local switching between CE11 and
CE12, which are mapped to two single-homed vESes on ENNI1. In CE12, which are mapped to two single-homed vESes on ENNI1. In
the case of Single-Active vESes, the local switching is the case of Single-Active vESes, the local switching is
performed among active EVCs associated with the same service performed among active EVCs associated with the same service
instance on the same ENNI. instance on the same ENNI.
3.3. EVC Service Types 3.3. EVC Service Types
A physical port, such as an ENNI of a PE device, can aggregate A physical port, such as an ENNI of a PE device, can aggregate
numerous EVCs, each associated with a vES. An EVC may carry one or numerous EVCs, each associated with a vES. An EVC may carry one or
more VLANs. Typically, an EVC carries a single VLAN and is therefore more VLANs. Typically, an EVC carries a single VLAN and is therefore
associated with a single broadcast domain. However, there are no associated with a single broadcast domain. However, there are no
restrictions preventing an EVC from carrying multiple VLANs. restrictions preventing an EVC from carrying multiple VLANs.
(R4a) An EVC can be associated with a single broadcast domain, such (R3a) An EVC can be associated with a single broadcast domain, such
as in a VLAN-based service or a VLAN bundle service. as in a VLAN-based service or a VLAN bundle service.
(R4b) An EVC MAY be associated with several broadcast domains, such (R3b) An EVC MAY be associated with several broadcast domains, such
as in a VLAN-aware bundle service. as in a VLAN-aware bundle service.
Similarly, a PE can aggregate multiple LSPs and PWs. In the case of Similarly, a PE can aggregate multiple LSPs and PWs. In the case of
individual PWs per vES, a PW is typically associated with a single individual PWs per vES, a PW is typically associated with a single
broadcast domain, although there are no restrictions preventing a PW broadcast domain, although there are no restrictions preventing a PW
from carrying multiple VLANs if the PW is configured in Raw mode. from carrying multiple VLANs if the PW is configured in Raw mode.
(R4c) A PW can be associated with a single broadcast domain, such as (R3c) A PW can be associated with a single broadcast domain, such as
in a VLAN-based service or a VLAN bundle service. in a VLAN-based service or a VLAN bundle service.
(R4d) A PW MAY be associated with several broadcast domains, such as (R3d) A PW MAY be associated with several broadcast domains, such as
in a VLAN-aware bundle service. in a VLAN-aware bundle service.
3.4. Designated Forwarder (DF) Election 3.4. Designated Forwarder (DF) Election
Section 8.5 of [RFC7432] specifies the default procedure for DF Section 8.5 of [RFC7432] specifies the default procedure for DF
election in EVPN, which is also applied in [RFC7623] and [RFC8214]. election in EVPN, which is also applied in [RFC7623] and [RFC8214].
[RFC8584] elaborates on additional procedures for DF election in [RFC8584] elaborates on additional procedures for DF election in
EVPN. These DF election procedures are performed at the granularity EVPN. These DF election procedures are performed at the granularity
of (ESI, Ethernet Tag). In the context of a vES, the same EVPN of (ESI, Ethernet Tag). In the context of a vES, the same EVPN
default procedure for DF election is applicable but at the default procedure for DF election is applicable but at the
granularity of (vESI, Ethernet Tag). In this context, the Ethernet granularity of (vESI, Ethernet Tag). In this context, the Ethernet
Tag is represented by an I-SID in PBB-EVPN and by a VLAN ID (VID) in Tag is represented by an I-SID in PBB-EVPN and by a VLAN ID (VID) in
EVPN. As described in [RFC7432], this default procedure for DF EVPN. As described in [RFC7432], this default procedure for DF
election at the granularity of (vESI, Ethernet Tag) is also known as election at the granularity of (vESI, Ethernet Tag) is also known as
"service carving." The goal of service carving is to evenly "service carving." The goal of service carving is to evenly
distribute the DFs for different vESes among various PEs, thereby distribute the DFs for different vESes among various PEs, thereby
ensuring an even distribution of traffic across the PEs. The ensuring an even distribution of traffic across the PEs. The
following requirements are applicable to the DF election of vESes for following requirements are applicable to the DF election of vESes for
EVPN and PBB-EVPN. EVPN and PBB-EVPN.
(R5a) A PE that supports vES function MUST support a vES with m EVCs (R4a) A PE that supports vES function MUST support a vES with m EVCs
among n ENNIs belonging to p PEs in any arbitrary order, where among n ENNIs belonging to p PEs in any arbitrary order, where
n >= p >= m >=2. For example, if there is a vES with 2 EVCs n >= p >= m >=2. For example, if there is a vES with 2 EVCs
and there are 5 ENNIs on 5 PEs (PE1 through PE5), then vES can and there are 5 ENNIs on 5 PEs (PE1 through PE5), then vES can
be dual-homed to PE2 and PE4, and the DF election must be be dual-homed to PE2 and PE4, and the DF election must be
performed between PE2 and PE4. performed between PE2 and PE4.
(R5b) Each vES MUST be identified by its own virtual ESI (vESI). (R4b) Each vES MUST be identified by its own virtual ESI (vESI).
3.5. EVC Monitoring 3.5. EVC Monitoring
To detect the failure of an individual EVC and subsequently perform To detect the failure of an individual EVC and subsequently perform
DF election for its associated vES as a result of this failure, each DF election for its associated vES as a result of this failure, each
EVC should be monitored independently. EVC should be monitored independently.
(R6a) Each EVC SHOULD be independently monitored for its operational (R5a) Each EVC SHOULD be independently monitored for its operational
health. health.
(R6b) A failure in a single EVC, among many aggregated on a single (R5b) A failure in a single EVC, among many aggregated on a single
physical port or ENNI, MUST trigger a DF election for its physical port or ENNI, MUST trigger a DF election for its
associated vES. associated vES.
3.6. Failure and Recovery 3.6. Failure and Recovery
(R7a) Failure and failure recovery of an EVC for a single-homed vES (R6a) Failure and failure recovery of an EVC for a single-homed vES
SHALL NOT impact any other EVCs within its service instance or SHALL NOT impact any other EVCs within its service instance or
any other service instances. In other words, for PBB-EVPN, it any other service instances. In other words, for PBB-EVPN, it
SHALL NOT trigger any MAC flushing within both its own I-SID SHALL NOT trigger any MAC flushing within both its own I-SID
and other I-SIDs. and other I-SIDs.
(R7b) In case of All-Active vES, failure and failure recovery of an (R6b) In case of All-Active vES, failure and failure recovery of an
EVC for that vES SHALL NOT impact any other EVCs within its EVC for that vES SHALL NOT impact any other EVCs within its
service instance or any other service instances. In other service instance or any other service instances. In other
words, for PBB-EVPN, it SHALL NOT trigger any MAC flushing words, for PBB-EVPN, it SHALL NOT trigger any MAC flushing
within both its own I-SID and other I-SIDs. within both its own I-SID and other I-SIDs.
(R7c) Failure and failure recovery of an EVC for a Single-Active vES (R6c) Failure and failure recovery of an EVC for a Single-Active vES
SHALL impact only its own service instance. In other words, SHALL impact only its own service instance. In other words,
for PBB-EVPN, MAC flushing SHALL be limited to the associated for PBB-EVPN, MAC flushing SHALL be limited to the associated
I-SID only and SHALL NOT impact any other I-SIDs. I-SID only and SHALL NOT impact any other I-SIDs.
(R7d) Failure and failure recovery of an EVC for a Single-Active vES (R6d) Failure and failure recovery of an EVC for a Single-Active vES
MUST only impact C-MACs associated with a multi-homed device/ MUST only impact C-MACs associated with a multihomed device/
network for that service instance. In other words, MAC network for that service instance. In other words, MAC
flushing MUST be limited to a single service instance (I-SID flushing MUST be limited to a single service instance (I-SID
in the case of PBB-EVPN) and only C-MACs for a Single-Active in the case of PBB-EVPN) and only C-MACs for a Single-Active
multi-homed device/network. multihomed device/network.
3.7. Fast Convergence 3.7. Fast Convergence
Since many EVCs (and their associated vESes) are aggregated via a Since many EVCs (and their associated vESes) are aggregated via a
single physical port (e.g., ENNI), when there is a failure of that single physical port (e.g., ENNI), when there is a failure of that
physical port, it impacts many vESes and equally triggers many ES physical port, it impacts many vESes and equally triggers many ES
route withdrawals. Formulating, sending, receiving, and processing route withdrawals. Formulating, sending, receiving, and processing
such large numbers of BGP messages can introduce delay in DF election such large numbers of BGP messages can introduce delay in DF election
and convergence time. As such, it is highly desirable to have a and convergence time. As such, it is highly desirable to have a
mass-withdraw mechanism similar to the one in [RFC7432] for mass-withdraw mechanism similar to the one in [RFC7432] for
withdrawing many Ethernet A-D per ES routes. withdrawing many Ethernet A-D per ES routes.
(R8a) There SHOULD be a mechanism equivalent to EVPN mass withdraw (R7a) There SHOULD be a mechanism equivalent to EVPN mass withdraw
such that upon an ENNI failure, only a single BGP message to such that upon an ENNI failure, only a single BGP message to
the PEs is needed to trigger DF election for all impacted the PEs is needed to trigger DF election for all impacted
vESes associated with that ENNI. vESes associated with that ENNI.
4. Solution Overview 4. Solution Overview
The solutions described in [RFC7432] and [RFC7623] are leveraged as The solutions described in [RFC7432] and [RFC7623] are leveraged as
is, with the modification that the ESI assignment is performed for an is, with the modification that the ESI assignment is performed for an
EVC or a group of EVCs or LSPs/PWs instead of a link or a group of EVC or a group of EVCs or LSPs/PWs instead of a link or a group of
physical links. In other words, the ESI is associated with a vES physical links. In other words, the ESI is associated with a vES
(hereby referred to as the "vESI"). (hereby referred to as the "vESI").
In the EVPN solution, the overall procedures remain consistent, with In the EVPN solution, the overall procedures remain consistent, with
the primary difference being the handling of physical port failures the primary difference being the handling of physical port failures
that can affect multiple vESes. Sections 5.1 and 5.3 describe the that can affect multiple vESes. Sections 5.1 and 5.3 describe the
procedures for managing physical port or link failures in the context procedures for managing physical port or link failures in the context
of EVPN. In a typical multi-homed setup, MAC addresses learned of EVPN. In a typical multihomed setup, MAC addresses learned behind
behind a vES are advertised using the ESI associated with the vES a vES are advertised using the ESI associated with the vES (i.e., the
(i.e., the vESI). EVPN aliasing and mass-withdraw operations are vESI). EVPN aliasing and mass-withdraw operations are conducted with
conducted with respect to the vES identifier. Specifically, the respect to the vES identifier. Specifically, the Ethernet A-D routes
Ethernet A-D routes for these operations are advertised using the for these operations are advertised using the vESI instead of the
vESI instead of the ESI. ESI.
For the PBB-EVPN solution, the main change is with respect to the For the PBB-EVPN solution, the main change is with respect to the
B-MAC address assignment, which is performed in a similar way to what B-MAC address assignment, which is performed in a similar way to what
is described in Section 7.2.1.1 of [RFC7623], with the following is described in Section 6.2.1.1 of [RFC7623], with the following
refinements: refinements:
* One shared B-MAC address SHOULD be used per PE for the single- * One shared B-MAC address SHOULD be used per PE for the single-
homed vESes. In other words, a single B-MAC is shared for all homed vESes. In other words, a single B-MAC is shared for all
single-homed vESes on that PE. single-homed vESes on that PE.
* One shared B-MAC address SHOULD be used per PE, per physical port * One shared B-MAC address SHOULD be used per PE, per physical port
(e.g., ENNI) for the Single-Active vESes. In other words, a (e.g., ENNI) for the Single-Active vESes. In other words, a
single B-MAC is shared for all Single-Active vESes that share the single B-MAC is shared for all Single-Active vESes that share the
same ENNI. same ENNI.
skipping to change at line 524 skipping to change at line 521
4.1. EVPN DF Election for vES 4.1. EVPN DF Election for vES
The service carving procedures for vESes are almost the same as the The service carving procedures for vESes are almost the same as the
procedures outlined in Section 8.5 of [RFC7432] and in [RFC8584], procedures outlined in Section 8.5 of [RFC7432] and in [RFC8584],
except that ES is replaced with vES. except that ES is replaced with vES.
For the sake of clarity and completeness, the default DF election For the sake of clarity and completeness, the default DF election
procedure of [RFC7432] is repeated below with the necessary changes: procedure of [RFC7432] is repeated below with the necessary changes:
1. When a PE discovers the vESI or is configured with the vESI 1. When a PE discovers the vESI or is configured with the vESI
associated with its attached vES, it advertises an Ethernet associated with its attached vES, it advertises an ES route with
Segment route with the associated ES-Import extended community the associated ES-Import Route Target extended community
attribute. attribute.
2. The PE then starts a timer (default value = 3 seconds) to allow 2. The PE then starts a timer (default value = 3 seconds) to allow
the reception of Ethernet Segment routes from other PE nodes the reception of ES routes from other PE nodes connected to the
connected to the same vES. This timer value MUST be the same same vES. This timer value MUST be the same across all PEs
across all PEs connected to the same vES. connected to the same vES.
3. When the timer expires, each PE builds an ordered list of the IP 3. When the timer expires, each PE builds an ordered list of the IP
addresses of all the PE nodes connected to the vES (including addresses of all the PE nodes connected to the vES (including
itself), in increasing numeric value. Each IP address in this itself), in increasing numeric value. Each IP address in this
list is extracted from the "Originator Router's IP address" field list is extracted from the "Originator Router's IP address" field
of the advertised Ethernet Segment route. Every PE is then given of the advertised ES route. Every PE is then given an ordinal
an ordinal indicating its position in the ordered list, starting indicating its position in the ordered list, starting with 0 as
with 0 as the ordinal for the PE with the numerically lowest IP the ordinal for the PE with the numerically lowest IP address.
address. The ordinals are used to determine which PE node will The ordinals are used to determine which PE node will be the DF
be the DF for a given EVPN instance on the vES using the for a given EVPN instance on the vES using the following rule:
following rule: Assuming a redundancy group of N PE nodes, the PE Assuming a redundancy group of N PE nodes, the PE with ordinal i
with ordinal i is the DF for an EVPN instance with an associated is the DF for an EVPN instance with an associated Ethernet Tag
Ethernet Tag value of V when (V mod N) = i. It should be noted value of V when (V mod N) = i. It should be noted that using the
that using the "Originator Router's IP address" field in the "Originator Router's IP address" field in the ES route to get the
Ethernet Segment route to get the PE IP address needed for the PE IP address needed for the ordered list allows a CE to be
ordered list allows a CE to be multi-homed across different ASes, multihomed across different ASes, if such need ever arises.
if such need ever arises.
4. The PE that is elected as a DF for a given EVPN instance will 4. The PE that is elected as a DF for a given EVPN instance will
unblock traffic for that EVPN instance. Note that the DF PE unblock traffic for that EVPN instance. Note that the DF PE
unblocks all traffic in both ingress and egress directions for unblocks all traffic in both ingress and egress directions for
Single-Active vESes and unblocks multi-destination in the egress Single-Active vESes and unblocks multi-destination in the egress
direction for All-Active multi-homed vESes. All non-DF PEs block direction for All-Active multihomed vESes. All non-DF PEs block
all traffic in both ingress and egress directions for Single- all traffic in both ingress and egress directions for Single-
Active vESes and block multi-destination traffic in the egress Active vESes and block multi-destination traffic in the egress
direction for All-Active vESes. direction for All-Active vESes.
In case of an EVC failure, the affected PE withdraws its In case of an EVC failure, the affected PE withdraws its
corresponding Ethernet Segment route if there are no more EVCs corresponding ES route if there are no more EVCs associated to the
associated to the vES in the PE. This will re-trigger the DF vES in the PE. This will re-trigger the DF election procedure on all
election procedure on all the PEs in the redundancy group. For PE the PEs in the redundancy group. For PE node failure, or upon PE
node failure, or upon PE commissioning or decommissioning, the PEs commissioning or decommissioning, the PEs re-trigger the DF election
re-trigger the DF election procedure across all affected vESes. In procedure across all affected vESes. In case of a Single-Active
case of a Single-Active, when a service moves from one PE in the scenario, when a service moves from one PE in the redundancy group to
redundancy group to another PE because of DF re-election, the PE another PE because of DF re-election, the PE (which ends up being the
(which ends up being the elected DF for the service) MUST trigger a elected DF for the service) MUST trigger a MAC address flush
MAC address flush notification towards the associated vES if the notification towards the associated vES if the multihoming device is
multi-homing device is a bridge or the multi-homing network is an a bridge or the multihoming network is an Ethernet bridged network.
Ethernet bridged network.
For LSP-based and PW-based vES, the non-DF PE SHOULD signal PW-status For LSP-based and PW-based vES, the non-DF PE SHOULD signal PW-status
'standby' to the Aggregation PE (e.g., AG1 and AG2 in Figure 2), and 'standby' to the Aggregation PE (e.g., AG1 and AG2 in Figure 2), and
a new DF PE MAY send a Label Distribution Protocol (LDP) MAC withdraw a new DF PE MAY send a Label Distribution Protocol (LDP) MAC withdraw
message as a MAC address flush notification. It should be noted that message as a MAC address flush notification. It should be noted that
the PW-status is signaled for the scenarios where there is a one-to- the PW-status is signaled for the scenarios where there is a one-to-
one mapping between EVI (EVPN instance) and the PW. one mapping between EVI (EVPN instance) and the PW.
4.2. Grouping and Route Coloring for vES 4.2. Grouping and Route Coloring for vES
skipping to change at line 593 skipping to change at line 588
By default, the MAC address of the corresponding port (e.g., ENNI) is By default, the MAC address of the corresponding port (e.g., ENNI) is
used to represent the 'color' of the port, and the EVPN Router's MAC used to represent the 'color' of the port, and the EVPN Router's MAC
Extended Community defined in [RFC9135] is used to signal this color. Extended Community defined in [RFC9135] is used to signal this color.
The difference between coloring mechanisms for EVPN and PBB-EVPN is The difference between coloring mechanisms for EVPN and PBB-EVPN is
that the extended community is advertised with the Ethernet A-D per that the extended community is advertised with the Ethernet A-D per
ES route for EVPN, whereas the extended community is advertised with ES route for EVPN, whereas the extended community is advertised with
the B-MAC route for PBB-EVPN. the B-MAC route for PBB-EVPN.
The subsequent sections detailing Grouping of Ethernet A-D per ES and The subsequent sections detailing Grouping of Ethernet A-D per ES
Grouping of B-MAC addresses will be essential for addressing port routes and Grouping of B-MAC addresses will be essential for
failure handling, as discussed in Sections 5.3, 5.4, and 5.5. addressing port failure handling, as discussed in Sections 5.3, 5.4,
and 5.5.
4.2.1. EVPN Route Coloring for vES 4.2.1. EVPN Route Coloring for vES
When a PE discovers the vESI or is configured with the vESI When a PE discovers the vESI or is configured with the vESI
associated with its attached vES, an Ethernet Segment route and associated with its attached vES, an ES route and Ethernet A-D per ES
Ethernet A-D per ES route are generated using the vESI identifier. route are generated using the vESI identifier.
These Ethernet Segment and Ethernet A-D per ES routes specific to These ES and Ethernet A-D per ES routes specific to each vES are
each vES are colored with an attribute representing their association colored with an attribute representing their association to a
to a physical port (e.g., ENNI). physical port (e.g., ENNI).
The corresponding port 'color' is encoded in the EVPN Router's MAC The corresponding port 'color' is encoded in the EVPN Router's MAC
Extended Community defined in [RFC9135] and advertised along with the Extended Community defined in [RFC9135] and advertised along with the
Ethernet Segment and Ethernet A-D per ES routes for this vES. The ES and Ethernet A-D per ES routes for this vES. The color (which is
color (which is the MAC address of the port) MUST be unique. the MAC address of the port) MUST be unique.
The PE also constructs a special Grouping Ethernet A-D per ES route The PE also constructs a special Grouping Ethernet A-D per ES route
that represents all the vESes associated with the port (e.g., ENNI). that represents all the vESes associated with the port (e.g., ENNI).
The corresponding port 'color' is encoded in the ESI field. For this The corresponding port 'color' is encoded in the ESI field. For this
encoding, Type 3 ESI (Section 5 of [RFC7432]) is used with the MAC encoding, Type 3 ESI (Section 5 of [RFC7432]) is used with the MAC
field set to the color (MAC address) of the port and the 3-octet field set to the color (MAC address) of the port and the 3-octet
local discriminator field set to 0xFFFFFF. local discriminator field set to 0xFFFFFF.
The ESI label extended community (Section 7.5 of [RFC7432]) is not The ESI label extended community (Section 7.5 of [RFC7432]) is not
relevant to Grouping Ethernet A-D per ES route. The label value is relevant to Grouping Ethernet A-D per ES route. The label value is
skipping to change at line 703 skipping to change at line 699
+-----+ | | | | +-------+ +-----+ | | | | +-------+
+-----+ +---+ +-----+ +---+
/\ /\ /\ /\ /\ /\
|| || || || || ||
A C E A C E
Figure 3: Failure Scenarios A, B, C, D, and E Figure 3: Failure Scenarios A, B, C, D, and E
5.1. EVC Failure Handling for Single-Active vES in EVPN 5.1. EVC Failure Handling for Single-Active vES in EVPN
In [RFC7432], when a DF PE connected to a Single-Active multi-homed In [RFC7432], when a DF PE connected to a Single-Active multihomed ES
Ethernet Segment loses connectivity to the segment, due to link or loses connectivity to the segment, due to link or port failure, it
port failure, it signals the remote PEs to invalidate all MAC signals the remote PEs to invalidate all MAC addresses associated
addresses associated with that Ethernet Segment. This is done by with that ES. This is done by means of a mass-withdraw message, by
means of a mass-withdraw message, by withdrawing the Ethernet A-D per withdrawing the Ethernet A-D per ES route. It should be noted that
ES route. It should be noted that for dual-homing use cases where for dual-homing use cases where there is only a single backup path,
there is only a single backup path, MAC invalidating can be avoided MAC invalidating can be avoided by the remote PEs as they can update
by the remote PEs as they can update their next hop associated with their next hop associated with the affected MAC entries to the backup
the affected MAC entries to the backup path per the procedure path per the procedure described in Section 8.2 of [RFC7432].
described in Section 8.2 of [RFC7432].
In case of an EVC failure that impacts a single vES, this same EVPN In case of an EVC failure that impacts a single vES, this same EVPN
procedure is used. In this case, the mass withdraw is conveyed by procedure is used. In this case, the mass withdraw is conveyed by
withdrawing the Ethernet A-D per vES route carrying the vESI withdrawing the Ethernet A-D per vES route carrying the vESI
representing the failed EVC. Upon receiving this message, the remote representing the failed EVC. Upon receiving this message, the remote
PEs perform the same procedures outlined in Section 8.2 of [RFC7432]. PEs perform the same procedures outlined in Section 8.2 of [RFC7432].
5.2. EVC Failure Handling for a Single-Active vES in PBB-EVPN 5.2. EVC Failure Handling for a Single-Active vES in PBB-EVPN
In [RFC7432], when a PE connected to a Single-Active Ethernet Segment In [RFC7432], when a PE connected to a Single-Active ES loses
loses connectivity to the segment, due to link or port failure, it connectivity to the segment, due to link or port failure, it signals
signals the remote PE to flush all C-MAC addresses associated with the remote PE to flush all C-MAC addresses associated with that ES.
that Ethernet Segment. This is done by updating the advertised B-MAC This is done by updating the advertised B-MAC route's MAC Mobility
route's MAC Mobility Extended Community. extended community.
In case of an EVC failure that impacts a single vES, if the above In case of an EVC failure that impacts a single vES, if the above
PBB-EVPN procedure is used, it results in excessive C-MAC flushing PBB-EVPN procedure is used, it results in excessive C-MAC flushing
because a single physical port can support a large number of EVCs because a single physical port can support a large number of EVCs
(and their associated vESes); therefore, updating the advertised (and their associated vESes); therefore, updating the advertised
B-MAC corresponding to the physical port, with MAC Mobility Extended B-MAC corresponding to the physical port, with MAC Mobility extended
Community, will result in flushing C-MAC addresses not just for the community, will result in flushing C-MAC addresses not just for the
impacted EVC but for all other EVCs on that port. impacted EVC but for all other EVCs on that port.
To reduce the scope of C-MAC flushing to only the impacted service To reduce the scope of C-MAC flushing to only the impacted service
instances (the service instance(s) impacted by the EVC failure), the instances (the service instance(s) impacted by the EVC failure), the
PBB-EVPN C-MAC flushing needs to be adapted on a per-service-instance PBB-EVPN C-MAC flushing needs to be adapted on a per-service-instance
basis (i.e., per I-SID). [RFC9541] introduces a B-MAC/I-SID route basis (i.e., per I-SID). [RFC9541] introduces a B-MAC/I-SID route
where the existing PBB-EVPN B-MAC route is modified to carry an I-SID where the existing PBB-EVPN B-MAC route is modified to carry an
in the "Ethernet Tag ID" field instead of NULL value. To the I-SID, instead of a NULL value, in the "Ethernet Tag ID" field. To
receiving PE, this field indicates flushing all C-MAC addresses the receiving PE, this field indicates flushing all C-MAC addresses
associated with that I-SID for that B-MAC. This C-MAC flushing associated with that I-SID for that B-MAC. This C-MAC flushing
mechanism per I-SID SHOULD be used in case of an EVC failure mechanism per I-SID SHOULD be used in case of an EVC failure
impacting a vES. Since an EVC typically maps to a single broadcast impacting a vES. Since an EVC typically maps to a single broadcast
domain and thus a single service instance, the affected PE only needs domain and thus a single service instance, the affected PE only needs
to advertise a single B-MAC/I-SID route. However, if the failed EVC to advertise a single B-MAC/I-SID route. However, if the failed EVC
carries multiple VLANs each with its own broadcast domain, then the carries multiple VLANs each with its own broadcast domain, then the
affected PE needs to advertise multiple B-MAC/I-SID routes -- one for affected PE needs to advertise multiple B-MAC/I-SID routes, i.e., one
each VLAN (broadcast domain) -- i.e., one for each I-SID. Each route for each VLAN (broadcast domain), meaning one route for each
B-MAC/I-SID route basically instructs the remote PEs to perform I-SID. Each B-MAC/I-SID route basically instructs the remote PEs to
flushing for C-MACs corresponding to the advertised B-MAC only for perform flushing for C-MACs corresponding to the advertised B-MAC
the advertised I-SID. only for the advertised I-SID.
The C-MAC flushing based on a B-MAC/I-SID route works fine when there The C-MAC flushing based on a B-MAC/I-SID route works fine when there
are only a few VLANs (e.g., I-SIDs) per EVC. However, if the number are only a few VLANs (e.g., I-SIDs) per EVC. However, if the number
of I-SIDs associated with a failed EVC is large, then it is of I-SIDs associated with a failed EVC is large, then it is
RECOMMENDED to assign a B-MAC per vES, and upon EVC failure, the RECOMMENDED to assign a B-MAC per vES, and upon EVC failure, the
affected PE simply withdraws this B-MAC message to other PEs. affected PE simply withdraws this B-MAC message to other PEs.
5.3. Port Failure Handling for Single-Active vESes in EVPN 5.3. Port Failure Handling for Single-Active vESes in EVPN
When many EVCs are aggregated via a single physical port on a PE, When many EVCs are aggregated via a single physical port on a PE,
skipping to change at line 789 skipping to change at line 784
for that color, which represents all the vESes associated with for that color, which represents all the vESes associated with
the port. the port.
3. Upon a port failure (e.g., an ENNI failure), the PE MAY send a 3. Upon a port failure (e.g., an ENNI failure), the PE MAY send a
mass-withdraw message by withdrawing the Grouping Ethernet A-D mass-withdraw message by withdrawing the Grouping Ethernet A-D
per ES route. per ES route.
4. When this message is received, the remote PE MAY detect the 4. When this message is received, the remote PE MAY detect the
special vES mass-withdraw message by identifying the Grouping special vES mass-withdraw message by identifying the Grouping
Ethernet A-D per ES route. The remote PEs MAY then access the Ethernet A-D per ES route. The remote PEs MAY then access the
list created in (1) of the vESes for the specified color and list of vESes created per item 1 for the specified color and
locally initiate MAC address invalidating procedures for each of locally initiate MAC address invalidating procedures for each of
the vESes in the list. the vESes in the list.
In scenarios where a logical ENNI is used, the above procedure In scenarios where a logical ENNI is used, the above procedure
equally applies. The logical ENNI is represented by a Grouping equally applies. The logical ENNI is represented by a Grouping
Ethernet A-D per ES where the Type 3 ESI and the 6 bytes used in the Ethernet A-D per ES route where the Type 3 ESI and the 6 bytes used
ENNI's ESI MAC address field are used as a color for the vESes as in the ENNI's ESI MAC address field are used as a color for the vESes
described above and in Section 4.2.1. as described above and in Section 4.2.1.
5.4. Port Failure Handling for Single-Active vESes in PBB-EVPN 5.4. Port Failure Handling for Single-Active vESes in PBB-EVPN
When many EVCs are aggregated via a single physical port on a PE, When many EVCs are aggregated via a single physical port on a PE,
where each EVC corresponds to a vES, then the port failure impacts where each EVC corresponds to a vES, then the port failure impacts
all the associated EVCs and their corresponding vESes. If the number all the associated EVCs and their corresponding vESes. If the number
of EVCs corresponding to the Single-Active vESes for that physical of EVCs corresponding to the Single-Active vESes for that physical
port is in the thousands, then thousands of service instances port is in the thousands, then thousands of service instances
(I-SIDs) are impacted. In such failure scenarios, the following two (I-SIDs) are impacted. In such failure scenarios, the following two
MAC flushing mechanisms per [RFC7623] can be performed. MAC flushing mechanisms per [RFC7623] can be performed.
1. If the MAC address of the physical port is used for PBB 1. If the MAC address of the physical port is used for PBB
encapsulation as B-MAC SA, then upon the port failure, the PE encapsulation as B-MAC SA, then upon the port failure, the PE
MUST use the EVPN MAC route withdrawal message to signal the MUST use the EVPN MAC route withdrawal message to signal the
flush. flush.
2. If the PE's shared MAC address is used for PBB encapsulation as 2. If the PE's shared MAC address is used for PBB encapsulation as
B-MAC SA, then upon the port failure, the PE MUST re-advertise B-MAC SA, then upon the port failure, the PE MUST re-advertise
this MAC route with the MAC Mobility Extended Community to signal this MAC route with the MAC Mobility extended community to signal
the flush. the flush.
The first method is recommended because it reduces the scope of The first method is recommended because it reduces the scope of
flushing the most. flushing the most.
As noted above, the advertisement of the extended community along As noted above, the advertisement of the extended community along
with the B-MAC route for coloring purposes is optional and only with the B-MAC route for coloring purposes is optional and only
recommended when there are many vESes per physical port and each vES recommended when there are many vESes per physical port and each vES
is associated with a very large number of service instances (i.e., a is associated with a very large number of service instances (i.e., a
large number of I-SIDs). large number of I-SIDs).
skipping to change at line 910 skipping to change at line 905
+----+ | | +---+ +----+ | | +---+
+-----+ +-----+
Figure 4: Fast Convergence Upon ENNI Failure Figure 4: Fast Convergence Upon ENNI Failure
As discussed in Section 4.2, it is highly desirable to have a mass- As discussed in Section 4.2, it is highly desirable to have a mass-
withdraw mechanism similar to the one in [RFC7432]. Although such an withdraw mechanism similar to the one in [RFC7432]. Although such an
optimization is desirable, it is OPTIONAL. If the optimization is optimization is desirable, it is OPTIONAL. If the optimization is
implemented, the following procedures are used: implemented, the following procedures are used:
1. When a vES is configured, the PE advertises the Ethernet Segment 1. When a vES is configured, the PE advertises the ES route for this
route for this vES with a color that corresponds to the vES with a color that corresponds to the associated physical
associated physical port. port.
2. All receiving PEs within the redundancy group record this color 2. All receiving PEs within the redundancy group record this color
and compile a list of vESes associated with it. and compile a list of vESes associated with it.
3. Additionally, the PE advertises a Grouping Ethernet A-D per ES 3. Additionally, the PE advertises a Grouping Ethernet A-D per ES
for EVPN, and a Grouping B-MAC for PBB-EVPN, which corresponds to route for EVPN, and a Grouping B-MAC route for PBB-EVPN, which
the color and vES grouping. corresponds to the color and vES grouping.
4. In the event of a port failure, such as an ENNI failure, the PE 4. In the event of a port failure, such as an ENNI failure, the PE
withdraws the previously advertised Grouping Ethernet A-D per ES withdraws the previously advertised Grouping Ethernet A-D per ES
or Grouping B-MAC associated with the failed port. The PE should route or Grouping B-MAC route associated with the failed port.
prioritize sending these Grouping route withdrawal messages over The PE should prioritize sending these Grouping route withdrawal
the withdrawal of individual vES routes affected by the failure. messages over the withdrawal of individual vES routes affected by
For instance, as depicted in Figure 4, when the physical port the failure. For instance, as depicted in Figure 4, when the
associated with ENNI3 fails on PE2, it withdraws the previously physical port associated with ENNI3 fails on PE2, it withdraws
advertised Grouping Ethernet A-D per ES route. Upon receiving the previously advertised Grouping Ethernet A-D per ES route.
this withdrawal message, other multi-homing PEs (such as PE1 and Upon receiving this withdrawal message, other multihoming PEs
PE3) recognize that the vESes associated with CE1 and CE3 are (such as PE1 and PE3) recognize that the vESes associated with
impacted, based on the associated color, and thus initiate the DF CE1 and CE3 are impacted, based on the associated color, and thus
election procedure for these vESes. Furthermore, upon receiving initiate the DF election procedure for these vESes. Furthermore,
this withdrawal message, remote PEs (such as PE4) initiate the upon receiving this withdrawal message, remote PEs (such as PE4)
failover procedure for the vESes associated with CE1 and CE3 and initiate the failover procedure for the vESes associated with CE1
switch to the other PE for each vES redundancy group. and CE3 and switch to the other PE for each vES redundancy group.
5. On reception of Grouping Ethernet A-D per ES or Grouping B-MAC 5. On reception of Grouping Ethernet A-D per ES route or Grouping
route withdrawal, other PEs in the redundancy group initiate DF B-MAC route withdrawal, other PEs in the redundancy group
election procedures across all their affected vESes. initiate DF election procedures across all their affected vESes.
6. The PE with the physical port failure (ENNI failure) sends a vES 6. The PE with the physical port failure (ENNI failure) sends a vES
route withdrawal for every impacted vES. Upon receiving these route withdrawal for every impacted vES. Upon receiving these
messages, the other PEs clear up their BGP tables. It should be messages, the other PEs clear up their BGP tables. It should be
noted that the vES route withdrawal messages are not used for noted that the vES route withdrawal messages are not used for
executing DF election procedures by the receiving PEs when executing DF election procedures by the receiving PEs when
Grouping Ethernet A-D per ES or Grouping B-MAC withdrawal has Grouping Ethernet A-D per ES route or Grouping B-MAC route
been previously received. withdrawal has been previously received.
6. Security Considerations 6. Security Considerations
All the security considerations in [RFC7432] and [RFC7623] apply All the security considerations in [RFC7432] and [RFC7623] apply
directly to this document because this document leverages the control directly to this document because this document leverages the control
and data plane procedures described in those documents. and data plane procedures described in those documents.
This document does not introduce any new security considerations This document does not introduce any new security considerations
beyond that of [RFC7432] and [RFC7623] because advertisements and the beyond that of [RFC7432] and [RFC7623] because advertisements and the
processing of Ethernet Segment routes for vES in this document follow processing of ES routes for vES in this document follow that of
that of physical ES in those RFCs. physical ES in those RFCs.
7. IANA Considerations 7. IANA Considerations
This document has no IANA actions. This document has no IANA actions.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
skipping to change at line 1013 skipping to change at line 1008
[RFC9541] Rabadan, J., Ed., Sathappan, S., Nagaraj, K., Miyake, M., [RFC9541] Rabadan, J., Ed., Sathappan, S., Nagaraj, K., Miyake, M.,
and T. Matsuda, "Flush Mechanism for Customer MAC and T. Matsuda, "Flush Mechanism for Customer MAC
Addresses Based on Service Instance Identifier (I-SID) in Addresses Based on Service Instance Identifier (I-SID) in
Provider Backbone Bridging EVPN (PBB-EVPN)", RFC 9541, Provider Backbone Bridging EVPN (PBB-EVPN)", RFC 9541,
DOI 10.17487/RFC9541, March 2024, DOI 10.17487/RFC9541, March 2024,
<https://www.rfc-editor.org/info/rfc9541>. <https://www.rfc-editor.org/info/rfc9541>.
8.2. Informative References 8.2. Informative References
[MEF63] Metro Ethernet Forum, "Subscriber Ethernet Services [MEF63] Metro Ethernet Forum, "Subscriber Ethernet Services
Definitions", MEF Standard, MEF 6.3, November 2019. Definitions", MEF Standard, MEF 6.3, November 2019,
<https://www.mef.net/resources/mef-6-3-subscriber-
ethernet-service-definitions>.
[RFC4377] Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S. [RFC4377] Nadeau, T., Morrow, M., Swallow, G., Allan, D., and S.
Matsushima, "Operations and Management (OAM) Requirements Matsushima, "Operations and Management (OAM) Requirements
for Multi-Protocol Label Switched (MPLS) Networks", for Multi-Protocol Label Switched (MPLS) Networks",
RFC 4377, DOI 10.17487/RFC4377, February 2006, RFC 4377, DOI 10.17487/RFC4377, February 2006,
<https://www.rfc-editor.org/info/rfc4377>. <https://www.rfc-editor.org/info/rfc4377>.
[RFC6310] Aissaoui, M., Busschbach, P., Martini, L., Morrow, M., [RFC6310] Aissaoui, M., Busschbach, P., Martini, L., Morrow, M.,
Nadeau, T., and Y. Stein, "Pseudowire (PW) Operations, Nadeau, T., and Y. Stein, "Pseudowire (PW) Operations,
Administration, and Maintenance (OAM) Message Mapping", Administration, and Maintenance (OAM) Message Mapping",
skipping to change at line 1071 skipping to change at line 1068
Ali Sajassi Ali Sajassi
Cisco Systems Cisco Systems
Email: sajassi@cisco.com Email: sajassi@cisco.com
Patrice Brissette Patrice Brissette
Cisco Systems Cisco Systems
Email: pbrisset@cisco.com Email: pbrisset@cisco.com
Rick Schell Rick Schell
Verizon Independent
Email: richard.schell@verizon.com Email: rick_schell@outlook.com
John E Drake John E. Drake
Juniper Independent
Email: jdrake@juniper.net Email: je_drake@yahoo.com
Jorge Rabadan Jorge Rabadan
Nokia Nokia
Email: jorge.rabadan@nokia.com Email: jorge.rabadan@nokia.com
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