draft-ietf-bess-evpn-pref-df-04.txt   draft-ietf-bess-evpn-pref-df-05.txt 
BESS Workgroup J. Rabadan, Ed. BESS Workgroup J. Rabadan, Ed.
Internet Draft S. Sathappan Internet-Draft S. Sathappan
Intended status: Standards Track Nokia Intended status: Standards Track Nokia
Expires: June 19, 2020 T. Przygienda
S. Boutros T. Przygienda W. Lin
VMWare W. Lin
J. Drake J. Drake
Juniper Networks Juniper Networks
A. Sajassi A. Sajassi
S. Mohanty S. Mohanty
Cisco Systems Cisco Systems
December 17, 2019
Expires: December 27, 2019 June 25, 2019
Preference-based EVPN DF Election Preference-based EVPN DF Election
draft-ietf-bess-evpn-pref-df-04 draft-ietf-bess-evpn-pref-df-05
Abstract Abstract
The Designated Forwarder (DF) in Ethernet Virtual Private Networks The Designated Forwarder (DF) in Ethernet Virtual Private Networks
(EVPN) is defined as the PE responsible for sending Broadcast, (EVPN) is defined as the PE responsible for sending Broadcast,
Unknown unicast and Broadcast traffic (BUM) to a multi-homed Unknown unicast and Broadcast traffic (BUM) to a multi-homed device/
device/network in the case of an all-active multi-homing Ethernet network in the case of an all-active multi-homing Ethernet Segment
Segment (ES), or BUM and unicast in the case of single-active multi- (ES), or BUM and unicast in the case of single-active multi-homing.
homing.
The DF is selected out of a candidate list of PEs that advertise the The DF is selected out of a candidate list of PEs that advertise the
same Ethernet Segment Identifier (ESI) to the EVPN network, according same Ethernet Segment Identifier (ESI) to the EVPN network, according
to the Default DF Election algorithm. to the Default DF Election algorithm.
While the Default Algorithm provides an efficient and automated way While the Default Algorithm provides an efficient and automated way
of selecting the DF across different Ethernet Tags in the ES, there of selecting the DF across different Ethernet Tags in the ES, there
are some use-cases where a more 'deterministic' and user-controlled are some use-cases where a more 'deterministic' and user-controlled
method is required. At the same time, Service Providers require an method is required. At the same time, Service Providers require an
easy way to force an on-demand DF switchover in order to carry out easy way to force an on-demand DF switchover in order to carry out
some maintenance tasks on the existing DF or control whether a new some maintenance tasks on the existing DF or control whether a new
active PE can preempt the existing DF PE. active PE can preempt the existing DF PE.
This document proposes an extension to the Default DF election This document proposes an extension to the Default DF election
procedures so that the above requirements can be met. procedures so that the above requirements can be met.
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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http://www.ietf.org/ietf/1id-abstracts.txt
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This Internet-Draft will expire on December 27, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Problem Statement . . . . . . . . . . . . . . . . . . . . . 3 1.1. Problem Statement . . . . . . . . . . . . . . . . . . . . 3
1.2 Solution requirements . . . . . . . . . . . . . . . . . . . 3 1.2. Solution requirements . . . . . . . . . . . . . . . . . . 3
2. Conventions and Terminology . . . . . . . . . . . . . . . . . . 4 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4
3. EVPN BGP Attributes Extensions . . . . . . . . . . . . . . . . 5 3. EVPN BGP Attributes Extensions . . . . . . . . . . . . . . . 5
4. Solution description . . . . . . . . . . . . . . . . . . . . . 6 4. Solution description . . . . . . . . . . . . . . . . . . . . 6
4.1 Use of the Preference algorithm . . . . . . . . . . . . . . 7 4.1. Use of the Preference algorithm . . . . . . . . . . . . . 7
4.2 Use of the Preference algorithm in [RFC7432] Ethernet 4.2. Use of the Preference algorithm in [RFC7432] Ethernet
Segments . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Segments . . . . . . . . . . . . . . . . . . . . . . . . 9
4.3 The Non-Revertive Capability . . . . . . . . . . . . . . . . 10 4.3. The Non-Revertive Capability . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 13 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
7.1 Normative References . . . . . . . . . . . . . . . . . . . . 13 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13
7.2 Informative References . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . 13
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . 14
10. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
1.1 Problem Statement 1. Introduction
1.1. Problem Statement
[RFC7432] defines the Designated Forwarder (DF) in (PBB-)EVPN [RFC7432] defines the Designated Forwarder (DF) in (PBB-)EVPN
networks as the PE responsible for sending broadcast, multicast and networks as the PE responsible for sending broadcast, multicast and
unknown unicast traffic (BUM) to a multi-homed device/network in the unknown unicast traffic (BUM) to a multi-homed device/network in the
case of an all-active multi-homing ES or BUM and unicast traffic to a case of an all-active multi-homing ES or BUM and unicast traffic to a
multi-homed device or network in case of single-active multi-homing. multi-homed device or network in case of single-active multi-homing.
The DF is selected out of a candidate list of PEs that advertise the The DF is selected out of a candidate list of PEs that advertise the
Ethernet Segment Identifier (ESI) to the EVPN network and according Ethernet Segment Identifier (ESI) to the EVPN network and according
to the DF Election Algorithm, or DF Alg as per [DF]. to the DF Election Algorithm, or DF Alg as per [RFC8584].
While the Default DF Alg [RFC7432] or HRW [DF] provide an efficient While the Default DF Alg [RFC7432] or HRW [RFC8584] provide an
and automated way of selecting the DF across different Ethernet Tags efficient and automated way of selecting the DF across different
in the ES, there are some use-cases where a more 'deterministic' and Ethernet Tags in the ES, there are some use-cases where a more
user-controlled method is required. At the same time, Service 'deterministic' and user-controlled method is required. At the same
Providers require an easy way to force an on-demand DF switchover in time, Service Providers require an easy way to force an on-demand DF
order to carry out some maintenance tasks on the existing DF or switchover in order to carry out some maintenance tasks on the
control whether a new active PE can preempt the existing DF PE. existing DF or control whether a new active PE can preempt the
existing DF PE.
This document proposes a new DF Alg and capability to address the This document proposes a new DF Alg and capability to address the
above needs. above needs.
1.2 Solution requirements 1.2. Solution requirements
The procedures described in this document meet the following The procedures described in this document meet the following
requirements: requirements:
a) The solution provides an administrative preference option so that a. The solution provides an administrative preference option so that
the user can control in what order the candidate PEs may become the user can control in what order the candidate PEs may become
DF, assuming they are all operationally ready to take over as DF. DF, assuming they are all operationally ready to take over as DF.
b) This extension works for [RFC7432] Ethernet Segments (ES) and b. This extension works for [RFC7432] Ethernet Segments and virtual
virtual ES, as defined in [vES]. ES, as defined in [I-D.ietf-bess-evpn-virtual-eth-segment].
c) The user may force a PE to preempt the existing DF for a given c. The user may force a PE to preempt the existing DF for a given
Ethernet Tag without re-configuring all the PEs in the ES. Ethernet Tag without re-configuring all the PEs in the ES.
d) The solution allows an option to NOT preempt the current DF, even d. The solution allows an option to NOT preempt the current DF, even
if the former DF PE comes back up after a failure. This is also if the former DF PE comes back up after a failure. This is also
known as "non-revertive" behavior, as opposed to the [RFC7432] DF known as "non-revertive" behavior, as opposed to the [RFC7432] DF
election procedures that are always revertive. election procedures that are always revertive.
e) The solution works for single-active and all-active multi-homing e. The solution works for single-active and all-active multi-homing
Ethernet Segments. Ethernet Segments.
2. Conventions and Terminology 2. Conventions and 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", "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
BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
o AC - Attachment Circuit. An AC has an Ethernet Tag associated to o AC - Attachment Circuit. An AC has an Ethernet Tag associated to
it. it.
o BUM - refers to the Broadcast, Unknown unicast and Multicast o BUM - refers to the Broadcast, Unknown unicast and Multicast
traffic. traffic.
o DF, NDF and BDF - Designated Forwarder, Non-Designated Forwarder o DF, NDF and BDF - Designated Forwarder, Non-Designated Forwarder
and Backup Designated Forwarder. and Backup Designated Forwarder.
o DF Alg - refers to Designated Forwarder Election Algorithm. o DF Alg - refers to Designated Forwarder Election Algorithm.
o HRW - Highest Random Weight, as per [DF]. o HRW - Highest Random Weight, as per [RFC8584].
o ES, vES and ESI - Ethernet Segment, virtual Ethernet Segment and o ES, vES and ESI - Ethernet Segment, virtual Ethernet Segment and
Ethernet Segment Identifier. Ethernet Segment Identifier.
o EVI - EVPN Instance. o EVI - EVPN Instance.
o ISID - refers to Service Instance Identifiers in Provider Backbone o ISID - refers to Service Instance Identifiers in Provider Backbone
Bridging (PBB) networks. Bridging (PBB) networks.
o MAC-VRF - A Virtual Routing and Forwarding table for Media Access o MAC-VRF - A Virtual Routing and Forwarding table for Media Access
Control (MAC) addresses on a PE. Control (MAC) addresses on a PE.
o BD - Broadcast Domain. An EVI may be comprised of one (VLAN-Based o BD - Broadcast Domain. An EVI may be comprised of one (VLAN-Based
or VLAN Bundle services) or multiple (VLAN-Aware Bundle services) or VLAN Bundle services) or multiple (VLAN-Aware Bundle services)
Broadcast Domains. Broadcast Domains.
o EVC - Ethernet Virtual Circuit. o EVC - Ethernet Virtual Circuit.
o DP - refers to the "Don't Preempt me" capability in the DF Election o DP - refers to the "Don't Preempt me" capability in the DF
extended community. Election extended community.
o OAM - refers to Operations And Maintenance protocols. o OAM - refers to Operations And Maintenance protocols.
o Ethernet A-D per ES route - refers to [RFC7432] route type 1 or o Ethernet A-D per ES route - refers to [RFC7432] route type 1 or
Auto-Discovery per Ethernet Segment route. Auto-Discovery per Ethernet Segment route.
o Ethernet A-D per EVI route - refers to [RFC7432] route type 1 or o Ethernet A-D per EVI route - refers to [RFC7432] route type 1 or
Auto-Discovery per EVPN Instance route. Auto-Discovery per EVPN Instance route.
o Ethernet Tag - used to represent a Broadcast Domain that is o Ethernet Tag - used to represent a Broadcast Domain that is
configured on a given ES for the purpose of DF election. Note that configured on a given ES for the purpose of DF election. Note
any of the following may be used to represent a Broadcast Domain: that any of the following may be used to represent a Broadcast
VIDs (including Q-in-Q tags), configured IDs, VNI (VXLAN Network Domain: VIDs (including Q-in-Q tags), configured IDs, VNI (VXLAN
Identifiers), normalized VID, I-SIDs (Service Instance Network Identifiers), normalized VID, I-SIDs (Service Instance
Identifiers), etc., as long as the representation of the broadcast Identifiers), etc., as long as the representation of the broadcast
domains is configured consistently across the multi-homed PEs domains is configured consistently across the multi-homed PEs
attached to that ES. The Ethernet Tag value MUST be different from attached to that ES. The Ethernet Tag value MUST be different
zero. from zero.
3. EVPN BGP Attributes Extensions 3. EVPN BGP Attributes Extensions
This solution reuses and extends the DF Election Extended Community This solution reuses and extends the DF Election Extended Community
defined in [DF] that is advertised along with the ES route: defined in [RFC8584] that is advertised along with the ES route:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=0x06 | Sub-Type(0x06)| RSV | DF Alg | Bitmap ~ | Type=0x06 | Sub-Type(0x06)| RSV | DF Alg | Bitmap ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Bitmap | Reserved | DF Preference (2 octets) | ~ Bitmap | Reserved | DF Preference (2 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 - DF Election Extended Community Figure 1: DF Election Extended Community
Where the following fields are defined as follows: Where the following fields are defined as follows:
o DF Alg can have the following values: o DF Alg can have the following values:
- Alg 0 - Default DF Election algorithm, or modulus-based algorithm - Alg 0 - Default DF Election algorithm, or modulus-based
as per [RFC7432]. algorithm as per [RFC7432].
- Alg 1 - HRW algorithm as per [DF]. - Alg 1 - HRW algorithm as per [RFC8584].
- Alg 2 - Preference algorithm (this document).
o Bitmap (2 octets) can have the following values: - Alg 2 - Preference algorithm (this document).
o Bitmap (2 octets) can have the following values:
1 1 1 1 1 1 1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D|A| | |D|A| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 - Bitmap field in the DF Election Extended Community Figure 2: Bitmap field in the DF Election Extended Community
- Bit 0 (corresponds to Bit 24 of the DF Election Extended - Bit 0 (corresponds to Bit 24 of the DF Election Extended
Community and it is defined by this document): D bit or 'Don't Community and it is defined by this document): D bit or 'Don't
Preempt' bit (DP hereafter), determines if the PE advertising the Preempt' bit (DP hereafter), determines if the PE advertising
ES route requests the remote PEs in the ES not to preempt it as the ES route requests the remote PEs in the ES not to preempt
DF. The default value is DP=0, which is compatible with the it as DF. The default value is DP=0, which is compatible with
'preempt' or 'revertive' behavior in the Default DF Alg the 'preempt' or 'revertive' behavior in the Default DF Alg
[RFC7432]. The DP bit SHOULD be ignored if the DF Alg is [RFC7432]. The DP bit SHOULD be ignored if the DF Alg is
different than 2. different than 2.
- Bit 1: AC-DF or AC-Influenced DF Election, as explained in [DF]. - Bit 1: AC-DF or AC-Influenced DF Election, as explained in
When set to 1, it indicates the desire to use AC-Influenced DF [RFC8584]. When set to 1, it indicates the desire to use AC-
Election with the rest of the PEs in the ES. The AC-DF capability Influenced DF Election with the rest of the PEs in the ES. The
bit MAY be set along with the DP capability and DF Alg 2. AC-DF capability bit MAY be set along with the DP capability
and DF Alg 2.
o DF Preference (defined in this document): defines a 2-octet value o DF Preference (defined in this document): defines a 2-octet value
that indicates the PE preference to become the DF in the ES. The that indicates the PE preference to become the DF in the ES. The
allowed values are within the range 0-65535, and the default value allowed values are within the range 0-65535, and the default value
MUST be 32767. This value is the midpoint in the allowed Preference MUST be 32767. This value is the midpoint in the allowed
range of values, which gives the operator the flexibility of Preference range of values, which gives the operator the
choosing a significant number of values, above or below the default flexibility of choosing a significant number of values, above or
Preference. The DF Preference field is specific to DF Alg 2 and below the default Preference. The DF Preference field is specific
does not represent any Preference value for other Algs. to DF Alg 2 and does not represent any Preference value for other
Algs.
4. Solution description 4. Solution description
Figure 3 illustrates an example that will be used in the description Figure 3 illustrates an example that will be used in the description
of the solution. of the solution.
EVPN network EVPN network
+-------------------+ +-------------------+
| +-------+ ENNI Aggregation | +-------+ ENNI Aggregation
| <---ESI1,500 | PE1 | /\ +----Network---+ | <---ESI1,500 | PE1 | /\ +----Network---+
| <-----ESI2,100 | |===||=== | | <-----ESI2,100 | |===||=== |
| | |===||== \ vES1 | +----+ | | |===||== \ vES1 | +----+
skipping to change at page 7, line 24 skipping to change at page 7, line 24
| | | X | | | | X |
| <---ESI1,255 +-----+============ \ | | <---ESI1,255 +-----+============ \ |
| <-----ESI2,200 | PE2 |========== \ vES2 | +----+ | <-----ESI2,200 | PE2 |========== \ vES2 | +----+
| +-----+ | \ ----------+CE2 | | +-----+ | \ ----------+CE2 |
| | | --------------| | | | | --------------| |
| +-----+ ----------------------+ | | +-----+ ----------------------+ |
| <-----ESI2,300 | PE3 +--/ | | +----+ | <-----ESI2,300 | PE3 +--/ | | +----+
| +-----+ +--------------+ | +-----+ +--------------+
--------------------+ --------------------+
Figure 3 - ES and Deterministic DF Election Figure 3: Preference-based DF Election
Figure 1 shows three PEs that are connecting EVCs coming from the Figure 3 shows three PEs that are connecting EVCs coming from the
Aggregation Network to their EVIs in the EVPN network. CE1 is Aggregation Network to their EVIs in the EVPN network. CE1 is
connected to vES1 - that spans PE1 and PE2 - and CE2 is connected to connected to vES1 - that spans PE1 and PE2 - and CE2 is connected to
vES2, that is defined in PE1, PE2 and PE3. vES2, that is defined in PE1, PE2 and PE3.
If the algorithm chosen for vES1 and vES2 is Alg 2, i.e. Preference- If the algorithm chosen for vES1 and vES2 is Alg 2, i.e., Preference-
based, the PEs may become DF irrespective of their IP address and based, the PEs may become DF irrespective of their IP address and
based on an administrative Preference value. The following sections based on an administrative Preference value. The following sections
provide some examples of the procedures and how they are applied in provide some examples of the procedures and how they are applied in
the use-case in Figure 1. the use-case of Figure 3.
4.1 Use of the Preference algorithm 4.1. Use of the Preference algorithm
Assuming the operator wants to control - in a flexible way - what PE Assuming the operator wants to control - in a flexible way - what PE
becomes the DF for a given vES and the order in which the PEs become becomes the DF for a given vES and the order in which the PEs become
DF in case of multiple failures, the following procedure may be used: DF in case of multiple failures, the following procedure may be used:
a) vES1 and vES2 are now configurable with three optional parameters a. vES1 and vES2 are now configurable with three optional parameters
that are signaled in the DF Election extended community. These that are signaled in the DF Election extended community. These
parameters are the Preference, Preemption option (or "Don't parameters are the Preference, Preemption option (or "Don't
Preempt Me" option) and DF Alg. We will represent these parameters Preempt Me" option) and DF Alg. We will represent these
as [Pref,DP,Alg]. Let's assume vES1 is configured as [500,0,Pref] parameters as [Pref,DP,Alg]. Let's assume vES1 is configured as
in PE1, and [255,0,Pref] in PE2. vES2 is configured as [500,0,Pref] in PE1, and [255,0,Pref] in PE2. vES2 is configured
[100,0,Pref], [200,0,Pref] and [300,0,Pref] in PE1, PE2 and PE3 as [100,0,Pref], [200,0,Pref] and [300,0,Pref] in PE1, PE2 and
respectively. PE3 respectively.
b) The PEs will advertise an ES route for each vES, including the 3 b. The PEs will advertise an ES route for each vES, including the 3
parameters in the DF Election Extended Community. parameters in the DF Election Extended Community.
c) According to [RFC7432], each PE will run the DF election algorithm c. According to [RFC8584], each PE will run the DF election
upon expiration of the DF Wait timer. In this case, each PE runs algorithm upon expiration of the DF Wait timer. In this case,
the Preference-based DF Alg for each ES as follows: each PE runs the Preference-based DF Alg for each ES as follows:
o The PE will check the DF Alg value in each ES route, and - The PE will check the DF Alg value in each ES route, and
assuming all the ES routes are consistent in this DF Alg and the assuming all the ES routes are consistent in this DF Alg and
value is 2 (Preference-based), the PE will run the new extended the value is 2 (Preference-based), the PE will run the new
procedure. Otherwise, the procedure will fall back to [RFC7432] extended procedure. Otherwise, the procedure will fall back
Default Alg. to [RFC7432] Default Alg.
o In this Preference-based Alg, each PE builds a list of candidate - In this Preference-based Alg, each PE builds a list of
PEs, ordered by Preference. E.g. PE1 will build a list of candidate PEs, ordered by Preference. E.g. PE1 will build a
candidate PEs for vES1 ordered by the Preference, from high to list of candidate PEs for vES1 ordered by the Preference, from
low: PE1>PE2. Hence PE1 will become the DF for vES1. In the same high to low: PE1>PE2. Hence PE1 will become the DF for vES1.
way, PE3 becomes the DF for vES2. In the same way, PE3 becomes the DF for vES2.
d) Note that, by default, the Highest-Preference is chosen for each d. Note that, by default, the Highest-Preference is chosen for each
ES or vES, however the ES configuration can be changed to the ES or vES, however the ES configuration can be changed to the
Lowest-Preference algorithm as long as this option is consistent Lowest-Preference algorithm as long as this option is consistent
in all the PEs in the ES. E.g. vES1 could have been explicitly in all the PEs in the ES. E.g. vES1 could have been explicitly
configured as Alg Preference-based with Lowest-Preference, in configured as Alg Preference-based with Lowest-Preference, in
which case, PE2 would have been the DF. which case, PE2 would have been the DF.
e) Assuming some maintenance tasks had to be executed on PE3, the e. Assuming some maintenance tasks had to be executed on PE3, the
operator could set vES2's Preference to e.g., 50 so that PE2 is operator could set vES2's Preference to e.g., 50 so that PE2 is
forced to take over as DF for vES2 (irrespective of the DP forced to take over as DF for vES2 (irrespective of the DP
capability). Once the maintenance on PE3 is over, the operator capability). Once the maintenance on PE3 is over, the operator
could decide to leave the existing preference or configure the old could decide to leave the existing preference or configure the
preference back. old preference back.
f) In case of equal Preference in two or more PEs in the ES, the tie- f. In case of equal Preference in two or more PEs in the ES, the
breakers will be the DP bit and the lowest IP PE in that order. tie-breakers will be the DP bit and the lowest IP PE, in that
For instance: order. For instance:
o If vES1 parameters were [500,0,Pref] in PE1 and [500,1,Pref] in - If vES1 parameters were [500,0,Pref] in PE1 and [500,1,Pref]
PE2, PE2 would be elected due to the DP bit. in PE2, PE2 would be elected due to the DP bit.
o If vES1 parameters were [500,0,Pref] in PE1 and [500,0,Pref] in - If vES1 parameters were [500,0,Pref] in PE1 and [500,0,Pref]
PE2, PE1 would be elected, assuming PE1's IP address is lower in PE2, PE1 would be elected, assuming PE1's IP address is
than PE2's. lower than PE2's.
g) The Preference is an administrative option that MUST be configured g. The Preference is an administrative option that MUST be
on a per-ES basis from the management plane, but MAY also be configured on a per-ES basis from the management plane, but MAY
dynamically changed based on the use of local policies. For also be dynamically changed based on the use of local policies.
instance, on PE1, ES1's Preference can be lowered from 500 to 100 For instance, on PE1, ES1's Preference can be lowered from 500 to
in case the bandwidth on the ENNI port is decreased a 50% (that 100 in case the bandwidth on the ENNI port is decreased a 50%
could happen if e.g. the 2-port LAG between PE1 and the (that could happen if e.g. the 2-port LAG between PE1 and the
Aggregation Network loses one port). Policies MAY also trigger Aggregation Network loses one port). Policies MAY also trigger
dynamic Preference changes based on the PE's bandwidth dynamic Preference changes based on the PE's bandwidth
availability in the core, of specific ports going operationally availability in the core, specific ports going operationally
down, etc. The definition of the actual local policies is out of down, etc. The definition of the actual local policies is out of
scope of this document. The default Preference value is 32767. scope of this document. The default Preference value is 32767.
The Preference Alg MAY be used along with the AC-DF capability. The Preference Alg MAY be used along with the AC-DF capability.
Assuming all the PEs in the ES are configured consistently with Assuming all the PEs in the ES are configured consistently with
Preference Alg and AC-DF capability, a given PE in the ES is not Preference Alg and AC-DF capability, a given PE in the ES is not
considered as candidate for DF Election until its corresponding considered as candidate for DF Election until its corresponding
Ethernet A-D per ES and Ethernet A-D per EVI routes are not received, Ethernet A-D per ES and Ethernet A-D per EVI routes are not received,
as described in [DF]. as described in [RFC8584].
The procedures in this document can be used in [RFC7432] based ES or The procedures in this document can be used in [RFC7432] based ES or
vES as in [vES], and including EVPN networks as in [RFC8214], vES as in [I-D.ietf-bess-evpn-virtual-eth-segment], and including
[RFC7623] or [RFC8365]. EVPN networks as in [RFC8214], [RFC7623] or [RFC8365].
4.2 Use of the Preference algorithm in [RFC7432] Ethernet Segments 4.2. Use of the Preference algorithm in [RFC7432] Ethernet Segments
While the Preference-based DF Alg described in section 4.1 is While the Preference-based DF Alg described in Section 4.1 is
typically used in virtual ES scenarios where there is normally an typically used in virtual ES scenarios where there is normally an
individual Ethernet Tag per vES, the existing [RFC7432] definition of individual Ethernet Tag per vES, the existing [RFC7432] definition of
ES allows potentially up to thousands of Ethernet Tags on the same ES allows potentially up to thousands of Ethernet Tags on the same
ES. If this is the case, and the operator still wants to control who ES. If this is the case, and the operator still wants to control who
the DF is for a given Ethernet Tag, the use of the Preference-based the DF is for a given Ethernet Tag, the use of the Preference-based
DF Alg can also provide some level of load balancing. DF Alg can also provide some level of load balancing.
In this type of scenarios, the ES is configured with an In this type of scenarios, the ES is configured with an
administrative Preference value, but then a range of Ethernet Tags administrative Preference value, but then a range of Ethernet Tags
can be defined to use the Highest-Preference or the Lowest-Preference can be defined to use the Highest-Preference or the Lowest-Preference
depending on the desired behavior. With this option, the PE will depending on the desired behavior. With this option, the PE will
build a list of candidate PEs ordered by Preference, however the DF build a list of candidate PEs ordered by Preference, however the DF
for a given Ethernet Tag will be determined by the local for a given Ethernet Tag will be determined by the local
configuration. configuration.
For instance: For instance:
o Assuming ES3 is defined in PE1 and PE2, PE1 may be configured as o Assuming ES3 is defined in PE1 and PE2, PE1 may be configured as
[500,0,Preference] for ES3 and PE2 as [100,0,Preference]. [500,0,Preference] for ES3 and PE2 as [100,0,Preference].
o In addition, assuming VLAN-based service interfaces, the PEs will o In addition, assuming VLAN-based service interfaces, the PEs will
be configured with (Ethernet Tag-range,high_or_low), E.g., (1- be configured with (Ethernet Tag-range,high_or_low), E.g.,
2000,high) and (2001-4000, low). (1-2000,high) and (2001-4000, low).
o This will result in PE1 being DF for Ethernet Tags 1-2000 and PE2 o This will result in PE1 being DF for Ethernet Tags 1-2000 and PE2
being DF for Ethernet Tags 2001-4000. being DF for Ethernet Tags 2001-4000.
For Ethernet Segments attached to three or more PEs, any other logic For Ethernet Segments attached to three or more PEs, any other logic
that provides a fair distribution of the DF function among the PEs is that provides a fair distribution of the DF function among the PEs is
valid, as long as that logic is consistent in all the PEs in the ES. valid, as long as that logic is consistent in all the PEs in the ES.
4.3 The Non-Revertive Capability 4.3. The Non-Revertive Capability
As discussed in section 1.2(d), a capability to NOT preempt the As discussed in Section 1.2 (d), a capability to NOT preempt the
existing DF for a given Ethernet Tag is required and therefore added existing DF for a given Ethernet Tag is required and therefore added
to the DF Election extended community. This option will allow a non- to the DF Election extended community. This option will allow a non-
revertive behavior in the DF election. revertive behavior in the DF election.
Note that, when a given PE in an ES is taken down for maintenance Note that, when a given PE in an ES is taken down for maintenance
operations, before bringing it back, the Preference may be changed in operations, before bringing it back, the Preference may be changed in
order to provide a non-revertive behavior. The DP bit and the order to provide a non-revertive behavior. The DP bit and the
mechanism explained in this section will be used for those cases when mechanism explained in this section will be used for those cases when
a former DF comes back up without any controlled maintenance a former DF comes back up without any controlled maintenance
operation, and the non-revertive option is desired in order to avoid operation, and the non-revertive option is desired in order to avoid
service impact. service impact.
In Figure 1, we assume that based on the Highest-Pref, PE3 is the DF In Figure 3, we assume that based on the Highest-Pref, PE3 is the DF
for ESI2. for ESI2.
If PE3 has a link, EVC or node failure, PE2 would take over as DF. If PE3 has a link, EVC or node failure, PE2 would take over as DF.
If/when PE3 comes back up again, PE3 will take over, causing some If/when PE3 comes back up again, PE3 will take over, causing some
unnecessary packet loss in the ES. unnecessary packet loss in the ES.
The following procedure avoids preemption upon failure recovery The following procedure avoids preemption upon failure recovery
(please refer to Figure 1): (please refer to Figure 1):
1) A new "Don't Preempt Me" capability is defined on a per-PE per-ES 1. A new "Don't Preempt Me" capability is defined on a per-PE per-ES
basis, as described in section 3. If "Don't Preempt Me" is basis, as described in Section 3. If "Don't Preempt Me" is
disabled (default behavior) the advertised DP bit will be 0. If disabled (default behavior), the advertised DP bit will be 0. If
"Don't Preempt Me" is enabled, the ES route will be advertised "Don't Preempt Me" is enabled, the ES route will be advertised
with DP=1 ("Don't Preempt Me"). All the PEs in an ES SHOULD be with DP=1 ("Don't Preempt Me"). All the PEs in an ES SHOULD be
consistent in their configuration of the DP capability, however consistent in their configuration of the DP capability, however
this document do not enforces the consistency across all the PEs. this document do not enforces the consistency across all the PEs.
2) Assuming we want to avoid 'preemption' in all the PEs in the ES, 2. Assuming we want to avoid 'preemption' in all the PEs in the ES,
the three PEs are configured with the "Don't Preempt Me" the three PEs are configured with the "Don't Preempt Me"
capability. In this example, we assume ESI2 is configured as capability. In this example, we assume ESI2 is configured as
'DP=enabled' in the three PEs. 'DP=enabled' in the three PEs.
3) Assuming Ethernet Tag-1 uses Highest-Pref in vES2 and Ethernet 3. Assuming Ethernet Tag-1 uses Highest-Pref in vES2 and Ethernet
Tag-2 uses Lowest-Pref, when vES2 is enabled in the three PEs, the Tag-2 uses Lowest-Pref, when vES2 is enabled in the three PEs,
PEs will exchange the ES routes and select PE3 as DF for Ethernet the PEs will exchange the ES routes and select PE3 as DF for
Tag-1 (due to the Highest-Pref type), and PE1 as DF for Ethernet Ethernet Tag-1 (due to the Highest-Pref type), and PE1 as DF for
Tag-2 (due to the Lowest-Pref). Ethernet Tag-2 (due to the Lowest-Pref).
4) If PE3's vES2 goes down (due to EVC failure - detected by OAM, or 4. If PE3's vES2 goes down (due to EVC failure - detected by OAM, or
port failure or node failure), PE2 will become the DF for Ethernet port failure or node failure), PE2 will become the DF for
Tag-1. No changes will occur for Ethernet Tag-2. Ethernet Tag-1. No changes will occur for Ethernet Tag-2.
5) When PE3's vES2 comes back up, PE3 will start a boot-timer (if 5. When PE3's vES2 comes back up, PE3 will start a boot-timer (if
booting up) or hold-timer (if the port or EVC recovers). That booting up) or hold-timer (if the port or EVC recovers). That
timer will allow some time for PE3 to receive the ES routes from timer will allow some time for PE3 to receive the ES routes from
PE1 and PE2. PE3 will then: PE1 and PE2. PE3 will then:
o Select two "reference-PEs" among the ES routes in the vES, the - Select two "reference-PEs" among the ES routes in the vES, the
"Highest-PE" and the "Lowest-PE": "Highest-PE" and the "Lowest-PE":
- The Highest-PE is the PE with higher Preference, using the DP * The Highest-PE is the PE with higher Preference, using the
bit first (with DP=1 being better) and, after that, the lower DP bit first (with DP=1 being better) and, after that, the
PE-IP address as tie-breakers. PE3 will select PE2 as Highest- lower PE-IP address as tie-breakers. PE3 will select PE2
PE over PE1, since, when comparing [Pref,DP,PE-IP], as Highest-PE over PE1, since, when comparing [Pref,DP,PE-
[200,1,PE2-IP] wins over [100,1,PE1-IP]. IP], [200,1,PE2-IP] wins over [100,1,PE1-IP].
- The Lowest-PE is the PE with lower Preference, using the DP * The Lowest-PE is the PE with lower Preference, using the DP
bit first (with DP=1 being better) and, after that, the lower bit first (with DP=1 being better) and, after that, the
PE-IP address as tie-breakers. PE3 will select PE1 as Lowest- lower PE-IP address as tie-breakers. PE3 will select PE1
PE over PE2, since [100,1,PE1-IP] wins over [200,1,PE2-IP]. as Lowest-PE over PE2, since [100,1,PE1-IP] wins over
[200,1,PE2-IP].
- Note that if there were only one remote PE in the ES, Lowest * Note that if there were only one remote PE in the ES,
and Highest PE would be the same PE. Lowest and Highest PE would be the same PE.
o Check its own administrative Pref and compares it with the one - Check its own administrative Pref and compares it with the one
of the Highest-PE and Lowest-PE that have DP=1 in their ES of the Highest-PE and Lowest-PE that have DP=1 in their ES
routes. Depending on this comparison PE3 will send the ES route routes. Depending on this comparison PE3 will send the ES
with a [Pref,DP] that may be different from its administrative route with a [Pref,DP] that may be different from its
[Pref,DP]: administrative [Pref,DP]:
- If PE3's Pref value is higher than the Highest-PE's, PE3 will * If PE3's Pref value is higher than the Highest-PE's, PE3
send the ES route with an 'in-use' operational Pref equal to will send the ES route with an 'in-use' operational Pref
the Highest-PE's and DP=0. equal to the Highest-PE's and DP=0.
- If PE3's Pref value is lower than the Lowest-PE's, PE3 will * If PE3's Pref value is lower than the Lowest-PE's, PE3 will
send the ES route with an 'in-use' operational Preference send the ES route with an 'in-use' operational Preference
equal to the Lowest-PE's and DP=0. equal to the Lowest-PE's and DP=0.
- If PE3's Pref value is neither higher nor lower than the * If PE3's Pref value is neither higher nor lower than the
Highest-PE's or the Lowest-PE's respectively, PE3 will send Highest-PE's or the Lowest-PE's respectively, PE3 will send
the ES route with its administrative [Pref,DP]=[300,1]. the ES route with its administrative [Pref,DP]=[300,1].
- In this example, PE3's administrative Pref=300 is higher than * In this example, PE3's administrative Pref=300 is higher
the Highest-PE with DP=1, that is, PE2 (Pref=200). Hence PE3 than the Highest-PE with DP=1, that is, PE2 (Pref=200).
will inherit PE2's preference and send the ES route with an
operational 'in-use' [Pref,DP]=[200,0].
Note that, a PE will always send DP=0 as long as the advertised Hence PE3 will inherit PE2's preference and send the ES
Pref is the 'in-use' operational Pref (as opposed to the route with an operational 'in-use' [Pref,DP]=[200,0].
'administrative' Pref).
This ES route update sent by PE3 (with [200,0,PE3-IP]) will not - Note that, a PE will always send DP=0 as long as the
cause any DF switchover for any Ethernet Tag. PE2 will continue advertised Pref is the 'in-use' operational Pref (as opposed
being DF for Ethernet Tag-1. This is because the DP bit will be to the 'administrative' Pref).
used as a tie-breaker in the DF election. That is, if a PE has two
candidate PEs with the same Pref, it will pick up the one with
DP=1. There are no DF changes for Ethernet Tag-2 either.
6) Subsequently, if PE2 fails, upon receiving PE2's ES route - This ES route update sent by PE3 (with [200,0,PE3-IP]) will
withdrawal, PE3 and PE1 will go through the process described in not cause any DF switchover for any Ethernet Tag. PE2 will
(5) to select new Highest and Lowest-PEs (considering their own continue being DF for Ethernet Tag-1. This is because the DP
active ES route) and then they will run the DF Election. bit will be used as a tie-breaker in the DF election. That
is, if a PE has two candidate PEs with the same Pref, it will
pick up the one with DP=1. There are no DF changes for
Ethernet Tag-2 either.
o If a PE selects itself as new Highest or Lowest-PE and it was 6. Subsequently, if PE2 fails, upon receiving PE2's ES route
not before, the PE will then compare its operational 'in-use' withdrawal, PE3 and PE1 will go through the process described in
Pref with its administrative Pref. If different, the PE will (5) to select new Highest and Lowest-PEs (considering their own
send an ES route update with its administrative Pref and DP active ES route) and then they will run the DF Election.
values. In the example, PE3 will be the new Highest-PE,
therefore it will send an ES route update with
[Pref,DP]=[300,1].
o After running the DF Election, PE3 will become the new DF for - If a PE selects itself as new Highest or Lowest-PE and it was
Ethernet Tag-1. No changes will occur for Ethernet Tag-2. not before, the PE will then compare its operational 'in-use'
Pref with its administrative Pref. If different, the PE will
send an ES route update with its administrative Pref and DP
values. In the example, PE3 will be the new Highest-PE,
therefore it will send an ES route update with
[Pref,DP]=[300,1].
- After running the DF Election, PE3 will become the new DF for
Ethernet Tag-1. No changes will occur for Ethernet Tag-2.
Note that, irrespective of the DP bit, when a PE or ES comes back and Note that, irrespective of the DP bit, when a PE or ES comes back and
the PE advertises a DF Election Alg different than 2 (Preference the PE advertises a DF Election Alg different than 2 (Preference
algorithm), the rest of the PEs in the ES MUST fall back to the algorithm), the rest of the PEs in the ES MUST fall back to the
Default [RFC7432] Alg. Default [RFC7432] Alg.
This document does not modify the use of the P and B bits in the This document does not modify the use of the P and B bits in the
Ethernet A-D per EVI routes [RFC8214] advertised by the PEs in the ES Ethernet A-D per EVI routes [RFC8214] advertised by the PEs in the ES
after running the DF Election, irrespective of the revertive or non- after running the DF Election, irrespective of the revertive or non-
revertive behavior in the PE. revertive behavior in the PE.
5. Security Considerations 5. Security Considerations
This document describes a DF Election Algorithm that provides This document describes a DF Election Algorithm that provides
absolute control (by configuration) over what PE is the DF for a absolute control (by configuration) over what PE is the DF for a
given Ethernet Tag. While this control is desired in many situations, given Ethernet Tag. While this control is desired in many situations,
a malicious user that gets access to the configuration of a PE in the a malicious user that gets access to the configuration of a PE in the
ES may change the behavior of the network. In other DF Algs such as ES may change the behavior of the network. In other DF Algs such as
HRW, the DF Election is more automated and cannot be determined by HRW, the DF Election is more automated and cannot be determined by
configuration. configuration.
The non-revertive capability described in this document may be seen The non-revertive capability described in this document may be seen
as a security improvement over the regular EVPN revertive DF as a security improvement over the regular EVPN revertive DF
Election: an intentional link (or node) "flapping" on a PE will only Election: an intentional link (or node) "flapping" on a PE will only
cause service disruption once, when the PE goes to NDF state. cause service disruption once, when the PE goes to NDF state.
6. IANA Considerations 6. IANA Considerations
This document solicits the allocation of the following values: This document solicits the allocation of the following values:
o DF Alg = 2 in the [DF] "DF Alg" registry, with name "Preference o DF Alg = 2 in the [RFC8584] "DF Alg" registry, with name
Algorithm". "Preference Algorithm".
o Bit 0 in the [DF] DF Election Capabilities registry, with name "D o Bit 0 in the [RFC8584] DF Election Capabilities registry, with
(Don't Preempt) Capability" for Non-revertive ES. name "D (Don't Preempt) Capability" for Non-revertive ES.
7. References 7. Acknowledgments
7.1 Normative References The authors would like to thank Kishore Tiruveedhula for his review
and comments.
8. Contributors
In addition to the authors listed, the following individuals also
contributed to this document:
Kiran Nagaraj, Nokia
Vinod Prabhu, Nokia
Selvakumar Sivaraj, Juniper
Sami Boutros, VMWare
9. References
9.1. Normative References
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., [RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based Ethernet Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
<https://www.rfc-editor.org/info/rfc7432>. 2015, <https://www.rfc-editor.org/info/rfc7432>.
[RFC8214] Boutros, S., Sajassi, A., Salam, S., Drake, J., and J. [RFC8214] Boutros, S., Sajassi, A., Salam, S., Drake, J., and J.
Rabadan, "Virtual Private Wire Service Support in Ethernet VPN", RFC Rabadan, "Virtual Private Wire Service Support in Ethernet
8214, DOI 10.17487/RFC8214, August 2017, <https://www.rfc- VPN", RFC 8214, DOI 10.17487/RFC8214, August 2017,
editor.org/info/rfc8214>. <https://www.rfc-editor.org/info/rfc8214>.
[RFC7623] Sajassi, A., Ed., Salam, S., Bitar, N., Isaac, A., and W. [RFC7623] Sajassi, A., Ed., Salam, S., Bitar, N., Isaac, A., and W.
Henderickx, "Provider Backbone Bridging Combined with Ethernet VPN Henderickx, "Provider Backbone Bridging Combined with
(PBB-EVPN)", RFC 7623, DOI 10.17487/RFC7623, September 2015, Ethernet VPN (PBB-EVPN)", RFC 7623, DOI 10.17487/RFC7623,
<https://www.rfc-editor.org/info/rfc7623>. September 2015, <https://www.rfc-editor.org/info/rfc7623>.
[RFC8365] Sajassi-Drake et al., "A Network Virtualization Overlay [RFC8365] Sajassi, A., Ed., Drake, J., Ed., Bitar, N., Shekhar, R.,
Solution using EVPN", RFC 8365, March 2017, <http://www.rfc- Uttaro, J., and W. Henderickx, "A Network Virtualization
editor.org/info/rfc8365> Overlay Solution Using Ethernet VPN (EVPN)", RFC 8365,
DOI 10.17487/RFC8365, March 2018,
<https://www.rfc-editor.org/info/rfc8365>.
[DF] Rabadan J., Mohanty S. et al. "Framework for EVPN Designated [RFC8584] Rabadan, J., Ed., Mohanty, S., Ed., Sajassi, A., Drake,
Forwarder Election Extensibility", draft-ietf-bess-evpn-df-election- J., Nagaraj, K., and S. Sathappan, "Framework for Ethernet
framework-07, work-in-progress, December, 2018. VPN Designated Forwarder Election Extensibility",
RFC 8584, DOI 10.17487/RFC8584, April 2019,
<https://www.rfc-editor.org/info/rfc8584>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March Requirement Levels", BCP 14, RFC 2119,
1997, <https://www.rfc-editor.org/info/rfc2119>. DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
<https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
7.2 Informative References 9.2. Informative References
[vES] Sajassi et al. "EVPN Virtual Ethernet Segment", draft-ietf- [I-D.ietf-bess-evpn-virtual-eth-segment]
bess-evpn-virtual-eth-segment-00, work-in-progress, June, 2018. Sajassi, A., Brissette, P., Schell, R., Drake, J., and J.
Rabadan, "EVPN Virtual Ethernet Segment", draft-ietf-bess-
evpn-virtual-eth-segment-04 (work in progress), January
2019.
8. Acknowledgments Authors' Addresses
The authors would like to thank Kishore Tiruveedhula for his review J. Rabadan (editor)
and comments. Nokia
777 Middlefield Road
Mountain View, CA 94043
USA
9. Contributors Email: jorge.rabadan@nokia.com
S. Sathappan
Nokia
In addition to the authors listed, the following individuals also Email: senthil.sathappan@nokia.com
contributed to this document:
Kiran Nagaraj, Nokia T. Przygienda
Vinod Prabhu, Nokia Juniper Networks
Selvakumar Sivaraj, Juniper
10. Authors' Addresses Email: prz@juniper.net
Jorge Rabadan W. Lin
Nokia Juniper Networks
777 E. Middlefield Road
Mountain View, CA 94043 USA
Email: jorge.rabadan@nokia.com
Senthil Sathappan Email: wlin@juniper.net
Nokia
Email: senthil.sathappan@nokia.com
Tony Przygienda J. Drake
Juniper Networks, Inc. Juniper Networks
Email: prz@juniper.net
John Drake
Juniper Networks, Inc.
Email: jdrake@juniper.net Email: jdrake@juniper.net
Wen Lin
Juniper Networks, Inc.
Email: wlin@juniper.net
Ali Sajassi A. Sajassi
Cisco Systems, Inc. Cisco Systems
Email: sajassi@cisco.com Email: sajassi@cisco.com
Satya Ranjan Mohanty S. Mohanty
Cisco Systems, Inc. Cisco Systems
Email: satyamoh@cisco.com
Sami Boutros Email: satyamoh@cisco.com
Email: boutros.sami@gmail.com
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