draft-ietf-bess-evpn-usage-06.txt   draft-ietf-bess-evpn-usage-07.txt 
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Internet Draft S. Palislamovic Internet Draft S. Palislamovic
W. Henderickx W. Henderickx
Intended status: Informational Nokia Intended status: Informational Nokia
A. Sajassi A. Sajassi
Cisco Cisco
J. Uttaro J. Uttaro
AT&T AT&T
Expires: March 1, 2018 August 28, 2017 Expires: August 2, 2018 January 29, 2018
Usage and applicability of BGP MPLS based Ethernet VPN Usage and applicability of BGP MPLS based Ethernet VPN
draft-ietf-bess-evpn-usage-06 draft-ietf-bess-evpn-usage-07
Abstract Abstract
This document discusses the usage and applicability of BGP MPLS based This document discusses the usage and applicability of BGP MPLS based
Ethernet VPN (EVPN) in a simple and fairly common deployment Ethernet VPN (EVPN) in a simple and fairly common deployment
scenario. The different EVPN procedures are explained on the example scenario. The different EVPN procedures are explained on the example
scenario, analyzing the benefits and trade-offs of each option. This scenario, analyzing the benefits and trade-offs of each option. This
document is intended to provide a simplified guide for the deployment document is intended to provide a simplified guide for the deployment
of EVPN networks. of EVPN networks.
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on March 1, 2018. This Internet-Draft will expire on August 2, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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7.3. Impact of MPLS-based forwarding on the VLAN-bundle 7.3. Impact of MPLS-based forwarding on the VLAN-bundle
service procedures . . . . . . . . . . . . . . . . . . . . 21 service procedures . . . . . . . . . . . . . . . . . . . . 21
7.4. Impact of MPLS-based forwarding on the VLAN-aware service 7.4. Impact of MPLS-based forwarding on the VLAN-aware service
procedures . . . . . . . . . . . . . . . . . . . . . . . . 21 procedures . . . . . . . . . . . . . . . . . . . . . . . . 21
8. Comparison between MAC-based and MPLS-based Egress Forwarding 8. Comparison between MAC-based and MPLS-based Egress Forwarding
Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9. Traffic flow optimization . . . . . . . . . . . . . . . . . . . 23 9. Traffic flow optimization . . . . . . . . . . . . . . . . . . . 23
9.1. Control Plane Procedures . . . . . . . . . . . . . . . . . 23 9.1. Control Plane Procedures . . . . . . . . . . . . . . . . . 23
9.1.1. MAC learning options . . . . . . . . . . . . . . . . . 23 9.1.1. MAC learning options . . . . . . . . . . . . . . . . . 23
9.1.2. Proxy-ARP/ND . . . . . . . . . . . . . . . . . . . . . 24 9.1.2. Proxy-ARP/ND . . . . . . . . . . . . . . . . . . . . . 24
9.1.3. Unknown Unicast flooding suppression . . . . . . . . . 24 9.1.3. Unknown Unicast flooding suppression . . . . . . . . . 25
9.1.4. Optimization of Inter-subnet forwarding . . . . . . . . 25 9.1.4. Optimization of Inter-subnet forwarding . . . . . . . . 25
9.2. Packet Walkthrough Examples . . . . . . . . . . . . . . . . 26 9.2. Packet Walkthrough Examples . . . . . . . . . . . . . . . . 26
9.2.1. Proxy-ARP example for CE2 to CE3 traffic . . . . . . . 26 9.2.1. Proxy-ARP example for CE2 to CE3 traffic . . . . . . . 26
9.2.2. Flood suppression example for CE1 to CE3 traffic . . . 26 9.2.2. Flood suppression example for CE1 to CE3 traffic . . . 26
9.2.3. Optimization of inter-subnet forwarding example for 9.2.3. Optimization of inter-subnet forwarding example for
CE3 to CE2 traffic . . . . . . . . . . . . . . . . . . 27 CE3 to CE2 traffic . . . . . . . . . . . . . . . . . . 27
10. Security Considerations . . . . . . . . . . . . . . . . . . . 28 10. Security Considerations . . . . . . . . . . . . . . . . . . . 28
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28
12.1. Normative References . . . . . . . . . . . . . . . . . . . 28 12.1. Normative References . . . . . . . . . . . . . . . . . . . 29
12.2. Informative References . . . . . . . . . . . . . . . . . . 29 12.2. Informative References . . . . . . . . . . . . . . . . . . 29
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29
14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 29 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 29
15. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 30 15. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
This document complements [RFC7432] by discussing the applicability This document complements [RFC7432] by discussing the applicability
of the technology in a simple and fairly common deployment scenario, of the technology in a simple and fairly common deployment scenario,
which is described in section 3. which is described in section 3.
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Therefore, besides the CE-VID bundle range bound to EVI300 in each Therefore, besides the CE-VID bundle range bound to EVI300 in each
PE, associations between each individual CE-VID and the corresponding PE, associations between each individual CE-VID and the corresponding
EVPN Ethernet Tag must be provisioned by the user. No auto-derived EVPN Ethernet Tag must be provisioned by the user. No auto-derived
EVI RDs/RTs are possible. EVI RDs/RTs are possible.
5. BGP EVPN NLRI usage 5. BGP EVPN NLRI usage
[RFC7432] defines four different route types and four different [RFC7432] defines four different route types and four different
extended communities. However, not all the PEs in an EVPN network extended communities. However, not all the PEs in an EVPN network
must generate and process all the different routes and extended must generate and process all the different routes and extended
communities. The following table shows the routes that must be communities. Table 1 shows the routes that must be exported and
exported and imported in the use-case described in this document. imported in the use-case described in this document. "Export", in
"Export", in this context, means that the PE must be capable of this context, means that the PE must be capable of generating and
generating and exporting a given route, assuming there are no BGP exporting a given route, assuming there are no BGP policies to
policies to prevent it. In the same way, "Import" means the PE must prevent it. In the same way, "Import" means the PE must be capable of
be capable of importing and processing a given route, assuming the importing and processing a given route, assuming the right RTs and
right RTs and policies. "N/A" means neither import nor export actions policies. "N/A" means neither import nor export actions are required.
are required.
+-------------------+---------------+---------------+ +-------------------+---------------+---------------+
| BGP EVPN routes | PE1-PE2 | PE3 | | BGP EVPN routes | PE1-PE2 | PE3 |
+-------------------+---------------+---------------+ +-------------------+---------------+---------------+
| ES | Export/import | N/A | | ES | Export/import | N/A |
| A-D per ESI | Export/import | Import | | A-D per ESI | Export/import | Import |
| A-D per EVI | Export/import | Import | | A-D per EVI | Export/import | Import |
| MAC | Export/import | Export/import | | MAC | Export/import | Export/import |
| Inclusive mcast | Export/import | Export/import | | Inclusive mcast | Export/import | Export/import |
+-------------------+---------------+---------------+ +-------------------+---------------+---------------+
Table 1 - Base EVPN Routes and Export/Import Actions
PE3 is only required to export MAC and Inclusive multicast routes and PE3 is only required to export MAC and Inclusive multicast routes and
be able to import and process A-D routes, as well as MAC and be able to import and process A-D routes, as well as MAC and
Inclusive multicast routes. If PE3 did not support importing and Inclusive multicast routes. If PE3 did not support importing and
processing A-D routes per ESI and per EVI, fast convergence and processing A-D routes per ESI and per EVI, fast convergence and
aliasing functions (respectively) would not be possible in this aliasing functions (respectively) would not be possible in this
use-case. use-case.
6. MAC-based forwarding model use-case 6. MAC-based forwarding model use-case
This section describes how the BGP EVPN routes are exported and This section describes how the BGP EVPN routes are exported and
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Both forwarding models are possible in a network deployment and each Both forwarding models are possible in a network deployment and each
one has its own trade-offs. one has its own trade-offs.
Both forwarding models can save A-D routes per EVI when VLAN-aware Both forwarding models can save A-D routes per EVI when VLAN-aware
bundling services are deployed and no CE-VID translation is required. bundling services are deployed and no CE-VID translation is required.
While this saves a significant amount of routes, customers normally While this saves a significant amount of routes, customers normally
require CE-VID translation, hence we assume an A-D per EVI route per require CE-VID translation, hence we assume an A-D per EVI route per
<ESI, Ethernet-Tag> is needed. <ESI, Ethernet-Tag> is needed.
This MAC-based model saves a significant amount of MPLS labels The MAC-based model saves a significant amount of MPLS labels
compared to the MPLS-based forwarding model. All the MACs and A-D compared to the MPLS-based forwarding model. All the MACs and A-D
routes for the same EVI can signal the same MPLS label, saving labels routes for the same EVI can signal the same MPLS label, saving labels
from the local PE space. A MAC FIB lookup at the egress PE is from the local PE space. A MAC FIB lookup at the egress PE is
required in order to do so. required in order to do so.
The MPLS-based forwarding model can save forwarding states at the The MPLS-based forwarding model can save forwarding states at the
egress PEs if labels per next hop CE (as opposed to per MAC) are egress PEs if labels per next hop CE (as opposed to per MAC) are
implemented. No egress MAC lookup is required. Also, a different implemented. No egress MAC lookup is required. Also, a different
label per next-hop CE per MAC-VRF is consumed, as opposed to a single label per next-hop CE per MAC-VRF is consumed, as opposed to a single
label per MAC-VRF. label per MAC-VRF.
The following table summarizes the implementation details of both Table 2 summarizes the resource implementation details of both
models. models.
+-----------------------------+----------------+----------------+ +-----------------------------+----------------+----------------+
| 4k CE-VID VLANs | MAC-based | MPLS-based | | Resources | MAC-based | MPLS-based |
| | Model | Model | | | Model | Model |
+-----------------------------+----------------+----------------+ +-----------------------------+----------------+----------------+
| MPLS labels consumed | 1 per MAC-VRF | 1 per CE/EVI | | MPLS labels consumed | 1 per MAC-VRF | 1 per CE/EVI |
| Egress PE Forwarding states | 1 per MAC | 1 per next-hop | | Egress PE Forwarding states | 1 per MAC | 1 per next-hop |
| Egress PE Lookups | 2 (MPLS+MAC) | 1 (MPLS) | | Egress PE Lookups | 2 (MPLS+MAC) | 1 (MPLS) |
+-----------------------------+----------------+----------------+ +-----------------------------+----------------+----------------+
Table 2 - Resource Comparison Between MAC-based and MPLS-based Models
The egress forwarding model is an implementation local to the egress The egress forwarding model is an implementation local to the egress
PE and is independent of the model supported on the rest of the PEs, PE and is independent of the model supported on the rest of the PEs,
i.e. in our use-case, PE1, PE2 and PE3 could have either egress i.e. in our use-case, PE1, PE2 and PE3 could have either egress
forwarding model without any dependencies. forwarding model without any dependencies.
9. Traffic flow optimization 9. Traffic flow optimization
In addition to the procedures described across sections 3 through 8, In addition to the procedures described across sections 3 through 8,
EVPN [RFC7432] procedures allow for optimized traffic handling in EVPN [RFC7432] procedures allow for optimized traffic handling in
order to minimize unnecessary flooding across the entire order to minimize unnecessary flooding across the entire
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10. Security Considerations 10. Security Considerations
Please refer to the "Security Considerations" section in [RFC7432]. Please refer to the "Security Considerations" section in [RFC7432].
11. IANA Considerations 11. IANA Considerations
No new IANA considerations are needed. No new IANA considerations are needed.
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC4761] Kompella, K., Ed., and Y. Rekhter, Ed., "Virtual Private
LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling",
RFC 4761, DOI 10.17487/RFC4761, January 2007, <http://www.rfc-
editor.org/info/rfc4761>.
[RFC4762] Lasserre, M., Ed., and V. Kompella, Ed., "Virtual Private
LAN Service (VPLS) Using Label Distribution Protocol (LDP)
Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
<http://www.rfc-editor.org/info/rfc4762>.
[RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo,
"Provisioning, Auto-Discovery, and Signaling in Layer 2 Virtual
Private Networks (L2VPNs)", RFC 6074, DOI 10.17487/RFC6074, January
2011, <http://www.rfc-editor.org/info/rfc6074>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 2006,
<http://www.rfc-editor.org/info/rfc4364>.
[RFC7209] Sajassi, A., Aggarwal, R., Uttaro, J., Bitar, N., [RFC7209] Sajassi, A., Aggarwal, R., Uttaro, J., Bitar, N.,
Henderickx, W., and A. Isaac, "Requirements for Ethernet VPN (EVPN)", Henderickx, W., and A. Isaac, "Requirements for Ethernet VPN (EVPN)",
RFC 7209, DOI 10.17487/RFC7209, May 2014, <http://www.rfc- RFC 7209, DOI 10.17487/RFC7209, May 2014, <http://www.rfc-
editor.org/info/rfc7209>. editor.org/info/rfc7209>.
[RFC7117] Aggarwal, R., Ed., Kamite, Y., Fang, L., Rekhter, Y., and
C. Kodeboniya, "Multicast in Virtual Private LAN Service (VPLS)",
RFC 7117, DOI 10.17487/RFC7117, February 2014, <http://www.rfc-
editor.org/info/rfc7117>.
[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 Ethernet
VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, <http://www.rfc- VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, <http://www.rfc-
editor.org/info/rfc7432>. editor.org/info/rfc7432>.
12.2. Informative References 12.2. Informative References
[EVPN-INTERSUBNET] Sajassi et al., "IP Inter-subnet forwarding in [EVPN-INTERSUBNET] Sajassi et al., "IP Inter-subnet forwarding in
EVPN", draft-ietf-bess-evpn-inter-subnet-forwarding-03.txt EVPN", draft-ietf-bess-evpn-inter-subnet-forwarding-03.txt
[RFC4761] Kompella, K., Ed., and Y. Rekhter, Ed., "Virtual Private
LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling",
RFC 4761, DOI 10.17487/RFC4761, January 2007, <http://www.rfc-
editor.org/info/rfc4761>.
[RFC4762] Lasserre, M., Ed., and V. Kompella, Ed., "Virtual Private
LAN Service (VPLS) Using Label Distribution Protocol (LDP)
Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
<http://www.rfc-editor.org/info/rfc4762>.
[RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo,
"Provisioning, Auto-Discovery, and Signaling in Layer 2 Virtual
Private Networks (L2VPNs)", RFC 6074, DOI 10.17487/RFC6074, January
2011, <http://www.rfc-editor.org/info/rfc6074>.
13. Acknowledgments 13. Acknowledgments
The authors want to thank Giles Heron for his detailed review of the The authors want to thank Giles Heron for his detailed review of the
document. We also thank Stefan Plug, and Eric Wunan for their document. We also thank Stefan Plug, and Eric Wunan for their
comments. comments.
14. Contributors 14. Contributors
In addition to the authors listed on the front page, the following In addition to the authors listed on the front page, the following
co-authors have also contributed to this document: co-authors have also contributed to this document:
Florin Balus Florin Balus
Keyur Patel Keyur Patel
Aldrin Isaac Aldrin Isaac
Truman Boyes Truman Boyes
15. Authors' Addresses 15. Authors' Addresses
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