< draft-boutros-l2vpn-evpn-vpws-00.txt   draft-boutros-l2vpn-evpn-vpws-01.txt >
INTERNET-DRAFT Sami Boutros INTERNET-DRAFT Sami Boutros
Intended Status: Informational Ali Sajassi Intended Status: Standard Track Ali Sajassi
Samer Salam Samer Salam
Expires: January 1, 2013 June 30, 2012 Cisco Systems
John Drake
Juniper Networks
Jeff Tantsura
Ericsson
Expires: August 28, 2013 February 24, 2013
VPWS support in E-VPN VPWS support in E-VPN
draft-boutros-l2vpn-evpn-vpws-00.txt draft-boutros-l2vpn-evpn-vpws-01.txt
Abstract Abstract
This document describes how E-VPN can be used to support virtual This document describes how E-VPN can be used to support virtual
private wire service (VPWS) in MPLS/IP networks. E-VPN enables the private wire service (VPWS) in MPLS/IP networks. E-VPN enables the
following characteristics for VPWS: 1) active/standby redundancy, 2) following characteristics for VPWS: active/standby as well as
active/active multi-homing with flow-based load-balancing, 3) active/active multi-homing with flow-based load-balancing, eliminates
eliminates the need for single-segment and multi-segment PW the need for single-segment and multi-segment PW signaling, and
signaling, and 4) provides faster convergence using data-plane prefix provides fast protection using data-plane prefix independent
independent convergence upon node or link failure in comparison to convergence upon node or link failure.
control-plane convergence with PW redundancy.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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other groups may also distribute working documents as other groups may also distribute working documents as
Internet-Drafts. Internet-Drafts.
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html http://www.ietf.org/1id-abstracts.html
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http://www.ietf.org/shadow.html http://www.ietf.org/shadow.html
Copyright and License Notice Copyright and License Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2013 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
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
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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
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
2. BGP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 4 2. BGP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 E-VPN Comparison to PW Signaling . . . . . . . . . . . . . . . . 5 4 E-VPN Comparison to PW Signaling . . . . . . . . . . . . . . . . 5
5 VPWS with multiple sites . . . . . . . . . . . . . . . . . . . . 5 5 ESI Bandwidth Attribute . . . . . . . . . . . . . . . . . . . . 5
6 Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6 VPWS with multiple sites . . . . . . . . . . . . . . . . . . . . 6
7 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7 Security Considerations . . . . . . . . . . . . . . . . . . . . 6
8 References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
8.1 Normative References . . . . . . . . . . . . . . . . . . . 6 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.2 Informative References . . . . . . . . . . . . . . . . . . 6 9.1 Normative References . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 9.2 Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
1 Introduction 1 Introduction
This document describes how E-VPN can be used to support virtual This document describes how E-VPN can be used to support virtual
private wire service (VPWS) in MPLS/IP networks. The use of E-VPN private wire service (VPWS) in MPLS/IP networks. The use of E-VPN
mechanisms for VPWS introduces all the benefits of E-VPN to p2p mechanisms for VPWS applies the benefits of E-VPN to p2p services.
services. These benefits include active/standby AC redundancy, These benefits include active/standby AC redundancy as well as
active/active multi-homing with flow-based load-balancing. active/active multi-homing with flow-based load-balancing.
Furthermore, the use of E-VPN for VPWS eliminates the need for Furthermore, the use of E-VPN for VPWS eliminates the need for
signaling single-segment and multi-segment PWs for p2p Ethernet signaling single-segment and multi-segment PWs for p2p Ethernet
services. services.
[E-VPN] has the ability to forward customer traffic to/from a given [E-VPN] has the ability to forward customer traffic to/from a given
customer Attachment Circuit (aka Ethernet AD route) without any MAC customer Attachment Circuit (AC), aka Ethernet Segment in E-VPN
lookup. This capability is ideal in providing P2P services (aka VPWS terminology, without any MAC lookup. This capability is ideal in
services). [MEF] defines EVPL service as P2P service between a pair providing p2p services (aka VPWS services). [MEF] defines EVPL
of ACs (designated by VLANs). EVPL can be considered as a VPWS with service as p2p service between a pair of ACs (designated by VLANs).
only two ACs. In delivering an EVPL service, traffic forwarding EVPL can be considered as a VPWS with only two ACs. In delivering an
capability of E-VPN between a pair of Ethernet AD routes is used; EVPL service, the traffic forwarding capability of E-VPN using only a
whereas, for more general VPWS, traffic forwarding capability of E- pair of Ethernet AD routes is used; whereas, for more general VPWS,
VPN among a group of Ethernet AD routes (one Ether AD route per traffic forwarding capability of E-VPN using a group of Ethernet AD
AC/site) is used. Since in VPWS services, the traffic from an routes (one Ethernet AD route per AC/segment) is used. Since in VPWS
originating Ether AD route can go only to a single destination Ether services, the traffic from an originating Ethernet Segment can go
AD route, no MAC lookup is needed and MPLS label associated with the only to a single destination Ethernet Segment, no MAC lookup is
destination Ether AD route can be used in forwarding user traffic to needed and the MPLS label associated with the per-EVI Ethernet AD
the destination AC. route can be used in forwarding user traffic to the destination AC.
In current PW redundancy mechanisms, convergence time is a function In current PW redundancy mechanisms, convergence time is a function
of control plane convergence characteristics. However, with E-VPN it of control plane convergence characteristics. However, with E-VPN it
is possible to attain faster convergence through the use of data- is possible to attain faster convergence through the use of data-
plane prefix independent convergence upon node or link failure. plane prefix independent convergence upon node or link failure.
This document proposes the use of the Ethernet AD route to signal This document proposes the use of the Ethernet AD route to signal
labels for P2P Ethernet services. As with E-VPN, the Ethernet Segment labels for P2P Ethernet services. As with E-VPN, the Ethernet Segment
route can be used to synchronize LACP and other state between the PEs route can be used to synchronize state between the PEs attached to
attached to the same multi-homed device. the same multi-homed Segment.
1.1 Terminology 1.1 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
MAC: Media Access Control MAC: Media Access Control
MPLS: Multi Protocol Label Switching. MPLS: Multi Protocol Label Switching.
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PE: Provide Edge Node. PE: Provide Edge Node.
CE: Customer Edge device e.g., host or router or switch. CE: Customer Edge device e.g., host or router or switch.
EVI: E-VPN Instance. EVI: E-VPN Instance.
2. BGP Extensions 2. BGP Extensions
[E-VPN] defines a new BGP NLRI for advertising different route types [E-VPN] defines a new BGP NLRI for advertising different route types
for E-VPN operation. This document does not define any new BGP for E-VPN operation. This document does not define any new BGP
messages, but rather repurposes one of the routes as described next. messages, but rather re-purposes one of the routes as described next.
This document proposes the use of the Ethernet AD route to signal P2P This document proposes the use of the per EVI Ethernet AD route to
services. The Ethernet Segment Identifier field is set to the ESI of signal P2P services. The Ethernet Segment Identifier field is set to
the attachment circuit of the VPWS service instance. The Ethernet Tag the ESI of the attachment circuit of the VPWS service instance. The
field is set to 0 in the case of an Ethernet Private Wire service, Ethernet Tag field is set to 0 in the case of an Ethernet Private
and to the VLAN identifier associated with the service for Ethernet Wire service, and to the VLAN identifier associated with the service
Virtual Private Wire service. The route is associated with a Route- for Ethernet Virtual Private Wire service. The route is associated
Target (RT) extended community attribute that identifies the service with a Route-Target (RT) extended community attribute that identifies
instance (together with the Ethernet Tag field when non-zero the service instance (together with the Ethernet Tag field when non-
zero).
3 Operation 3 Operation
The following figure shows an example of a P2P service deployed with The following figure shows an example of a P2P service deployed with
E-VPN. E-VPN.
Ethernet Ethernet Ethernet Ethernet
Native |<---------E-VPN Instance------------>| Native Native |<---------E-VPN Instance------------>| Native
Service | | Service Service | | Service
(AC) | |<-PSN1->| |<-PSN2->| | (AC) (AC) | |<-PSN1->| |<-PSN2->| | (AC)
| V V V V V V | | V V V V V V |
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|<---------------- Emulated Service -------------------->| |<---------------- Emulated Service -------------------->|
iBGP sessions will be established between PE1, PE2, ASBR1 and ASBR3, iBGP sessions will be established between PE1, PE2, ASBR1 and ASBR3,
possibly via a BGP route-reflector. Similarly, iBGP sessions will be possibly via a BGP route-reflector. Similarly, iBGP sessions will be
established between PE3, PE4, ASBR2 and ASBR4. eBGP sessions will be established between PE3, PE4, ASBR2 and ASBR4. eBGP sessions will be
established among ASBR1, ASBR2, ASBR3, and ASBR4. established among ASBR1, ASBR2, ASBR3, and ASBR4.
All PEs and ASBRs are enabled for the E-VPN SAFI, and exchange E-VPN All PEs and ASBRs are enabled for the E-VPN SAFI, and exchange E-VPN
Ethernet A-D routes - one route per AC. The ASBRs re-advertise the Ethernet A-D routes - one route per AC. The ASBRs re-advertise the
Ethernet A-D routes with Next Hop attribute set to their IP Ethernet A-D routes with Next Hop attribute set to their IP
addresses. The link between the CE and the PE is an C-TAG or S-TAG addresses. The link between the CE and the PE is either a C-tagged or
interface as described in [802.1Q] that can carry a single vlan tag S-tagged interface, as described in [802.1Q], that can carry a single
or two vlan tags nested in each other. This interface is setup as a VLAN tag or two nested VLAN tags. This interface is set up as a trunk
trunk with multiple VLANs. with multiple VLANs.
A VPWS with multiple sites or multiple EVPL services on the same CE A VPWS with multiple sites or multiple EVPL services on the same CE
port can be included in one EVI between 2 or more PEs. An Ethernet port can be included in one EVI between 2 or more PEs. An Ethernet
Tag corresponding to each P2P connection and known to both PEs is Tag corresponding to each P2P connection and known to both PEs is
used to identify the services multiplexed in the same EVI. For CE used to identify the services multiplexed in the same EVI.
multi-homing, the Ethernet AD Route encodes the ESI associated with
the CE. This allows flow-based load-balancing of traffic between PEs For CE multi-homing, the Ethernet AD Route encodes the ESI associated
connected to the same multi-homed CE. The VPN ID MUST be the same on with the CE. This allows flow-based load-balancing of traffic between
both PEs attached to the site. The Ethernet Segment route may be used PEs connected to the same multi-homed CE. The VPN ID MUST be the same
too, for discovery of multi-homed CEs. In all cases traffic follows on both PEs attached to the site. The Ethernet Segment route may be
the transport paths, which may be asymmetric. used too, for discovery of multi-homed CEs. In all cases traffic
follows the transport paths, which may be asymmetric.
4 E-VPN Comparison to PW Signaling 4 E-VPN Comparison to PW Signaling
In E-VPN, service endpoint discovery and label signaling are done In E-VPN, service endpoint discovery and label signaling are done
concurrently using BGP. Whereas, with VPWS based on [RFC4448], label concurrently using BGP. Whereas, with VPWS based on [RFC4448], label
signaling is done via LDP and service endpoint discovery is either signaling is done via LDP and service endpoint discovery is either
through manual provisioning or through BGP. In VPWS, redundancy is through manual provisioning or through BGP. In VPWS, redundancy is
limited to Active/Standby mode, while with E-VPN both Active/Active limited to Active/Standby mode, while with E-VPN both Active/Active
and Active/Standby redundancy modes can be supported. In VPWS, backup and Active/Standby redundancy modes can be supported. In VPWS, backup
PWs are not used to carry traffic, while E-VPN traffic can be load- PWs are not used to carry traffic, while E-VPN traffic can be load-
balanced among primary and secondary PEs. On link or node failure, E- balanced among primary and secondary PEs. On link or node failure, E-
VPN can trigger failover with the withdrawal of a single BGP route VPN can trigger failover with the withdrawal of a single BGP route
per service, whereas with VPWS PW redundancy, the failover sequence per service, whereas with VPWS PW redundancy, the failover sequence
requires exchange of two control plane messages: one message to requires exchange of two control plane messages: one message to
deactivate the group of primary PWs and a second message to activate deactivate the group of primary PWs and a second message to activate
the group of backup PWs associated with the access link. Finally, E- the group of backup PWs associated with the access link. Finally, E-
VPN may employ data plane local repair mechanisms not available in VPN may employ data plane local repair mechanisms not available in
VPWS. VPWS.
5 VPWS with multiple sites 5 ESI Bandwidth Attribute
The ESI Bandwidth Attribute is a new optional BGP attribute that will
be associated with the Ethernet AD route used to realize the EVPL
services.
+---------------------------------------+
| Type (2 octets) |
+---------------------------------------+
| Length (2 octets) |
+---------------------------------------+
| Flags (1 Octet) |
+---------------------------------------+
| Reserved=0(1 Octet) |
+---------------------------------------+
| Reverse SENDER_TSPEC |
+---------------------------------------+
The content of the SENDER_TSPEC are as defined in [RFC 2210] section
3.1.
When a PE receives this attribute for a given EVPL it MUST request
the appropriate resources described in the SENDER_TSPEC from the PSN
towards the other EVPL service destination PE originating the
message. When resources are allocated from the PSN for a given EVPL
service, then the PSN SHOULD account for the Bandwidth requested by
this EVPL service.
In the case where PSN resources are not available, the PE receiving
this attribute MUST re-send its local Ethernet AD routes for this
EVPL service with the ESI Bandwidth attribute and with the Flags set
to 1 "PSN Resources Unavailable".
6 VPWS with multiple sites
The future revision of this draft will describe how a VPWS among The future revision of this draft will describe how a VPWS among
multiple sites (full mesh of P2P connections - one per pair of sites) multiple sites (full mesh of P2P connections - one per pair of sites)
can be setup automatically without any explicit provisioning of P2P can be setup automatically without any explicit provisioning of P2P
connections among the sites. connections among the sites.
6 Security Considerations 7 Security Considerations
This document does not introduce any additional security constraints. This document does not introduce any additional security constraints.
7 IANA Considerations 8 IANA Considerations
TBD TBD
8 References 9 References
8.1 Normative References 9.1 Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2 Informative References [RFC 2210] Wroclawski, J. "The Use of RSVP with IETF Integrated
Services", RFC 2210, September 1997
9.2 Informative References
[EVPN-REQ] A. Sajassi, R. Aggarwal et. al., "Requirements for [EVPN-REQ] A. Sajassi, R. Aggarwal et. al., "Requirements for
Ethernet VPN", draft-ietf-l2vpn-evpn-req-00.txt. Ethernet VPN", draft-ietf-l2vpn-evpn-req-00.txt.
[EVPN] A. Sajassi, R. Aggarwal et. al., "BGP MPLS Based Ethernet [EVPN] A. Sajassi, R. Aggarwal et. al., "BGP MPLS Based Ethernet
VPN", draft-ietf-l2vpn-evpn-00.txt. VPN", draft-ietf-l2vpn-evpn-00.txt.
Authors' Addresses Authors' Addresses
Sami Boutros Sami Boutros
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Cisco Cisco
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134, US San Jose, CA 95134, US
Email: sajassi@cisco.com Email: sajassi@cisco.com
Samer Salam Samer Salam
Cisco Cisco
595 Burrard Street, Suite 2123 595 Burrard Street, Suite 2123
Vancouver, BC V7X 1J1, Canada Vancouver, BC V7X 1J1, Canada
Email: ssalam@cisco.com Email: ssalam@cisco.com
John Drake
Juniper Networks
Email: jdrake@juniper.net
Jeff Tantsura
Ericsson
Email: jeff.tantsura@ericsson.com
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