< draft-boutros-l2vpn-evpn-vpws-01.txt   draft-boutros-l2vpn-evpn-vpws-02.txt >
INTERNET-DRAFT Sami Boutros INTERNET-DRAFT Sami Boutros
Intended Status: Standard Track Ali Sajassi Intended Status: Standard Track Ali Sajassi
Samer Salam Samer Salam
Cisco Systems Cisco Systems
John Drake John Drake
Juniper Networks Juniper Networks
Jeff Tantsura Jeff Tantsura
Ericsson Ericsson
Expires: August 28, 2013 February 24, 2013 Expires: April 24, 2014 October 21, 2013
VPWS support in E-VPN VPWS support in E-VPN
draft-boutros-l2vpn-evpn-vpws-01.txt draft-boutros-l2vpn-evpn-vpws-02.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: active/standby as well as following characteristics for VPWS: single-active as well as all-
active/active multi-homing with flow-based load-balancing, eliminates active multi-homing with flow-based load-balancing, eliminates the
the need for single-segment and multi-segment PW signaling, and need for single-segment and multi-segment PW signaling, and provides
provides fast protection using data-plane prefix independent fast protection using data-plane prefix independent convergence upon
convergence upon node or link failure. node or link failure.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as other groups may also distribute working documents as
Internet-Drafts. Internet-Drafts.
skipping to change at page 2, line 26 skipping to change at page 2, line 26
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 EVPN Comparison to PW Signaling . . . . . . . . . . . . . . . . 5
5 ESI Bandwidth Attribute . . . . . . . . . . . . . . . . . . . . 5 5 ESI Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . 6
6 VPWS with multiple sites . . . . . . . . . . . . . . . . . . . . 6 6 ESI value derivation . . . . . . . . . . . . . . . . . . . . . . 6
7 Security Considerations . . . . . . . . . . . . . . . . . . . . 6 7 VPWS with multiple sites . . . . . . . . . . . . . . . . . . . . 6
8 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 8 Security Considerations . . . . . . . . . . . . . . . . . . . . 6
9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 9 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
9.1 Normative References . . . . . . . . . . . . . . . . . . . 6 10 References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.2 Informative References . . . . . . . . . . . . . . . . . . 7 10.1 Normative References . . . . . . . . . . . . . . . . . . . 7
10.2 Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
1 Introduction 1 Introduction
This document describes how E-VPN can be used to support virtual This document describes how EVPN 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 EVPN
mechanisms for VPWS applies the benefits of E-VPN to p2p services. mechanisms for VPWS brings the benefits of EVPN to p2p services.
These benefits include active/standby AC redundancy as well as These benefits include single-active redundancy as well as all-active
active/active multi-homing with flow-based load-balancing. redundancy with flow-based load-balancing. Furthermore, the use of
Furthermore, the use of E-VPN for VPWS eliminates the need for EVPN for VPWS eliminates the need for signaling single-segment and
signaling single-segment and multi-segment PWs for p2p Ethernet multi-segment PWs for p2p Ethernet services.
services.
[E-VPN] has the ability to forward customer traffic to/from a given [EVPN] has the ability to forward customer traffic to/from a given
customer Attachment Circuit (AC), aka Ethernet Segment in E-VPN customer Attachment Circuit (AC), aka Ethernet Segment in EVPN
terminology, without any MAC lookup. This capability is ideal in terminology, without any MAC lookup. This capability is ideal in
providing p2p services (aka VPWS services). [MEF] defines EVPL providing p2p services (aka VPWS services). [MEF] defines Ethernet
service as p2p service between a pair of ACs (designated by VLANs). Virtual Private Line (EVPL) service as p2p service between a pair of
EVPL can be considered as a VPWS with only two ACs. In delivering an ACs (designated by VLANs). EVPL can be considered as a VPWS with only
EVPL service, the traffic forwarding capability of E-VPN using only a two ACs. In delivering an EVPL service, the traffic forwarding
pair of Ethernet AD routes is used; whereas, for more general VPWS, capability of EVPN based on the exchange of a pair of Ethernet AD
traffic forwarding capability of E-VPN using a group of Ethernet AD routes is used; whereas, for more general VPWS, traffic forwarding
routes (one Ethernet AD route per AC/segment) is used. Since in VPWS capability of EVPN based on the exchange of a group of Ethernet AD
services, the traffic from an originating Ethernet Segment can go routes (one Ethernet AD route per AC/segment) is used. In a VPWS
only to a single destination Ethernet Segment, no MAC lookup is service, the traffic from an originating Ethernet Segment can be
needed and the MPLS label associated with the per-EVI Ethernet AD forwarded only to a single destination Ethernet Segment; hence, no
route can be used in forwarding user traffic to the destination AC. MAC lookup is needed and the MPLS label associated with the per-EVI
Ethernet AD 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 EVPN 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 EVPN, the Ethernet Segment
route can be used to synchronize state between the PEs attached to route can be used to synchronize state between the PEs attached to
the same multi-homed Segment. the same multi-homed Ethernet 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.
OAM: Operations, Administration and Maintenance. OAM: Operations, Administration and Maintenance.
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: EVPN Instance.
Single-Active Mode: When a device or a network is multi-homed to two
or more PEs and when only a single PE in such redundancy group can
forward traffic to/from the multi-homed device or network for a given
VLAN, then such multi-homing or redundancy is referred to as "Single-
Active".
All-Active: When a device is multi-homed to two or more PEs and when
all PEs in such redundancy group can forward traffic to/from the
multi-homed device for a given VLAN, then such multi-homing or
redundancy is referred to as "All-Active".
2. BGP Extensions 2. BGP Extensions
[E-VPN] defines a new BGP NLRI for advertising different route types [EVPN] defines a new BGP NLRI for advertising different route types
for E-VPN operation. This document does not define any new BGP for EVPN operation. This document does not define any new BGP
messages, but rather re-purposes 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 per EVI Ethernet AD route to This document proposes the use of the per EVI Ethernet AD route to
signal P2P services. The Ethernet Segment Identifier field is set to signal P2P services. The Ethernet Segment Identifier field is set to
the ESI of the attachment circuit of the VPWS service instance. The the ESI of the attachment circuit of the VPWS service instance. The
Ethernet Tag field is set to 0 in the case of an Ethernet Private Ethernet Tag field is set to 0 in the case of an Ethernet Private
Wire service, and to the VLAN identifier associated with the service Wire service, and to the VLAN identifier associated with the service
for Ethernet Virtual Private Wire service. The route is associated for Ethernet Virtual Private Wire service. The route is associated
with a Route-Target (RT) extended community attribute that identifies with a Route-Target (RT) extended community attribute that identifies
the service instance (together with the Ethernet Tag field when non- the service instance (together with the Ethernet Tag field when non-
zero). 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. EVPN.
Ethernet Ethernet Ethernet Ethernet
Native |<---------E-VPN Instance------------>| Native Native |<--------- EVPN 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 |
| +-----+ +-----+ +-----+ +-----+ | | +-----+ +-----+ +-----+ +-----+ |
+----+ | | PE1 |======|ASBR1|==|ASBR2|===| PE3 | | +----+ +----+ | | PE1 |======|ASBR1|==|ASBR2|===| PE3 | | +----+
| |-------+-----+ +-----+ +-----+ +-----+-------| | | |-------+-----+ +-----+ +-----+ +-----+-------| |
| CE1| | | |CE2 | | CE1| | | |CE2 |
| |-------+-----+ +-----+ +-----+ +-----+-------| | | |-------+-----+ +-----+ +-----+ +-----+-------| |
+----+ | | PE2 |======|ASBR3|==|ASBR4|===| PE4 | | +----+ +----+ | | PE2 |======|ASBR3|==|ASBR4|===| PE4 | | +----+
^ +-----+ +-----+ +-----+ +-----+ ^ ^ +-----+ +-----+ +-----+ +-----+ ^
| Provider Edge 1 ^ Provider Edge 2 | | Provider Edge 1 ^ Provider Edge 2 |
| | | | | |
| | | | | |
| E-VPN Inter-provider point | | EVPN Inter-provider point |
| | | |
|<---------------- Emulated Service -------------------->| |<---------------- Emulated Service -------------------->|
iBGP sessions will be established between PE1, PE2, ASBR1 and ASBR3, iBGP sessions are 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 are
established between PE3, PE4, ASBR2 and ASBR4. eBGP sessions will be established between PE3, PE4, ASBR2 and ASBR4. eBGP sessions are
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 EVPN SAFI, and exchange EVPN
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 either a C-tagged or addresses. The link between the CE and the PE is either a C-tagged or
S-tagged interface, as described in [802.1Q], that can carry a single S-tagged interface, as described in [802.1Q], that can carry a single
VLAN tag or two nested VLAN tags. This interface is set up as a trunk VLAN tag or two nested VLAN tags. This interface is set up as a 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. used to identify the services multiplexed in the same EVI.
For CE multi-homing, the Ethernet AD Route encodes the ESI associated For CE multi-homing, the Ethernet AD Route encodes the ESI associated
with the CE. This allows flow-based load-balancing of traffic between with the CE. This allows flow-based load-balancing of traffic between
PEs connected to the same multi-homed CE. The VPN ID MUST be the same PEs connected to the same multi-homed CE. The VPN ID MUST be the same
on both PEs attached to the site. The Ethernet Segment route may be on both PEs attached to the site. The Ethernet Segment route may be
used too, for discovery of multi-homed CEs. In all cases traffic used too, for discovery of multi-homed CEs. In all cases traffic
follows the transport paths, which may be asymmetric. follows the transport paths, which may be asymmetric.
4 E-VPN Comparison to PW Signaling 4 EVPN Comparison to PW Signaling
In E-VPN, service endpoint discovery and label signaling are done In EVPN, 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 existing
limited to Active/Standby mode, while with E-VPN both Active/Active implementation of VPWS using pseudowires(PWs), redundancy is limited
and Active/Standby redundancy modes can be supported. In VPWS, backup to single-active mode, while with EVPN implementation of VPWS both
PWs are not used to carry traffic, while E-VPN traffic can be load- single-active and all-active redundancy modes can be supported. In
balanced among primary and secondary PEs. On link or node failure, E- existing implementation with PWs, backup PWs are not used to carry
VPN can trigger failover with the withdrawal of a single BGP route traffic, while with EVPN, traffic can be load-balanced among primary
per service, whereas with VPWS PW redundancy, the failover sequence and secondary PEs. Upon link or node failure, EVPN can trigger
requires exchange of two control plane messages: one message to failover with the withdrawal of a single BGP route per service,
deactivate the group of primary PWs and a second message to activate whereas with VPWS PW redundancy, the failover sequence requires
the group of backup PWs associated with the access link. Finally, E- exchange of two control plane messages: one message to deactivate the
VPN may employ data plane local repair mechanisms not available in group of primary PWs and a second message to activate the group of
VPWS. backup PWs associated with the access link. Finally, EVPN may employ
data plane local repair mechanisms not available in VPWS.
5 ESI Bandwidth Attribute
The ESI Bandwidth Attribute is a new optional BGP attribute that will 5 ESI Bandwidth
be associated with the Ethernet AD route used to realize the EVPL
services.
+---------------------------------------+ The ESI Bandwidth will be encoded using the Link Bandwidth Extended
| Type (2 octets) | community defined in [draft-ietf-idr-link-bandwidth] and associated
+---------------------------------------+ with the Ethernet AD route used to realize the EVPL services.
| 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 When a PE receives this attribute for a given EVPL it MUST request
the appropriate resources described in the SENDER_TSPEC from the PSN the required bandwidth from the PSN towards the other EVPL service
towards the other EVPL service destination PE originating the destination PE originating the message. When resources are allocated
message. When resources are allocated from the PSN for a given EVPL from the PSN for a given EVPL service, then the PSN SHOULD account
service, then the PSN SHOULD account for the Bandwidth requested by for the Bandwidth requested by this EVPL service.
this EVPL service.
In the case where PSN resources are not available, the PE receiving In the case where PSN resources are not available, the PE receiving
this attribute MUST re-send its local Ethernet AD routes for this this attribute MUST re-send its local Ethernet AD routes for this
EVPL service with the ESI Bandwidth attribute and with the Flags set EVPL service with the ESI Bandwidth = All FFs to declare that the
to 1 "PSN Resources Unavailable". "PSN Resources Unavailable".
6 VPWS with multiple sites 6 ESI value derivation
The 10 bytes ESI value will contain:-
1) 6-byte System-ID that is globally unique. These 6 bytes can be
auto derived using a mechanism similar to the one used for
automating B-MAC Address Assignment in [PBB-EVPN].
2) 4-byte Local-AC-ID that is unique within each PE.
The combination of System-ID and Local-AC-ID makes the associated AC-
ID globally unique. A pair of such globally unique AC-ID identifies a
point-to-point service (EVPL or EPL) uniquely in the provider
network.
7 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.
7 Security Considerations 8 Security Considerations
This document does not introduce any additional security constraints. This document does not introduce any additional security constraints.
8 IANA Considerations 9 IANA Considerations
TBD TBD
9 References 10 References
9.1 Normative References 10.1 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.
[RFC 2210] Wroclawski, J. "The Use of RSVP with IETF Integrated 10.2 Informative References
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-04.txt.
[PBB-EVPN] A. Sajassi et. al., "PBB-EVPN", draft-ietf-l2vpn-pbb-evpn-
05.txt.
[draft-ietf-idr-link-bandwidth] P. Mohapatra, R. Fernando, "BGP Link
Bandwidth Extended Community", draft-ietf-idr-link-bandwidth-06.txt
Authors' Addresses Authors' Addresses
Sami Boutros Sami Boutros
Cisco Cisco
170 West Tasman Drive 170 West Tasman Drive
San Jose, CA 95134, US San Jose, CA 95134, US
Email: sboutros@cisco.com Email: sboutros@cisco.com
Ali Sajassi Ali Sajassi
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