Internet DRAFT - draft-sajassi-l2vpn-evpn-vpls-integration
draft-sajassi-l2vpn-evpn-vpls-integration
INTERNET-DRAFT Ali Sajassi
Intended Status: Standard Track Samer Salam
Cisco
Nick Del Regno
Verizon
Expires: April 21, 2014 October 21, 2013
(PBB-)EVPN Seamless Integration with (PBB-)VPLS
draft-sajassi-l2vpn-evpn-vpls-integration-00
Abstract
This draft discusses the backward compatibility of the (PBB-)EVPN
solution with (PBB-)VPLS and provides mechanisms for seamless
integration of the two technologies in the same MPLS/IP network on a
per-VPN-instance basis.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
Copyright and License Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
Sajassi et al. Expires April 21, 2014 [Page 1]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 PBB-VPLS Integration with PBB-EVPN . . . . . . . . . . . . . . . 4
3.1 Capability Discovery . . . . . . . . . . . . . . . . . . . . 4
3.2 Forwarding Setup and Unicast Operation . . . . . . . . . . . 5
3.3 Multicast Operation . . . . . . . . . . . . . . . . . . . . 6
3.3.1 Ingress Replication . . . . . . . . . . . . . . . . . . 6
3.3.2 LSM . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4 VPLS Integration with EVPN . . . . . . . . . . . . . . . . . . . 6
4.1 Capability Discovery . . . . . . . . . . . . . . . . . . . . 6
4.2 Forwarding Setup and Unicast Operation . . . . . . . . . . . 6
4.3 Multicast Operation . . . . . . . . . . . . . . . . . . . . 7
4.3.1 Ingress Replication . . . . . . . . . . . . . . . . . . 7
4.3.2 LSM . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5 VPLS Integration with PBB-EVPN . . . . . . . . . . . . . . . . . 7
5.1 Capability Discovery . . . . . . . . . . . . . . . . . . . . 7
5.2 Forwarding Setup and Unicast Operation . . . . . . . . . . . 7
5.3 Multicast Operation . . . . . . . . . . . . . . . . . . . . 7
5.3.1 Ingress Replication . . . . . . . . . . . . . . . . . . 7
5.3.2 LSM . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Solution Advantages . . . . . . . . . . . . . . . . . . . . . . 7
7 Security Considerations . . . . . . . . . . . . . . . . . . . . 8
8 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1 Normative References . . . . . . . . . . . . . . . . . . . 8
9.2 Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
Sajassi et al. Expires April 21, 2014 [Page 2]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
1 Introduction
VPLS and PBB-VPLS are widely-deployed L2VPN technologies. Many SPs
who are looking at adopting EVPN and PBB-EVPN want to preserve their
investment in the (PBB-)VPLS networks. Hence, it is required to
provide mechanisms by which (PBB-)EVPN technology can be introduced
into existing L2VPN networks without requiring a fork-lift upgrade.
This document discusses mechanisms for the seamless integration of
the two technologies in the same MPLS/IP network.
Section 2 provides the details of the requirements. Section 3
discusses PBB-VPLS integration with PBB-EVPN. Section 4 discusses the
integration of VPLS and EVPN. Section 5 discusses the integration of
VPLS and PBB-EVPN, and finally Section 6 discusses the solution
advantages.
It is worth noting that the scenario where PBB-VPLS is integrated
with EVPN, is for future study and upon market validation. The reason
for that is that deployments which employ PBB-VPLS typically require
PBB encapsulation for various reasons. Hence, it is expected that for
those deployments the evolution path would be from PBB-VPLS towards
PBB-EVPN, rather than EVPN.
1.1 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [KEYWORDS].
2. Requirements
Following are the key requirements for backward compatibility between
(PBB-)EVPN and (PBB-)VPLS:
1. The solution MUST allow for staged migration towards (PBB-)EVPN on
a site-by-site basis per VPN instance - e.g., new EVPN sites to be
provisioned on (PBB-)EVPN PEs.
2. The solution MUST require no changes to existing VPLS or PBB-VPLS
PEs, not even a software upgrade.
3. The solution MUST allow for the coexistence of PE nodes running
(PBB-)EVPN and (PBB-)VPLS for the same VPN instance and single-homed
segments.
4. The solution MUST support single-active redundancy of multi-homed
networks and multi-homed devices for (PBB-)EVPN PEs.
Sajassi et al. Expires April 21, 2014 [Page 3]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
5. In case of single-active redundancy, the participant VPN instances
MAY span across both (PBB-)EVPN PEs and (PBB-)VPLS PEs as long as
single-active redundancy is employed by (PBB-)EVPN PEs.
6. The solution SHOULD support all-active redundancy of multi-homed
networks and multi-homed devices for (PBB-)EVPN PEs.
7. In case of all-active redundancy, the participant VPN instances
SHOULD be confined to (PBB-)EVPN PEs only.
8. In case of all-active redundancy, the participant VPN instances
MAY span across (PBB-)EVPN and (PBB-)VPLS PEs.
These requirements collectively allow for the seamless insertion of
the (PBB-)EVPN technology into brown-field (PBB-)VPLS deployments.
3 PBB-VPLS Integration with PBB-EVPN
In order to support seamless integration with (PBB-)VPLS, the (PBB-
)EVPN PEs MUST support EVPN BGP routes (EVPN SAFI) and SHOULD support
VPLS AD route (VPLS SAFI). All the logic for the integration will
reside on the (PBB-)EVPN PEs side. However, if a VPLS instance is
setup without the use of BGP auto-discovery, it is still possible
(but cumbersome) for (PBB-)EVPN PEs to integrate into that VPLS
instance.
3.1 Capability Discovery
The (PBB-)EVPN PEs must advertise both the BGP VPLS auto-discovery
(AD) route as well as the BGP EVPN Inclusive Multicast route for a
given VPN instance. The (PBB-)VPLS PEs only advertise the BGP VPLS AD
route, per current standard procedures specified in [RFC4761] and
[RFC6074]. The operator may decide to use the same BGP RT for both
(PBB-)EVPN and (PBB-)VPLS. In this case, when a (PBB-)VPLS PE
receives the EVPN Inclusive Multicast route, it will ignore it on the
basis that it belongs to an unknown SAFI. However, the operator may
use two RTs (one for (PBB-)VPLS and another for (PBB-)EVPN) and
employ RT-constraint in order to prevent EVPN BGP routes from
reaching the (PBB-)VPLS PEs. This provides an optimization in case
required by the scale of the network.
When a (PBB-)EVPN PE receives both a VPLS AD route as well as an EVPN
Inclusive Multicast route from a given remote PE for the same VPN
instance, it MUST give preference to the EVPN route for the purpose
of discovery. This ensures that, at the end of the route exchanges,
all (PBB-)EVPN capable PEs discover other (PBB-)EVPN capable PEs as
well as the (PBB-)VPLS-only PEs for that VPN instance. Furthermore,
all the (PBB-)VPLS-only PEs would discover the (PBB-)EVPN PEs as if
Sajassi et al. Expires April 21, 2014 [Page 4]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
they were standard (PBB-)VPLS nodes. In other words, when the
discovery phase is complete, the (PBB-)EVPN PEs would have discovered
all the PEs in the VPN instance, and their associated capability:
(PBB-)EVPN or VPLS-only. Whereas the (PBB-)VPLS PEs would have
discovered all the PEs in the VPN instance, as if they were all VPLS-
only nodes.
3.2 Forwarding Setup and Unicast Operation
The procedures for forwarding setup and unicast operation on the
(PBB-)VPLS PE are per [RFC4447] and [PBB-VPLS].
The procedures for forwarding state setup and unicast operation on
the (PBB-)EVPN PE are as follows:
- The (PBB-)EVPN PE must establish a pseudowire to a remote PE from
which it has received only a VPLS AD route, for the VPN instance in
question, and set up the label stack corresponding to the pseudowire
FEC. This PW is between B-components of PBB-EVPN PE and PBB-VPLS PE
per section 4 of [PBB-VPLS-PE-MODEL].
- The (PBB-)EVPN PE must set up the label stack corresponding to the
MP2P (PBB-)VPN unicast FEC to any remote PE that has advertised EVPN
AD route.
- If a (PBB-)EVPN PE receives a VPLS AD route followed by an EVPN AD
route from the same PE and a pseudowire is setup to that PE, then the
(PBB-)EVPN PE MUST deactivate that pseudowire.
- If a (PBB-)EVPN PE receives an EVPN AD route followed by a VPLS AD
route from the same PE, then the (PBB-)EVPN PE MUST ignore the VPLS
AD route.
When the (PBB-)EVPN PE receives traffic over the pseudowires, it
learns the associated MAC addresses in the data-plane. This is
analogous to dynamic learning in IEEE bridges. The (PBB-)EVPN PE
learns MAC addresses in the control plane, via the EVPN MAC
Advertisement routes sent by remote (PBB-)EVPN PEs, and updates its
MAC forwarding table accordingly. This is analogous to static
learning in IEEE bridges. In PBB-EVPN, a given B-MAC address can be
learnt either over the BGP control-plane from a remote PBB-EVPN PE,
or in the data-plane over a pseudowire from a remote PBB-VPLS PE.
There is no mobility associated with B-MAC addresses in this context.
Hence, when the same B-MAC address shows up behind both a remote PBB-
VPLS PE as well as a PBB-EVPN PE, the local PE can deduce that there
is an anomaly in the network.
Sajassi et al. Expires April 21, 2014 [Page 5]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
3.3 Multicast Operation
3.3.1 Ingress Replication The procedures for multicast operation on the
(PBB-)VPLS PE, using ingress replication, are per [RFC4447] and [PBB-
VPLS].
The procedures for multicast operation on the PBB-EVPN PE, for
ingress replication, are as follows:
- The PBB-EVPN PE builds a replication sub-list per I-SID to all the
remote PBB-EVPN PEs in a given VPN instance, as a result of the
exchange of the EVPN Inclusive multicast routes, as described in
[PBB-EVPN]. This will be referred to as sub-list A. It comprises MP2P
tunnels used for delivering PBB-EVPN BUM traffic [EVPN].
- The PBB-EVPN PE builds a replication sub-list per VPN instance to
all the remote PBB-VPLS PEs , as a result of the exchange of the VPLS
AD routes. This will be referred to as sub-list B. It comprises
pseudowires from the PBB-EVPN PE in question to all the remote PBB-
VPLS PEs in the same VPN instance.
- The PBB-EVPN PE may further prune sub-list B, on a per I-SID basis,
if [MMRP] is run over the PBB-VPLS network. This will be referred to
as sub-list C. This list comprises a pruned set of the pseudowires in
sub-list B.
The replication list, maintained per I-SID, on a given PBB-EVPN PE
will be the union of sub-list A and sub-list B if [MMRP] is NOT used,
and the union of sub-list A and sub-list C if [MMRP] is used. Note
that the PE must enable split-horizon over all the entries in the
replication list, across both pseudowires and MP2P tunnels.
3.3.2 LSM Will be covered in a future revision of this document.
4 VPLS Integration with EVPN
4.1 Capability Discovery
The procedures for capability discovery are per Section 3.1 above.
4.2 Forwarding Setup and Unicast Operation
The operation here is largely similar to that of PBB-EVPN integration
with PBB-VPLS, with the exception of the need to handle MAC mobility,
the details of which will be covered in a future revision of this
document.
Sajassi et al. Expires April 21, 2014 [Page 6]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
4.3 Multicast Operation
4.3.1 Ingress Replication
The operation is per the procedures of Section 3.3.1 above for the
scenario WITHOUT [MMRP]. The replication list is maintained per VPN
instance, rather than per I-SID.
4.3.2 LSM Will be covered in a future revision of this document.
5 VPLS Integration with PBB-EVPN
5.1 Capability Discovery
The procedures for capability discovery are per Section 3.1 above.
5.2 Forwarding Setup and Unicast Operation
The operation here is largely similar to that of PBB-EVPN integration
with PBB-VPLS, with a few exceptions listed below:
- When a PW is setup between a PBB-EVPN PE and a VPLS PE, it gets
setup between the I-component of PBB-EVPN PE and the bridge component
of VPLS PE.
- The MAC mobility needs to be handled. The details of which will be
covered in a future revision of this document.
5.3 Multicast Operation
5.3.1 Ingress Replication
The operation is per the procedures of Section 3.3.1 above for the
scenario WITHOUT [MMRP]. The replication list is maintained per I-SID
on the PBB-EVPN PEs and per VPN instance on the VPLS PEs.
5.3.2 LSM Will be covered in a future revision of this document.
6 Solution Advantages
The solution for seamless integration of (PBB-)EVPN with (PBB-)VPLS
has the following advantages:
- When ingress replication is used for multi-destination traffic
delivery, the solution reduces the scope of [MMRP] (which is a soft-
Sajassi et al. Expires April 21, 2014 [Page 7]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
state protocol) to only that of existing VPLS PEs, and uses the more
robust BGP-based mechanism for multicast pruning among new EVPN PEs.
- It is completely backward compatible.
- New PEs can leverage the extensive multi-homing mechanisms and
provisioning simplifications of PBB-EVPN:
1. Auto-sensing of MHN / MHD
2. Auto-discovery of redundancy group
3.Auto-provisioning of DF election and VLAN carving
7 Security Considerations
No new security considerations beyond those for VPLS and EVPN.
8 IANA Considerations
This document has no actions for IANA.
9 References
9.1 Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4448] Martini, L., Ed., Rosen, E., El-Aawar, N., and G. Heron,
"Encapsulation Methods for Transport of Ethernet over MPLS
Networks", RFC 4448, April 2006.
[RFC4447] Martini, et al., "Pseudowire Setup and Maintenance using
the Label Distribution Protocol", draft-ietf-pwe3-
rfc4447bis-02.txt, October 2013.
[EVPN] Sajassi et al., "BGP MPLS Based Ethernet VPN", draft-ietf-
l2vpn-evpn-04.txt, work in progress, July, 2013.
[PBB-EVPN] Sajassi et al., "PBB-EVPN", draft-ietf-l2vpn-pbb-evpn-
05.txt, work in progress, October, 2013.
9.2 Informative References
[MMRP] Clause 10 of "IEEE Standard for Local and metropolitan area
Sajassi et al. Expires April 21, 2014 [Page 8]
INTERNET DRAFT draft-sajassi-l2vpn-evpn-vpls-integration Oct 21, 2013
networks - Media Access Control (MAC) Bridges and Virtual Bridged
Local Area Networks", IEEE Std 802.1Q, 2013.
[PBB-VPLS-PE-MODEL] Balus, F., Sajassi, S., Bitar, N., "Extensions to
VPLS PE model for Provider Backbone Bridging", RFC xxxx, June 2013.
[PBB-VPLS] Sajassi, et al., "VPLS Interoperability with Provider
Backbone Bridges", draft-ietf-l2vpn-pbb-vpls-interop-05.txt, work in
progress, October, 2013.
Authors' Addresses
Ali Sajassi
Cisco
170 West Tasman Drive
San Jose, CA 95134, US
Email: sajassi@cisco.com
Samer Salam
Cisco
595 Burrard Street, Suite 2123
Vancouver, BC V7X 1J1, Canada
Email: ssalam@cisco.com
Nick Del Regno
Verizon
400 International Pkwy
Richardson, TX 75089, US
Email: nick.delregno@verizon.com
Sajassi et al. Expires April 21, 2014 [Page 9]
