Network Working Group A. Sajassi
INTERNET-DRAFT Cisco
Category: Standards Track
R. Aggarwal
N. Bitar Arktan
Verizon
W. Henderickx
S. Boutros F. Balus
K. Patel Alcatel-Lucent
S. Salam
Cisco Aldrin Isaac
Bloomberg
J. Drake
R. Shekhar J. Uttaro
Juniper Networks AT&T
Expires: August 25, 2013 February 25, 2013
BGP MPLS Based Ethernet VPN
draft-ietf-l2vpn-evpn-03
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) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
Sajassi, et al. Expires August 25, 2013 [Page 1]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 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.
Abstract
This document describes procedures for BGP MPLS based Ethernet VPNs
(E-VPN).
Table of Contents
1. Specification of requirements . . . . . . . . . . . . . . . . . 5
2. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. BGP MPLS Based E-VPN Overview . . . . . . . . . . . . . . . . . 6
6. Ethernet Segment . . . . . . . . . . . . . . . . . . . . . . . 7
7. Ethernet Tag . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1 VLAN Based Service Interface . . . . . . . . . . . . . . . . 9
7.2 VLAN Bundle Service Interface . . . . . . . . . . . . . . . 9
7.2.1 Port Based Service Interface . . . . . . . . . . . . . . 10
7.3 VLAN Aware Bundle Service Interface . . . . . . . . . . . . 10
7.3.1 Port Based VLAN Aware Service Interface . . . . . . . . 10
8. BGP E-VPN NLRI . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Ethernet Auto-Discovery Route . . . . . . . . . . . . . . . 11
8.2. MAC Advertisement Route . . . . . . . . . . . . . . . . . 12
8.3. Inclusive Multicast Ethernet Tag Route . . . . . . . . . . 12
8.4 Ethernet Segment Route . . . . . . . . . . . . . . . . . . . 13
8.5 ESI Label Extended Community . . . . . . . . . . . . . . . . 13
8.6 ES-Import Route Target . . . . . . . . . . . . . . . . . . . 14
8.7 MAC Mobility Extended Community . . . . . . . . . . . . . . 14
8.8 Default Gateway Extended Community . . . . . . . . . . . . . 15
9. Multi-homing Functions . . . . . . . . . . . . . . . . . . . . 15
9.1 Multi-homed Ethernet Segment Auto-Discovery . . . . . . . . 15
9.1.1 Constructing the Ethernet Segment Route . . . . . . . . 15
9.2 Fast Convergence . . . . . . . . . . . . . . . . . . . . . . 16
9.2.1 Constructing the Ethernet A-D Route per Ethernet
Segment . . . . . . . . . . . . . . . . . . . . . . . . 16
9.2.1.1. Ethernet A-D Route Targets . . . . . . . . . . . . 17
9.3 Split Horizon . . . . . . . . . . . . . . . . . . . . . . . 17
9.3.1 ESI Label Assignment . . . . . . . . . . . . . . . . . . 18
9.3.1.1 Ingress Replication . . . . . . . . . . . . . . . . 18
Sajassi, et al. Expires August 25, 2013 [Page 2]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
9.3.1.2. P2MP MPLS LSPs . . . . . . . . . . . . . . . . . . 19
9.3.1.3. MP2MP LSPs . . . . . . . . . . . . . . . . . . . . 20
9.4 Aliasing and Backup-Path . . . . . . . . . . . . . . . . . . 20
9.4.1 Constructing the Ethernet A-D Route per EVI . . . . . . 21
9.4.1.1 Ethernet A-D Route Targets . . . . . . . . . . . . . 22
9.5 Designated Forwarder Election . . . . . . . . . . . . . . . 22
10. Determining Reachability to Unicast MAC Addresses . . . . . . 24
10.1. Local Learning . . . . . . . . . . . . . . . . . . . . . . 25
10.2. Remote learning . . . . . . . . . . . . . . . . . . . . . 25
10.2.1. Constructing the BGP E-VPN MAC Address Advertisement . 25
10.2.2 Route Resolution . . . . . . . . . . . . . . . . . . . 27
11. ARP and ND . . . . . . . . . . . . . . . . . . . . . . . . . . 28
11.1 Default Gateway . . . . . . . . . . . . . . . . . . . . . . 29
12. Handling of Multi-Destination Traffic . . . . . . . . . . . . 29
12.1. Construction of the Inclusive Multicast Ethernet Tag
Route . . . . . . . . . . . . . . . . . . . . . . . . . . 30
12.2. P-Tunnel Identification . . . . . . . . . . . . . . . . . 30
13. Processing of Unknown Unicast Packets . . . . . . . . . . . . 31
13.1. Ingress Replication . . . . . . . . . . . . . . . . . . . 32
13.2. P2MP MPLS LSPs . . . . . . . . . . . . . . . . . . . . . . 32
14. Forwarding Unicast Packets . . . . . . . . . . . . . . . . . . 32
14.1. Forwarding packets received from a CE . . . . . . . . . . 32
14.2. Forwarding packets received from a remote PE . . . . . . . 34
14.2.1. Unknown Unicast Forwarding . . . . . . . . . . . . . . 34
14.2.2. Known Unicast Forwarding . . . . . . . . . . . . . . . 34
15. Load Balancing of Unicast Frames . . . . . . . . . . . . . . . 34
15.1. Load balancing of traffic from an PE to remote CEs . . . . 34
15.1.1 Single-Active Redundancy Mode . . . . . . . . . . . . . 34
15.1.2 All-Active Redundancy Mode . . . . . . . . . . . . . . 35
15.2. Load balancing of traffic between an PE and a local CE . . 37
15.2.1. Data plane learning . . . . . . . . . . . . . . . . . 37
15.2.2. Control plane learning . . . . . . . . . . . . . . . . 37
16. MAC Mobility . . . . . . . . . . . . . . . . . . . . . . . . . 37
16.1. MAC Duplication Issue . . . . . . . . . . . . . . . . . . 39
17. Multicast . . . . . . . . . . . . . . . . . . . . . . . . . . 39
17.1. Ingress Replication . . . . . . . . . . . . . . . . . . . 40
17.2. P2MP LSPs . . . . . . . . . . . . . . . . . . . . . . . . 40
17.3. MP2MP LSPs . . . . . . . . . . . . . . . . . . . . . . . . 40
17.3.1. Inclusive Trees . . . . . . . . . . . . . . . . . . . 40
17.3.2. Selective Trees . . . . . . . . . . . . . . . . . . . 41
17.4. Explicit Tracking . . . . . . . . . . . . . . . . . . . . 42
18. Convergence . . . . . . . . . . . . . . . . . . . . . . . . . 42
18.1. Transit Link and Node Failures between PEs . . . . . . . . 42
18.2. PE Failures . . . . . . . . . . . . . . . . . . . . . . . 42
18.2.1. Local Repair . . . . . . . . . . . . . . . . . . . . . 42
18.3. PE to CE Network Failures . . . . . . . . . . . . . . . . 42
19. LACP State Synchronization . . . . . . . . . . . . . . . . . . 43
20. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 44
Sajassi, et al. Expires August 25, 2013 [Page 3]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
21. Security Considerations . . . . . . . . . . . . . . . . . . . 44
22. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 44
23. References . . . . . . . . . . . . . . . . . . . . . . . . . . 44
23.1 Normative References . . . . . . . . . . . . . . . . . . . 44
23.2 Informative References . . . . . . . . . . . . . . . . . . 45
24. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 45
Sajassi, et al. Expires August 25, 2013 [Page 4]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
1. Specification of requirements
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 [RFC2119].
2. Contributors
In addition to the authors listed above, the following individuals
also contributed to this document:
Quaizar Vohra
Kireeti Kompella
Apurva Mehta
Nadeem Mohammad
Juniper Networks
Clarence Filsfils
Dennis Cai
Cisco
3. Introduction
This document describes procedures for BGP MPLS based Ethernet VPNs
(E-VPN). The procedures described here are intended to meet the
requirements specified in [EVPN-REQ]. Please refer to [EVPN-REQ] for
the detailed requirements and motivation. E-VPN requires extensions
to existing IP/MPLS protocols as described in this document. In
addition to these extensions E-VPN uses several building blocks from
existing MPLS technologies.
4. Terminology
All-Active Mode: 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".
CE: Customer Edge device e.g., host or router or switch
E-VPN Instance (EVI): An E-VPN routing and forwarding instance on a
PE.
Ethernet segment identifier (ESI): If a CE is multi-homed to two or
more PEs, the set of Ethernet links that attaches the CE to the PEs
is an 'Ethernet segment'. Ethernet segments MUST have a unique non-
zero identifier, the 'Ethernet Segment Identifier'.
Sajassi, et al. Expires August 25, 2013 [Page 5]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
Ethernet Tag: An Ethernet Tag identifies a particular broadcast
domain, e.g., a VLAN. An E-VPN instance consists of one or more
broadcast domains. Ethernet tag(s) are assigned to the broadcast
domains of a given E-VPN instance by the provider of that E-VPN, and
each PE in that E-VPN instance performs a mapping between broadcast
domain identifier(s) understood by each of its attached CEs and the
corresponding Ethernet tag.
Link Aggregation Control Protocol (LACP):
Multipoint to Multipoint (MP2MP):
Point to Multipoint (P2MP):
Point to Point (P2P):
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".
5. BGP MPLS Based E-VPN Overview
This section provides an overview of E-VPN.
An E-VPN comprises CEs that are connected to PEs that form the edge
of the MPLS infrastructure. A CE may be a host, a router or a switch.
The PEs provide virtual Layer 2 bridged connectivity between the CEs.
There may be multiple E-VPNs in the provider's network.
The PEs may be connected by an MPLS LSP infrastructure which provides
the benefits of MPLS technology such as fast-reroute, resiliency,
etc. The PEs may also be connected by an IP infrastructure in which
case IP/GRE tunneling or other IP tunneling can be used between the
PEs. The detailed procedures in this version of this document are
specified only for MPLS LSPs as the tunneling technology. However
these procedures are designed to be extensible to IP tunneling as the
PSN tunneling technology.
In an E-VPN, MAC learning between PEs occurs not in the data plane
(as happens with traditional bridging) but in the control plane.
Control plane learning offers greater control over the MAC learning
process, such as restricting who learns what, and the ability to
apply policies. Furthermore, the control plane chosen for
advertising MAC reachability information is multi-protocol (MP) BGP
(similar to IP VPNs (RFC 4364)). This provides greater scalability
Sajassi, et al. Expires August 25, 2013 [Page 6]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
and the ability to preserve the "virtualization" or isolation of
groups of interacting agents (hosts, servers, virtual machines) from
each other. In E-VPN, PEs advertise the MAC addresses learned from
the CEs that are connected to them, along with an MPLS label, to
other PEs in the control plane using MP-BGP. Control plane learning
enables load balancing of traffic to and from CEs that are multi-
homed to multiple PEs. This is in addition to load balancing across
the MPLS core via multiple LSPs between the same pair of PEs. In
other words it allows CEs to connect to multiple active points of
attachment. It also improves convergence times in the event of
certain network failures.
However, learning between PEs and CEs is done by the method best
suited to the CE: data plane learning, IEEE 802.1x, LLDP, 802.1aq,
ARP, management plane or other protocols.
It is a local decision as to whether the Layer 2 forwarding table on
an PE is populated with all the MAC destination addresses known to
the control plane, or whether the PE implements a cache based scheme.
For instance the MAC forwarding table may be populated only with the
MAC destinations of the active flows transiting a specific PE.
The policy attributes of E-VPN are very similar to those of IP-VPN.
An EVI requires a Route-Distinguisher (RD) and one or more Route-
Targets (RTs). A CE attaches to an E-VPN instance (EVI) on an PE, on
an Ethernet interface which may be configured for one or more
Ethernet Tags, e.g., VLANs. Some deployment scenarios guarantee
uniqueness of VLANs across E-VPNs: all points of attachment of a
given EVI use the same VLAN, and no other EVI uses this VLAN. This
document refers to this case as a "Unique VLAN E-VPN" and describes
simplified procedures to optimize for it.
6. Ethernet Segment
If a CE is multi-homed to two or more PEs, the set of Ethernet links
constitutes an "Ethernet Segment". An Ethernet segment may appear to
the CE as a Link Aggregation Group (LAG). Ethernet segments have an
identifier, called the "Ethernet Segment Identifier" (ESI) which is
encoded as a ten octets integer. The following two ESI values are
reserved:
- ESI 0 denotes a single-homed CE.
- ESI {0xFF} (repeated 10 times) is known as MAX-ESI and is reserved.
In general, an Ethernet segment MUST have a non-reserved ESI that is
unique network wide (e.g., across all EVPNs on all the PEs). If the
Sajassi, et al. Expires August 25, 2013 [Page 7]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
CE(s) constituting an Ethernet Segment is (are) managed by the
network operator, then ESI uniqueness should be guranteed; however,
if the CE(s) is (are) not managed, then the operator MUST configure a
network-wide unique ESI for that Ethernet Segment. This is required
to enable auto-discovery of Ethernet Segments and DF election. The
ESI can be assigned using various mechanisms:
1. If IEEE 802.1AX LACP is used between the PEs and CEs, then
the ESI is determined from LACP by concatenating the following
parameters:
+ CE LACP System Identifier comprised of two octets of System
Priority and six octets of System MAC address, where the
System Priority is encoded in the most significant two octets.
The CE LACP identifier MUST be encoded in the high order eight
octets of the ESI.
+ CE LACP two octets Port Key. The CE LACP port key MUST be
encoded in the low order two octets of the ESI.
As far as the CE is concerned, it would treat the multiple PEs
that it is connected to as the same switch. This allows the CE
to aggregate links that are attached to different PEs in the
same bundle.
This mechanism could be used only if it produces ESIs that satisfy
the uniqueness requirement specified above.
2. If LLDP is used between the PEs and CEs that are hosts, then
the ESI is determined by LLDP. The ESI will be specified in a
following version.
This mechanism could be used only if it produces ESIs that satisfy
the uniqueness requirement specified above.
3. In the case of indirectly connected hosts via a bridged LAN
between the CEs and the PEs, the ESI is determined based on the
Layer 2 bridge protocol as follows: If MST is used in the bridged
LAN then the value of the ESI is derived by listening to BPDUs on
the Ethernet segment. To achieve this the PE is not required to
run MST. However the PE must learn the Root Bridge MAC address
and Bridge Priority of the root of the Internal Spanning Tree
(IST) by listening to the BPDUs. The ESI is constructed as
follows:
{Bridge Priority (16 bits) , Root Bridge MAC Address (48 bits)}
This mechanism could be used only if it produces ESIs that satisfy
Sajassi, et al. Expires August 25, 2013 [Page 8]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
the uniqueness requirement specified above.
4. The ESI may be configured.
7. Ethernet Tag
An Ethernet Tag identifies a particular broadcast domain, e.g. a
VLAN, in an EVI. An EVI consists of one or more broadcast domains.
Ethernet Tags are assigned to the broadcast domains of a given EVI by
the provider of the E-VPN service. Each PE, in a given EVI, performs
a mapping between the Ethernet Tag and the corresponding broadcast
domain identifier(s) understood by each of its attached CEs (e.g. CE
VLAN Identifiers or CE-VIDs).
If the broadcast domain identifiers(s) are understood consistently by
all of the CEs in an EVI, the broadcast domain identifier(s) MAY be
used as the corresponding Ethernet Tag(s). In other words, the
Ethernet Tag ID assigned by the provider is numerically equal to the
broadcast domain identifier (e.g., CE-VID = Ethernet Tag).
Further, some deployment scenarios guarantee uniqueness of broadcast
domain identifiers across all EVIs; all points of attachment of a
given EVI use the same broadcast domain identifier(s) and no other
EVI uses these broadcast domain identifier(s). This allows the RT(s)
for each EVI to be derived automatically, as described in section
9.4.1.1.1 "Auto-Derivation from the Ethernet Tag ID".
The following subsections discuss the relationship between Ethernet
Tags, EVIs and broadcast domain identifiers as well as the setting of
the Ethernet Tag Identifier, in the various E-VPN BGP routes (defined
in section 8), for the different types of service interfaces
described in [EVPN-REQ].
7.1 VLAN Based Service Interface
With this service interface, there is a one-to-one mapping between
the broadcast domain identifier understood by a CE on a port (e.g.
CE-VID) and an EVI. Furthermore, there is a single bridge domain per
PE for the EVI. Different CEs connected to different PE ports MAY use
different broadcast domain identifiers (e.g. CE-VIDs) for the same
EVI. If said identifiers are different, the frames SHOULD remain
tagged with the originating CE's broadcast domain identifier (e.g.
CE-VID). When the CE broadcast domain identifiers are not consistent,
a tag translation function MUST be supported in the data path and
MUST be performed on the disposition PE. The Ethernet Tag Identifier
in all E-VPN routes MUST be set to 0.
7.2 VLAN Bundle Service Interface
Sajassi, et al. Expires August 25, 2013 [Page 9]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
With this service interface, there is a many-to-one mapping between
the broadcast domain identifier understood by a CE on a port (e.g.
CE-VID) and an EVI. Furthermore, there is a single bridge domain per
PE for the EVI. Different CEs connected to different PE ports MUST
use the same broadcast domain identifiers (e.g. CE-VIDs) for the same
EVI. The MPLS encapsulated frames MUST remain tagged with the
originating CE's broadcast domain identifier (e.g. CE-VID). Tag
translation is NOT permitted. The Ethernet Tag Identifier in all E-
VPN routes MUST be set to 0.
7.2.1 Port Based Service Interface
This service interface is a special case of the VLAN Bundle service
interface, where all of the VLANs on the port are part of the same
service and map to the same bundle. The procedures are identical to
those described in section 7.2.
7.3 VLAN Aware Bundle Service Interface
With this service interface, there is a many-to-one mapping between
the broadcast domain identifier understood by a CE on a port (e.g.
CE-VID) and an EVI. Furthermore, there are multiple bridge domains
per PE for the EVI: one broadcast domain per CE broadcast domain
identifier. In the case where the CE broadcast domain identifiers are
not consistent for different CEs, a normalized Ethernet Tag MUST be
carried in the MPLS encapsulated frames and a tag translation
function MUST be supported in the data path. This translation MUST be
performed on both the imposition as well as the disposition PEs. The
Ethernet Tag Identifier in all E-VPN routes MUST be set to the
normalized Ethernet Tag assigned by the E-VPN provider.
7.3.1 Port Based VLAN Aware Service Interface
This service interface is a special case of the VLAN Aware Bundle
service interface, where all of the VLANs on the port are part of the
same service and map to the same bundle. The procedures are identical
to those described in section 7.3.
8. BGP E-VPN NLRI
This document defines a new BGP NLRI, called the E-VPN NLRI.
Following is the format of the E-VPN NLRI:
Sajassi, et al. Expires August 25, 2013 [Page 10]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
+-----------------------------------+
| Route Type (1 octet) |
+-----------------------------------+
| Length (1 octet) |
+-----------------------------------+
| Route Type specific (variable) |
+-----------------------------------+
The Route Type field defines encoding of the rest of the E-VPN NLRI
(Route Type specific E-VPN NLRI).
The Length field indicates the length in octets of the Route Type
specific field of E-VPN NLRI.
This document defines the following Route Types:
+ 1 - Ethernet Auto-Discovery (A-D) route
+ 2 - MAC advertisement route
+ 3 - Inclusive Multicast Route
+ 4 - Ethernet Segment Route
The detailed encoding and procedures for these route types are
described in subsequent sections.
The E-VPN NLRI is carried in BGP [RFC4271] using BGP Multiprotocol
Extensions [RFC4760] with an AFI of 25 (L2VPN) and a SAFI of 70 (E-
VPN). The NLRI field in the MP_REACH_NLRI/MP_UNREACH_NLRI attribute
contains the E-VPN NLRI (encoded as specified above).
In order for two BGP speakers to exchange labeled E-VPN NLRI, they
must use BGP Capabilities Advertisement to ensure that they both are
capable of properly processing such NLRI. This is done as specified
in [RFC4760], by using capability code 1 (multiprotocol BGP) with an
AFI of 25 (L2VPN) and a SAFI of 70 (E-VPN).
8.1. Ethernet Auto-Discovery Route
A Ethernet A-D route type specific E-VPN NLRI consists of the
following:
Sajassi, et al. Expires August 25, 2013 [Page 11]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
+---------------------------------------+
| RD (8 octets) |
+---------------------------------------+
|Ethernet Segment Identifier (10 octets)|
+---------------------------------------+
| Ethernet Tag ID (4 octets) |
+---------------------------------------+
| MPLS Label (3 octets) |
+---------------------------------------+
For procedures and usage of this route please see section 9.2 "Fast
Convergence" and section 9.4 "Aliasing".
8.2. MAC Advertisement Route
A MAC advertisement route type specific E-VPN NLRI consists of the
following:
+---------------------------------------+
| RD (8 octets) |
+---------------------------------------+
|Ethernet Segment Identifier (10 octets)|
+---------------------------------------+
| Ethernet Tag ID (4 octets) |
+---------------------------------------+
| MAC Address Length (1 octet) |
+---------------------------------------+
| MAC Address (6 octets) |
+---------------------------------------+
| IP Address Length (1 octet) |
+---------------------------------------+
| IP Address (4 or 16 octets) |
+---------------------------------------+
| MPLS Label (3 octets) |
+---------------------------------------+
For the purpose of BGP route key processing, only the Ethernet Tag
ID, MAC Address Length, MAC Address, IP Address Length, and IP
Address Address fields are considered to be part of the prefix in the
NLRI. The Ethernet Segment Identifier and MPLS Label fields are to be
treated as route attributes as opposed to being part of the "route".
For procedures and usage of this route please see section 10
"Determining Reachability to Unicast MAC Addresses" and section 15
"Load Balancing of Unicast Packets".
8.3. Inclusive Multicast Ethernet Tag Route
Sajassi, et al. Expires August 25, 2013 [Page 12]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
An Inclusive Multicast Ethernet Tag route type specific E-VPN NLRI
consists of the following:
+---------------------------------------+
| RD (8 octets) |
+---------------------------------------+
| Ethernet Tag ID (4 octets) |
+---------------------------------------+
| IP Address Length (1 octet) |
+---------------------------------------+
| Originating Router's IP Addr |
| (4 or 16 octets) |
+---------------------------------------+
For procedures and usage of this route please see section 12
"Handling of Multi-Destination Traffic", section 13 "Processing of
Unknown Unicast Traffic" and section 17 "Multicast".
8.4 Ethernet Segment Route
The Ethernet Segment Route is encoded in the E-VPN NLRI using the
Route Type value of 4. The Route Type Specific field of the NLRI is
formatted as follows:
+---------------------------------------+
| RD (8 octets) |
+---------------------------------------+
|Ethernet Segment Identifier (10 octets)|
+---------------------------------------+
For procedures and usage of this route please see section 9.5
"Designated Forwarder Election".
8.5 ESI Label Extended Community
This extended community is a new transitive extended community with
the Type field is 0x06, and the Sub-Type of 0x01. It may be
advertised along with Ethernet Auto-Discovery routes and it enables
split-horizon procedures for multi-homed sites as described in
section 9.3 "Split Horizon".
Each ESI Label Extended Community is encoded as a 8-octet value as
follows:
Sajassi, et al. Expires August 25, 2013 [Page 13]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
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=0x01 | Flags (One Octet) |Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved = 0| ESI Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The low order bit of the flags octet is defined as the "Active-
Standby" bit and may be set to 1. A value of 0 means that the multi-
homed site is operating in All-Active mode; whereas, a value of 1
means that the multi-homed site is operating in Single-Active mode.
The second low order bit of the flags octet is defined as the "Root-
Leaf". A value of 0 means that this label is associated with a Root
site; whereas, a value of 1 means that this label is associate with a
Leaf site. The other bits must be set to 0.
8.6 ES-Import Route Target
This is a new transitive Route Target extended community carried with
the Ethernet Segment route. When used, it enables all the PEs
connected to the same multi-homed site to import the Ethernet Segment
routes. The value is derived automatically from the ESI by encoding
the 6-byte MAC address portion of the ESI in the ES-Import Route
Target. The format of this extended community is as follows:
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=0x02 | ES-Import |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ES-Import Cont'd |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This document expands the definition of the Route Target extended
community to allow the value of high order octet (Type field) to be
0x06 (in addition to the values specified in rfc4360). The value of
low order octet (Sub-Type field) of 0x02 indicates that this extended
community is of type "Route Target". The new value for Type field of
0x06 indicates that the structure of this RT is a six bytes value
(e.g., a MAC address). A BGP speaker that implements RT-Constrain
(RFC4684) MUST apply the RT-Constrain procedures to the ES-import RT
as-well.
For procedures and usage of this attribute, please see section 9.1
"Redundancy Group Discovery".
8.7 MAC Mobility Extended Community
Sajassi, et al. Expires August 25, 2013 [Page 14]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
This extended community is a new transitive extended community with
the Type field of 0x06 and the Sub-Type of 0x00. It may be advertised
along with MAC Advertisement routes. The procedures for using this
Extended Community are described in section 16 "MAC Mobility".
The MAC Mobility Extended Community is encoded as a 8-octet value as
follows:
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=0x00 | Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8.8 Default Gateway Extended Community
The Default Gateway community is an Extended Community of an Opaque
Type (see 3.3 of rfc4360). It is a transitive community, which means
that the first octet is 0x03. The value of the second octet (Sub-
Type) is 0x030d (Default Gateway) as defined by IANA. The Value field
of this community is reserved (set to 0 by the senders, ignored by
the receivers).
9. Multi-homing Functions
This section discusses the functions, procedures and associated BGP
routes used to support multi-homing in E-VPN. This covers both multi-
homed device (MHD) as well as multi-homed network (MHN) scenarios.
9.1 Multi-homed Ethernet Segment Auto-Discovery
PEs connected to the same Ethernet segment can automatically discover
each other with minimal to no configuration through the exchange of
the Ethernet Segment route.
9.1.1 Constructing the Ethernet Segment Route
The Route-Distinguisher (RD) MUST be a Type 1 RD [RFC4364]. The value
field comprises an IP address of the MES (typically, the loopback
address) followed by 0's.
The Ethernet Segment Identifier MUST be set to the ten octet ESI
identifier described in section 6.
The BGP advertisement that advertises the Ethernet Segment route MUST
also carry an ES-Import extended community attribute, as defined in
Sajassi, et al. Expires August 25, 2013 [Page 15]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
section 8.6.
The Ethernet Segment Route filtering MUST be done such that the
Ethernet Segment Route is imported only by the PEs that are multi-
homed to the same Ethernet Segment. To that end, each PE that is
connected to a particular Ethernet segment constructs an import
filtering rule to import a route that carries the ES-Import extended
community, constructed from the ESI.
Note that the new ES-Import extended community is not the same as the
Route Target Extended Community. The Ethernet Segment route carries
this new ES-Import extended community. The PEs apply filtering on
this new extended community. As a result the Ethernet Segment route
is imported only by the PEs that are connected to the same Ethernet
segment.
9.2 Fast Convergence
In E-VPN, MAC address reachability is learnt via the BGP control-
plane over the MPLS network. As such, in the absence of any fast
protection mechanism, the network convergence time is a function of
the number of MAC Advertisement routes that must be withdrawn by the
PE encountering a failure. For highly scaled environments, this
scheme yields slow convergence.
To alleviate this, E-VPN defines a mechanism to efficiently and
quickly signal, to remote PE nodes, the need to update their
forwarding tables upon the occurrence of a failure in connectivity to
an Ethernet segment. This is done by having each PE advertise an
Ethernet A-D Route per Ethernet segment for each locally attached
segment (refer to section 9.2.1 below for details on how this route
is constructed). Upon a failure in connectivity to the attached
segment, the PE withdraws the corresponding Ethernet A-D route. This
triggers all PEs that receive the withdrawal to update their next-hop
adjacencies for all MAC addresses associated with the Ethernet
segment in question. If no other PE had advertised an Ethernet A-D
route for the same segment, then the PE that received the withdrawal
simply invalidates the MAC entries for that segment. Otherwise, the
PE updates the next-hop adjacencies to point to the backup PE(s).
9.2.1 Constructing the Ethernet A-D Route per Ethernet Segment
This section describes procedures to construct the Ethernet A-D route
when a single such route is advertised by an PE for a given Ethernet
Segment. This flavor of the Ethernet A-D route is used for fast
convergence (as discussed above) as well as for advertising the ESI
label used for split-horizon filtering (as discussed in section 9.3).
Support of this route flavor is MANDATORY.
Sajassi, et al. Expires August 25, 2013 [Page 16]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
Route-Distinguisher (RD) MUST be a Type 1 RD [RFC4364]. The value
field comprises an IP address of the PE (typically, the loopback
address) followed by 0.
The Ethernet Segment Identifier MUST be a ten octet entity as
described in section "Ethernet Segment". This document does not
specify the use of the Ethernet A-D route when the Segment Identifier
is set to 0.
The Ethernet Tag ID MUST be set to 0.
The MPLS label in the NLRI MUST be set to 0.
The "ESI Label Extended Community" MUST be included in the route. If
all-Active multi-homing is desired, then the "Active-Standby" bit in
the flags of the ESI Label Extended Community MUST be set to 0 and
the MPLS label in that extended community MUST be set to a valid MPLS
label value. The MPLS label in this Extended Community is referred to
as an "ESI label". This label MUST be a downstream assigned MPLS
label if the advertising PE is using ingress replication for
receiving multicast, broadcast or unknown unicast traffic from other
PEs. If the advertising PE is using P2MP MPLS LSPs for sending
multicast, broadcast or unknown unicast traffic, then this label MUST
be an upstream assigned MPLS label. The usage of this label is
described in section 9.3.
If the Ethernet Segment is connected to more than one PE and Single-
Active multi-homing is desired, then the "Active-Standby" bit in the
flags of the ESI Label Extended Community MUST be set to 1 and ESI
label MUST be set to zero.
9.2.1.1. Ethernet A-D Route Targets
The Ethernet A-D route MUST carry one or more Route Target (RT)
attributes. These RTs MUST be the set of RTs associated with all the
EVIs to which the Ethernet Segment, corresponding to the Ethernet A-D
route, belongs.
9.3 Split Horizon
Consider a CE that is multi-homed to two or more PEs on an Ethernet
segment ES1 operating in All-Active mode. If the CE sends a
broadcast, unknown unicast, or multicast (BUM) packet to one of the
non-DF (Designated Forwarder) PEs, say PE1, then PE1 will forward
that packet to all or subset of the other PEs in the EVI including
the DF PE for that Ethernet segment. In this case the DF PE that the
CE is multi-homed to MUST drop the packet and not forward back to the
CE. This filtering is referred to as "split horizon" filtering in
Sajassi, et al. Expires August 25, 2013 [Page 17]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
this document.
In order to achieve this split horizon function, every BUM packet
originating from a non-DF PE is encapsulated with an MPLS label that
identifies the Ethernet segment of origin (i.e. the segment from
which the frame entered the E-VPN network). This label is referred to
as the ESI label, and MUST be distributed by all PEs when operating
in All-Active multi-homing mode using the "Ethernet A-D route per
Ethernet Segment" as per the procedures in section 9.2.1 above. This
route is imported by the PEs connected to the Ethernet Segment and
also by the PEs that have at least one EVI in common with the
Ethernet Segment in the route. As described in section 9.1.1, the
route MUST carry an ESI Label Extended Community with a valid ESI
label. The disposition DF PE rely on the value of the ESI label to
determine whether or not a BUM frame is allowed to egress a specific
Ethernet segment. It should be noted that if the BUM frame is
originated from the DF PE operating in All-Active multi-homing mode,
then the DF PE MAY not encapsulate the frame with the ESI label.
Furthermore, if the multi-homed PEs operate in active/standby mode,
then the packet MUST not be encapsulated with the ESI label and the
label value MUST be set to zero in ESI Label Extended Community per
section 9.2.1 above.
9.3.1 ESI Label Assignment
The following subsections describe the assignment procedures for the
ESI label, which differ depending on the type of tunnels being used
to deliver multi-destination packets in the E-VPN network.
9.3.1.1 Ingress Replication
All PEs operating in an All-Active multi-homing mode that rely on
ingress replication for the reception of BUM traffic, distribute to
other PEs, that belong to the Ethernet segment, a downstream assigned
"ESI label" in the Ethernet A-D route per ESI. This label MUST be
programmed in the platform label space by the advertising PE. Further
the forwarding entry for this label must result in NOT forwarding
packets received with this label onto the Ethernet segment that the
label was distributed for.
Consider PE1 and PE2 that are multi-homed to CE1 on ES1 and operating
in All-Active multi-homing mode. Further consider that PE1 is using
P2P or MP2P LSPs to send packets to PE2. Consider that PE1 is the
non-DF for VLAN1 and PE2 is the DF for VLAN1, and PE1 receives a BUM
packet from CE1 on VLAN1 on ES1. In this scenario, PE2 distributes an
Inclusive Multicast Ethernet Tag route for VLAN1 in the associated
EVI. So, when PE1 sends a BUM packet, that it receives from CE1, it
MUST first push onto the MPLS label stack the ESI label that PE2 has
Sajassi, et al. Expires August 25, 2013 [Page 18]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
distributed for ES1. It MUST then push on the MPLS label distributed
by PE2 in the Inclusive Multicast Ethernet Tag route for VLAN1. The
resulting packet is further encapsulated in the P2P or MP2P LSP label
stack required to transmit the packet to PE2. When PE2 receives this
packet, it determines the set of ESIs to replicate the packet to from
the top MPLS label, after any P2P or MP2P LSP labels have been
removed. If the next label is the ESI label assigned by PE2 for ES1,
then PE2 MUST NOT forward the packet onto ES1. If the next label is
an ESI label which has not been assigned by PE2, then PE2 MUST drop
the packet. It should be noted that in this scenario, if PE2 receives
a BUM traffic for VLAN1 from CE1, then it doesn't need to encapsulate
the packet with an ESI label when sending it to the PE1 since PE1 can
use its DF logic to filter the BUM packets and thus doesn't need to
use split-horizon filtering for ES1.
9.3.1.2. P2MP MPLS LSPs
The non-DF PEs operating in an All-Active multi-homing mode that is
using P2MP LSPs for sending BUM traffic, distribute to other PEs,
that belong to the Ethernet segment or have an E-VPN in common with
the Ethernet Segment, an upstream assigned "ESI label" in the
Ethernet A-D route. This label is upstream assigned by the PE that
advertises the route. This label MUST be programmed by the other PEs,
that are connected to the ESI advertised in the route, in the context
label space for the advertising PE. Further the forwarding entry for
this label must result in NOT forwarding packets received with this
label onto the Ethernet segment that the label was distributed for.
This label MUST also be programmed by the other PEs, that import the
route but are not connected to the ESI advertised in the route, in
the context label space for the advertising PE. Further the
forwarding entry for this label must be a POP with no other
associated action.
Consider PE1 and PE2 that are multi-homed to CE1 on ES1 and operating
in All-Active multi-homing mode. Also consider PE3 that is in the
same EVI as one of the EVIs to which ES1 belongs. Further, assume
that PE1 which is the non-DF, using P2MP MPLS LSPs to send BUM
packets. When PE1 sends a BUM packet, that it receives from CE1, it
MUST first push onto the MPLS label stack the ESI label that it has
assigned for the ESI that the packet was received on. The resulting
packet is further encapsulated in the P2MP MPLS label stack necessary
to transmit the packet to the other PEs. Penultimate hop popping MUST
be disabled on the P2MP LSPs used in the MPLS transport
infrastructure for E-VPN. When PE2 receives this packet, it de-
capsulates the top MPLS label and forwards the packet using the
context label space determined by the top label. If the next label is
the ESI label assigned by PE1 to ES1, then PE2 MUST NOT forward the
packet onto ES1. When PE3 receives this packet, it de-capsulates the
Sajassi, et al. Expires August 25, 2013 [Page 19]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
top MPLS label and forwards the packet using the context label space
determined by the top label. If the next label is the ESI label
assigned by PE1 to ES1 and PE3 is not connected to ES1, then PE3 MUST
pop the label and flood the packet over all local ESIs in the EVI. It
should be noted that when PE2 sends a BUM frame over a P2MP LSP, it
does not need to encapsulate the frame with an ESI label because it
is the DF for that VLAN.
9.3.1.3. MP2MP LSPs
The procedures for ESI Label assignment and usage for MP2MP LSPs will
be described in a future version.
9.4 Aliasing and Backup-Path
In the case where a CE is multi-homed to multiple PE nodes, using a
LAG with All-Active redundancy, it is possible that only a single PE
learns a set of the MAC addresses associated with traffic transmitted
by the CE. This leads to a situation where remote PE nodes receive
MAC advertisement routes, for these addresses, from a single PE even
though multiple PEs are connected to the multi-homed segment. As a
result, the remote PEs are not able to effectively load-balance
traffic among the PE nodes connected to the multi-homed Ethernet
segment. This could be the case, for e.g. when the PEs perform data-
path learning on the access, and the load-balancing function on the
CE hashes traffic from a given source MAC address to a single PE.
Another scenario where this occurs is when the PEs rely on control
plane learning on the access (e.g. using ARP), since ARP traffic will
be hashed to a single link in the LAG.
To alleviate this issue, E-VPN introduces the concept of 'Aliasing'.
Aliasing refers to the ability of a PE to signal that it has
reachability to a given locally attached Ethernet segment, even when
it has learnt no MAC addresses from that segment. The Ethernet A-D
route per EVI is used to that end. Remote PEs which receive MAC
advertisement routes with non-reserved ESI SHOULD consider the
advertised MAC address as reachable via all PEs which have advertised
reachability to the relevant Segment using: (1) Ethernet A-D routes
per EVI with the same ESI (and Ethernet Tag if applicable) AND
(2)Ethernet A-D routes per ESI with the same ESI and with the
Active/Standby bit set to 0 in the ESI Label Extended Community.
This flavor of Ethernet A-D route per EVI, associated with aliasing,
can arrive at target PEs asynchronously relative to the flavor of
Ethernet A-D route associated with split-horizon and mass-withdraw
(i.e. per ESI). Therefore, if the Ethernet A-D route per EVI arrives
ahead of the Ethernet A-D route per ESI, then the former must NOT be
used for traffic forwarding till the latter arrives. This will take
Sajassi, et al. Expires August 25, 2013 [Page 20]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
care of corner cases and race conditions where the Ethernet A-D route
associated with mass-withdraw is withdrawn but a PE still receives
the route associated with aliasing.
Backup-Path is a closely related function, albeit it applies to the
case where the redundancy mode is Active/Standby. In this case, the
PE advertises that it has reachability to a given locally attached
Ethernet Segment using the Ethernet A-D route as well. Remote PEs
which receive the MAC advertisement routes, with non-reserved ESI,
MUST consider the MAC address as reachable via the advertising PE.
Furthermore, the remote PEs SHOULD install a Backup-Path, for said
MAC, to the PE which had advertised reachability to the relevant
Segment using (1) an Ethernet A-D routes per EVI with the same ESI
(and Ethernet Tag if applicable) AND (2)Ethernet A-D routes per ESI
with the same ESI and with the Active/Standby bit set to 1 in the ESI
Label Extended Community.
9.4.1 Constructing the Ethernet A-D Route per EVI
This section describes procedures to construct the Ethernet A-D route
when one or more such routes are advertised by an PE for a given EVI.
This flavor of the Ethernet A-D route is used for aliasing, and
support of this route flavor is OPTIONAL.
Route-Distinguisher (RD) MUST be set to the RD of the EVI that is
advertising the NLRI. An RD MUST be assigned for a given EVI on an
PE. This RD MUST be unique across all EVIs on an PE. It is
RECOMMENDED to use the Type 1 RD [RFC4364]. The value field comprises
an IP address of the PE (typically, the loopback address) followed by
a number unique to the PE. This number may be generated by the PE.
Or in the Unique VLAN E-VPN case, the low order 12 bits may be the 12
bit VLAN ID, with the remaining high order 4 bits set to 0.
The Ethernet Segment Identifier MUST be a ten octet entity as
described in section "Ethernet Segment Identifier". This document
does not specify the use of the Ethernet A-D route when the Segment
Identifier is set to 0.
The Ethernet Tag ID is the identifier of an Ethernet Tag on the
Ethernet segment. This value may be a 12 bit VLAN ID, in which case
the low order 12 bits are set to the VLAN ID and the high order 20
bits are set to 0. Or it may be another Ethernet Tag used by the E-
VPN. It MAY be set to the default Ethernet Tag on the Ethernet
segment or to the value 0.
Note that the above allows the Ethernet A-D route to be advertised
with one of the following granularities:
Sajassi, et al. Expires August 25, 2013 [Page 21]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
+ One Ethernet A-D route for a given <ESI, Ethernet Tag ID> tuple
per EVI. This is applicable when the PE uses MPLS-based
disposition.
+ One Ethernet A-D route per <ESI, EVI> (where the Ethernet
Tag ID is set to 0). This is applicable when the PE uses
MAC-based disposition, or when the PE uses MPLS-based
disposition when no VLAN translation is required.
The usage of the MPLS label is described in the section on "Load
Balancing of Unicast Packets".
The Next Hop field of the MP_REACH_NLRI attribute of the route MUST
be set to the IPv4 or IPv6 address of the advertising PE.
9.4.1.1 Ethernet A-D Route Targets
The Ethernet A-D route MUST carry one or more Route Target (RT)
attributes. RTs may be configured (as in IP VPNs), or may be derived
automatically.
If an PE uses Route Target Constrain [RT-CONSTRAIN], the PE SHOULD
advertise all such RTs using Route Target Constrains. The use of RT
Constrains allows each Ethernet A-D route to reach only those PEs
that are configured to import at least one RT from the set of RTs
carried in the Ethernet A-D route.
9.4.1.1.1 Auto-Derivation from the Ethernet Tag ID
The following is the procedure for deriving the RT attribute
automatically from the Ethernet Tag ID associated with the
advertisement:
+ The Global Administrator field of the RT MUST
be set to the Autonomous System (AS) number that the PE
belongs to.
+ The Local Administrator field of the RT contains a 4
octets long number that encodes the Ethernet Tag-ID. If the
Ethernet Tag-ID is a two octet VLAN ID then it MUST be
encoded in the lower two octets of the Local Administrator
field and the higher two octets MUST be set to zero.
For the "Unique VLAN E-VPN" this results in auto-deriving the RT from
the Ethernet Tag, e.g., VLAN ID for that E-VPN.
9.5 Designated Forwarder Election
Sajassi, et al. Expires August 25, 2013 [Page 22]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
Consider a CE that is a host or a router that is multi-homed directly
to more than one PE in an E-VPN on a given Ethernet segment. One or
more Ethernet Tags may be configured on the Ethernet segment. In this
scenario only one of the PEs, referred to as the Designated Forwarder
(DF), is responsible for certain actions:
- Sending multicast and broadcast traffic, on a given Ethernet
Tag on a particular Ethernet segment, to the CE.
- Flooding unknown unicast traffic (i.e. traffic for
which an PE does not know the destination MAC address),
on a given Ethernet Tag on a particular Ethernet segment
to the CE, if the environment requires flooding of
unknown unicast traffic.
Note that this behavior, which allows selecting a DF at the
granularity of <ESI, EVI> for multicast, broadcast and unknown
unicast traffic, is the default behavior in this specification.
Optional mechanisms, which will be specified in the future, will
allow selecting a DF at the granularity of <ESI, EVI, S, G>.
Note that a CE always sends packets belonging to a specific flow
using a single link towards an PE. For instance, if the CE is a host
then, as mentioned earlier, the host treats the multiple links that
it uses to reach the PEs as a Link Aggregation Group (LAG). The CE
employs a local hashing function to map traffic flows onto links in
the LAG.
If a bridged network is multi-homed to more than one PE in an E-VPN
via switches, then the support of All-Active points of attachments,
as described in this specification, requires the bridge network to be
connected to two or more PEs using a LAG. In this case the reasons
for doing DF election are the same as those described above when a CE
is a host or a router.
If a bridged network does not connect to the PEs using LAG, then only
one of the links between the switched bridged network and the PEs
must be the active link for a given Ethernet Tag. In this case, the
Ethernet A-D route per Ethernet segment MUST be advertised with the
"Active-Standby" flag set to one. Procedures for supporting All-
Active points of attachments, when a bridge network connects to the
PEs using LAG, are for further study.
The default procedure for DF election at the granularity of <ESI,
EVI> is referred to as "service carving". With service carving, it is
possible to elect multiple DFs per Ethernet Segment (one per EVI) in
order to perform load-balancing of multi-destination traffic destined
to a given Segment. The load-balancing procedures carve up the EVI
space among the PE nodes evenly, in such a way that every PE is the
Sajassi, et al. Expires August 25, 2013 [Page 23]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
DF for a disjoint set of EVIs. The procedure for service carving is
as follows:
1. When a PE discovers the ESI of the attached Ethernet Segment, it
advertises an Ethernet Segment route with the associated ES-Import
extended community attribute.
2. The PE then starts a timer (default value = 3 seconds) to allow
the reception of Ethernet Segment routes from other PE nodes
connected to the same Ethernet Segment. This timer value MUST be same
across all PEs connected to the same Ethernet Segment.
3. When the timer expires, each PE builds an ordered list of the IP
addresses of all the PE nodes connected to the Ethernet Segment
(including itself), in increasing numeric value. Every PE is then
given an ordinal indicating its position in the ordered list,
starting with 0 as the ordinal for the PE with the numerically lowest
IP address. The ordinals are used to determine which PE node will be
the DF for a given EVI on the Ethernet Segment using the following
rule: Assuming a redundancy group of N PE nodes, the PE with ordinal
i is the DF for an EVI with an associated Ethernet Tag value V when
(V mod N) = i. In the case where multiple Ethernet Tags are
associated with a single EVI, then the numerically lowest Ethernet
Tag value in that EVI MUST be used in the modulo function.
4. The PE that is elected as a DF for a given EVI will unblock
traffic for the Ethernet Tags associated with that EVI. Note that the
DF PE unblocks multi-destination traffic in the egress direction
towards the Segment. All non-DF PEs continue to drop multi-
destination traffic (for the associated EVIs) in the egress direction
towards the Segment.
In the case of link or port failure, the affected PE withdraws its
Ethernet Segment route. This will re-trigger the service carving
procedures on all the PEs in the RG. For PE node failure, or upon PE
commissioning or decommissioning, the PEs re-trigger the service
carving. In case of a Single-Active multi-homing, when a service
moves from one PE in the RG to another PE as a result of re-carving,
the PE, which ends up being the elected DF for the service, must
trigger a MAC address flush notification towards the associated
Ethernet Segment. This can be done, for e.g. using IEEE 802.1ak MVRP
'new' declaration.
10. Determining Reachability to Unicast MAC Addresses
PEs forward packets that they receive based on the destination MAC
address. This implies that PEs must be able to learn how to reach a
given destination unicast MAC address.
Sajassi, et al. Expires August 25, 2013 [Page 24]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
There are two components to MAC address learning, "local learning"
and "remote learning":
10.1. Local Learning
A particular PE must be able to learn the MAC addresses from the CEs
that are connected to it. This is referred to as local learning.
The PEs in a particular E-VPN MUST support local data plane learning
using standard IEEE Ethernet learning procedures. An PE must be
capable of learning MAC addresses in the data plane when it receives
packets such as the following from the CE network:
- DHCP requests
- ARP request for its own MAC.
- ARP request for a peer.
Alternatively PEs MAY learn the MAC addresses of the CEs in the
control plane or via management plane integration between the PEs and
the CEs.
There are applications where a MAC address that is reachable via a
given PE on a locally attached Segment (e.g. with ESI X) may move
such that it becomes reachable via another PE on another Segment
(e.g. with ESI Y). This is referred to as a "MAC Mobility".
Procedures to support this are described in section "MAC Mobility".
10.2. Remote learning
A particular PE must be able to determine how to send traffic to MAC
addresses that belong to or are behind CEs connected to other PEs
i.e. to remote CEs or hosts behind remote CEs. We call such MAC
addresses as "remote" MAC addresses.
This document requires an PE to learn remote MAC addresses in the
control plane. In order to achieve this, each PE advertises the MAC
addresses it learns from its locally attached CEs in the control
plane, to all the other PEs in the EVI, using MP-BGP and specifically
the MAC Advertisement route.
10.2.1. Constructing the BGP E-VPN MAC Address Advertisement
BGP is extended to advertise these MAC addresses using the MAC
Advertisement route type in the E-VPN NLRI.
The RD MUST be the RD of the EVI that is advertising the NLRI. The
Sajassi, et al. Expires August 25, 2013 [Page 25]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
procedures for setting the RD for a given EVI are described in
section 9.4.1.
The Ethernet Segment Identifier is set to the ten octet ESI described
in section "Ethernet Segment".
The Ethernet Tag ID may be zero or may represent a valid Ethernet Tag
ID. This field may be non-zero when there are multiple bridge
domains in the EVI (e.g., the PE needs to perform qualified learning
for the VLANs in that EVI).
When the the Ethernet Tag ID in the NLRI is set to a non-zero value,
for a particular bridge domain, then this Ethernet Tag may either be
the Ethernet tag value associated with the CE, e.g., VLAN ID, or it
may be the Ethernet Tag Identifier, e.g., VLAN ID assigned by the E-
VPN provider and mapped to the CE's Ethernet tag. The latter would be
the case if the CE Ethernet tags, e.g., VLAN ID, for a particular
bridge domain are different on different CEs.
The MAC address length field is typically set to 48. However this
specification enables specifying the MAC address as a prefix; in
which case, the MAC address length field is set to the length of the
prefix. This provides the ability to aggregate MAC addresses if the
deployment environment supports that. The encoding of a MAC address
MUST be the 6-octet MAC address specified by [802.1D-ORIG] [802.1D-
REV]. If the MAC address is advertised as a prefix then the trailing
bits of the prefix MUST be set to 0 to ensure that the entire prefix
is encoded as 6 octets.
The IP Address Length field value is set to the number of octets in
the IP Address field.
The IP Address field is optional. By default, the IP Address Length
field is set to 0 and the IP address field is omitted from the route.
When a valid IP address needs to be advertised (e.g., for ARP
suppression purposes or for inter-subnet switching), it is then
encoded in this route.
The MPLS label field carries one or more labels (that corresponds to
the stack of labels [MPLS-ENCAPS]). Each label is encoded as 3
octets, where the high-order 20 bits contain the label value, and the
low order bit contains "Bottom of Stack" (as defined in [MPLS-
ENCAPS]). The MPLS label stack MUST be the downstream assigned E-VPN
MPLS label stack that is used by the PE to forward MPLS-encapsulated
Ethernet frames received from remote PEs, where the destination MAC
address in the Ethernet frame is the MAC address advertised in the
above NLRI. The forwarding procedures are specified in section
"Forwarding Unicast Packets" and "Load Balancing of Unicast Packets".
Sajassi, et al. Expires August 25, 2013 [Page 26]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
An PE may advertise the same single E-VPN label for all MAC addresses
in a given EVI. This label assignment methodology is referred to as a
per EVI label assignment. Alternatively, an PE may advertise a unique
E-VPN label per <ESI, Ethernet Tag> combination. This label
assignment methodology is referred to as a per <ESI, Ethernet Tag>
label assignment. As a third option, an PE may advertise a unique E-
VPN label per MAC address. All of these methodologies have their
tradeoffs.
Per EVI label assignment requires the least number of E-VPN labels,
but requires a MAC lookup in addition to an MPLS lookup on an egress
PE for forwarding. On the other hand, a unique label per <ESI,
Ethernet Tag> or a unique label per MAC allows an egress PE to
forward a packet that it receives from another PE, to the connected
CE, after looking up only the MPLS labels without having to perform a
MAC lookup. This includes the capability to perform appropriate VLAN
ID translation on egress to the CE.
The Next Hop field of the MP_REACH_NLRI attribute of the route MUST
be set to the IPv4 or IPv6 address of the advertising PE.
The BGP advertisement for the MAC advertisement route MUST also carry
one or more Route Target (RT) attributes. RTs may be configured (as
in IP VPNs), or may be derived automatically from the Ethernet Tag
ID, in the Unique VLAN case, as described in section "Ethernet A-D
Route per E-VPN".
It is to be noted that this document does not require PEs to create
forwarding state for remote MACs when they are learnt in the control
plane. When this forwarding state is actually created is a local
implementation matter.
10.2.2 Route Resolution
If the Ethernet Segment Identifier field in a received MAC
Advertisement route is set to the reserved ESI value of 0 or MAX-ESI,
then the receiving PE MUST install forwarding state for the
associated MAC Address based on the MAC Advertisement route alone.
If the Ethernet Segment Identifier field in a received MAC
Advertisement route is set to a non-reserved ESI, and the receiving
PE is locally attached to the same ESI, then the PE does not alter
its forwarding state based on the received route. This ensures that
local routes are preferred to remote routes.
If the Ethernet Segment Identifier field in a received MAC
Advertisement route is set to a non-reserved ESI, then the receiving
PE MUST install forwarding state for a given MAC address only when
Sajassi, et al. Expires August 25, 2013 [Page 27]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
both the MAC Advertisement route AND the associated Ethernet A-D
route per ESI have been received.
To illustrate this with an example, consider two PEs (PE1 and PE2)
connected to a multi-homed Ethernet Segment ES1. All-Active
redundancy mode is assumed. A given MAC address M1 is learnt by PE1
but not PE2. On PE3, the following states may arise:
T1- When the MAC Advertisement Route from PE1 and the Ethernet A-D
routes per ESI from PE1 and PE2 are received, PE3 can forward traffic
destined to M1 to both PE1 and PE2.
T2- If after T1, PE1 withdraws its Ethernet A-D route per ESI, then
PE3 forwards traffic destined to M1 to PE2 only.
T3- If after T1, PE2 withdraws its Ethernet A-D route per ESI, then
PE3 forwards traffic destined to M1 to PE1 only.
T4- If after T1, PE1 withdraws its MAC Advertisement route, then PE3
treats traffic to M1 as unknown unicast. Note, here, that had PE2
also advertised a MAC route for M1 before PE1 withdraws its MAC
route, then PE3 would have continued forwarding traffic destined to
M1 to PE2.
11. ARP and ND
The IP address field in the MAC advertisement route may optionally
carry one of the IP addresses associated with the MAC address. This
provides an option which can be used to minimize the flooding of ARP
or Neighbor Discovery (ND) messages over the MPLS network and to
remote CEs. This option also minimizes ARP (or ND) message processing
on end-stations/hosts connected to the E-VPN network. An PE may learn
the IP address associated with a MAC address in the control or
management plane between the CE and the PE. Or, it may learn this
binding by snooping certain messages to or from a CE. When an PE
learns the IP address associated with a MAC address, of a locally
connected CE, it may advertise this address to other PEs by including
it in the MAC Advertisement route. The IP Address may be an IPv4
address encoded using four octets, or an IPv6 address encoded using
sixteen octets. The IP Address length field MUST be set to 32 for an
IPv4 address or to 128 for an IPv6 address.
If there are multiple IP addresses associated with a MAC address,
then multiple MAC advertisement routes MUST be generated, one for
each IP address. For instance, this may be the case when there are
both an IPv4 and an IPv6 address associated with the MAC address.
When the IP address is dissociated with the MAC address, then the MAC
advertisement route with that particular IP address MUST be
Sajassi, et al. Expires August 25, 2013 [Page 28]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
withdrawn.
When an PE receives an ARP request for an IP address from a CE, and
if the PE has the MAC address binding for that IP address, the PE
SHOULD perform ARP proxy and respond to the ARP request.
11.1 Default Gateway
A PE MAY choose to terminate ARP messages instead of performing ARP
proxy for them. Such scenarios arises when the PE needs to perform
inter-subnet forwarding where each subnet is represented by a
different bridge domain/EVI. In such scenarios the inter-subnet
forwarding is performed at layer 3 and the PE that performs such
function is called the default gateway.
Each PE that acts as a default gateway for a given E-VPN advertises
in the E-VPN control plane its default gateway IP and MAC address
using the MAC advertisement route, and indicates that such route is
associated with the default gateway. This is accomplished by
requiring the route to carry the Default Gateway extended community
defined in [Section 8.8 Default Gateway Extended Community].
Each PE that receives this route and imports it as per procedures
specified in this document follows the procedures in this section
when replying to ARP Requests that it receives if such Requests are
for the IP address in the received E-VPN route.
Each PE that acts as a default gateway for a given E-VPN that
receives this route and imports it as per procedures specified in
this document MUST create MAC forwarding state that enables it to
apply IP forwarding to the packets destined to the MAC address
carried in the route.
12. Handling of Multi-Destination Traffic
Procedures are required for a given PE to send broadcast or multicast
traffic, received from a CE encapsulated in a given Ethernet Tag in
an EVI, to all the other PEs that span that Ethernet Tag in the EVI.
In certain scenarios, described in section "Processing of Unknown
Unicast Packets", a given PE may also need to flood unknown unicast
traffic to other PEs.
The PEs in a particular E-VPN may use ingress replication, P2MP LSPs
or MP2MP LSPs to send unknown unicast, broadcast or multicast traffic
to other PEs.
Each PE MUST advertise an "Inclusive Multicast Ethernet Tag Route" to
Sajassi, et al. Expires August 25, 2013 [Page 29]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
enable the above. The following subsection provides the procedures to
construct the Inclusive Multicast Ethernet Tag route. Subsequent
subsections describe in further detail its usage.
12.1. Construction of the Inclusive Multicast Ethernet Tag Route
The RD MUST be the RD of the EVI that is advertising the NLRI. The
procedures for setting the RD for a given E-VPN are described in
section 9.4.1.
The Ethernet Tag ID is the identifier of the Ethernet Tag. It MAY be
set to 0 or to a valid Ethernet Tag value.
The Originating Router's IP address MUST be set to an IP address of
the PE. This address SHOULD be common for all the EVIs on the PE
(e.,g., this address may be PE's loopback address).
The Next Hop field of the MP_REACH_NLRI attribute of the route MUST
be set to the same IP address as the one carried in the Originating
Router's IP Address field.
The BGP advertisement for the Inclusive Multicast Ethernet Tag route
MUST also carry one or more Route Target (RT) attributes. The
assignment of RTs described in the section on "Constructing the BGP
E-VPN MAC Address Advertisement" MUST be followed.
12.2. P-Tunnel Identification
In order to identify the P-Tunnel used for sending broadcast, unknown
unicast or multicast traffic, the Inclusive Multicast Ethernet Tag
route MUST carry a "PMSI Tunnel Attribute" as specified in [BGP
MVPN].
Depending on the technology used for the P-tunnel for the E-VPN on
the PE, the PMSI Tunnel attribute of the Inclusive Multicast Ethernet
Tag route is constructed as follows.
+ If the PE that originates the advertisement uses a
P-Multicast tree for the P-tunnel for E-VPN, the PMSI
Tunnel attribute MUST contain the identity of the tree
(note that the PE could create the identity of the
tree prior to the actual instantiation of the tree).
+ An PE that uses a P-Multicast tree for the P-tunnel MAY
aggregate two or more Ethernet Tags in the same or different
EVIs present on the PE onto the same tree. In this case, in
addition to carrying the identity of the tree, the PMSI Tunnel
attribute MUST carry an MPLS upstream assigned label which
Sajassi, et al. Expires August 25, 2013 [Page 30]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
the PE has bound uniquely to the Ethernet Tag for the EVI
associated with this update (as determined by its RTs).
If the PE has already advertised Inclusive Multicast
Ethernet Tag routes for two or more Ethernet Tags that it
now desires to aggregate, then the PE MUST re-advertise
those routes. The re-advertised routes MUST be the same
as the original ones, except for the PMSI Tunnel attribute
and the label carried in that attribute.
+ If the PE that originates the advertisement uses ingress
replication for the P-tunnel for E-VPN, the route MUST
include the PMSI Tunnel attribute with the Tunnel Type set to
Ingress Replication and Tunnel Identifier set to a routable
address of the PE. The PMSI Tunnel attribute MUST carry a
downstream assigned MPLS label. This label is used to
demultiplex the broadcast, multicast or unknown unicast E-VPN
traffic received over a MP2P tunnel by the PE.
+ The Leaf Information Required flag of the PMSI Tunnel
attribute MUST be set to zero, and MUST be ignored on receipt.
13. Processing of Unknown Unicast Packets
The procedures in this document do not require the PEs to flood
unknown unicast traffic to other PEs. If PEs learn CE MAC addresses
via a control plane protocol, the PEs can then distribute MAC
addresses via BGP, and all unicast MAC addresses will be learnt prior
to traffic to those destinations.
However, if a destination MAC address of a received packet is not
known by the PE, the PE may have to flood the packet. Flooding must
take into account "split horizon forwarding" as follows: The
principles behind the following procedures are borrowed from the
split horizon forwarding rules in VPLS solutions [RFC4761] and
[RFC4762]. When an PE capable of flooding (say PEx) receives a
broadcast or multicast Ethernet frame, or one with an unknown
destination MAC address, it must flood the frame. If the frame
arrived from an attached CE, PEx must send a copy of the frame to
every other attached CE participating in the EVI, on a different ESI
than the one it received the frame on, as long as the PE is the DF
for the egress ESI. In addition, the PE must flood the frame to all
other PEs participating in the EVI. If, on the other hand, the frame
arrived from another PE (say PEy), PEx must send a copy of the packet
only to attached CEs as long as it is the DF for the egress ESI. PEx
MUST NOT send the frame to other PEs, since PEy would have already
done so. Split horizon forwarding rules apply to broadcast and
multicast packets, as well as packets to an unknown MAC address.
Sajassi, et al. Expires August 25, 2013 [Page 31]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
Whether or not to flood packets to unknown destination MAC addresses
should be an administrative choice, depending on how learning happens
between CEs and PEs.
The PEs in a particular E-VPN may use ingress replication using RSVP-
TE P2P LSPs or LDP MP2P LSPs for sending broadcast, multicast and
unknown unicast traffic to other PEs. Or they may use RSVP-TE P2MP or
LDP P2MP or LDP MP2MP LSPs for sending such traffic to other PEs.
13.1. Ingress Replication
If ingress replication is in use, the P-Tunnel attribute, carried in
the Inclusive Multicast Ethernet Tag routes for the EVI, specifies
the downstream label that the other PEs can use to send unknown
unicast, multicast or broadcast traffic for the EVI to this
particular PE.
The PE that receives a packet with this particular MPLS label MUST
treat the packet as a broadcast, multicast or unknown unicast packet.
Further if the MAC address is a unicast MAC address, the PE MUST
treat the packet as an unknown unicast packet.
13.2. P2MP MPLS LSPs
The procedures for using P2MP LSPs are very similar to VPLS
procedures [VPLS-MCAST]. The P-Tunnel attribute used by an PE for
sending unknown unicast, broadcast or multicast traffic for a
particular EVI is advertised in the Inclusive Ethernet Tag Multicast
route as described in section "Handling of Multi-Destination
Traffic".
The P-Tunnel attribute specifies the P2MP LSP identifier. This is the
equivalent of an Inclusive tree in [VPLS-MCAST]. Note that multiple
Ethernet Tags, which may be in different EVIs, may use the same P2MP
LSP, using upstream labels [VPLS-MCAST]. This is the equivalent of an
Aggregate Inclusive tree in [VPLS-MCAST]. When P2MP LSPs are used for
flooding unknown unicast traffic, packet re-ordering is possible.
The PE that receives a packet on the P2MP LSP specified in the PMSI
Tunnel Attribute MUST treat the packet as a broadcast, multicast or
unknown unicast packet. Further if the MAC address is a unicast MAC
address, the PE MUST treat the packet as an unknown unicast packet.
14. Forwarding Unicast Packets
14.1. Forwarding packets received from a CE
When an PE receives a packet from a CE, on a given Ethernet Tag, it
Sajassi, et al. Expires August 25, 2013 [Page 32]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
must first look up the source MAC address of the packet. In certain
environments the source MAC address MAY be used to authenticate the
CE and determine that traffic from the host can be allowed into the
network. Source MAC lookup MAY also be used for local MAC address
learning.
If the PE decides to forward the packet, the destination MAC address
of the packet must be looked up. If the PE has received MAC address
advertisements for this destination MAC address from one or more
other PEs or learned it from locally connected CEs, it is considered
as a known MAC address. Otherwise, the MAC address is considered as
an unknown MAC address.
For known MAC addresses the PE forwards this packet to one of the
remote PEs or to a locally attached CE. When forwarding to a remote
PE, the packet is encapsulated in the E-VPN MPLS label advertised by
the remote PE, for that MAC address, and in the MPLS LSP label stack
to reach the remote PE.
If the MAC address is unknown and if the administrative policy on the
PE requires flooding of unknown unicast traffic then:
- The PE MUST flood the packet to other PEs. The
PE MUST first encapsulate the packet in the ESI MPLS
label as described in section 9.3.
If ingress replication is used, the packet MUST be replicated
one or more times to each remote PE with the outermost
label being an MPLS label determined as follows: This
is the MPLS label advertised by the remote PE in a PMSI
Tunnel Attribute in the Inclusive Multicast Ethernet Tag
route for an <EVI, Ethernet Tag> combination. The Ethernet
Tag in the route must be the same as the Ethernet Tag
associated with the interface on which the ingress PE
receives the packet. If P2MP LSPs are being used the packet
MUST be sent on the P2MP LSP that the PE is the root of for
the Ethernet Tag in the EVI. If the same P2MP LSP is used
for all Ethernet Tags, then all the PEs in the EVI MUST
be the leaves of the P2MP LSP. If a distinct P2MP LSP is
used for a given Ethernet Tag in the EVI, then only the
PEs in the Ethernet Tag MUST be the leaves of the P2MP
LSP. The packet MUST be encapsulated in the P2MP LSP label
stack.
If the MAC address is unknown then, if the administrative policy on
the PE does not allow flooding of unknown unicast traffic:
- The PE MUST drop the packet.
Sajassi, et al. Expires August 25, 2013 [Page 33]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
14.2. Forwarding packets received from a remote PE
14.2.1. Unknown Unicast Forwarding
When an PE receives an MPLS packet from a remote PE then, after
processing the MPLS label stack, if the top MPLS label ends up being
a P2MP LSP label associated with an EVI or the downstream label
advertised in the P-Tunnel attribute, and after performing the split
horizon procedures described in section "Split Horizon":
- If the PE is the designated forwarder of unknown unicast, broadcast
or multicast traffic, on a particular set of ESIs for the Ethernet
Tag, the default behavior is for the PE to flood the packet on these
ESIs. In other words, the default behavior is for the PE to assume
that the destination MAC address is unknown unicast, broadcast or
multicast and it is not required to perform a destination MAC address
lookup. As an option, the PE may perform a destination MAC lookup to
flood the packet to only a subset of the CE interfaces in the
Ethernet Tag. For instance the PE may decide to not flood an unknown
unicast packet on certain Ethernet segments even if it is the DF on
the Ethernet segment, based on administrative policy.
- If the PE is not the designated forwarder on any of the ESIs for
the Ethernet Tag, the default behavior is for it to drop the packet.
14.2.2. Known Unicast Forwarding
If the top MPLS label ends up being an E-VPN label that was
advertised in the unicast MAC advertisements, then the PE either
forwards the packet based on CE next-hop forwarding information
associated with the label or does a destination MAC address lookup to
forward the packet to a CE.
15. Load Balancing of Unicast Frames
This section specifies the load balancing procedures for sending
known unicast frames to a multi-homed CE.
15.1. Load balancing of traffic from an PE to remote CEs
Whenever a remote PE imports a MAC advertisement for a given <ESI,
Ethernet Tag> in an EVI, it MUST examine all imported Ethernet A-D
routes for that ESI in order to determine the load-balancing
characteristics of the Ethernet segment.
15.1.1 Single-Active Redundancy Mode
For a given ESI, if the remote PE has imported an Ethernet A-D route
per Ethernet Segment from at least one PE, where the "Active-Standby"
Sajassi, et al. Expires August 25, 2013 [Page 34]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
flag in the ESI Label Extended Community is set, then the remote PE
MUST deduce that the Ethernet segment is operating in Single-Active
redundancy mode. As such, the MAC address will be reachable only via
the PE announcing the associated MAC Advertisement route - this is
referred to as the primary PE. The set of other PE nodes advertising
Ethernet A-D routes per Ethernet Segment for the same ESI serve as
backup paths, in case the active PE encounters a failure. These are
referred to as the backup PEs. It should be noted that the primary PE
for a given <ESI, EVI> is the DF for that <ESI, EVI>.
If the primary PE encounters a failure, it MAY withdraw its Ethernet
A-D route for the affected segment prior to withdrawing the entire
set of MAC Advertisement routes.
In the case where only a single other backup PE in the network had
advertised an Ethernet A-D route for the same ESI, the remote PE can
then use the Ethernet A-D route withdrawal as a trigger to update its
forwarding entries, for the associated MAC addresses, to point
towards the backup PE. As the backup PE starts learning the MAC
addresses over its attached Ethernet segment, it will start sending
MAC Advertisement routes while the failed PE withdraws its own. This
mechanism minimizes the flooding of traffic during fail-over events.
In the case where multiple other backup PE in the network had
advertised an Ethernet A-D route for the same ESI, the remote PE MUST
then use the Ethernet A-D route withdrawal as a trigger to start
flooding traffic destined to the associated MAC addresses (as long as
flooding of unknown unicast is administratively allowed). It is not
possible to select a single backup path in this case.
15.1.2 All-Active Redundancy Mode
If for the given ESI, none of the Ethernet A-D routes per Ethernet
Segment imported by the remote PE have the "Active-Standby" flag set
in the ESI Label Extended Community, then the remote PE MUST treat
the Ethernet segment as operating in All-Active redundancy mode. The
remote PE would then treat the MAC address as reachable via all of
the PE nodes from which it has received both an Ethernet A-D route
per Ethernet Segment as well as an Ethernet A-D route per EVI for the
ESI in question. The remote PE MUST use the MAC advertisement and
eligible Ethernet A-D routes to construct the set of next-hops that
it can use to send the packet to the destination MAC. Each next-hop
comprises an MPLS label stack that is to be used by the egress PE to
forward the packet. This label stack is determined as follows:
-If the next-hop is constructed as a result of a MAC route then this
label stack MUST be used. However, if the MAC route doesn't exist,
then the next-hop and MPLS label stack is constructed as a result of
Sajassi, et al. Expires August 25, 2013 [Page 35]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
the Ethernet A-D routes. Note that the following description applies
to determining the label stack for a particular next-hop to reach a
given PE, from which the remote PE has received and imported Ethernet
A-D routes that have the matching ESI and Ethernet Tag as the one
present in the MAC advertisement. The Ethernet A-D routes mentioned
in the following description refer to the ones imported from this
given PE.
-If an Ethernet A-D route per Ethernet Segment for that ESI exists,
together with an Ethernet A-D route per EVI, then the label from that
latter route must be used.
The following example explains the above.
Consider a CE (CE1) that is dual-homed to two PEs (PE1 and PE2) on a
LAG interface (ES1), and is sending packets with MAC address MAC1 on
VLAN1. A remote PE, say PE3, is able to learn that MAC1 is reachable
via PE1 and PE2. Both PE1 and PE2 may advertise MAC1 in BGP if they
receive packets with MAC1 from CE1. If this is not the case, and if
MAC1 is advertised only by PE1, PE3 still considers MAC1 as reachable
via both PE1 and PE2 as both PE1 and PE2 advertise a Ethernet A-D
route per ESI for ES1 as well as an Ethernet A-D route per EVI for
<ES1, VLAN1>.
The MPLS label stack to send the packets to PE1 is the MPLS LSP stack
to get to PE1 and the E-VPN label advertised by PE1 for CE1's MAC.
The MPLS label stack to send packets to PE2 is the MPLS LSP stack to
get to PE2 and the MPLS label in the Ethernet A-D route advertised by
PE2 for <ES1, VLAN1>, if PE2 has not advertised MAC1 in BGP.
We will refer to these label stacks as MPLS next-hops.
The remote PE (PE3) can now load balance the traffic it receives from
its CEs, destined for CE1, between PE1 and PE2. PE3 may use N-Tuple
flow information to hash traffic into one of the MPLS next-hops for
load balancing of IP traffic. Alternatively PE3 may rely on the
source MAC addresses for load balancing.
Note that once PE3 decides to send a particular packet to PE1 or PE2
it can pick one out of multiple possible paths to reach the
particular remote PE using regular MPLS procedures. For instance, if
the tunneling technology is based on RSVP-TE LSPs, and PE3 decides to
send a particular packet to PE1, then PE3 can choose from multiple
RSVP-TE LSPs that have PE1 as their destination.
When PE1 or PE2 receive the packet destined for CE1 from PE3, if the
packet is a unicast MAC packet it is forwarded to CE1. If it is a
Sajassi, et al. Expires August 25, 2013 [Page 36]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
multicast or broadcast MAC packet then only one of PE1 or PE2 must
forward the packet to the CE. Which of PE1 or PE2 forward this packet
to the CE is determined based on which of the two is the DF.
If the connectivity between the multi-homed CE and one of the PEs
that it is attached to fails, the PE MUST withdraw the Ethernet Tag
A-D routes, that had been previously advertised, for the Ethernet
Segment to the CE. When the MAC entry on the PE ages out, the PE MUST
withdraw the MAC address from BGP. Note that to aid convergence, the
Ethernet Tag A-D routes MAY be withdrawn before the MAC routes. This
enables the remote PEs to remove the MPLS next-hop to this particular
PE from the set of MPLS next-hops that can be used to forward traffic
to the CE. For further details and procedures on withdrawal of E-VPN
route types in the event of PE to CE failures please section "PE to
CE Network Failures".
15.2. Load balancing of traffic between an PE and a local CE
A CE may be configured with more than one interface connected to
different PEs or the same PE for load balancing, using a technology
such as LAG. The PE(s) and the CE can load balance traffic onto these
interfaces using one of the following mechanisms.
15.2.1. Data plane learning
Consider that the PEs perform data plane learning for local MAC
addresses learned from local CEs. This enables the PE(s) to learn a
particular MAC address and associate it with one or more interfaces,
if the technology between the PE and the CE supports multi-pathing.
The PEs can now load balance traffic destined to that MAC address on
the multiple interfaces.
Whether the CE can load balance traffic that it generates on the
multiple interfaces is dependent on the CE implementation.
15.2.2. Control plane learning
The CE can be a host that advertises the same MAC address using a
control protocol on both interfaces. This enables the PE(s) to learn
the host's MAC address and associate it with one or more interfaces.
The PEs can now load balance traffic destined to the host on the
multiple interfaces. The host can also load balance the traffic it
generates onto these interfaces and the PE that receives the traffic
employs E-VPN forwarding procedures to forward the traffic.
16. MAC Mobility
It is possible for a given host or end-station (as defined by its MAC
Sajassi, et al. Expires August 25, 2013 [Page 37]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
address) to move from one Ethernet segment to another; this is
referred to as 'MAC Mobility' or 'MAC move' and it is different from
the multi-homing situation in which a given MAC address is reachable
via multiple PEs for the same Ethernet segment. In a MAC move, there
would be two sets of MAC Advertisement routes, one set with the new
Ethernet segment and one set with the previous Ethernet segment, and
the MAC address would appear to be reachable via each of these
segments.
In order to allow all of the PEs in the E-VPN to correctly determine
the current location of the MAC address, all advertisements of it
being reachable via the previous Ethernet segment MUST be withdrawn
by the PEs, for the previous Ethernet segment, that had advertised
it.
If local learning is performed using the data plane, these PEs will
not be able to detect that the MAC address has moved to another
Ethernet segment and the receipt of MAC Advertisement routes, with
the MAC Mobility extended community attribute, from other PEs serves
as the trigger for these PEs to withdraw their advertisements. If
local learning is performed using the control or management planes,
these interactions serve as the trigger for these PEs to withdraw
their advertisements.
In a situation where there are multiple moves of a given MAC,
possibly between the same two Ethernet segments, there may be
multiple withdrawals and re-advertisements. In order to ensure that
all PEs in the E-VPN receive all of these correctly through the
intervening BGP infrastructure, it is necessary to introduce a
sequence number into the MAC Mobility extended community attribute.
Since the sequence number is an unsigned 32 bit integer, all sequence
number comparisons must be performed modulo 2**32. This unsigned
arithmetic preserves the relationship of sequence numbers as they
cycle from 2**32 - 1 to 0.
Every MAC mobility event for a given MAC address will contain a
sequence number that is set using the following rules:
- A PE advertising a MAC address for the first time advertises it
with no MAC Mobility extended community attribute.
- A PE detecting a locally attached MAC address for which it had
previously received a MAC Advertisement route with a different
Ethernet segment identifier advertises the MAC address in a MAC
Advertisement route tagged with a MAC Mobility extended community
attribute with a sequence number one greater than the sequence number
in the MAC mobility attribute of the received MAC Advertisement
Sajassi, et al. Expires August 25, 2013 [Page 38]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
route. In the case of the first mobility event for a given MAC
address, where the received MAC Advertisement route does not carry a
MAC Mobility attribute, the value of the sequence number in the
received route is assumed to be 0 for purpose of this processing.
- A PE detecting a locally attached MAC address for which it had
previously received a MAC Advertisement route with the same Ethernet
segment identifier advertises it with:
i. no MAC Mobility extended community attribute, if the received
route did not carry said attribute.
ii. a MAC Mobility extended community attribute with the sequence
number equal to the highest of the sequence number(s) in the
received MAC Advertisement route(s), if the received route(s) is
(are) tagged with a MAC Mobility extended community attribute.
A PE receiving a MAC Advertisement route for a MAC address with a
different Ethernet segment identifier and a higher sequence number
than that which it had previously advertised, withdraws its MAC
Advertisement route. If two (or more) PEs advertise the same MAC
address with same sequence number but different Ethernet segment
identifiers, a PE that receives these routes selects the route
advertised by the PE with lowest IP address as the best route.
16.1. MAC Duplication Issue
A situation may arise where the same MAC address is learned by
different PEs in the same VLAN because of two (or more hosts) being
mis-configured with the same (duplicate) MAC address. In such
situation, the traffic originating from these hosts would trigger
continuous MAC moves among the PEs attached to these hosts. It is
important to recognize such situation and avoid incrementing the
sequence number (in the MAC Mobility attribute) to infinity. In order
to remedy such situation, a PE that detects a MAC mobility event by
way of local learning starts an M-second timer (default value of M =
5) and if it detects N MAC moves before the timer expires (default
value for N = 3), it concludes that a duplicate MAC situation has
occurred. The PE MUST alert the operator and stop sending and
processing any BGP MAC Advertisement routes for that MAC address till
a corrective action is taken by the operator. The values of M and N
MUST be configurable to allow for flexibility in operator control.
17. Multicast
The PEs in a particular E-VPN may use ingress replication or P2MP
LSPs to send multicast traffic to other PEs.
Sajassi, et al. Expires August 25, 2013 [Page 39]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
17.1. Ingress Replication
The PEs may use ingress replication for flooding unknown unicast,
multicast or broadcast traffic as described in section "Handling of
Multi-Destination Traffic". A given unknown unicast or broadcast
packet must be sent to all the remote PEs. However a given multicast
packet for a multicast flow may be sent to only a subset of the PEs.
Specifically a given multicast flow may be sent to only those PEs
that have receivers that are interested in the multicast flow.
Determining which of the PEs have receivers for a given multicast
flow is done using explicit tracking described below.
17.2. P2MP LSPs
An PE may use an "Inclusive" tree for sending an unknown unicast,
broadcast or multicast packet or a "Selective" tree. This terminology
is borrowed from [VPLS-MCAST].
A variety of transport technologies may be used in the SP network.
For inclusive P-Multicast trees, these transport technologies include
point-to-multipoint LSPs created by RSVP-TE or mLDP. For selective P-
Multicast trees, only unicast PE-PE tunnels (using MPLS or IP/GRE
encapsulation) and P2MP LSPs are supported, and the supported P2MP
LSP signaling protocols are RSVP-TE, and mLDP.
17.3. MP2MP LSPs
The root of the MP2MP LDP LSP advertises the Inclusive Multicast Tag
route with the PMSI Tunnel attribute set to the MP2MP Tunnel
identifier. This advertisement is then sent to all PEs in the E-VPN.
Upon receiving the Inclusive Multicast Tag routes with a PMSI Tunnel
attribute that contains the MP2MP Tunnel identifier, the receiving
PEs initiate the setup of the MP2MP tunnel towards the root using the
procedures in [MLDP].
17.3.1. Inclusive Trees
An Inclusive Tree allows the use of a single multicast distribution
tree, referred to as an Inclusive P-Multicast tree, in the SP network
to carry all the multicast traffic from a specified set of EVIs on a
given PE. A particular P-Multicast tree can be set up to carry the
traffic originated by sites belonging to a single E-VPN, or to carry
the traffic originated by sites belonging to different E-VPNs. The
ability to carry the traffic of more than one E-VPN on the same tree
is termed 'Aggregation'. The tree needs to include every PE that is a
member of any of the E-VPNs that are using the tree. This implies
that an PE may receive multicast traffic for a multicast stream even
if it doesn't have any receivers that are interested in receiving
Sajassi, et al. Expires August 25, 2013 [Page 40]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
traffic for that stream.
An Inclusive P-Multicast tree as defined in this document is a P2MP
tree. A P2MP tree is used to carry traffic only for E-VPN CEs that
are connected to the PE that is the root of the tree.
The procedures for signaling an Inclusive Tree are the same as those
in [VPLS-MCAST] with the VPLS-AD route replaced with the Inclusive
Multicast Ethernet Tag route. The P-Tunnel attribute [VPLS-MCAST] for
an Inclusive tree is advertised in the Inclusive Multicast route as
described in section "Handling of Multi-Destination Traffic". Note
that an PE can "aggregate" multiple inclusive trees for different
EVIs on the same P2MP LSP using upstream labels. The procedures for
aggregation are the same as those described in [VPLS-MCAST], with
VPLS A-D routes replaced by E-VPN Inclusive Multicast routes.
17.3.2. Selective Trees
A Selective P-Multicast tree is used by an PE to send IP multicast
traffic for one or more specific IP multicast streams, originated by
CEs connected to the PE, that belong to the same or different E-VPNs,
to a subset of the PEs that belong to those E-VPNs. Each of the PEs
in the subset should be on the path to a receiver of one or more
multicast streams that are mapped onto the tree. The ability to use
the same tree for multicast streams that belong to different E-VPNs
is termed an PE the ability to create separate SP multicast trees for
specific multicast streams, e.g. high bandwidth multicast streams.
This allows traffic for these multicast streams to reach only those
PE routers that have receivers in these streams. This avoids flooding
other PE routers in the E-VPN.
An SP can use both Inclusive P-Multicast trees and Selective P-
Multicast trees or either of them for a given E-VPN on an PE, based
on local configuration.
The granularity of a selective tree is <RD, PE, S, G> where S is an
IP multicast source address and G is an IP multicast group address or
G is a multicast MAC address. Wildcard sources and wildcard groups
are supported. Selective trees require explicit tracking as described
below.
A E-VPN PE advertises a selective tree using a E-VPN selective A-D
route. The procedures are the same as those in [VPLS-MCAST] with S-
PMSI A-D routes in [VPLS-MCAST] replaced by E-VPN Selective A-D
routes. The information elements of the E-VPN selective A-D route
are similar to those of the VPLS S-PMSI A-D route with the following
differences. A E-VPN Selective A-D route includes an optional
Ethernet Tag field. Also an E-VPN selective A-D route may encode a
Sajassi, et al. Expires August 25, 2013 [Page 41]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
MAC address in the Group field. The encoding details of the E-VPN
selective A-D route will be described in the next revision.
Selective trees can also be aggregated on the same P2MP LSP using
aggregation as described in [VPLS-MCAST].
17.4. Explicit Tracking
[VPLS-MCAST] describes procedures for explicit tracking that rely on
Leaf A-D routes. The same procedures are used for explicit tracking
in this specification with VPLS Leaf A-D routes replaced with E-VPN
Leaf A-D routes. These procedures allow a root PE to request
multicast membership information for a given (S, G), from leaf PEs.
Leaf PEs rely on IGMP snooping or PIM snooping between the PE and the
CE to determine the multicast membership information. Note that the
procedures in [VPLS-MCAST] do not describe how explicit tracking is
performed if the CEs are enabled with join suppression. The
procedures for this case will be described in a future version.
18. Convergence
This section describes failure recovery from different types of
network failures.
18.1. Transit Link and Node Failures between PEs
The use of existing MPLS Fast-Reroute mechanisms can provide failure
recovery in the order of 50ms, in the event of transit link and node
failures in the infrastructure that connects the PEs.
18.2. PE Failures
Consider a host host1 that is dual homed to PE1 and PE2. If PE1
fails, a remote PE, PE3, can discover this based on the failure of
the BGP session. This failure detection can be in the sub-second
range if BFD is used to detect BGP session failure. PE3 can update
its forwarding state to start sending all traffic for host1 to only
PE2. It is to be noted that this failure recovery is potentially
faster than what would be possible if data plane learning were to be
used. As in that case PE3 would have to rely on re-learning of MAC
addresses via PE2.
18.2.1. Local Repair
It is possible to perform local repair in the case of PE failures.
Details will be specified in the future.
18.3. PE to CE Network Failures
Sajassi, et al. Expires August 25, 2013 [Page 42]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
When an Ethernet segment connected to an PE fails or when a Ethernet
Tag is decommissioned on an Ethernet segment, then the PE MUST
withdraw the Ethernet A-D route(s) announced for the <ESI, Ethernet
Tags> that are impacted by the failure or decommissioning. In
addition, the PE MUST also withdraw the MAC advertisement routes that
are impacted by the failure or decommissioning.
The Ethernet A-D routes should be used by an implementation to
optimize the withdrawal of MAC advertisement routes. When an PE
receives a withdrawal of a particular Ethernet A-D route from an PE
it SHOULD consider all the MAC advertisement routes, that are learned
from the same <ESI, Ethernet Tag> as in the Ethernet A-D route, from
the advertising PE, as having been withdrawn. This optimizes the
network convergence times in the event of PE to CE failures.
19. LACP State Synchronization
This section requires review and discussion amongst the authors and
will be revised in the next version.
To support CE multi-homing with multi-chassis Ethernet bundles, the
PEs connected to a given CE should synchronize [802.1AX] LACP state
amongst each other. This ensures that the PEs can present a single
LACP bundle to the CE. This is required for initial system bring-up
and upon any configuration change.
This includes at least the following LACP specific configuration
parameters:
- System Identifier (MAC Address): uniquely identifies a LACP
speaker.
- System Priority: determines which LACP speaker's port
priorities are used in the Selection logic.
- Aggregator Identifier: uniquely identifies a bundle within
a LACP speaker.
- Aggregator MAC Address: identifies the MAC address of the
bundle.
- Aggregator Key: used to determine which ports can join an
Aggregator.
- Port Number: uniquely identifies an interface within a LACP
speaker.
- Port Key: determines the set of ports that can be bundled.
- Port Priority: determines a port's precedence level to join
a bundle in case the number of eligible ports exceeds the
maximum number of links allowed in a bundle.
Furthermore, the PEs should also synchronize operational (run-time)
data, in order for the LACP Selection logic state-machines to
Sajassi, et al. Expires August 25, 2013 [Page 43]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
execute. This operational data includes the following LACP
operational parameters, on a per port basis:
- Partner System Identifier: this is the CE System MAC address.
- Partner System Priority: the CE LACP System Priority
- Partner Port Number: CE's AC port number.
- Partner Port Priority: CE's AC Port Priority.
- Partner Key: CE's key for this AC.
- Partner State: CE's LACP State for the AC.
- Actor State: PE's LACP State for the AC.
- Port State: PE's AC port status.
The above state needs to be communicated between PEs forming a multi-
chassis bundle during LACP initial bringup, upon any configuration
change and upon the occurrence of a failure.
It should be noted that the above configuration and operational state
is localized in scope and is only relevant to PEs which connect to
the same multi-homed CE over a given Ethernet bundle.
Furthermore, the communication of state changes, upon failures, must
occur with minimal latency, in order to minimize the switchover time
and consequent service disruption. The protocol details for
synchronizing the LACP state will be described in the following
version.
20. Acknowledgements
We would like to thank Yakov Rekhter, Pedro Marques, Kaushik Ghosh,
Nischal Sheth, Robert Raszuk, Amit Shukla and Nadeem Mohammed for
discussions that helped shape this document. We would also like to
thank Han Nguyen for his comments and support of this work. We would
also like to thank Steve Kensil and Reshad Rahman for their reviews.
Last but not least, many thanks to Jakob Heitz for his help to
improve several sections of this draft.
21. Security Considerations
22. IANA Considerations
23. References
23.1 Normative References
Sajassi, et al. Expires August 25, 2013 [Page 44]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
[RFC4364] "BGP/MPLS IP VPNs", Rosen, Rekhter, et. al., February 2006
[RFC4761] Kompella, K. and Y. Rekhter, "Virtual Private LAN Service
(VPLS) Using BGP for Auto-Discovery and Signaling", RFC
4761, January 2007.
[RFC4762] Lasserre, M. and V. Kompella, "Virtual Private LAN Service
(VPLS) Using Label Distribution Protocol (LDP) Signaling",
RFC 4762, January 2007.
[RFC4271] Y. Rekhter et. al., "A Border Gateway Protocol 4 (BGP-4)",
RFC 4271, January 2006
[RFC4760] T. Bates et. al., "Multiprotocol Extensions for BGP-4", RFC
4760, January 2007
23.2 Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[EVPN-REQ] A. Sajassi, R. Aggarwal et. al., "Requirements for
Ethernet VPN", draft-ietf-l2vpn-evpn-req-01.txt
[VPLS-MCAST] "Multicast in VPLS". R. Aggarwal et.al., draft-ietf-
l2vpn-vpls-mcast-11.txt
[RT-CONSTRAIN] P. Marques et. al., "Constrained Route Distribution
for Border Gateway Protocol/MultiProtocol Label Switching
(BGP/MPLS) Internet Protocol (IP) Virtual Private Networks
(VPNs)", RFC 4684, November 2006
[BGP-VPLS-MH] "BGP based Multi-homing in Virtual Private LAN
Service", K. Kompella et. al., draft-ietf-l2vpn-vpls-
multihoming-04.txt
24. Author's Address
Ali Sajassi
Cisco
Email: sajassi@cisco.com
Rahul Aggarwal
Email: raggarwa_1@yahoo.com
Sajassi, et al. Expires August 25, 2013 [Page 45]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
Wim Henderickx
Alcatel-Lucent
e-mail: wim.henderickx@alcatel-lucent.com
Aldrin Isaac
Bloomberg
Email: aisaac71@bloomberg.net
James Uttaro
AT&T
200 S. Laurel Avenue
Middletown, NJ 07748
USA
Email: uttaro@att.com
Nabil Bitar
Verizon Communications
Email : nabil.n.bitar@verizon.com
Ravi Shekhar
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089 US
Email: rshekhar@juniper.net
Florin Balus
Alcatel-Lucent
e-mail: Florin.Balus@alcatel-lucent.com
Keyur Patel
Cisco
170 West Tasman Drive
San Jose, CA 95134, US
Email: keyupate@cisco.com
Sami Boutros
Cisco
170 West Tasman Drive
San Jose, CA 95134, US
Email: sboutros@cisco.com
Sajassi, et al. Expires August 25, 2013 [Page 46]
INTERNET DRAFT BGP MPLS Based Ethernet VPN February 25, 2013
Samer Salam
Cisco
Email: ssalam@cisco.com
John Drake
Juniper Networks
Email: jdrake@juniper.net
Sajassi, et al. Expires August 25, 2013 [Page 47]
