draft-ietf-bess-evpn-etree-04.txt   draft-ietf-bess-evpn-etree-05.txt 
skipping to change at page 1, line 15 skipping to change at page 1, line 15
Intended Status: Standards Track Sami Boutros Intended Status: Standards Track Sami Boutros
Cisco Cisco
Wim Henderickx Wim Henderickx
Jorge Rabadan Jim Uttaro Jorge Rabadan Jim Uttaro
Alcatel-Lucent AT&T Alcatel-Lucent AT&T
John Drake Aldrin Isaac John Drake Aldrin Isaac
Wen Lin Juniper Wen Lin Juniper
Juniper Juniper
Expires: August 2, 2016 February 2, 2016 Expires: November 10, 2016 May 10, 2016
E-TREE Support in EVPN & PBB-EVPN E-TREE Support in EVPN & PBB-EVPN
draft-ietf-bess-evpn-etree-04 draft-ietf-bess-evpn-etree-05
Abstract Abstract
The Metro Ethernet Forum (MEF) has defined a rooted-multipoint The Metro Ethernet Forum (MEF) has defined a rooted-multipoint
Ethernet service known as Ethernet Tree (E-Tree). [ETREE-FMWK] Ethernet service known as Ethernet Tree (E-Tree). A solution
proposes a solution framework for supporting this service in MPLS framework for supporting this service in MPLS networks is proposed in
networks. This document discusses how those functional requirements and RFC called "A Framework for E-Tree Service over MPLS Network".
can be easily met with (PBB-)EVPN and how (PBB-)EVPN offers a more This document discusses how those functional requirements can be
efficient implementation of these functions. easily met with (PBB-)EVPN and how (PBB-)EVPN offers a more efficient
implementation of these functions.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as other groups may also distribute working documents as
Internet-Drafts. Internet-Drafts.
skipping to change at page 1, line 46 skipping to change at page 2, line 4
other groups may also distribute working documents as other groups may also distribute working documents as
Internet-Drafts. Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html http://www.ietf.org/shadow.html
Copyright and License Notice Copyright and License Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
skipping to change at page 2, line 46 skipping to change at page 2, line 47
3.2.3 BUM traffic originated from a multi-homed site on a 3.2.3 BUM traffic originated from a multi-homed site on a
leaf AC . . . . . . . . . . . . . . . . . . . . . . . . 9 leaf AC . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.4 BUM traffic originated from a multi-homed site on a 3.2.4 BUM traffic originated from a multi-homed site on a
root AC . . . . . . . . . . . . . . . . . . . . . . . . 9 root AC . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 E-TREE Traffic Flows for EVPN . . . . . . . . . . . . . . . 10 3.3 E-TREE Traffic Flows for EVPN . . . . . . . . . . . . . . . 10
3.3.1 E-Tree with MAC Learning . . . . . . . . . . . . . . . . 10 3.3.1 E-Tree with MAC Learning . . . . . . . . . . . . . . . . 10
3.3.2 E-Tree without MAC Learning . . . . . . . . . . . . . . 11 3.3.2 E-Tree without MAC Learning . . . . . . . . . . . . . . 11
4 Operation for PBB-EVPN . . . . . . . . . . . . . . . . . . . . . 11 4 Operation for PBB-EVPN . . . . . . . . . . . . . . . . . . . . . 11
4.1 Known Unicast Traffic . . . . . . . . . . . . . . . . . . . 12 4.1 Known Unicast Traffic . . . . . . . . . . . . . . . . . . . 12
4.2 BUM Traffic . . . . . . . . . . . . . . . . . . . . . . . . 12 4.2 BUM Traffic . . . . . . . . . . . . . . . . . . . . . . . . 12
4.3 E-Tree without MAC Learning . . . . . . . . . . . . . . . . 13
5 BGP Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5 BGP Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1 E-TREE Extended Community . . . . . . . . . . . . . . . . . 13 5.1 E-TREE Extended Community . . . . . . . . . . . . . . . . . 13
5.2 PMSI Tunnel Attribute . . . . . . . . . . . . . . . . . . . 14 5.2 PMSI Tunnel Attribute . . . . . . . . . . . . . . . . . . . 14
6 Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . 15
6 Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . 14 7 Security Considerations . . . . . . . . . . . . . . . . . . . . 15
7 Security Considerations . . . . . . . . . . . . . . . . . . . . 14 8 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 15
8 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 14
9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1 Normative References . . . . . . . . . . . . . . . . . . . 15 9.1 Normative References . . . . . . . . . . . . . . . . . . . 15
9.2 Informative References . . . . . . . . . . . . . . . . . . 15 9.2 Informative References . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
1 Introduction 1 Introduction
The Metro Ethernet Forum (MEF) has defined a rooted-multipoint The Metro Ethernet Forum (MEF) has defined a rooted-multipoint
Ethernet service known as Ethernet Tree (E-Tree). In an E-Tree Ethernet service known as Ethernet Tree (E-Tree). In an E-Tree
service, endpoints are labeled as either Root or Leaf sites. Root service, endpoints are labeled as either Root or Leaf sites. Root
sites can communicate with all other sites. Leaf sites can sites can communicate with all other sites. Leaf sites can
communicate with Root sites but not with other Leaf sites. communicate with Root sites but not with other Leaf sites.
[ETREE-FMWK] proposes the solution framework for supporting E-Tree [RFC7387] proposes the solution framework for supporting E-Tree
service in MPLS networks. The document identifies the functional service in MPLS networks. The document identifies the functional
components of the overall solution to emulate E-Tree services in components of the overall solution to emulate E-Tree services in
addition to Ethernet LAN (E-LAN) services on an existing MPLS addition to Ethernet LAN (E-LAN) services on an existing MPLS
network. network.
[EVPN] is a solution for multipoint L2VPN services, with advanced [RFC7432] is a solution for multipoint L2VPN services, with advanced
multi-homing capabilities, using BGP for distributing customer/client multi-homing capabilities, using BGP for distributing customer/client
MAC address reach-ability information over the MPLS/IP network. [PBB- MAC address reach-ability information over the MPLS/IP network.
EVPN] combines the functionality of EVPN with [802.1ah] Provider [RFC7623] combines the functionality of EVPN with [802.1ah] Provider
Backbone Bridging for MAC address scalability. Backbone Bridging for MAC address scalability.
This document discusses how the functional requirements for E-Tree This document discusses how the functional requirements for E-Tree
service can be easily met with (PBB-)EVPN and how (PBB-)EVPN offers a service can be easily met with (PBB-)EVPN and how (PBB-)EVPN offers a
more efficient implementation of these functions. more efficient implementation of these functions.
1.1 Terminology 1.1 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
skipping to change at page 7, line 7 skipping to change at page 7, line 7
| | V | | | /IP | | | V | | | | V | | | /IP | | | V | |
| | I | | | | | | I | | +---+ | | I | | | | | | I | | +---+
| | | | | | | | +--+---ES2/AC2--+CE3| | | | | | | | | +--+---ES2/AC2--+CE3|
| +---+ | +------+ | +---+ | (Leaf) +---+ | +---+ | +------+ | +---+ | (Leaf) +---+
+---------+ +---------+ +---------+ +---------+
Figure 3: Scenario 3 Figure 3: Scenario 3
3 Operation for EVPN 3 Operation for EVPN
[EVPN] defines the notion of ESI MPLS label used for split-horizon [RFC7432] defines the notion of ESI MPLS label used for split-horizon
filtering of BUM traffic at the egress PE. Such egress filtering filtering of BUM traffic at the egress PE. Such egress filtering
capabilities can be leveraged in provision of E-TREE services as seen capabilities can be leveraged in provision of E-TREE services as seen
shortly. In other words, [EVPN] has inherent capability to support E- shortly. In other words, [RFC7432] has inherent capability to support
TREE services without defining any new BGP routes but by just E-TREE services without defining any new BGP routes but by just
defining a new BGP Extended Community for leaf indication as shown defining a new BGP Extended Community for leaf indication as shown
later in this document. later in this document.
3.1 Known Unicast Traffic 3.1 Known Unicast Traffic
Since in EVPN, MAC learning is performed in control plane via Since in EVPN, MAC learning is performed in control plane via
advertisement of BGP routes, the filtering needed by E-TREE service advertisement of BGP routes, the filtering needed by E-TREE service
for known unicast traffic can be performed at the ingress PE, thus for known unicast traffic can be performed at the ingress PE, thus
providing very efficient filtering and avoiding sending known unicast providing very efficient filtering and avoiding sending known unicast
traffic over MPLS/IP core to be filtered at the egress PE as done in traffic over MPLS/IP core to be filtered at the egress PE as done in
skipping to change at page 8, line 30 skipping to change at page 8, line 30
For BUM traffic, it is not possible to perform filtering on the For BUM traffic, it is not possible to perform filtering on the
ingress PE, as is the case with known unicast, because of the multi- ingress PE, as is the case with known unicast, because of the multi-
destination nature of the traffic. As such, the solution relies on destination nature of the traffic. As such, the solution relies on
egress filtering. In order to apply the proper egress filtering, egress filtering. In order to apply the proper egress filtering,
which varies based on whether a packet is sent from a Leaf AC or a which varies based on whether a packet is sent from a Leaf AC or a
root AC, the MPLS-encapsulated frames MUST be tagged with an root AC, the MPLS-encapsulated frames MUST be tagged with an
indication when they originated from a Leaf AC. In other words, leaf indication when they originated from a Leaf AC. In other words, leaf
indication for BUM traffic is done at the granularity of AC. This can indication for BUM traffic is done at the granularity of AC. This can
be achieved in EVPN through the use of a MPLS label where it can be be achieved in EVPN through the use of a MPLS label where it can be
used to either identify the Ethernet segment of origin per [RFC 7432] used to either identify the Ethernet segment of origin per [RFC7432]
(i.e., ESI label) or it can be used to indicate that the packet is (i.e., ESI label) or it can be used to indicate that the packet is
originated from a leaf site (Leaf label). originated from a leaf site (Leaf label).
BUM traffic sent over a P2MP LSP or ingress replication, may need to BUM traffic sent over a P2MP LSP or ingress replication, may need to
carry an upstream assigned or downstream assigned MPLS label carry an upstream assigned or downstream assigned MPLS label
(respectively) for the purpose of egress filtering to indicate to the (respectively) for the purpose of egress filtering to indicate to the
egress PEs whether this packet is originated from a leaf AC. egress PEs whether this packet is originated from a leaf AC.
The main difference between downstream and upstream assigned MPLS The main difference between downstream and upstream assigned MPLS
label is that in case of downstream assigned not all egress PE label is that in case of downstream assigned not all egress PE
skipping to change at page 9, line 18 skipping to change at page 9, line 18
In this scenario, the ingress PE adds a special MPLS label indicating In this scenario, the ingress PE adds a special MPLS label indicating
a Leaf site. This special Leaf MPLS label, used for single-homing a Leaf site. This special Leaf MPLS label, used for single-homing
scenarios, is not on a per ES basis but rather on a per PE basis - scenarios, is not on a per ES basis but rather on a per PE basis -
i.e., a single Leaf MPLS label is used for all single-homed ES's on i.e., a single Leaf MPLS label is used for all single-homed ES's on
that PE. This Leaf label is advertised to other PE devices, using a that PE. This Leaf label is advertised to other PE devices, using a
new EVPN Extended Community called E-TREE Extended Community (section new EVPN Extended Community called E-TREE Extended Community (section
5.1) along with an Ethernet A-D per ES route with ESI of zero and a 5.1) along with an Ethernet A-D per ES route with ESI of zero and a
set of Route Targets (RTs) corresponding to all EVIs on the PE with set of Route Targets (RTs) corresponding to all EVIs on the PE with
at least one leaf site per EVI. The set of Ethernet A-D per ES routes at least one leaf site per EVI. The set of Ethernet A-D per ES routes
may be needed if the number of Route Targets (RTs) that need to be may be needed if the number of Route Targets (RTs) that need to be
sent exceed the limit on a single route per [RFC 7432]. The ESI for sent exceed the limit on a single route per [RFC7432]. The ESI for
the Ethernet A-D per ES route is set to zero to indicate single-homed the Ethernet A-D per ES route is set to zero to indicate single-homed
sites. sites.
When a PE receives this special Leaf label in the data path, it When a PE receives this special Leaf label in the data path, it
blocks the packet if the destination AC is of type Leaf; otherwise, blocks the packet if the destination AC is of type Leaf; otherwise,
it forwards the packet. it forwards the packet.
3.2.2 BUM traffic originated from a single-homed site on a root AC 3.2.2 BUM traffic originated from a single-homed site on a root AC
In this scenario, the ingress PE does not add any ESI or Leaf label In this scenario, the ingress PE does not add any ESI or Leaf label
skipping to change at page 9, line 50 skipping to change at page 9, line 50
In such scenarios, If a multicast packet is originated from a leaf In such scenarios, If a multicast packet is originated from a leaf
AC, then it only needs to carry Leaf label described in section AC, then it only needs to carry Leaf label described in section
3.2.1. This label is sufficient in providing the necessary egress 3.2.1. This label is sufficient in providing the necessary egress
filtering of BUM traffic from getting sent to leaf ACs including the filtering of BUM traffic from getting sent to leaf ACs including the
leaf AC on the same Ethernet Segment. leaf AC on the same Ethernet Segment.
3.2.4 BUM traffic originated from a multi-homed site on a root AC 3.2.4 BUM traffic originated from a multi-homed site on a root AC
In this scenario, both the ingress and egress PE devices follows the In this scenario, both the ingress and egress PE devices follows the
procedure defined in [RFC 7432] for adding and/or processing an ESI procedure defined in [RFC7432] for adding and/or processing an ESI
MPLS label. MPLS label.
3.3 E-TREE Traffic Flows for EVPN 3.3 E-TREE Traffic Flows for EVPN
Per [ETREE-FMWK], a generic E-Tree service supports all of the Per [RFC7387], a generic E-Tree service supports all of the following
following traffic flows: traffic flows:
- Ethernet Unicast from Root to Roots & Leaf - Ethernet Unicast from Root to Roots & Leaf
- Ethernet Unicast from Leaf to Root - Ethernet Unicast from Leaf to Root
- Ethernet Broadcast/Multicast from Root to Roots & Leafs - Ethernet Broadcast/Multicast from Root to Roots & Leafs
- Ethernet Broadcast/Multicast from Leaf to Roots - Ethernet Broadcast/Multicast from Leaf to Roots
A particular E-Tree service may need to support all of the above A particular E-Tree service may need to support all of the above
types of flows or only a select subset, depending on the target types of flows or only a select subset, depending on the target
application. In the case where unicast flows need not be supported, application. In the case where unicast flows need not be supported,
the L2VPN PEs can avoid performing any MAC learning function. the L2VPN PEs can avoid performing any MAC learning function.
skipping to change at page 10, line 39 skipping to change at page 10, line 39
MAC Advertisement routes. These routes will be imported by all PEs MAC Advertisement routes. These routes will be imported by all PEs
for that EVI (i.e., PEs that have Leaf sites as well as PEs that have for that EVI (i.e., PEs that have Leaf sites as well as PEs that have
Root sites). Similarly, the PEs with Leaf sites perform MAC learning Root sites). Similarly, the PEs with Leaf sites perform MAC learning
in the data-path over their Ethernet Segments, and advertise in the data-path over their Ethernet Segments, and advertise
reachability in EVPN MAC Advertisement routes. For the scenario reachability in EVPN MAC Advertisement routes. For the scenario
described in section 2.1 (or possibly section 2.2), these routes are described in section 2.1 (or possibly section 2.2), these routes are
imported only by PEs with at least one Root site in the EVI - i.e., a imported only by PEs with at least one Root site in the EVI - i.e., a
PE with only Leaf sites will not import these routes. PEs with Root PE with only Leaf sites will not import these routes. PEs with Root
and/or Leaf sites may use the Ethernet A-D routes for aliasing (in and/or Leaf sites may use the Ethernet A-D routes for aliasing (in
the case of multi-homed segments) and for mass MAC withdrawal per the case of multi-homed segments) and for mass MAC withdrawal per
[RFC 7432]. [RFC7432].
To support multicast/broadcast from Root to Leaf sites, either a P2MP To support multicast/broadcast from Root to Leaf sites, either a P2MP
tree rooted at the PE(s) with the Root site(s) or ingress replication tree rooted at the PE(s) with the Root site(s) or ingress replication
can be used. The multicast tunnels are set up through the exchange of can be used. The multicast tunnels are set up through the exchange of
the EVPN Inclusive Multicast route, as defined in [RFC7432]. the EVPN Inclusive Multicast route, as defined in [RFC7432].
To support multicast/broadcast from Leaf to Root sites, ingress To support multicast/broadcast from Leaf to Root sites, ingress
replication should be sufficient for most scenarios where there are replication should be sufficient for most scenarios where there are
only a few Roots (typically two). Therefore, in a typical scenario, a only a few Roots (typically two). Therefore, in a typical scenario, a
root PE needs to support both a P2MP tunnel in transmit direction root PE needs to support both a P2MP tunnel in transmit direction
skipping to change at page 11, line 34 skipping to change at page 11, line 34
in [RFC7432], and the multicast tunnel setup criteria are as in [RFC7432], and the multicast tunnel setup criteria are as
described in the previous section. described in the previous section.
Just as in the previous section, if the number of PEs with root sites Just as in the previous section, if the number of PEs with root sites
are only a few and thus ingress replication is desired from leaf PEs are only a few and thus ingress replication is desired from leaf PEs
to these root PEs, then the modified PMSI attribute as defined in to these root PEs, then the modified PMSI attribute as defined in
section 5.3 should be used. section 5.3 should be used.
4 Operation for PBB-EVPN 4 Operation for PBB-EVPN
In PBB-EVPN, the PE must advertise a Root/Leaf indication along with In PBB-EVPN, the PE advertises a Root/Leaf indication along with each
each B-MAC Advertisement route, to indicate whether the associated B- B-MAC Advertisement route, to indicate whether the associated B-MAC
MAC address corresponds to a Root or a Leaf site. Similar to the EVPN address corresponds to a Root or a Leaf site. Just like the EVPN
case, this flag will be added to the new E-TREE Extended Community case, the new E-TREE Extended Community defined in section [5.1] is
defined in section [5.2], and advertised with each MAC Advertisement advertised with each MAC Advertisement route.
route.
In the case where a multi-homed Ethernet Segment has both Root and In the case where a multi-homed Ethernet Segment has both Root and
Leaf sites attached, two B-MAC addresses are allocated and Leaf sites attached, two B-MAC addresses are advertised: one B-MAC
advertised: one B-MAC address implicitly denoting Root and the other address is per ES as specified in [RFC7623] and implicitly denoting
explicitly denoting Leaf. The former B-MAC address is not advertised Root, and the other B-MAC address is per PE and explicitly denoting
with the E-TREE extended community but the latter B-MAC denoting Leaf Leaf. The former B-MAC address is not advertised with the E-TREE
is advertised with the new E-TREE extended community. extended community but the latter B-MAC denoting Leaf is advertised
with the new E-TREE extended community where "Leaf-indication" flag
is set. In such multi-homing scenarios where and Ethernet Segment has
both Root and Leaf ACs, it is assumed that While different ACs
(VLANs) on the same ES could have different root/leaf designation
(some being roots and some being leaves), the same VLAN does have the
same root/leaf designation on all PEs on the same ES. Furthermore, it
is assumed that there is no forwarding among subnets - ie, the
service is L2 and not IRB. IRB use case is outside the scope of this
document.
The ingress PE uses the right B-MAC source address depending on The ingress PE uses the right B-MAC source address depending on
whether the Ethernet frame originated from the Root or Leaf site on whether the Ethernet frame originated from the Root or Leaf AC on
that Ethernet Segment. The mechanism by which the PE identifies that Ethernet Segment. The mechanism by which the PE identifies
whether a given frame originated from a Root or Leaf site on the whether a given frame originated from a Root or Leaf site on the
segment is based on the Ethernet Tag associated with the frame. Other segment is based on the Ethernet Tag associated with the frame. Other
mechanisms of identification, beyond the Ethernet Tag, are outside mechanisms of identification, beyond the Ethernet Tag, are outside
the scope of this document. It should be noted that support for both the scope of this document.
Root and Leaf sites on a single Ethernet Segment requires that the PE
performs the Ethernet Segment split-horizon check on a per Ethernet
Tag basis.
In the case where a multi-homed Ethernet Segment has only Root OR
Leaf sites attached, then a single B-MAC address is allocated and
advertised per segment.
Furthermore, a PE advertises two special global B-MAC addresses: one Furthermore, a PE advertises two special global B-MAC addresses: one
for Root and another for Leaf, and tags the Leaf one as such in the for Root and another for Leaf, and tags the Leaf one as such in the
MAC Advertisement route. These B-MAC addresses are used as source MAC Advertisement route. These B-MAC addresses are used as source
addresses for traffic originating from single-homed segments. addresses for traffic originating from single-homed segments. The B-
MAC address used for indicating Leaf sites can be the same for both
single-homed and multi-homed segments.
4.1 Known Unicast Traffic 4.1 Known Unicast Traffic
For known unicast traffic, the PEs perform ingress filtering: On the For known unicast traffic, the PEs perform ingress filtering: On the
ingress PE, the C-MAC destination address lookup yields, in addition ingress PE, the C-MAC destination address lookup yields, in addition
to the target B-MAC address and forwarding adjacency, a flag which to the target B-MAC address and forwarding adjacency, a flag which
indicates whether the target B-MAC is associated with a Root or a indicates whether the target B-MAC is associated with a Root or a
Leaf site. The ingress PE cross-checks this flag with the status of Leaf site. The ingress PE cross-checks this flag with the status of
the originating site, and if both are a Leaf, then the packet is not the originating site, and if both are a Leaf, then the packet is not
forwarded. forwarded.
4.2 BUM Traffic 4.2 BUM Traffic
For BUM traffic, the PEs must perform egress filtering. When a PE For BUM traffic, the PEs must perform egress filtering. When a PE
receives a MAC advertisement route, it updates its Ethernet Segment receives a MAC advertisement route (which will be used as a source B-
egress filtering function (based on the B-MAC source address), as MAC), it updates its Ethernet Segment egress filtering function
follows: (based on the source B-MAC address), as follows:
- If the MAC Advertisement route indicates that the advertised B-MAC - If the MAC Advertisement route indicates that the advertised B-MAC
is a Leaf, and the local Ethernet Segment is a Leaf as well, then the is a Leaf, and the local Ethernet Segment is a Leaf as well, then the
source B-MAC address is added to the B-MAC filtering list. source B-MAC address is added to the B-MAC filtering list.
- Otherwise, the B-MAC filtering list is not updated. - Otherwise, the B-MAC filtering list is not updated.
When the egress PE receives the packet, it examines the B-MAC source When the egress PE receives the packet, it examines the B-MAC source
address to check whether it should filter or forward the frame. Note address to check whether it should filter or forward the frame. Note
that this uses the same filtering logic as baseline [PBB-EVPN] and that this uses the same filtering logic as baseline [RFC7623] and
does not require any additional flags in the data-plane. does not require any additional flags in the data-plane.
The PE places all Leaf Ethernet Segments of a given bridge domain in The PE places all Leaf Ethernet Segments of a given bridge domain in
a single split-horizon group in order to prevent intra-PE forwarding a single split-horizon group in order to prevent intra-PE forwarding
among Leaf segments. This split-horizon function applies to BUM among Leaf segments. This split-horizon function applies to BUM
traffic. traffic.
4.3 E-Tree without MAC Learning
In scenarios where the traffic of interest is only Multicast and/or
broadcast, the PEs implementing an E-Tree service do not need to do
any MAC learning. In such scenarios the filtering must be performed
on egress PEs. For PBB-EVPN, the handling of such traffic is per
section 4.2 without C-MAC learning part of it at both ingress and
egress PEs.
5 BGP Encoding 5 BGP Encoding
This document defines two new BGP Extended Community for EVPN. This document defines two new BGP Extended Community for EVPN.
5.1 E-TREE Extended Community 5.1 E-TREE Extended Community
This Extended Community is a new transitive Extended Community having This Extended Community is a new transitive Extended Community having
a Type field value of 0x06 (EVPN) and the Sub-Type 0x04. It is used a Type field value of 0x06 (EVPN) and the Sub-Type 0x05. It is used
for leaf indication of known unicast and BUM traffic. For BUM for leaf indication of known unicast and BUM traffic. For BUM
traffic, the Leaf Label field is set to a valid MPLS label and this traffic, the Leaf Label field is set to a valid MPLS label and this
EC is advertised along with Ethernet A-D per ES route with an ESI of EC is advertised along with Ethernet A-D per ES route with an ESI of
zero to enable egress filtering on disposition PEs per section 3.2.1 zero to enable egress filtering on disposition PEs per section 3.2.1
and 3.2.3. For known unicast traffic, the Leaf flag bit is set to one and 3.2.3. There is no need to send ESI Label Extended Community when
and this EC is advertised along with MAC/IP Advertisement route per sending Ethernet A-D per ES route with an ESI of zero. For known
section 3.1. unicast traffic, the Leaf flag bit is set to one and this EC is
advertised along with MAC/IP Advertisement route per section 3.1.
The E-TREE Extended Community is encoded as an 8-octet value as The E-TREE Extended Community is encoded as an 8-octet value as
follows: follows:
0 1 2 3 0 1 2 3
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 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=0x04 | Flags(1 Octet)| Reserved=0 | | Type=0x06 | Sub-Type=0x05 | Flags(1 Octet)| Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved=0 | Leaf Label | | Reserved=0 | Leaf Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The low-order bit of the Flags octet is defined as the "Leaf- The low-order bit of the Flags octet is defined as the "Leaf-
Indication" bit. A value of one indicates a Leaf AC/Site. Indication" bit. A value of one indicates a Leaf AC/Site.
When this EC is advertised along with MAC/IP Advertisement route, the When this EC is advertised along with MAC/IP Advertisement route (for
Leaf-Indication flag MUST be set to one and Leaf Label is set to known unicast traffic), the Leaf-Indication flag MUST be set to one
zero. The received PE should ignore Leaf Label and only processes and Leaf Label is set to zero. The received PE should ignore Leaf
Leaf-Indication flag. A value of zero for Leaf-Indication flag is Label and only processes Leaf-Indication flag. A value of zero for
invalid when sent along with MAC/IP advertisement route and an error Leaf-Indication flag is invalid when sent along with MAC/IP
should be logged. advertisement route and an error should be logged.
When this EC is advertised along with Ethernet A-D per ES route (with When this EC is advertised along with Ethernet A-D per ES route (with
ESI of zero), the Leaf Label MUST be set to a valid MPLS label and ESI of zero) for BUM traffic, the Leaf Label MUST be set to a valid
the Leaf-Indication flag should be set to zero. The received PE MPLS label and the Leaf-Indication flag should be set to zero. The
should ignore the Leaf-Indication flag. A non-valid MPLS label when received PE should ignore the Leaf-Indication flag. A non-valid MPLS
sent along with the Ethernet A-D per ES route, should be logged as an label when sent along with the Ethernet A-D per ES route, should be
error. logged as an error.
5.2 PMSI Tunnel Attribute 5.2 PMSI Tunnel Attribute
[RFC 6514] defines PMSI Tunnel attribute which is an optional [RFC6514] defines PMSI Tunnel attribute which is an optional
transitive attribute with the following format: transitive attribute with the following format:
+---------------------------------+ +---------------------------------+
| Flags (1 octet) | | Flags (1 octet) |
+---------------------------------+ +---------------------------------+
| Tunnel Type (1 octets) | | Tunnel Type (1 octets) |
+---------------------------------+ +---------------------------------+
| MPLS Label (3 octets) | | MPLS Label (3 octets) |
+---------------------------------+ +---------------------------------+
| Tunnel Identifier (variable) | | Tunnel Identifier (variable) |
skipping to change at page 14, line 38 skipping to change at page 15, line 8
identifier for the transmit tunnel. PEs that don't understand the identifier for the transmit tunnel. PEs that don't understand the
new meaning of the high-order bit would treat the tunnel type as an new meaning of the high-order bit would treat the tunnel type as an
invalid tunnel type. For the PEs that do understand the new meaning invalid tunnel type. For the PEs that do understand the new meaning
of the high-order, if ingress replication is desired when sending BUM of the high-order, if ingress replication is desired when sending BUM
traffic, the PE will use the the label in the Tunnel Identifier field traffic, the PE will use the the label in the Tunnel Identifier field
when sending its BUM traffic. when sending its BUM traffic.
6 Acknowledgement 6 Acknowledgement
We would like to thank Dennis Cai, Antoni Przygienda, and Jeffrey We would like to thank Dennis Cai, Antoni Przygienda, and Jeffrey
Zhang for their valueable comments. Zhang for their valuable comments.
7 Security Considerations 7 Security Considerations
Same security considerations as [RFC7432]. Since this draft uses the EVPN constructs of [RFC7432] and [RFC7623],
the same security considerations in these drafts are also applicable
here. Furthermore, this draft provides additional security check by
allowing sites (or ACs) of an EVPN instance to be designated as
"Root" or "Leaf" and preventing any traffic exchange among "Leaf"
sites of that VPN through ingress filtering for known unicast traffic
and egress filtering for BUM traffic.
8 IANA Considerations 8 IANA Considerations
This document requests the allocation of value 4 in the "EVPN This document requests the allocation of value 5 in the "EVPN
Extended Community Sub-Types" registry defined in [RFC7153] and Extended Community Sub-Types" registry defined in [RFC7153] and
modification of the registry as follow: modification of the registry as follow:
SUB-TYPE VALUE NAME Reference SUB-TYPE VALUE NAME Reference
0x04 E-TREE Extended Community This document 0x05 E-TREE Extended Community This document
6-255 Unassigned 6-255 Unassigned
9 References 9 References
9.1 Normative References 9.1 Normative References
[KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC7432] Sajassi et al., "BGP MPLS Based Ethernet VPN", February, [RFC7432] Sajassi et al., "BGP MPLS Based Ethernet VPN", February,
2015. 2015.
9.2 Informative References [RFC7623] Sajassi et al., "Provider Backbone Bridging Combined with
Ethernet VPN (PBB-EVPN)", September, 2015.
[ETREE-FMWK] Key et al., "A Framework for E-Tree Service over MPLS 9.2 Informative References
Network", draft-ietf-l2vpn-etree-frwk-03, work in progress, September
2013.
[PBB-EVPN] Sajassi et al., "PBB-EVPN", draft-ietf-l2vpn-pbb-evpn- [RFC7387] Key et al., "A Framework for E-Tree Service over MPLS
05.txt, work in progress, October, 2013. Network", October 2014.
[RFC4360] S. Sangli et al, "BGP Extended Communities Attribute", [RFC4360] S. Sangli et al, "BGP Extended Communities Attribute",
February, 2006. February, 2006.
[RFC7153] Rosen et al., "IANA Registries for BGP Extended [RFC7153] Rosen et al., "IANA Registries for BGP Extended
Communities", March, 2014. Communities", March, 2014.
[RFC6514] Aggarwal et al., "BGP Encodings and Procedures for
Multicast in MPLS/BGP IP VPNs", February, 2012.
Authors' Addresses Authors' Addresses
Ali Sajassi Ali Sajassi
Cisco Cisco
Email: sajassi@cisco.com Email: sajassi@cisco.com
Samer Salam Samer Salam
Cisco Cisco
Email: ssalam@cisco.com Email: ssalam@cisco.com
Wim Henderickx Wim Henderickx
Alcatel-Lucent Alcatel-Lucent
Email: wim.henderickx@alcatel-lucent.com Email: wim.henderickx@alcatel-lucent.com
Jim Uttaro Jim Uttaro
AT&T AT&T
Email: ju1738@att.com Email: ju1738@att.com
Aldrin Aldrin
Bloomberg Issac Bloomberg Issac
Email: aisaac71@bloomberg.net Email: aisaac@juniper.net
Sami Boutros Sami Boutros
Cisco Cisco
Email: sboutros@cisco.com Email: boutros.sami@gmail.com
John Drake
Juniper
Email: jdrake@juniper.net
Wen Lin
Juniper
Email: wlin@juniper.net
 End of changes. 42 change blocks. 
80 lines changed or deleted 101 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/