draft-ietf-l2vpn-vpls-ldp-05.txt   draft-ietf-l2vpn-vpls-ldp-06.txt 
Internet Draft Document Marc Lasserre Internet Draft Document Marc Lasserre
Provider Provisioned VPN Working Group Vach Kompella L2VPN Working Group Vach Kompella
draft-ietf-l2vpn-vpls-ldp-05.txt (Editors) (Editors)
Expires: February 2005 September 2004 draft-ietf-l2vpn-vpls-ldp-06.txt
Expires: August 2005 Feb 2005
Virtual Private LAN Services over MPLS Virtual Private LAN Services over MPLS
draft-ietf-l2vpn-vpls-ldp-05.txt
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance By submitting this Internet-Draft, I certify that any applicable
with all provisions of Section 10 of RFC2026. patent or other IPR claims of which I am aware have been disclosed,
or will be disclosed, and any of which I become aware will be
disclosed, in accordance with RFC 3668.
This document is an Internet-Draft and is in full conformance with
Sections 5 and 6 of RFC3667 and Section 5 of RFC3668.
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Abstract Abstract
This document describes a virtual private LAN service (VPLS) This document describes a virtual private LAN service (VPLS)
solution using pseudo-wires, a service previously implemented over solution using pseudo-wires, a service previously implemented over
other tunneling technologies and known as Transparent LAN Services other tunneling technologies and known as Transparent LAN Services
(TLS). A VPLS creates an emulated LAN segment for a given set of (TLS). A VPLS creates an emulated LAN segment for a given set of
users. It delivers a layer 2 broadcast domain that is fully capable users. It delivers a layer 2 broadcast domain that is fully capable
of learning and forwarding on Ethernet MAC addresses that is closed of learning and forwarding on Ethernet MAC addresses that is closed
to a given set of users. Multiple VPLS services can be supported to a given set of users. Multiple VPLS services can be supported
from a single PE node. from a single PE node.
This document describes the control plane functions of signaling This document describes the control plane functions of signaling
demultiplexor labels, extending [PWE3-CTRL]. It is agnostic to demultiplexor labels, extending [PWE3-CTRL]. It is agnostic to
discovery protocols. The data plane functions of forwarding are discovery protocols. The data plane functions of forwarding are also
also described, focusing, in particular, on the learning of MAC described, focusing, in particular, on the learning of MAC
addresses. The encapsulation of VPLS packets is described by [PWE3- addresses. The encapsulation of VPLS packets is described by [PWE3-
ETHERNET]. ETHERNET].
Conventions Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 document are to be interpreted as described in RFC 2119
Placement of this Memo in Sub-IP Area
RELATED DOCUMENTS RELATED DOCUMENTS
www.ietf.org/internet-drafts/draft-ietf-l2vpn-requirements-01.txt www.ietf.org/internet-drafts/draft-ietf-l2vpn-requirements-01.txt
www.ietf.org/internet-drafts/draft-ietf-l2vpn-l2-framework-03.txt www.ietf.org/internet-drafts/draft-ietf-l2vpn-l2-framework-03.txt
www.ietf.org/internet-drafts/draft-ietf-pwe3-ethernet-encap-02.txt www.ietf.org/internet-drafts/draft-ietf-pwe3-ethernet-encap-02.txt
www.ietf.org/internet-drafts/draft-ietf-pwe3-control-protocol-01.txt www.ietf.org/internet-drafts/draft-ietf-pwe3-control-protocol-01.txt
Table of Contents
1. Introduction....................................................3
2. Topological Model for VPLS......................................4
2.1. Flooding and Forwarding.......................................4
2.2. Address Learning..............................................5
2.3. Tunnel Topology...............................................5
2.4. Loop free L2 VPN..............................................5
3. Discovery.......................................................6
4. Control Plane...................................................6
4.1. LDP Based Signaling of Demultiplexors.........................6
4.1.1. Using the Generalized PWid FEC Element......................7
4.1.2. Address Withdraw Message Containing MAC TLV.................7
4.2. MAC Address Withdrawal........................................8
4.2.1. MAC List TLV................................................8
5. Data Forwarding on an Ethernet VC PW............................9
5.1. VPLS Encapsulation actions....................................9
5.2. VPLS Learning actions........................................10
6. Data Forwarding on an Ethernet VLAN PW.........................11
6.1. VPLS Encapsulation actions...................................11
7. Operation of a VPLS............................................12
7.1. MAC Address Aging............................................13
8. A Hierarchical VPLS Model......................................13
8.1. Hierarchical connectivity....................................14
8.1.1. Spoke connectivity for bridging-capable devices............14
8.1.2. Advantages of spoke connectivity...........................15
8.1.3. Spoke connectivity for non-bridging devices................16
8.2. Redundant Spoke Connections..................................17
8.2.1. Dual-homed MTU device......................................18
8.2.2. Failure detection and recovery.............................18
8.3. Multi-domain VPLS service....................................19
9. Hierarchical VPLS model using Ethernet Access Network..........19
9.1. Scalability..................................................20
9.2. Dual Homing and Failure Recovery.............................21
10. Significant Modifications.....................................21
11. Contributors..................................................21
12. Acknowledgments...............................................21
13. Security Considerations.......................................22
1. Introduction 1. Introduction
Ethernet has become the predominant technology for Local Area Ethernet has become the predominant technology for Local Area
Networks (LANs) connectivity and is gaining acceptance as an access Networks (LANs) connectivity and is gaining acceptance as an access
technology, specifically in Metropolitan and Wide Area Networks (MAN technology, specifically in Metropolitan and Wide Area Networks (MAN
and WAN respectively). The primary motivation behind Virtual and WAN respectively). The primary motivation behind Virtual Private
Private LAN Services (VPLS) is to provide connectivity between LAN Services (VPLS) is to provide connectivity between
geographically dispersed customer sites across MAN/WAN network(s), as geographically dispersed customer sites across MAN/WAN network(s),
if they were connected using a LAN. The intended application for the as if they were connected using a LAN. The intended application for
end-user can be divided into the following two categories: the end-user can be divided into the following two categories:
- Connectivity between customer routers: LAN routing application - Connectivity between customer routers: LAN routing application
- Connectivity between customer Ethernet switches: LAN switching - Connectivity between customer Ethernet switches: LAN switching
application application
Broadcast and multicast services are available over traditional Broadcast and multicast services are available over traditional
LANs. Sites that belong to the same broadcast domain and that are LANs. Sites that belong to the same broadcast domain and that are
connected via an MPLS network expect broadcast, multicast and connected via an MPLS network expect broadcast, multicast and
unicast traffic to be forwarded to the proper location(s). This unicast traffic to be forwarded to the proper location(s). This
requires MAC address learning/aging on a per LSP basis, packet requires MAC address learning/aging on a per LSP basis, packet
replication across LSPs for multicast/broadcast traffic and for replication across LSPs for multicast/broadcast traffic and for
flooding of unknown unicast destination traffic. flooding of unknown unicast destination traffic.
[PWE3-ETHERNET] defines how to carry L2 PDUs over point-to-point [PWE3-ETHERNET] defines how to carry L2 PDUs over point-to-point
MPLS LSPs, called pseudowires (PW). Such PWs can be carried over MPLS LSPs, called Pseudo-Wires (PW). Such PWs can be carried over
MPLS or GRE tunnels. This document describes extensions to [PWE3- MPLS or GRE tunnels. This document describes extensions to [PWE3-
CTRL] for transporting Ethernet/802.3 and VLAN [802.1Q] traffic CTRL] for transporting Ethernet/802.3 and VLAN [802.1Q] traffic
across multiple sites that belong to the same L2 broadcast domain or across multiple sites that belong to the same L2 broadcast domain or
VPLS. Note that the same model can be applied to other 802.1 VPLS. Note that the same model can be applied to other 802.1
technologies. It describes a simple and scalable way to offer technologies. It describes a simple and scalable way to offer
Virtual LAN services, including the appropriate flooding of Virtual LAN services, including the appropriate flooding of
broadcast, multicast and unknown unicast destination traffic over broadcast, multicast and unknown unicast destination traffic over
MPLS, without the need for address resolution servers or other MPLS, without the need for address resolution servers or other
external servers, as discussed in [L2VPN-REQ]. external servers, as discussed in [L2VPN-REQ].
skipping to change at page 3, line 33 skipping to change at page 4, line 29
. +----+ . . +----+ .
..........| PE |........... ..........| PE |...........
+----+ ^ +----+ ^
| | | |
| +-- Emulated LAN | +-- Emulated LAN
+----+ +----+
| C1 | | C1 |
+----+ +----+
Site C Site C
The set of PE devices interconnected via pseudowires appears as a The set of PE devices interconnected via PWs appears as a single
single emulated LAN to customer C1. Each PE device will learn remote emulated LAN to customer C1. Each PE device will learn remote MAC
MAC address to pseudowire associations and will also learn directly address to PW associations and will also learn directly attached MAC
attached MAC addresses on customer facing ports. addresses on customer facing ports.
We note here again that while this document shows specific examples We note here again that while this document shows specific examples
using MPLS transport tunnels, other tunnels that can be used by using MPLS transport tunnels, other tunnels that can be used by PWs,
pseudo-wires, e.g., GRE, L2TP, IPSEC, etc., can also be used, as e.g., GRE, L2TP, IPSEC, etc., can also be used, as long as the
long as the originating PE can be identified, since this is used in originating PE can be identified, since this is used in the MAC
the MAC learning process. learning process.
The scope of the VPLS lies within the PEs in the service provider The scope of the VPLS lies within the PEs in the service provider
network, highlighting the fact that apart from customer service network, highlighting the fact that apart from customer service
delineation, the form of access to a customer site is not relevant delineation, the form of access to a customer site is not relevant
to the VPLS [L2VPN-REQ]. to the VPLS [L2VPN-REQ].
The PE device is typically an edge router capable of running the LDP The PE device is typically an edge router capable of running the LDP
signaling protocol and/or routing protocols to set up pseudowires. signaling protocol and/or routing protocols to set up PWs.
In addition, it is capable of setting up transport tunnels to other In addition, it is capable of setting up transport tunnels to other
PEs and deliver traffic over a pseudowire. PEs and of delivering traffic over a PW.
2.1. Flooding and Forwarding 2.1. Flooding and Forwarding
One of attributes of an Ethernet service is that packets to One of attributes of an Ethernet service is that packets to
broadcast packets and to unknown destination MAC addresses are broadcast packets and to unknown destination MAC addresses are
flooded to all ports. To achieve flooding within the service flooded to all ports. To achieve flooding within the service
provider network, all address unknown unicast, broadcast and provider network, all address unknown unicast, broadcast and
multicast frames are flooded over the corresponding pseudowires to multicast frames are flooded over the corresponding PWs to all
all relevant PE nodes participating in the VPLS. relevant PE nodes participating in the VPLS.
Note that multicast frames are a special case and do not necessarily Note that multicast frames are a special case and do not necessarily
have to be sent to all VPN members. For simplicity, the default have to be sent to all VPN members. For simplicity, the default
approach of broadcasting multicast frames can be used. The use of approach of broadcasting multicast frames can be used. The use of
IGMP snooping and PIM snooping techniques should be used to improve IGMP snooping and PIM snooping techniques should be used to improve
multicast efficiency. multicast efficiency.
To forward a frame, a PE MUST be able to associate a destination MAC To forward a frame, a PE MUST be able to associate a destination MAC
address with a pseudowire. It is unreasonable and perhaps impossible address with a PW. It is unreasonable and perhaps impossible to
to require PEs to statically configure an association of every require PEs to statically configure an association of every possible
possible destination MAC address with a pseudowire. Therefore, VPLS- destination MAC address with a PW. Therefore, VPLS-capable PEs
capable PEs SHOULD have the capability to dynamically learn MAC SHOULD have the capability to dynamically learn MAC addresses on
addresses on both physical ports and virtual circuits and to forward both physical ports and virtual circuits and to forward and
and replicate packets across both physical ports and pseudowires. replicate packets across both physical ports and PWs.
2.2. Address Learning 2.2. Address Learning
Unlike BGP VPNs [BGP-VPN], reachability information does not need to Unlike BGP VPNs [BGP-VPN], reachability information does not need to
be advertised and distributed via a control plane. Reachability is be advertised and distributed via a control plane. Reachability is
obtained by standard learning bridge functions in the data plane. obtained by standard learning bridge functions in the data plane.
A pseudowire consists of a pair of uni-directional VC LSPs. The A PW consists of a pair of uni-directional VC LSPs. The state of
state of this pseudowire is considered operationally up when both this PW is considered operationally up when both incoming and
incoming and outgoing VC LSPs are established. Similarly, it is outgoing VC LSPs are established. Similarly, it is considered
considered operationally down when one of these two VC LSPs is torn operationally down when one of these two VC LSPs is torn down. When
down. When a previously unknown MAC address is learned on an a previously unknown MAC address is learned on an inbound VC LSP, it
inbound VC LSP, it needs to be associated with the its counterpart needs to be associated with the its counterpart outbound VC LSP in
outbound VC LSP in that pseudowire. that PW.
Standard learning, filtering and forwarding actions, as defined in Standard learning, filtering and forwarding actions, as defined in
[802.1D-ORIG], [802.1D-REV] and [802.1Q], are required when a [802.1D-ORIG], [802.1D-REV] and [802.1Q], are required when a
logical link state changes. logical link state changes.
2.3. Tunnel Topology 2.3. Tunnel Topology
PE routers are assumed to have the capability to establish transport PE routers are assumed to have the capability to establish transport
tunnels. Tunnels are set up between PEs to aggregate traffic. tunnels. Tunnels are set up between PEs to aggregate traffic. PWs
Pseudowires are signaled to demultiplex the L2 encapsulated packets are signaled to demultiplex the L2 encapsulated packets that
that traverse the tunnels. traverse the tunnels.
In an Ethernet L2VPN, it becomes the responsibility of the service In an Ethernet L2VPN, it becomes the responsibility of the service
provider to create the loop free topology. For the sake of provider to create the loop free topology. For the sake of
simplicity, we define that the topology of a VPLS is a full mesh of simplicity, we define that the topology of a VPLS is a full mesh of
tunnels and pseudowires. tunnels and PWs.
2.4. Loop free L2 VPN 2.4. Loop free L2 VPN
For simplicity, a full mesh of pseudowires is established between For simplicity, a full mesh of PWs is established between PEs.
PEs. Ethernet bridges, unlike Frame Relay or ATM where the Ethernet bridges, unlike Frame Relay or ATM where the termination
termination point becomes the CE node, have to examine the layer 2 point becomes the CE node, have to examine the layer 2 fields of the
fields of the packets to make a switching decision. If the frame is packets to make a switching decision. If the frame is directed to an
directed to an unknown destination, or is a broadcast or multicast unknown destination, or is a broadcast or multicast frame, the frame
frame, the frame must be flooded. must be flooded.
Therefore, if the topology isn't a full mesh, the PE devices may Therefore, if the topology isn't a full mesh, the PE devices may
need to forward these frames to other PEs. However, this would need to forward these frames to other PEs. However, this would
require the use of spanning tree protocol to form a loop free require the use of spanning tree protocol to form a loop free
topology that may have characteristics that are undesirable to the topology that may have characteristics that are undesirable to the
provider. The use of a full mesh and split-horizon forwarding provider. The use of a full mesh and split-horizon forwarding
obviates the need for a spanning tree protocol. obviates the need for a spanning tree protocol.
Each PE MUST create a rooted tree to every other PE router that Each PE MUST create a rooted tree to every other PE router that
serves the same VPLS. Each PE MUST support a "split-horizon" scheme serves the same VPLS. Each PE MUST support a "split-horizon" scheme
in order to prevent loops, that is, a PE MUST NOT forward traffic in order to prevent loops, that is, a PE MUST NOT forward traffic
from one pseudowire to another in the same VPLS mesh (since each PE from one PW to another in the same VPLS mesh (since each PE has
has direct connectivity to all other PEs in the same VPLS). direct connectivity to all other PEs in the same VPLS).
Note that customers are allowed to run STP such as when a customer Note that customers are allowed to run STP such as when a customer
has "back door" links used to provide redundancy in the case of a has "back door" links used to provide redundancy in the case of a
failure within the VPLS. In such a case, STP BPDUs are simply failure within the VPLS. In such a case, STP BPDUs are simply
tunneled through the provider cloud. tunneled through the provider cloud.
3. Discovery 3. Discovery
The capability to manually configure the addresses of the remote PEs The capability to manually configure the addresses of the remote PEs
is REQUIRED. However, the use of manual configuration is not is REQUIRED. However, the use of manual configuration is not
necessary if an auto-discovery procedure is used. A number of necessary if an auto-discovery procedure is used. A number of auto-
auto-discovery procedures are compatible with this document discovery procedures are compatible with this document ([RADIUS-
([RADIUS-DISC], [BGP-DISC], [LDP-DISC]). DISC], [BGP-DISC]).
4. Control Plane 4. Control Plane
This document describes the control plane functions of Demultiplexor This document describes the control plane functions of Demultiplexor
Exchange (signaling of VC labels). Some foundational work in the Exchange (signaling of VC labels). Some foundational work in the
area of support for multi-homing is laid. The extensions to provide area of support for multi-homing is laid. The extensions to provide
multi-homing support should work independently of the basic VPLS multi-homing support should work independently of the basic VPLS
operation, and are not described here. operation, and are not described here.
4.1. LDP Based Signaling of Demultiplexors 4.1. LDP Based Signaling of Demultiplexors
In order to establish a full mesh of pseudowires, all PEs in a VPLS In order to establish a full mesh of PWs, all PEs in a VPLS must
must have a full mesh of LDP sessions. have a full mesh of LDP sessions.
Once an LDP session has been formed between two PEs, all pseudowires Once an LDP session has been formed between two PEs, all PWs are
are signaled over this session. signaled over this session.
In [PWE3-CTRL], two types of FECs are described, the FEC type 128 In [PWE3-CTRL], two types of FECs are described, the FEC type 128
PWid FEC Element and the FEC type 129 Generalized PWid FEC Element. PWid FEC Element and the FEC type 129 Generalized PWid FEC Element.
The original FEC element used for VPLS was compatible with the PWid The original FEC element used for VPLS was compatible with the PWid
FEC Element. The text for signaling using PWid FEC Element has been FEC Element. The text for signaling using PWid FEC Element has been
moved to Appendix 1. What we describe below replaces that with a moved to Appendix 1. What we describe below replaces that with a
more generalized L2VPN descriptor through the Generalized PWid FEC more generalized L2VPN descriptor through the Generalized PWid FEC
Element. Element.
4.1.1. Using the Generalized PWid FEC Element 4.1.1. Using the Generalized PWid FEC Element
[PWE3-CTRL] describes a generalized FEC structure that is be used [PWE3-CTRL] describes a generalized FEC structure that is be used
for VPLS signaling in the following manner. The following describes for VPLS signaling in the following manner. The following describes
the assignment of the Generalized PWid FEC Element fields in the the assignment of the Generalized PWid FEC Element fields in the
context of VPLS signaling. context of VPLS signaling.
Control bit (C): Depending on whether, on that particular Control bit (C): Depending on whether, on that particular PW, the
pseudowire, the control word is desired or not, the control bit may control word is desired or not, the control bit may be specified.
be specified.
PW type: The allowed PW types in this version are Ethernet and PW type: The allowed PW types in this version are Ethernet and
Ethernet VLAN. Ethernet VLAN.
VC info length: Same as in [PWE3-CTRL]. VC info length: Same as in [PWE3-CTRL].
AGI, Length, Value: The unique name of this VPLS. The AGI AGI, Length, Value: The unique name of this VPLS. The AGI identifies
identifies a type of name, the length denotes the length of Value, a type of name, the length denotes the length of Value, which is the
which is the name of the VPLS. We will use the term AGI name of the VPLS. We will use the term AGI interchangeably with VPLS
interchangeably with VPLS identifier. identifier.
TAII, SAII: These are null because the mesh of PWs in a VPLS TAII, SAII: These are null because the mesh of PWs in a VPLS
terminate on MAC learning tables, rather than on individual terminate on MAC learning tables, rather than on individual
attachment circuits. attachment circuits.
Interface Parameters: The relevant interface parameters are: Interface Parameters: The relevant interface parameters are:
MTU: the MTU of the VPLS MUST be the same across all the PWs in
- MTU: the MTU of the VPLS MUST be the same across all the PWs in
the mesh. the mesh.
Optional Description String: same as [PWE3-CTRL].
Requested VLAN ID: If the PW type is Ethernet VLAN, this - Optional Description String: same as [PWE3-CTRL].
- Requested VLAN ID: If the PW type is Ethernet VLAN, this
parameter may be used to signal the insertion of the parameter may be used to signal the insertion of the
appropriate VLAN ID. appropriate VLAN ID.
4.1.2. Address Withdraw Message Containing MAC TLV 4.1.2. Address Withdraw Message Containing MAC TLV
When MAC addresses are being removed or relearned explicitly, e.g., When MAC addresses are being removed or relearned explicitly, e.g.,
the primary link of a dual-homed MTU-s (Multi-Tenant Unit switch) the primary link of a dual-homed MTU-s (Multi-Tenant Unit switch)
has failed, an MAC Address Withdraw Message with the list of MAC has failed, an MAC Address Withdraw Message with the list of MAC
addresses to be relearned can be sent to all other PEs over the addresses to be relearned can be sent to all other PEs over the
corresponding directed LDP sessions. corresponding directed LDP sessions.
skipping to change at page 7, line 7 skipping to change at page 7, line 52
4.1.2. Address Withdraw Message Containing MAC TLV 4.1.2. Address Withdraw Message Containing MAC TLV
When MAC addresses are being removed or relearned explicitly, e.g., When MAC addresses are being removed or relearned explicitly, e.g.,
the primary link of a dual-homed MTU-s (Multi-Tenant Unit switch) the primary link of a dual-homed MTU-s (Multi-Tenant Unit switch)
has failed, an MAC Address Withdraw Message with the list of MAC has failed, an MAC Address Withdraw Message with the list of MAC
addresses to be relearned can be sent to all other PEs over the addresses to be relearned can be sent to all other PEs over the
corresponding directed LDP sessions. corresponding directed LDP sessions.
The processing for MAC List TLVs received in an Address Withdraw The processing for MAC List TLVs received in an Address Withdraw
Message is: Message is:
For each MAC address in the TLV: For each MAC address in the TLV:
- Relearn the association between the MAC address and the - Relearn the association between the MAC address and the
interface/pseudowire over which this message is received interface/PW over which this message is received
For a MAC Address Withdraw message with empty list: For a MAC Address Withdraw message with empty list:
- Remove all the MAC addresses associated with the VPLS instance - Remove all the MAC addresses associated with the VPLS instance
(specified by the FEC TLV) except the MAC addresses learned (specified by the FEC TLV) except the MAC addresses learned
over this link (over the pseudowire associated with the over this link (over the PW associated with the signaling link
signaling link over which the message is received) over which the message is received)
The scope of a MAC List TLV is the VPLS specified in the FEC TLV in The scope of a MAC List TLV is the VPLS specified in the FEC TLV in
the MAC Address Withdraw Message. The number of MAC addresses can be the MAC Address Withdraw Message. The number of MAC addresses can be
deduced from the length field in the TLV. deduced from the length field in the TLV.
4.2. MAC Address Withdrawal 4.2. MAC Address Withdrawal
It MAY be desirable to remove or relearn MAC addresses that have It MAY be desirable to remove or relearn MAC addresses that have
been dynamically learned for faster convergence. been dynamically learned for faster convergence.
skipping to change at page 8, line 4 skipping to change at page 8, line 50
PE (MAC address removal is required for all VPLS instances that are PE (MAC address removal is required for all VPLS instances that are
affected). Note that the definition of such a notification message affected). Note that the definition of such a notification message
is outside the scope of the document, unless it happens to come from is outside the scope of the document, unless it happens to come from
an MTU connected to the PE as a spoke. In such a scenario, the an MTU connected to the PE as a spoke. In such a scenario, the
message will be just an Address Withdraw message as noted above. message will be just an Address Withdraw message as noted above.
4.2.1. MAC List TLV 4.2.1. MAC List TLV
MAC addresses to be relearned can be signaled using an LDP Address MAC addresses to be relearned can be signaled using an LDP Address
Withdraw Message that contains a new TLV, the MAC List TLV. Its Withdraw Message that contains a new TLV, the MAC List TLV. Its
format is described below. The encoding of a MAC List TLV address format is described below. The encoding of a MAC List TLV address is
is the 6-byte MAC address specified by IEEE 802 documents [g-ORIG] the 6-byte MAC address specified by IEEE 802 documents [g-ORIG]
[802.1D-REV]. [802.1D-REV].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type | Length | |U|F| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC address #1 | | MAC address #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MAC address #n | | MAC address #n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
U bit U bit: Unknown bit. This bit MUST be set to 1. If the MAC address
Unknown bit. This bit MUST be set to 1. If the MAC address
format is not understood, then the TLV is not understood, and MUST format is not understood, then the TLV is not understood, and MUST
be ignored. be ignored.
F bit F bit: Forward bit. This bit MUST be set to 0. Since the LDP
Forward bit. This bit MUST be set to 0. Since the LDP
mechanism used here is Targeted, the TLV MUST NOT be forwarded. mechanism used here is Targeted, the TLV MUST NOT be forwarded.
Type Type: Type field. This field MUST be set to 0x0404 (subject to IANA
Type field. This field MUST be set to 0x0404 (subject to IANA
approval). This identifies the TLV type as MAC List TLV. approval). This identifies the TLV type as MAC List TLV.
Length Length: Length field. This field specifies the total length of the
Length field. This field specifies the total length of the MAC MAC addresses in the TLV.
addresses in the TLV.
MAC Address MAC Address: The MAC address(es) being removed.
The MAC address(es) being removed.
The LDP Address Withdraw Message contains a FEC TLV (to identify the The LDP Address Withdraw Message contains a FEC TLV (to identify the
VPLS in consideration), a MAC Address TLV and optional parameters. VPLS in consideration), a MAC Address TLV and optional parameters.
No optional parameters have been defined for the MAC Address No optional parameters have been defined for the MAC Address
Withdraw signaling. Withdraw signaling.
5. Data Forwarding on an Ethernet VC Pseudowire 5. Data Forwarding on an Ethernet VC PW
This section describes the dataplane behavior on an Ethernet This section describes the dataplane behavior on an Ethernet
pseudowire used in a VPLS. While the encapsulation is similar to PW used in a VPLS. While the encapsulation is similar to that
that described in [PWE3-ETHERNET], the NSP functions of stripping described in [PWE3-ETHERNET], the NSP functions of stripping the
the service-delimiting tag and using a "normalized" Ethernet packet service-delimiting tag and using a "normalized" Ethernet packet are
are described. described.
5.1. VPLS Encapsulation actions 5.1. VPLS Encapsulation actions
In a VPLS, a customer Ethernet packet without preamble is In a VPLS, a customer Ethernet packet without preamble is
encapsulated with a header as defined in [PWE3-ETHERNET]. A encapsulated with a header as defined in [PWE3-ETHERNET]. A customer
customer Ethernet packet is defined as follows: Ethernet packet is defined as follows:
- If the packet, as it arrives at the PE, has an encapsulation - If the packet, as it arrives at the PE, has an encapsulation
that is used by the local PE as a service delimiter, i.e., to that is used by the local PE as a service delimiter, i.e., to
identify the customer and/or the particular service of that identify the customer and/or the particular service of that
customer, then that encapsulation is stripped before the packet customer, then that encapsulation is stripped before the packet
is sent into the VPLS. As the packet exits the VPLS, the is sent into the VPLS. As the packet exits the VPLS, the packet
packet may have a service-delimiting encapsulation inserted. may have a service-delimiting encapsulation inserted.
- If the packet, as it arrives at the PE, has an encapsulation - If the packet, as it arrives at the PE, has an encapsulation
that is not service delimiting, then it is a customer packet that is not service delimiting, then it is a customer packet
whose encapsulation should not be modified by the VPLS. This whose encapsulation should not be modified by the VPLS. This
covers, for example, a packet that carries customer-specific covers, for example, a packet that carries customer-specific
VLAN-Ids that the service provider neither knows about nor VLAN-Ids that the service provider neither knows about nor
wants to modify. wants to modify.
As an application of these rules, a customer packet may arrive at a As an application of these rules, a customer packet may arrive at a
customer-facing port with a VLAN tag that identifies the customer's customer-facing port with a VLAN tag that identifies the customer's
VPLS instance. That tag would be stripped before it is encapsulated VPLS instance. That tag would be stripped before it is encapsulated
in the VPLS. At egress, the packet may be tagged again, if a in the VPLS. At egress, the packet may be tagged again, if a
service-delimiting tag is used, or it may be untagged if none is service-delimiting tag is used, or it may be untagged if none is
used. used.
Likewise, if a customer packet arrives at a customer-facing port Likewise, if a customer packet arrives at a customer-facing port
over an ATM VC that identifies the customer's VPLS instance, then over an ATM or Frame Relay VC that identifies the customer's VPLS
the ATM encapsulation is removed before the packet is passed into instance, then the ATM or FR encapsulation is removed before the
the VPLS. packet is passed into the VPLS.
Contrariwise, if a customer packet arrives at a customer-facing port Contrariwise, if a customer packet arrives at a customer-facing port
with a VLAN tag that identifies a VLAN domain in the customer L2 with a VLAN tag that identifies a VLAN domain in the customer L2
network, then the tag is not modified or stripped, as it belongs network, then the tag is not modified or stripped, as it belongs
with the rest of the customer frame. with the rest of the customer frame.
By following the above rules, the Ethernet packet that traverses a By following the above rules, the Ethernet packet that traverses a
VPLS is always a customer Ethernet packet. Note that the two VPLS is always a customer Ethernet packet. Note that the two
actions, at ingress and egress, of dealing with service delimiters actions, at ingress and egress, of dealing with service delimiters
are local actions that neither PE has to signal to the other. They are local actions that neither PE has to signal to the other. They
allow, for example, a mix-and-match of VLAN tagged and untagged allow, for example, a mix-and-match of VLAN tagged and untagged
services at either end, and do not carry across a VPLS a VLAN tag services at either end, and do not carry across a VPLS a VLAN tag
that has local significance only. The service delimiter may be an that has local significance only. The service delimiter may be an
MPLS label also, whereby an Ethernet pseudowire given by [PWE3- MPLS label also, whereby an Ethernet PW given by [PWE3-ETHERNET] can
ETHERNET] can serve as the access side connection into a PE. An serve as the access side connection into a PE. An RFC1483 PVC
RFC1483 PVC encapsulation could be another service delimiter. By encapsulation could be another service delimiter. By limiting the
limiting the scope of locally significant encapsulations to the scope of locally significant encapsulations to the edge,
edge, hierarchical VPLS models can be developed that provide the hierarchical VPLS models can be developed that provide the
capability to network-engineer VPLS deployments, as described below. capability to network-engineer VPLS deployments, as described below.
5.2 VPLS Learning actions 5.2. VPLS Learning actions
Learning is done based on the customer Ethernet packet, as defined Learning is done based on the customer Ethernet packet, as defined
above. The Forwarding Information Base (FIB) keeps track of the above. The Forwarding Information Base (FIB) keeps track of the
mapping of customer Ethernet packet addressing and the appropriate mapping of customer Ethernet packet addressing and the appropriate
pseudowire to use. We define two modes of learning: qualified and PW to use. We define two modes of learning: qualified and
unqualified learning. unqualified learning.
In unqualified learning, all the customer VLANs are handled by a In unqualified learning, all the customer VLANs are handled by a
single VPLS, which means they all share a single broadcast domain single VPLS, which means they all share a single broadcast domain
and a single MAC address space. This means that MAC addresses need and a single MAC address space. This means that MAC addresses need
to be unique and non-overlapping among customer VLANs or else they to be unique and non-overlapping among customer VLANs or else they
cannot be differentiated within the VPLS instance and this can cannot be differentiated within the VPLS instance and this can
result in loss of customer frames. An application of unqualified result in loss of customer frames. An application of unqualified
learning is port-based VPLS service for a given customer (e.g., learning is port-based VPLS service for a given customer (e.g.,
customer with non-multiplexed UNI interface where all the traffic on customer with non-multiplexed UNI interface where all the traffic on
skipping to change at page 10, line 41 skipping to change at page 11, line 33
Martini) can be added by MTU-s nodes such that PEs can unambiguously Martini) can be added by MTU-s nodes such that PEs can unambiguously
identify all customer traffic, including STP/MSTP BPDUs. In a basic identify all customer traffic, including STP/MSTP BPDUs. In a basic
VPLS case, upstream switches must insert such service delimiting VPLS case, upstream switches must insert such service delimiting
tags. When an access port is shared among multiple customers, a tags. When an access port is shared among multiple customers, a
reserved VLAN per customer domain must be used to carry STP/MSTP reserved VLAN per customer domain must be used to carry STP/MSTP
traffic. The STP/MSTP frames are encapsulated with a unique provider traffic. The STP/MSTP frames are encapsulated with a unique provider
tag per customer (as the regular customer traffic), and a PEs looks tag per customer (as the regular customer traffic), and a PEs looks
up the provider tag to send such frames across the proper VPLS up the provider tag to send such frames across the proper VPLS
instance. instance.
6. Data Forwarding on an Ethernet VLAN Pseudowire 6. Data Forwarding on an Ethernet VLAN PW
This section describes the dataplane behavior on an Ethernet VLAN This section describes the dataplane behavior on an Ethernet VLAN PW
pseudowire in a VPLS. While the encapsulation is similar to that in a VPLS. While the encapsulation is similar to that described in
described in [PWE3-ETHERNET], the NSP functions of imposing tags, [PWE3-ETHERNET], the NSP functions of imposing tags, and using a
and using a "normalized" Ethernet packet are described. The "normalized" Ethernet packet are described. The learning behavior is
learning behavior is the same as for Ethernet pseudowires. the same as for Ethernet PWs.
6.1. VPLS Encapsulation actions 6.1. VPLS Encapsulation actions
In a VPLS, a customer Ethernet packet without preamble is In a VPLS, a customer Ethernet packet without preamble is
encapsulated with a header as defined in [PWE3-ETHERNET]. A encapsulated with a header as defined in [PWE3-ETHERNET]. A customer
customer Ethernet packet is defined as follows: Ethernet packet is defined as follows:
- If the packet, as it arrives at the PE, has an encapsulation - If the packet, as it arrives at the PE, has an encapsulation
that is part of the customer frame, and is also used by the that is part of the customer frame, and is also used by the
local PE as a service delimiter, i.e., to identify the customer local PE as a service delimiter, i.e., to identify the customer
and/or the particular service of that customer, then that and/or the particular service of that customer, then that
encapsulation is preserved as the packet is sent into the VPLS, encapsulation is preserved as the packet is sent into the VPLS,
unless the Requested VLAN ID optional parameter was signaled. unless the Requested VLAN ID optional parameter was signaled.
In that case, the VLAN tag is overwritten before the packet is In that case, the VLAN tag is overwritten before the packet is
sent out on the pseudowire. sent out on the PW.
- If the packet, as it arrives at the PE, has an encapsulation - If the packet, as it arrives at the PE, has an encapsulation
that does not have the required VLAN tag, a null tag is imposed that does not have the required VLAN tag, a null tag is imposed
if the Requested VLAN ID optional parameter was not signaled. if the Requested VLAN ID optional parameter was not signaled.
As an application of these rules, a customer packet may arrive at a As an application of these rules, a customer packet may arrive at a
customer-facing port with a VLAN tag that identifies the customer's customer-facing port with a VLAN tag that identifies the customer's
VPLS instance and also identifies a customer VLAN. That tag would VPLS instance and also identifies a customer VLAN. That tag would be
be preserved as it is encapsulated in the VPLS. preserved as it is encapsulated in the VPLS.
The Ethernet VLAN pseudowire is a simple way to preserve customer The Ethernet VLAN PW is a simple way to preserve customer 802.1p
802.1p bits. bits.
A VPLS MAY have both Ethernet and Ethernet VLAN pseudowires. A VPLS MAY have both Ethernet and Ethernet VLAN PWs. However, if a
However, if a PE is not able to support both pseudowires PE is not able to support both PWs simultaneously, it can send a
simultaneously, it can send a Label Release on the pseudowire Label Release on the PW messages that it cannot support with a
messages that it cannot support with a status code "Unknown FEC" as status code "Unknown FEC" as given in [RFC3036].
given in [RFC3036].
7. Operation of a VPLS 7. Operation of a VPLS
We show here an example of how a VPLS works. The following We show here an example of how a VPLS works. The following
discussion uses the figure below, where a VPLS has been set up discussion uses the figure below, where a VPLS has been set up
between PE1, PE2 and PE3. between PE1, PE2 and PE3.
Initially, the VPLS is set up so that PE1, PE2 and PE3 have a full Initially, the VPLS is set up so that PE1, PE2 and PE3 have a full
mesh of Ethernet pseudowires. The VPLS instance is assigned a mesh of Ethernet PWs. The VPLS instance is assigned a unique VCID.
unique VCID.
For the above example, say PE1 signals VC Label 102 to PE2 and 103 For the above example, say PE1 signals VC Label 102 to PE2 and 103
to PE3, and PE2 signals VC Label 201 to PE1 and 203 to PE3. to PE3, and PE2 signals VC Label 201 to PE1 and 203 to PE3.
Assume a packet from A1 is bound for A2. When it leaves CE1, say it Assume a packet from A1 is bound for A2. When it leaves CE1, say it
has a source MAC address of M1 and a destination MAC of M2. If PE1 has a source MAC address of M1 and a destination MAC of M2. If PE1
does not know where M2 is, it will multicast the packet to PE2 and does not know where M2 is, it will multicast the packet to PE2 and
PE3. When PE2 receives the packet, it will have an inner label of PE3. When PE2 receives the packet, it will have an inner label of
201. PE2 can conclude that the source MAC address M1 is behind PE1, 201. PE2 can conclude that the source MAC address M1 is behind PE1,
since it distributed the label 201 to PE1. It can therefore since it distributed the label 201 to PE1. It can therefore
skipping to change at page 12, line 31 skipping to change at page 13, line 20
---- ---- ---- ----
7.1. MAC Address Aging 7.1. MAC Address Aging
PEs that learn remote MAC addresses need to have an aging mechanism PEs that learn remote MAC addresses need to have an aging mechanism
to remove unused entries associated with a VC Label. This is to remove unused entries associated with a VC Label. This is
important both for conservation of memory as well as for important both for conservation of memory as well as for
administrative purposes. For example, if a customer site A is shut administrative purposes. For example, if a customer site A is shut
down, eventually, the other PEs should unlearn A's MAC address. down, eventually, the other PEs should unlearn A's MAC address.
As packets arrive, MAC addresses are remembered. The aging timer As packets arrive, MAC addresses are remembered. The aging timer for
for MAC address M SHOULD be reset when a packet is received with MAC address M SHOULD be reset when a packet is received with source
source MAC address M. MAC address M.
8. A Hierarchical VPLS Model 8. A Hierarchical VPLS Model
The solution described above requires a full mesh of tunnel LSPs The solution described above requires a full mesh of tunnel LSPs
between all the PE routers that participate in the VPLS service. between all the PE routers that participate in the VPLS service.
For each VPLS service, n*(n-1)/2 pseudowires must be setup between For each VPLS service, n*(n-1)/2 PWs must be setup between the PE
the PE routers. While this creates signaling overhead, the real routers. While this creates signaling overhead, the real detriment
detriment to large scale deployment is the packet replication to large scale deployment is the packet replication requirements for
requirements for each provisioned VCs on a PE router. Hierarchical each provisioned VCs on a PE router. Hierarchical connectivity,
connectivity, described in this document reduces signaling and described in this document reduces signaling and replication
replication overhead to allow large scale deployment. overhead to allow large scale deployment.
In many cases, service providers place smaller edge devices in In many cases, service providers place smaller edge devices in
multi-tenant buildings and aggregate them into a PE device in a multi-tenant buildings and aggregate them into a PE device in a
large Central Office (CO) facility. In some instances, standard IEEE large Central Office (CO) facility. In some instances, standard IEEE
802.1q (Dot 1Q) tagging techniques may be used to facilitate mapping 802.1q (Dot 1Q) tagging techniques may be used to facilitate mapping
CE interfaces to PE VPLS access points. CE interfaces to PE VPLS access points.
It is often beneficial to extend the VPLS service tunneling It is often beneficial to extend the VPLS service tunneling
techniques into the MTU (multi-tenant unit) domain. This can be techniques into the MTU (multi-tenant unit) domain. This can be
accomplished by treating the MTU device as a PE device and accomplished by treating the MTU device as a PE device and
provisioning pseudowires between it and every other edge, as an provisioning PWs between it and every other edge, as an basic VPLS.
basic VPLS. An alternative is to utilize [PWE3-ETHERNET] An alternative is to utilize [PWE3-ETHERNET] PWs or Q-in-Q logical
pseudowires or Q-in-Q logical interfaces between the MTU and interfaces between the MTU and selected VPLS enabled PE routers. Q-
selected VPLS enabled PE routers. Q-in-Q encapsulation is another in-Q encapsulation is another form of L2 tunneling technique, which
form of L2 tunneling technique, which can be used in conjunction can be used in conjunction with MPLS signaling as will be described
with MPLS signaling as will be described later. The following two later. The following two sections focus on this alternative
sections focus on this alternative approach. The VPLS core approach. The VPLS core PWs (Hub) are augmented with access PWs
pseudowires (Hub) are augmented with access pseudowires (Spoke) to (Spoke) to form a two-tier hierarchical VPLS (H-VPLS).
form a two-tier hierarchical VPLS (H-VPLS).
Spoke pseudowires may be implemented using any L2 tunneling Spoke PWs may be implemented using any L2 tunneling mechanism,
mechanism, expanding the scope of the first tier to include non- expanding the scope of the first tier to include non-bridging VPLS
bridging VPLS PE routers. The non-bridging PE router would extend a PE routers. The non-bridging PE router would extend a Spoke PW from
Spoke pseudowire from a Layer-2 switch that connects to it, through a Layer-2 switch that connects to it, through the service core
the service core network, to a bridging VPLS PE router supporting network, to a bridging VPLS PE router supporting Hub PWs. We also
Hub pseudowires. We also describe how VPLS-challenged nodes and describe how VPLS-challenged nodes and low-end CEs without MPLS
low-end CEs without MPLS capabilities may participate in a capabilities may participate in a hierarchical VPLS.
hierarchical VPLS.
8.1. Hierarchical connectivity 8.1. Hierarchical connectivity
This section describes the hub and spoke connectivity model and This section describes the hub and spoke connectivity model and
describes the requirements of the bridging capable and non-bridging describes the requirements of the bridging capable and non-bridging
MTU devices for supporting the spoke connections. MTU devices for supporting the spoke connections.
For rest of this discussion we will refer to a bridging capable MTU For rest of this discussion we will refer to a bridging capable MTU
device as MTU-s and a non-bridging capable PE device as PE-r. A device as MTU-s and a non-bridging capable PE device as PE-r. A
routing and bridging capable device will be referred to as PE-rs. routing and bridging capable device will be referred to as PE-rs.
8.1.1. Spoke connectivity for bridging-capable devices 8.1.1. Spoke connectivity for bridging-capable devices
As shown in the figure below, consider the case where an MTU-s As shown in the figure below, consider the case where an MTU-s
device has a single connection to the PE-rs device placed in the CO. device has a single connection to the PE-rs device placed in the CO.
The PE-rs devices are connected in a basic VPLS full mesh. For each The PE-rs devices are connected in a basic VPLS full mesh. For each
VPLS service, a single spoke pseudowire is set up between the MTU-s VPLS service, a single spoke PW is set up between the MTU-s and the
and the PE-rs based on [PWE3-CTRL]. Unlike traditional pseudowires PE-rs based on [PWE3-CTRL]. Unlike traditional PWs that terminate on
that terminate on a physical (or a VLAN-tagged logical) port at each a physical (or a VLAN-tagged logical) port at each end, the spoke PW
end, the spoke pseudowire terminates on a virtual bridge instance on terminates on a virtual bridge instance on the MTU-s and the PE-rs
the MTU-s and the PE-rs devices. devices.
PE2-rs PE2-rs
------ ------
/ \ / \
| -- | | -- |
| / \ | | / \ |
CE-1 | \B / | CE-1 | \B / |
\ \ -- / \ \ -- /
\ /------ \ /------
\ MTU-s PE1-rs / | \ MTU-s PE1-rs / |
skipping to change at page 14, line 40 skipping to change at page 15, line 15
-- --
/ \ / \
\B / = Virtual VPLS(Bridge)Instance \B / = Virtual VPLS(Bridge)Instance
-- --
Agg = Layer-2 Aggregation Agg = Layer-2 Aggregation
The MTU-s device and the PE-rs device treat each spoke connection The MTU-s device and the PE-rs device treat each spoke connection
like an access port of the VPLS service. On access ports, the like an access port of the VPLS service. On access ports, the
combination of the physical port and/or the VLAN tag is used to combination of the physical port and/or the VLAN tag is used to
associate the traffic to a VPLS instance while the pseudowire tag associate the traffic to a VPLS instance while the PW tag (e.g., VC
(e.g., VC label) is used to associate the traffic from the virtual label) is used to associate the traffic from the virtual spoke port
spoke port with a VPLS instance, followed by a standard L2 lookup to with a VPLS instance, followed by a standard L2 lookup to identify
identify which customer port the frame needs to be sent to. which customer port the frame needs to be sent to.
8.1.1.1. MTU-s Operation 8.1.1.1. MTU-s Operation
MTU-s device is defined as a device that supports layer-2 switching MTU-s device is defined as a device that supports layer-2 switching
functionality and does all the normal bridging functions of learning functionality and does all the normal bridging functions of learning
and replication on all its ports, including the virtual spoke port. and replication on all its ports, including the virtual spoke port.
Packets to unknown destination are replicated to all ports in the Packets to unknown destination are replicated to all ports in the
service including the virtual spoke port. Once the MAC address is service including the virtual spoke port. Once the MAC address is
learned, traffic between CE1 and CE2 will be switched locally by the learned, traffic between CE1 and CE2 will be switched locally by the
MTU-s device saving the link capacity of the connection to the PE- MTU-s device saving the link capacity of the connection to the PE-
rs. Similarly traffic between CE1 or CE2 and any remote destination rs. Similarly traffic between CE1 or CE2 and any remote destination
is switched directly on to the spoke connection and sent to the PE- is switched directly on to the spoke connection and sent to the PE-
rs over the point-to-point pseudowire. rs over the point-to-point PW.
Since the MTU-s is bridging capable, only a single pseudowire is Since the MTU-s is bridging capable, only a single PW is required
required per VPLS instance for any number of access connections in per VPLS instance for any number of access connections in the same
the same VPLS service. This further reduces the signaling overhead VPLS service. This further reduces the signaling overhead between
between the MTU-s and PE-rs. the MTU-s and PE-rs.
If the MTU-s is directly connected to the PE-rs, other encapsulation If the MTU-s is directly connected to the PE-rs, other encapsulation
techniques such as Q-in-Q can be used for the spoke connection techniques such as Q-in-Q can be used for the spoke connection PW.
pseudowire.
8.1.1.2. PE-rs Operation 8.1.1.2. PE-rs Operation
The PE-rs device is a device that supports all the bridging The PE-rs device is a device that supports all the bridging
functions for VPLS service and supports the routing and MPLS functions for VPLS service and supports the routing and MPLS
encapsulation, i.e. it supports all the functions described for a encapsulation, i.e. it supports all the functions described for a
basic VPLS as described above. basic VPLS as described above.
The operation of PE-rs is independent of the type of device at the The operation of PE-rs is independent of the type of device at the
other end of the spoke pseudowire. Thus, the spoke pseudowire from other end of the spoke PW. Thus, the spoke PW from the PE-r is
the PE-r is treated as a virtual port and the PE-rs device will treated as a virtual port and the PE-rs device will switch traffic
switch traffic between the spoke pseudowire, hub pseudowires, and between the spoke PW, hub PWs, and access ports once it has learned
access ports once it has learned the MAC addresses. the MAC addresses.
8.1.2. Advantages of spoke connectivity 8.1.2. Advantages of spoke connectivity
Spoke connectivity offers several scaling and operational advantages Spoke connectivity offers several scaling and operational advantages
for creating large scale VPLS implementations, while retaining the for creating large scale VPLS implementations, while retaining the
ability to offer all the functionality of the VPLS service. ability to offer all the functionality of the VPLS service.
- Eliminates the need for a full mesh of tunnels and full mesh of - Eliminates the need for a full mesh of tunnels and full mesh of
pseudowires per service between all devices participating in the PWs per service between all devices participating in the VPLS
VPLS service. service.
- Minimizes signaling overhead since fewer pseudowires are required - Minimizes signaling overhead since fewer PWs are required for
for the VPLS service. the VPLS service.
- Segments VPLS nodal discovery. MTU-s needs to be aware of only - Segments VPLS nodal discovery. MTU-s needs to be aware of only
the PE-rs node although it is participating in the VPLS service the PE-rs node although it is participating in the VPLS service
that spans multiple devices. On the other hand, every VPLS PE-rs that spans multiple devices. On the other hand, every VPLS PE-
must be aware of every other VPLS PE-rs device and all of it's rs must be aware of every other VPLS PE-rs device and all of
locally connected MTU-s and PE-r. it's locally connected MTU-s and PE-r.
- Addition of other sites requires configuration of the new MTU-s - Addition of other sites requires configuration of the new MTU-s
device but does not require any provisioning of the existing MTU-s device but does not require any provisioning of the existing
devices on that service. MTU-s devices on that service.
- Hierarchical connections can be used to create VPLS service that - Hierarchical connections can be used to create VPLS service
spans multiple service provider domains. This is explained in a that spans multiple service provider domains. This is explained
later section. in a later section.
8.1.3. Spoke connectivity for non-bridging devices 8.1.3. Spoke connectivity for non-bridging devices
In some cases, a bridging PE-rs device may not be deployed in a CO In some cases, a bridging PE-rs device may not be deployed in a CO
or a multi-tenant building while a PE-r might already be deployed. or a multi-tenant building while a PE-r might already be deployed.
If there is a need to provide VPLS service from the CO where the PE- If there is a need to provide VPLS service from the CO where the PE-
rs device is not available, the service provider may prefer to use rs device is not available, the service provider may prefer to use
the PE-r device in the interim. In this section, we explain how a the PE-r device in the interim. In this section, we explain how a
PE-r device that does not support any of the VPLS bridging PE-r device that does not support any of the VPLS bridging
functionality can participate in the VPLS service. functionality can participate in the VPLS service.
As shown in this figure, the PE-r device creates a point-to-point As shown in this figure, the PE-r device creates a point-to-point
tunnel LSP to a PE-rs device. Then for every access port that needs tunnel LSP to a PE-rs device.
PE2-rs PE2-rs
------ ------
/ \ / \
| -- | | -- |
| / \ | | / \ |
CE-1 | \B / | CE-1 | \B / |
\ \ -- / \ \ -- /
\ /------ \ /------
\ PE-r PE1-rs / | \ PE-r PE1-rs / |
skipping to change at page 16, line 37 skipping to change at page 17, line 15
/ \ | / \ |
---- \------ ---- \------
| Agg| / \ | Agg| / \
---- | -- | ---- | -- |
/ \ | / \ | / \ | / \ |
CE-2 CE-3 | \B / | CE-2 CE-3 | \B / |
\ -- / \ -- /
------ ------
PE3-rs PE3-rs
to participate in a VPLS service, the PE-r device creates a point- Then for every access port that needs to participate in a VPLS
to-point [PWE3-ETHERNET] pseudowire that terminates on the physical service, the PE-r device creates a point-to-point [PWE3-ETHERNET] PW
port at the PE-r and terminates on the virtual bridge instance of that terminates on the physical port at the PE-r and terminates on
the VPLS service at the PE-rs. the virtual bridge instance of the VPLS service at the PE-rs.
8.1.3.1. PE-r Operation
The PE-r device is defined as a device that supports routing but The PE-r device is defined as a device that supports routing but
does not support any bridging functions. However, it is capable of does not support any bridging functions. However, it is capable of
setting up [PWE3-ETHERNET] pseudowires between itself and the PE-rs. setting up [PWE3-ETHERNET] PWs between itself and the PE-rs. For
For every port that is supported in the VPLS service, a [PWE3- every port that is supported in the VPLS service, a [PWE3-ETHERNET]
ETHERNET] pseudowire is setup from the PE-r to the PE-rs. Once the PW is setup from the PE-r to the PE-rs. Once the PWs are setup,
pseudowires are setup, there is no learning or replication function there is no learning or replication function required on part of the
required on part of the PE-r. All traffic received on any of the PE-r. All traffic received on any of the access ports is transmitted
access ports is transmitted on the pseudowire. Similarly all on the PW. Similarly all traffic received on a PW is transmitted to
traffic received on a pseudowire is transmitted to the access port the access port where the PW terminates. Thus traffic from CE1
where the pseudowire terminates. Thus traffic from CE1 destined for destined for CE2 is switched at PE-rs and not at PE-r.
CE2 is switched at PE-rs and not at PE-r.
Note that in the case where PE-r devices use Provider VLANs (P-VLAN)
as demultiplexors instead of PWs, and PE-rs can treat them as such,
PE-rs can map these "circuits" into a VPLS domain and provide
bridging support between them.
This approach adds more overhead than the bridging capable (MTU-s) This approach adds more overhead than the bridging capable (MTU-s)
spoke approach since a pseudowire is required for every access port spoke approach since a PW is required for every access port that
that participates in the service versus a single pseudowire required participates in the service versus a single PW required per service
per service (regardless of access ports) when a MTU-s type device is (regardless of access ports) when a MTU-s type device is used.
used. However, this approach offers the advantage of offering a However, this approach offers the advantage of offering a VPLS
VPLS service in conjunction with a routed internet service without service in conjunction with a routed internet service without
requiring the addition of new MTU device. requiring the addition of new MTU device.
8.2. Redundant Spoke Connections 8.2. Redundant Spoke Connections
An obvious weakness of the hub and spoke approach described thus far An obvious weakness of the hub and spoke approach described thus far
is that the MTU device has a single connection to the PE-rs device. is that the MTU device has a single connection to the PE-rs device.
In case of failure of the connection or the PE-rs device, the MTU In case of failure of the connection or the PE-rs device, the MTU
device suffers total loss of connectivity. device suffers total loss of connectivity.
In this section we describe how the redundant connections can be In this section we describe how the redundant connections can be
skipping to change at page 17, line 26 skipping to change at page 18, line 4
An obvious weakness of the hub and spoke approach described thus far An obvious weakness of the hub and spoke approach described thus far
is that the MTU device has a single connection to the PE-rs device. is that the MTU device has a single connection to the PE-rs device.
In case of failure of the connection or the PE-rs device, the MTU In case of failure of the connection or the PE-rs device, the MTU
device suffers total loss of connectivity. device suffers total loss of connectivity.
In this section we describe how the redundant connections can be In this section we describe how the redundant connections can be
provided to avoid total loss of connectivity from the MTU device. provided to avoid total loss of connectivity from the MTU device.
The mechanism described is identical for both, MTU-s and PE-r type The mechanism described is identical for both, MTU-s and PE-r type
of devices of devices
8.2.1. Dual-homed MTU device 8.2.1. Dual-homed MTU device
To protect from connection failure of the pseudowire or the failure To protect from connection failure of the PW or the failure of the
of the PE-rs device, the MTU-s device or the PE-r is dual-homed into PE-rs device, the MTU-s device or the PE-r is dual-homed into two
two PE-rs devices, as shown in figure-3. The PE-rs devices must be PE-rs devices, as shown in figure-3. The PE-rs devices must be part
part of the same VPLS service instance. of the same VPLS service instance.
An MTU-s device will setup two [PWE3-ETHERNET] pseudowires (one each An MTU-s device will setup two [PWE3-ETHERNET] PWs (one each to PE-
to PE-rs1 and PE-rs2) for each VPLS instance. One of the two rs1 and PE-rs2) for each VPLS instance. One of the two PWs is
pseudowires is designated as primary and is the one that is actively designated as primary and is the one that is actively used under
used under normal conditions, while the second pseudowire is normal conditions, while the second PW is designated as secondary
designated as secondary and is held in a standby state. The MTU and is held in a standby state. The MTU device negotiates the PW
device negotiates the pseudowire labels for both the primary and labels for both the primary and secondary PWs, but does not use the
secondary pseudowires, but does not use the secondary pseudowire secondary PW unless the primary PW fails. Since only one link is
unless the primary pseudowire fails. Since only one link is active active at a given time, a loop does not exist and hence 802.1D
at a given time, a loop does not exist and hence 802.1D spanning spanning tree is not required.
tree is not required.
PE2-rs PE2-rs
------ ------
/ \ / \
| -- | | -- |
| / \ | | / \ |
CE-1 | \B / | CE-1 | \B / |
\ \ -- / \ \ -- /
\ /------ \ /------
\ MTU-s PE1-rs / | \ MTU-s PE1-rs / |
skipping to change at page 18, line 33 skipping to change at page 18, line 49
/ \ / \ / \ / \
CE-2 \ | -- | CE-2 \ | -- |
\ Secondary PW | / \ | \ Secondary PW | / \ |
- - - - - - - - - - - - - - - - - |-\B / | - - - - - - - - - - - - - - - - - |-\B / |
\ -- / \ -- /
------ ------
PE3-rs PE3-rs
8.2.2. Failure detection and recovery 8.2.2. Failure detection and recovery
The MTU-s device controls the usage of the pseudowires to the PE-rs The MTU-s device controls the usage of the PWs to the PE-rs nodes.
nodes. Since LDP signaling is used to negotiate the pseudowire Since LDP signaling is used to negotiate the PW labels, the hello
labels, the hello messages used for the LDP session can be used to messages used for the LDP session can be used to detect failure of
detect failure of the primary pseudowire. the primary PW.
Upon failure of the primary pseudowire, MTU-s device immediately Upon failure of the primary PW, MTU-s device immediately switches to
switches to the secondary pseudowire. At this point the PE3-rs the secondary PW. At this point the PE3-rs device that terminates
device that terminates the secondary pseudowire starts learning MAC the secondary PW starts learning MAC addresses on the spoke PW. All
addresses on the spoke pseudowire. All other PE-rs nodes in the other PE-rs nodes in the network think that CE-1 and CE-2 are behind
network think that CE-1 and CE-2 are behind PE1-rs and may continue PE1-rs and may continue to send traffic to PE1-rs until they learn
to send traffic to PE1-rs until they learn that the devices are now that the devices are now behind PE3-rs. The relearning process can
behind PE3-rs. The relearning process can take a long time and may take a long time and may adversely affect the connectivity of higher
adversely affect the connectivity of higher level protocols from CE1 level protocols from CE1 and CE2. To enable faster convergence, the
and CE2. To enable faster convergence, the PE3-rs device where the PE3-rs device where the secondary PW got activated may send out a
secondary pseudowire got activated may send out a flush message, flush message (as explained in section 4.2), using the MAC TLV as
using the MAC TLV as defined in Section 6, to all PE-rs nodes. Upon defined in Section 6, to all PE-rs nodes. Upon receiving the
receiving the message, PE-rs nodes flush the MAC addresses message, PE-rs nodes flush the MAC addresses associated with that
associated with that VPLS instance. VPLS instance.
8.3. Multi-domain VPLS service 8.3. Multi-domain VPLS service
Hierarchy can also be used to create a large scale VPLS service Hierarchy can also be used to create a large scale VPLS service
within a single domain or a service that spans multiple domains within a single domain or a service that spans multiple domains
without requiring full mesh connectivity between all VPLS capable without requiring full mesh connectivity between all VPLS capable
devices. Two fully meshed VPLS networks are connected together using devices. Two fully meshed VPLS networks are connected together using
a single LSP tunnel between the VPLS "border" devices. A single a single LSP tunnel between the VPLS "border" devices. A single
spoke pseudowire per VPLS service is set up to connect the two spoke PW per VPLS service is set up to connect the two domains
domains together. together.
When more than two domains need to be connected, a full mesh of When more than two domains need to be connected, a full mesh of
inter-domain spokes is created between border PEs. Forwarding rules inter-domain spokes is created between border PEs. Forwarding rules
over this mesh are identical to the rules defined in section 5. over this mesh are identical to the rules defined in section 5.
This creates a three-tier hierarchical model that consists of a hub- This creates a three-tier hierarchical model that consists of a hub-
and-spoke topology between MTU-s and PE-rs devices, a full-mesh and-spoke topology between MTU-s and PE-rs devices, a full-mesh
topology between PE-rs, and a full mesh of inter-domain spokes topology between PE-rs, and a full mesh of inter-domain spokes
between border PE-rs devices. between border PE-rs devices.
This document does not specify how redundant border PEs per domain
per VPLS instance can be supported.
9. Hierarchical VPLS model using Ethernet Access Network 9. Hierarchical VPLS model using Ethernet Access Network
In this section the hierarchical model is expanded to include an In this section the hierarchical model is expanded to include an
Ethernet access network. This model retains the hierarchical Ethernet access network. This model retains the hierarchical
architecture discussed previously in that it leverages the full-mesh architecture discussed previously in that it leverages the full-mesh
topology among PE-rs devices; however, no restriction is imposed on topology among PE-rs devices; however, no restriction is imposed on
the topology of the Ethernet access network (e.g., the topology the topology of the Ethernet access network (e.g., the topology
between MTU-s and PE-rs devices are not restricted to hub and spoke). between MTU-s and PE-rs devices are not restricted to hub and
spoke).
The motivation for an Ethernet access network is that Ethernet-based The motivation for an Ethernet access network is that Ethernet-based
networks are currently deployed by some service providers to offer networks are currently deployed by some service providers to offer
VPLS services to their customers. Therefore, it is important to VPLS services to their customers. Therefore, it is important to
provide a mechanism that allows these networks to integrate with an provide a mechanism that allows these networks to integrate with an
IP or MPLS core to provide scalable VPLS services. IP or MPLS core to provide scalable VPLS services.
One approach of tunneling a customer's Ethernet traffic via an One approach of tunneling a customer's Ethernet traffic via an
Ethernet access network is to add an additional VLAN tag to the Ethernet access network is to add an additional VLAN tag to the
customer's data (which may be either tagged or untagged). The customer's data (which may be either tagged or untagged). The
additional tag is referred to as Provider's VLAN (P-VLAN). Inside the additional tag is referred to as Provider's VLAN (P-VLAN). Inside
provider's network each P-VLAN designates a customer or more the provider's network each P-VLAN designates a customer or more
specifically a VPLS instance for that customer. Therefore, there is a specifically a VPLS instance for that customer. Therefore, there is
one to one correspondence between a P-VLAN and a VPLS instance. a one to one correspondence between a P-VLAN and a VPLS instance. In
this model, the MTU-S device needs to have the capability of adding
In this model, the MTU-S device needs to have the capability of the additional P-VLAN tag for non-multiplexed customer UNI port
adding the additional P-VLAN tag for non-multiplexed customer UNI where customer VLANs are not used as service delimiter. If customer
port where customer VLANs are not used as service delimiter. If VLANs need to be treated as service delimiter (e.g., customer UNI
customer VLANs need to be treated as service delimiter (e.g., port is a multiplexed port), then the MTU-s needs to have the
customer UNI port is a multiplexed port), then the MTU-s needs to additional capability of translating a customer VLAN (C-VLAN) to a
have the additional capability of translating a customer VLAN (C- P-VLAN in order to resolve overlapping VLAN-ids used by different
VLAN) to a P-VLAN in order to resolve overlapping VLAN-ids used by customers. Therefore, the MTU-s device in this model can be
different customers. Therefore, the MTU-s device in this model can be
considered as a typical bridge with this additional UNI capability. considered as a typical bridge with this additional UNI capability.
The PE-rs device needs to be able to perform bridging functionality The PE-rs device needs to be able to perform bridging functionality
over the standard Ethernet ports toward the access network as well as over the standard Ethernet ports toward the access network as well
over the pseudowires toward the network core. The set of pseudowires as over the PWs toward the network core. The set of PWs that
that corresponds to a VPLS instance would look just like a P-VLAN to corresponds to a VPLS instance would look just like a P-VLAN to the
the bridge portion of the PE-rs and that is why sometimes it is bridge portion of the PE-rs and that is why sometimes it is referred
referred to as Emulated VLAN. In this model the PE-rs may need to run to as Emulated VLAN. In this model the PE-rs may need to run STP
STP protocol in addition to split-horizon. Split horizon is run over protocol in addition to split-horizon. Split horizon is run over
MPLS-core; whereas, STP is run over the access network to accommodate MPLS-core; whereas, STP is run over the access network to
any arbitrary access topology. In this model, the PE-rs needs to map accommodate any arbitrary access topology. In this model, the PE-rs
a P-VLAN to a VPLS-instance and its associated pseudowires and vise needs to map a P-VLAN to a VPLS-instance and its associated PWs and
versa. vise versa.
The details regarding bridge operation for MTU-s and PE-rs (e.g., The details regarding bridge operation for MTU-s and PE-rs (e.g.,
encapsulation format for QinQ messages, customer's Ethernet control encapsulation format for QinQ messages, customer's Ethernet control
protocol handling, etc.) are outside of the scope of this document protocol handling, etc.) are outside of the scope of this document
and they are covered in [802.1ad]. However, the relevant part is the and they are covered in [802.1ad]. However, the relevant part is the
interaction between the bridge module and the MPLS/IP pseudowires in interaction between the bridge module and the MPLS/IP PWs in the PE-
the PE-rs device. rs device.
9.1. Scalability 9.1. Scalability
Given that each P-VLAN corresponds to a VPLS instance, one may think Given that each P-VLAN corresponds to a VPLS instance, one may think
that the total number of VPLS instances supported is limited to 4K. that the total number of VPLS instances supported is limited to 4K.
However, the 4K limit applies only to each Ethernet access network However, the 4K limit applies only to each Ethernet access network
(Ethernet island) and not to the entire network. The SP network, in (Ethernet island) and not to the entire network. The SP network, in
this model, consists of a core MPLS/IP network that connects many this model, consists of a core MPLS/IP network that connects many
Ethernet islands. Therefore, the number of VPLS instances can scale Ethernet islands. Therefore, the number of VPLS instances can scale
accordingly with the number of Ethernet islands (a metro region can accordingly with the number of Ethernet islands (a metro region can
be represented by one or more islands). Each island may consist of be represented by one or more islands). Each island may consist of
many MTU-s devices, several aggregators, and one or more PE-rs many MTU-s devices, several aggregators, and one or more PE-rs
devices. The PE-rs devices enable a P-VLAN to be extended from one devices. The PE-rs devices enable a P-VLAN to be extended from one
island to others using a set of pseudowires (associated with that island to others using a set of PWs (associated with that VPLS
VPLS instance) and providing a loop free mechanism across the core instance) and providing a loop free mechanism across the core
network through split-horizon. Since a P-VLAN serves as a service network through split-horizon. Since a P-VLAN serves as a service
delimiter within the provider's network, it does not get carried over delimiter within the provider's network, it does not get carried
the pseudowires and furthermore the mapping between P-VLAN and the over the PWs and furthermore the mapping between P-VLAN and the PWs
pseudowires is a local matter. This means a VPLS instance can be is a local matter. This means a VPLS instance can be represented by
represented by different P-VLAN in different Ethernet islands and different P-VLAN in different Ethernet islands and furthermore each
furthermore each island can support 4K VPLS instances independent island can support 4K VPLS instances independent from one another.
from one another.
9.2. Dual Homing and Failure Recovery 9.2. Dual Homing and Failure Recovery
In this model, an MTU-s can be dual or triple homed to different In this model, an MTU-s can be dual or triple homed to different
devices (aggregators and/or PE-rs devices). The failure protection devices (aggregators and/or PE-rs devices). The failure protection
for access network nodes and links can be provided through running for access network nodes and links can be provided through running
MSTP in each island. The MSTP of each island is independent from MSTP in each island. The MSTP of each island is independent from
other islands and do not interact with each other. If an island has other islands and do not interact with each other. If an island has
more than one PE-rs, then a dedicated full-mesh of pseudowires is more than one PE-rs, then a dedicated full-mesh of PWs is used among
used among these PE-rs devices for carrying the SP BPDU packets for these PE-rs devices for carrying the SP BPDU packets for that
that island. On a per P-VLAN basis, the MSTP will designate a single island. On a per P-VLAN basis, the MSTP will designate a single PE-
PE-rs to be used for carrying the traffic across the core. The loop- rs to be used for carrying the traffic across the core. The loop-
free protection through the core is performed using split-horizon and free protection through the core is performed using split-horizon
the failure protection in the core is performed through standard and the failure protection in the core is performed through standard
IP/MPLS re-routing. IP/MPLS re-routing.
10. Significant Modifications 10. Significant Modifications
Between rev 04 and this one, these are the changes: Between rev 05 and this one, these are the changes:
o Fixed idnits - Incorporated comments from WG last call
- Fixed idnits
11. Contributors 11. Contributors
Loa Andersson, TLA Loa Andersson, TLA
Ron Haberman, Masergy Ron Haberman, Masergy
Juha Heinanen, Independent Juha Heinanen, Independent
Giles Heron, Tellabs Giles Heron, Tellabs
Sunil Khandekar, Alcatel Sunil Khandekar, Alcatel
Luca Martini, Cisco Luca Martini, Cisco
Pascal Menezes, Terabeam Pascal Menezes, Terabeam
skipping to change at page 21, line 41 skipping to change at page 22, line 7
Tom Soon, SBC Tom Soon, SBC
Nick Tingle, Alcatel Nick Tingle, Alcatel
12. Acknowledgments 12. Acknowledgments
We wish to thank Joe Regan, Kireeti Kompella, Anoop Ghanwani, Joel We wish to thank Joe Regan, Kireeti Kompella, Anoop Ghanwani, Joel
Halpern, Rick Wilder, Jim Guichard, Steve Phillips, Norm Finn, Matt Halpern, Rick Wilder, Jim Guichard, Steve Phillips, Norm Finn, Matt
Squire, Muneyoshi Suzuki, Waldemar Augustyn, Eric Rosen, Yakov Squire, Muneyoshi Suzuki, Waldemar Augustyn, Eric Rosen, Yakov
Rekhter, and Sasha Vainshtein for their valuable feedback. Rekhter, and Sasha Vainshtein for their valuable feedback.
We would also ike to thank Rajiv Papneja (ISOCORE), Winston Liu We would also like to thank Rajiv Papneja (ISOCORE), Winston Liu
(ISOCORE), and Charlie Hundall (Extreme) for identifying issues (Ixia), and Charlie Hundall (Extreme) for identifying issues with
with the draft in the course of the interoperability tests. the draft in the course of the interoperability tests.
13. Security Considerations 13. Security Considerations
A more comprehensive description of the security issues involved in A more comprehensive description of the security issues involved in
L2VPNs is covered in [VPN-SEC]. An unguarded VPLS service is L2VPNs is covered in [VPN-SEC]. An unguarded VPLS service is
vulnerable to some security issues which pose risks to the customer vulnerable to some security issues which pose risks to the customer
and provider networks. Most of the security issues can be avoided and provider networks. Most of the security issues can be avoided
through implementation of appropriate guards. A couple of them can through implementation of appropriate guards. A couple of them can
be prevented through existing protocols. be prevented through existing protocols.
. Data plane aspects - Data plane aspects
o Traffic isolation between VPLS domains is guaranteed by - Traffic isolation between VPLS domains is guaranteed by the
the use of per VPLS L2 FIB table and the use of per VPLS use of per VPLS L2 FIB table and the use of per VPLS PWs
pseudowires - The customer traffic, which consists of Ethernet frames, is
o The customer traffic, which consists of Ethernet frames, carried unchanged over VPLS. If security is required,
is carried unchanged over VPLS. If security is required,
the customer traffic SHOULD be encrypted and/or the customer traffic SHOULD be encrypted and/or
authenticated before entering the service provider network authenticated before entering the service provider network
o Preventing broadcast storms can be achieved by using - Preventing broadcast storms can be achieved by using
routers as CPE devices or by rate policing the amount of routers as CPE devices or by rate policing the amount of
broadcast traffic that customers can send. broadcast traffic that customers can send.
. Control plane aspects - Control plane aspects
o LDP security (authentication) methods as described in - LDP security (authentication) methods as described in [RFC-
[RFC-3036] SHOULD be applied. This would prevent 3036] SHOULD be applied. This would prevent
unauthorized participation by a PE in a VPLS. unauthorized participation by a PE in a VPLS.
. Denial of service attacks - Denial of service attacks
o Some means to limit the number of MAC addresses (per site - Some means to limit the number of MAC addresses (per site
per VPLS) that a PE can learn SHOULD be implemented. per VPLS) that a PE can learn SHOULD be implemented.
14. Full Copyright Statement IANA Considerations
Copyright (C) The Internet Society (2001). All Rights Reserved. The type field in the Mac TLV is defined as 0x404 in section 4.2.1
This document and translations of it may be copied and furnished to and is subject to IANA approval.
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be Copyright Notice
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an Copyright (C) The Internet Society (2004). This document is subject
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING to the rights, licenses and restrictions contained in BCP 78, and
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING except as set forth therein, the authors retain all their rights.
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
15. IPR Notice Disclaimer
This document and the information contained herein are provided on
an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
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IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
IPR Disclosure Acknowledgement
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The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
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16. Normative References Release Statement
By submitting this Internet-Draft, the authors accept the provisions
of Section 4 of RFC 3667.
Normative References
[PWE3-ETHERNET] "Encapsulation Methods for Transport of Ethernet [PWE3-ETHERNET] "Encapsulation Methods for Transport of Ethernet
Frames Over IP/MPLS Networks", draft-ietf-pwe3-ethernet-encap-06. Frames Over IP/MPLS Networks", draft-ietf-pwe3-ethernet-encap-
txt, Work in progress, April 2004. 08.txt, Work in progress, September 2004.
[PWE3-CTRL] "Transport of Layer 2 Frames over MPLS", draft-ietf- [PWE3-CTRL] "Transport of Layer 2 Frames over MPLS", draft-ietf-
pwe3-control-protocol-06.txt, Work in progress, March 2004. pwe3-control-protocol-06.txt, Work in progress, March 2004.
[802.1D-ORIG] Original 802.1D - ISO/IEC 10038, ANSI/IEEE Std 802.1D- [802.1D-ORIG] Original 802.1D - ISO/IEC 10038, ANSI/IEEE Std 802.1D-
1993 "MAC Bridges". 1993 "MAC Bridges".
[802.1D-REV] 802.1D - "Information technology - Telecommunications [802.1D-REV] 802.1D - "Information technology - Telecommunications
and information exchange between systems - Local and metropolitan and information exchange between systems - Local and metropolitan
area networks - Common specifications - Part 3: Media Access Control area networks - Common specifications - Part 3: Media Access Control
skipping to change at page 23, line 45 skipping to change at page 24, line 14
802.1j-1992 and 802.6k-1992. It incorporates P802.11c, P802.1p and 802.1j-1992 and 802.6k-1992. It incorporates P802.11c, P802.1p and
P802.12e." ISO/IEC 15802-3: 1998. P802.12e." ISO/IEC 15802-3: 1998.
[802.1Q] 802.1Q - ANSI/IEEE Draft Standard P802.1Q/D11, "IEEE [802.1Q] 802.1Q - ANSI/IEEE Draft Standard P802.1Q/D11, "IEEE
Standards for Local and Metropolitan Area Networks: Virtual Bridged Standards for Local and Metropolitan Area Networks: Virtual Bridged
Local Area Networks", July 1998. Local Area Networks", July 1998.
[RFC3036] "LDP Specification", L. Andersson, et al. RFC 3036. [RFC3036] "LDP Specification", L. Andersson, et al. RFC 3036.
January 2001. January 2001.
17. Informative References Informative References
[BGP-VPN] "BGP/MPLS VPNs". draft-ietf-l3vpn-rfc2547bis-01.txt, Work [BGP-VPN] "BGP/MPLS VPNs". draft-ietf-l3vpn-rfc2547bis-03.txt, Work
in Progress, September 2003. in Progress, October 2004.
[RADIUS-DISC] "Using Radius for PE-Based VPN Discovery", draft-ietf- [RADIUS-DISC] "Using Radius for PE-Based VPN Discovery", draft-ietf-
l2vpn-radius-pe-discovery-00.txt, Work in Progress, February 2004. l2vpn-radius-pe-discovery-00.txt, Work in Progress, February 2004.
[BGP-DISC] "Using BGP as an Auto-Discovery Mechanism for Network- [BGP-DISC] "Using BGP as an Auto-Discovery Mechanism for Network-
based VPNs", draft-ietf-l3vpn-bgpvpn-auto-02.txt, Work in Progress, based VPNs", draft-ietf-l3vpn-bgpvpn-auto-04.txt, Work in Progress,
April 2004. November 2004.
[LDP-DISC] "Discovering Nodes and Services in a VPLS Network",
draft-stokes-ppvpn-vpls-discover-00.txt, Work in Progress, June
2002.
[L2FRAME] "Framework for Layer 2 Virtual Private Networks (L2VPNs)", [L2FRAME] "Framework for Layer 2 Virtual Private Networks (L2VPNs)",
draft-ietf-l2vpn-l2-framework-04, Work in Progress, March 2004. draft-ietf-l2vpn-l2-framework-05, Work in Progress, June 2004.
[L2VPN-REQ] "Service Requirements for Layer-2 Provider Provisioned [L2VPN-REQ] "Service Requirements for Layer-2 Provider Provisioned
Virtual Private Networks", draft-ietf-l2vpn-requirements-01.txt, Virtual Private Networks", draft-ietf-l2vpn-requirements-03.txt,
Work in Progress, February 2004. Work in Progress, October 2005.
[VPN-SEC] "Security Framework for Provider Provisioned Virtual [VPN-SEC] "Security Framework for Provider Provisioned Virtual
Private Networks", draft-ietf-l3vpn-security-framework-01.txt, Work Private Networks", draft-ietf-l3vpn-security-framework-03.txt, Work
in Progress, February 2004. in Progress, November 2004.
[802.1ad] "IEEE standard for Provider Bridges", Work in Progress, [802.1ad] "IEEE standard for Provider Bridges", Work in Progress,
December 2002. December 2002.
Appendix 1. Signaling a VPLS Using the PWid FEC Element Appendix: VPLS Signaling using the PWid FEC Element
This section is being retained because live deployments use this This section is being retained because live deployments use this
version of the signaling for VPLS. version of the signaling for VPLS.
The VPLS signaling information is carried in a Label Mapping message The VPLS signaling information is carried in a Label Mapping message
sent in downstream unsolicited mode, which contains the following VC sent in downstream unsolicited mode, which contains the following VC
FEC TLV. FEC TLV.
VC, C, VC Info Length, Group ID, Interface parameters are as defined VC, C, VC Info Length, Group ID, Interface parameters are as defined
in [PWE3-CTRL]. in [PWE3-CTRL].
skipping to change at page 24, line 49 skipping to change at page 25, line 16
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group ID | | Group ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VCID | | VCID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface parameters | | Interface parameters |
~ ~ ~ ~
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
We use the Ethernet pseudowire type to identify pseudowires that We use the Ethernet PW type to identify PWs that carry Ethernet
carry Ethernet traffic for multipoint connectivity. traffic for multipoint connectivity.
In a VPLS, we use a VCID (which has been substituted with a more In a VPLS, we use a VCID (which has been substituted with a more
general identifier, to address extending the scope of a VPLS) to general identifier, to address extending the scope of a VPLS) to
identify an emulated LAN segment. Note that the VCID as specified identify an emulated LAN segment. Note that the VCID as specified in
in [PWE3-CTRL] is a service identifier, identifying a service [PWE3-CTRL] is a service identifier, identifying a service emulating
emulating a point-to-point virtual circuit. In a VPLS, the VCID is a point-to-point virtual circuit. In a VPLS, the VCID is a single
a single service identifier. service identifier.
18. Authors' Addresses Authors' Addresses
Marc Lasserre Marc Lasserre
Riverstone Networks Riverstone Networks
Email: marc@riverstonenet.com Email: marc@riverstonenet.com
Vach Kompella Vach Kompella
Alcatel Alcatel
Email: vach.kompella@alcatel.com Email: vach.kompella@alcatel.com
 End of changes. 

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