One document matched: draft-ram-l2vpn-ldp-vpls-etree-2pw-00.txt
Network Working Group Rafi Ram, Orckit-Corrigent
Internet Draft Amir Halperin, Orckit-Corrigent
Category: Standard Track Raymond Key, Telstra
Expires: April 2011
October 4, 2010
Extension to LDP-VPLS for E-Tree Using Two PW
draft-ram-l2vpn-ldp-vpls-etree-2pw-00.txt
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 4, 2011.
Abstract
This document proposes a solution for Metro Ethernet Forum (MEF)
Ethernet Tree (E-Tree) support in Virtual Private LAN Service using
LDP Signaling (LDP-VPLS) [RFC4762]. The proposed solution is
characterized by the use of two PWs between a pair of PEs. This
solution is applicable for both VPLS and H-VPLS.
Ram, et al. Expires April 2011 [Page 1]
Internet Draft Ext to LDP-VPLS for E-Tree 2-PW October 2010
Table of Contents
1. Introduction....................................................3
2. The Problem.....................................................3
3. The 2-PW Solution...............................................3
4. Extension to VPLS for E-Tree....................................4
4.1. AC E-Tree Type................................................4
4.2. PW VSI Type..................... .............................4
4.3. Additional Filtering in Data Forwarding.......................4
4.4. Root/Leaf PWs Signaling.......................................5
4.5. Supporting Remote ACs.........................................5
5. Backward Compatibility..........................................6
6. Compliance with Requirements....................................6
7. Security Considerations.........................................6
8. IANA Considerations.............................................6
9. Acknowledgements................................................6
10. References.....................................................7
10.1. Normative References.........................................7
10.2. Informative References.......................................7
Authors' Addresses.................................................7
Copyright Notice...................................................7
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
Ram, et al. Expires April 2011 [Page 2]
Internet Draft Ext to LDP-VPLS for E-Tree 2-PW October 2010
1. Introduction
This document proposes a solution for Metro Ethernet Forum (MEF)
Ethernet Tree (E-Tree) support in Virtual Private LAN Service using
LDP Signaling (LDP-VPLS) [RFC4762].
[Draft ETree VPLS Req] is used as requirement specification.
The proposed solution is characterized by the use of two PWs between
a pair of PEs, which requires extension to the currnet VPLS standard
[RFC4762].
This solution is applicable for both VPLS and H-VPLS.
The proposed solution is composed of three main components:
- Current standard LDP-VPLS [RFC4762]
- Extension to LDP-VPLS specified in this document
- PE local split horizon mechanism
2. The Problem
[Draft ETree VPLS Req] identifies the problem when there are two or
more PEs with both Root AC and Leaf AC.
<--------------E-Tree-------------->
+---------+ +---------+
| PE1 | | PE2 |
+---+ | +---+ | | +---+ | +---+
|CE1+----AC1----+--+ | | | | +--+----AC3----+CE3|
+---+ (Root AC) | | V | | | | V | | (Root AC) +---+
| | S +--+------PW------+--+ S | |
+---+ | | I | | | | I | | +---+
|CE2+----AC2----+--+ | | | | +--+----AC4----+CE4|
+---+ (Leaf AC) | +---+ | | +---+ | (Leaf AC) +---+
+---------+ +---------+
Figure 1: Problem Scenario for Leaf-to-Leaf Communication Restriction
When PE2 receives a frame from PE1 via the Ethernet PW,
- PE2 does not know whether the ingress AC is a Leaf AC or not
- PE2 does not have sufficient information to enforce the
Leaf-to-Leaf communication restriction
3. The 2-PW Solution
A simple fix is to carry additional information with each frame on
the PW, indicating whether the frame is originated from a Leaf AC or
a Root AC on the ingress PE.
This solution uses a pair of PWs between a pair of VPLS PEs.
- First PW is used for frames originated from Root ACs
- Second PW is used for frames originated from Leaf ACs
Ram, et al. Expires April 2011 [Page 3]
Internet Draft Ext to LDP-VPLS for E-Tree 2-PW October 2010
<--------------E-Tree-------------->
+---------+ +---------+
| PE1 | | PE2 |
+---+ | +---+ | | +---+ | +---+
|CE1+----AC1----+--+ | | | | +--+----AC3----+CE3|
+---+ (Root AC) | | V +--+-VSI Root PW -+--+ V | | (Root AC) +---+
| | S | | | | S | |
+---+ | | I +--+-VSI Leaf PW -+--+ I | | +---+
|CE2+----AC2----+--+ | | | | +--+----AC4----+CE4|
+---+ (Leaf AC) | +---+ | | +---+ | (Leaf AC) +---+
+---------+ +---------+
Figure 2: Two-PW Solution for Leaf-to-Leaf Communication Restriction
Extension to current VPLS standard [RFC4762] is required.
4. Extension to VPLS for E-Tree
4.1. AC E-Tree Type
Each AC connected to a specific VPLS instance on a PE MUST have an AC
E-Tree Type attribute, either Leaf AC or Root AC. For backward
compatibility, the default AC E-Tree Type MUST be Root.
This AC E-Tree Type is locally configured on a PE and no signaling is
required between PEs.
4.2. PW VSI Type
Use a pair of PWs to interconnect between a pair of VPLS PEs:
- Root PW use VSI Root PW type
- Leaf PW use VSI Leaf PW type
Both PWs SHALL use the same PW-id. This is for indicating in the
local node that a pair of such PWs are part of the same logical VSI
interface.
On reception, the two PWs SHALL be handled as the same logical VSI
interface with respect to MAC address learning/forwarding, e.g.
traffic SHALL not forwarded between such PWs, MAC addresses arrives
from one of the PWs SHALL be learnt with a common logical VSI
interface.
The VPLS processing entity SHALL send Root originated traffic via
the Root PW, and SHALL send Leaf originated traffic via the Leaf PW.
4.3. Additional Filtering in Data Forwarding
An egress PE SHALL NOT deliver a frame originated from a Leaf AC to
another Leaf AC.
Ram, et al. Expires April 2011 [Page 4]
Internet Draft Ext to LDP-VPLS for E-Tree 2-PW October 2010
The following specifies how AC E-Tree type per frame is determined:
- A frame received from a root PW indicates that the frame was
originated from a Root AC.
- A frame received from a leaf PW indicates that the frame was
originated from a Leaf AC.
- For the case where both ingress AC and egress AC are on the same
PE, local split horizon implementation on the PE will be
sufficient, and is not further discussed in this document.
4.4. Root/Leaf PWs Signaling
Signaling of root and leaf PWs is require only when two PWs are used
for interconnecting between pair of VSIs. For this purpose a new PW
types SHALL be used:
- VSI Root PW type SHALL be used to signal a root PW.
- VSI Leaf PW type SHALL be used to signal a leaf PW.
PW type signaling rules remains as defined in [RFC4447].
4.5. Supporting Remote AC
When PW is used to interconnect between VSI and a remote AC (e.g. the
PW1, PW2 in Figure 3), a Ethernet Raw or Ethernet tagged PW types
SHALL be used as defined in [RFC4762].
<----------------------E-Tree------------>
+-------+ +-------+
+----+ | PE1 | | PE2 |
+---+ | | | +---+ | | +---+ |
|CE1+---AC1---+----+-PW1-+-+ | | | | | | +---+
+---+(Root AC)| | | | | | | | +-+----AC4----+CE4|
|PE-r| | | V +-+-VSI Root PW-+-+ V | | (Root AC) +---+
+---+ | | | | | | | | | |
|CE2+---AC2---+----+-PW2-+-+ S | | | | S | |
+---+(Leaf AC)| | | | | | | | | |
+----+ | | I +-+-VSI Leaf PW-+-+ I | |
+---+ | | | | | | | | +---+
|CE3+--------AC3---------+-+ | | | | +-+----AC5----+CE5|
+---+ (Leaf AC) | +---+ | | +---+ | (Leaf AC) +---+
+-------+ +-------+
Figure 3: VPLS with Remote AC Connectivity
In addition, the AC type i.e. Root or leaf, SHALL be locally
provisioned on the VSI side to specifies the remote AC E-Tree Type per
PW. Moreover, such PWs that are used for interconnecting between a remote
AC and a VSI SHALL considered as separate logical VSI interfaces with
respect to MAC address learning/forwarding e.g. traffic forwarding between
such PWs is allowed as long as they are not both defined as Leaf.
Ram, et al. Expires April 2011 [Page 5]
Internet Draft Ext to LDP-VPLS for E-Tree 2-PW October 2010
In Figure 3, AC1 is remotely interconnected to the VPLS service via
PW1, and AC2 is remotely interconnected to the VPLS service via PW2.
AC1 is a Root AC and therefore the local type for PW1 in PE1 SHALL be
Root.
AC2 is a Leaf AC and therefore the local type for PW2 in PE1 SHALL be
Leaf.
5. Backward Compatibility
VSI root or VSI leaf PW type SHALL be used only in cases where both
PEs are VPLS capable and both supports E-Tree root/leaf.
In a case where one of the peers do not support E-Tree, an Ethernet
Raw or Ethernet tagged PW types SHALL be used as defined in
[RFC4762].
6. Compliance with Requirements
This refers to [Draft ETree VPLS Req] Section 5. Requirements.
The solution prohibits communication between any two Leaf ACs in a
VPLS instance.
The solution allows multiple Root ACs in a VPLS instance.
The solution allows Root AC and Leaf AC of a VPLS instance co-exist
on any PE.
The solution is applicable to LDP-VPLS [RFC4762].
The solution is applicable to Case 1: Single technology "VPLS Only".
7. Security Considerations
This will be added in later version.
8. IANA Considerations
Additional assignments will be required for the new MPLS PW types
introduced in Section 4.2. Details will be added in later version.
9. Acknowledgements
This will be added in later version.
Ram, et al. Expires April 2011 [Page 6]
Internet Draft Ext to LDP-VPLS for E-Tree 2-PW October 2010
10. References
10.1. Normative References
[RFC2119] Bradner, S., Key words for use in RFCs to Indicate
Requirement Levels, BCP 14, RFC 2119, March 1997.
[RFC4447] Martini, L., and al, Pseudowire Setup and Maintenance
Using the Label Distribution Protocol (LDP), April 2006
[RFC4762] Lasserre & Kompella, Virtual Private LAN Service (VPLS)
Using Label Distribution Protocol (LDP) Signaling,
January 2007
10.2. Informative References
[Draft VPLS ETree Req]
Key, et al., Requirements for MEF E-Tree Support in
VPLS, draft-key-l2vpn-vpls-etree-reqt-01.txt,
September 2010
Authors' Addresses
Rafi Ram
Orckit-Corrigent
126 Yigal Alon st.
Tel Aviv, Israel
Email: rafir@orckit.com
Amir Halperin
Orckit-Corrigent
126 Yigal Alon st.
Tel Aviv, Israel
Email: amirh@orckit.com
Raymond Key
Telstra
242 Exhibition Street, Melbourne
VIC 3000, Australia
Email: raymond.key@team.telstra.com
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (http://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document.
Ram, et al. Expires April 2011 [Page 7]
| PAFTECH AB 2003-2026 | 2026-04-22 07:44:15 |