PWE3Network Working GroupInternet DraftA. Malisdraft-ietf-pwe3-cell-transport-06.txt Tellabs Expires: April 2007Request for Comments: 4816 Verizon Category: Standards Track L. Martini Cisco Systems J. Brayley ECI Telecom T. Walsh Juniper NetworksOctober 2006 PWE3 ATMFebruary 2007 Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous Transfer Mode (ATM) Transparent Cell Transport ServiceIPR Statement By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79.Status ofthisThis MemoInternet-Drafts are working documents ofThis document specifies an Internet standards track protocol for the InternetEngineering Task Force (IETF), its areas,community, andits working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents validrequests discussion and suggestions fora maximumimprovements. Please refer to the current edition ofsix monthsthe "Internet Official Protocol Standards" (STD 1) for the standardization state andmay 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 liststatus ofcurrent Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The listthis protocol. Distribution ofInternet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.htmlthis memo is unlimited. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract The document describes a transparent cell transport service that makes use of the "N-to-one" cell relay mode forPWE3 ATMPseudowire Emulation Edge-to-Edge (PWE3) Asynchronous Transfer-Mode (ATM) cell encapsulation. 1. Introduction This transparent cell transport service allows migration of ATM services to a PSN without having to provision the ATM subscriber or customer edge (CE) devices. The ATM CEs will view the ATM transparent cell transport service as if they were directly connected via a Time Division Multiplexer (TDM) leased line. This service is most likely to be used as an internal function in an ATM service provider's network as a way to connect existing ATM switches via a higher-speed PSN, or to provide ATM "backhaul" services for remote access to existing ATM networks. 1.1. Specification of Requirements The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [1].PWE3 ATM2. Transparent Cell TransportService October 2006 1. Intellectual Property StatementDefinition TheIETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or usetransparent port service is a natural application of thetechnology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found"N-to- one" Virtual Circuit Connection (VCC) cell transport mode for PWE3 ATM encapsulation described inBCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat[2], andany assurances of licenses toMUST bemade available, or the resultused with pseudowires ofan attempt madetype 0x0003, "ATM transparent cell transport" [4]. The ATM transparent port service emulates connectivity between two remote ATM ports. This service is useful when one desires toobtain a general licenseconnect two CEs without processing orpermission forswitching at theuse of such proprietary rights by implementersVirtual Path Connection (VPC) orusers of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr.VCC layer. TheIETF invites any interested party to bring to its attentioningress PE discards anycopyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information toidle/unassigned cells received from theIETF at ietf-ipr@ietf.org. 2. Introduction This transparent cell transport service allows migration ofingress ATMservicesport, and maps all other received cells to aPSN without having to provisionsingle pseudowire. The egress PE does not change theATM subscriberVirtual Path Identifier (VPI), Virtual Circuit Identifier (VCI), Payload Type Identifier (PTI), orcustomer edge (CE) devices. The ATM CEs will viewCell Loss Priority (CLP) bits when it sends these cells on the egress ATM port. Therefore, the transparentcell transport service as if they were directly connected via a TDM leased line. This service is most likely to be used as an internal function in a ATM service provider's network as a way to connect existing ATM switches via a higher speed PSN, or to provide ATM "backhaul" services for remote access to existing ATM networks. 3. Transparent Cell Transport Definition The transparent port service is a natural application of the "N-to- one" VCC cell transport mode for PWE3 ATM encapsulation described in [2], and MUST be used with pseudowires of type 0x0003, "ATM transparent cell transport" [4]. The ATM transparent port service emulates connectivity between two remote ATM ports. This service is useful when one desires to connect two CEs without processing or switching at the VPC or VCC layer. The ingress PE discards any idle/unassigned cells received from the ingress ATM port, and maps all other received cells to a single pseudowire. The egress PE does not change the VPI, VCI, PTI, or CLP bits when it sends these cells on the egress ATM port. Therefore the transparent PWE3 ATM Transparent Cell Transport Service October 2006 portport service appears to emulate an ATM transmission convergence layer connection between two ports. However, since the ingress PE discards idle/unassigned cells, this service benefits from statistical multiplexing bandwidth savings. In accordance with [2], cell concatenation MAY be used for transparentcell relaycell-relay transport in order to save the PSN bandwidth. If used, it MUST be agreed between the ingress and egress PEs. In particular, if the Pseudo Wire has been set up using the PWE3 control protocol [3], the ingress PE MUST NOT exceed the value of the "Maximum Number of concatenated ATM cells" Pseudowire Interface Parameter Sub-TLVtype(Interface Parameter ID = 0x02 [4]) received in the Label Mapping message for the Pseudo Wire, and MUST NOT use cell concatenation if this parameter has been omitted by the egress PE. ATMOAMOperations and Management (OAM) cells MUST be transported transparently, and the PEs do not act on them. If the PEs detect a PSN or pseudowire failure between them, they do not generate any OAM cells, but rather bring down the ATM interfaces to the CEs(e.g.(e.g., generating LOS on the ATM port), just as if it were a transmission layer failure. Similarly, ATMILMIIntegrated Local Management Interface (ILMI) signaling from the CEs, if any, MUST be transported transparently, and the PEs do not act on it. However, the PEs must act on physical interface failure by either withdrawing the PW labels or by using pseudowire status signaling to indicate the interface failure. The procedures for both alternatives are described in [3].4.3. Security Considerations Thisdraftdocument does not introduce any new security considerations beyond those in [2] and [3]. This document defines an application that utilizes the encapsulation specified in [2], and does not specify the protocols used to carry the encapsulated packets across the PSN. Each such protocol may have its own set of security issues, but those issues are not affected by the application specified herein. Note that the security of the transported ATM service will only be as good as the security of the PSN. This level of security might be less rigorousthenthan a native ATM service.5.4. Congestion Control Since this document discusses an application of the"N-to- one""N-to-one" VCC cell transport mode for PWE3 ATM encapsulation described in [2], the congestion control considerations are identical to those discussed in section 15 of [2]. The PWE3 Working Group is also undertaking additional work on ATM-related congestion issues, and implementers should anticipate that an RFC will be published describing additional congestion control techniques that should be applied to ATM emulation over pseudowires.PWE3 ATM Transparent Cell Transport Service October 2006 6. IANA Considerations This document does not require any IANA actions. 7.5. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Martini, L.,et al,Jayakumar, J., Bocci, M., El-Aawar, N., Brayley, J., and G. Koleyni, "Encapsulation Methods for Transport ofATM OverAsynchronous Transfer Mode (ATM) over MPLS Networks",draft-ietf-pwe3-atm-encap-11.txt, May 2006, work in progress.RFC 4717, December 2006. [3] Martini, L.,et al,Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and MaintenanceusingUsing the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [4] Martini,L. et al,L., "IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3)",RFC 4446,BCP 116, RFC 4446, April 2006.7. Full Copyright Statement Copyright (C)Acknowledgments TheInternet Society (2006). This document is subjectauthors would like to thank therights, licensesmembers of the PWE3 working group for their assistance on this document, andrestrictions containedSasha Vainshtein of Axerra in particular for his comments and suggestions. Author's Addresses Andrew G. Malis Verizon Communications 40 Sylvan Road Waltham, MA EMail: andrew.g.malis@verizon.com Luca Martini Cisco Systems, Inc. 9155 East Nichols Avenue, Suite 400 Englewood, CO, 80112 EMail: lmartini@cisco.com Jeremy Brayley ECI Telecom Omega Corporate Center 1300 Omega Drive Pittsburgh, PA 15205 EMail: jeremy.brayley@ecitele.com Tom Walsh Juniper Networks 1194 N Mathilda Ave Sunnyvale, CA 94089 EMail: twalsh@juniper.net Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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 INTERNETSOCIETYSOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR 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.8. AcknowledgmentsIntellectual Property Theauthors would likeIETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain tothankthemembersimplementation or use of thePWE3 working group for their assistance ontechnology described in thisdraft,document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 andSasha VainshteinBCP 79. Copies ofAxerra in particular for his commentsIPR disclosures made to the IETF Secretariat andsuggestions. 9. Author's Addresses Andrew G. Malis Tellabs 90 Rio Robles Drive San Jose, CA 95134 Email: Andy.Malis@tellabs.com PWE3 ATM Transparent Cell Transport Service October 2006 Luca Martini Cisco Systems, Inc. 9155 East Nichols Avenue, Suite 400 Englewood, CO, 80112 e-mail: lmartini@cisco.com Jeremy Brayley ECI Telecom Omega Corporate Center 1300 Omega Drive Pittsburgh, PA 15205 Email: jeremy.brayley@ecitele.com Tom Walsh Juniper Networks 1194 N Mathilda Ave Sunnyvale, CA 94089 Email: twalsh@juniper.netany assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society.