Internet Draft Lou Berger (LabN) Category: Attila Takacs (Ericsson) Expiration Date: November 8, 2007 Diego Caviglia (Ericsson) Don Fedyk (Nortel) Julien Meuric (France Telecom) May 8, 2007 GMPLS Asymmetric Bandwidth Bidirectional LSPs draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt Status of this Memo 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. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on November 8, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document defines two alternate methods for the support of GMPLS Asymmetric Bandwidth Bidirectional LSPs. One method is Ethernet specific the other method is generic and applicable to any switching technology. The objective of this document is aid the working group in selecting one of these two methods, and to fully define the mechanisms for the selected method. [Note: this is an in-progress version of the draft.] Berger, et. al. Expires November 8, 2007 [Page 1] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 Contents 1 Background ................................................ 3 2 Overview .................................................. 3 2.1 Conventions used in this document ......................... 5 3 Asymmetric Bandwidth Bidirectional LSPs Using ADSPEC Object ...5 3.1 Procedures ................................................ 6 3.2 Compatibility ............................................. 6 3.3 IANA Considerations: ...................................... 6 4 Generalized Asymmetric Bandwidth Bidirectional LSPs ....... 7 4.1 UPSTREAM_FLOWSPEC Object .................................. 7 4.1.1 Procedures ................................................ 7 4.2 UPSTREAM_TSPEC Object ..................................... 8 4.2.1 Procedures ................................................ 8 4.3 UPSTREAM_ADSPEC Object .................................... 8 4.3.1 Procedures ................................................ 8 4.4 Packet Formats ............................................ 9 4.5 Compatibility ............................................. 10 4.6 IANA Considerations ....................................... 10 4.6.1 UPSTREAM_FLOWSPEC Object .................................. 10 4.6.2 UPSTREAM_TSPEC Object ..................................... 10 5 Discussion ................................................ 11 6 Security Considerations ................................... 11 7 References ................................................ 11 7.1 Normative References ...................................... 11 7.2 Informative References .................................... 12 8 Author's Addresses ........................................ 12 9 Full Copyright Statement .................................. 13 10 Intellectual Property ..................................... 14 Berger, et. al. Expires November 8, 2007 [Page 2] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 1. Background GMPLS introduced explicit support for bidirectional LSPs. The defined support matched the switching technologies covered by GMPLS, notably TDM and lambdas, and specifically only supported bidirectional LSPs with symmetric bandwidth allocation. Symmetric bandwidth requirements are conveyed using the semantics objects defined in [RFC2205] and [RFC2210]. Recent work, see [GMPLS-PBBTE] and [MEF-TRAFFIC], has looked at extending GMPLS to control Ethernet switching. In this context there has been a requirement identified for bidirectional LSPs with asymmetric bandwidth. This note defines extensions to enable support for such asymmetric bandwidth bidirectional LSPs. 2. Overview Bandwidth parameters are transported within RSVP (see [RFC2210], [RFC3209] and [RFC3473]) via several objects that are opaque to RSVP. While opaque to RSVP, these objects support a particular model for the communication of bandwidth information between an RSVP session sender (ingress) and receiver (egress). The original model of communication defined in [RFC2205] and maintained in [RFC3209] used the SENDER_TSPEC and ADSPEC objects in Path messages and the FLOWSPEC object in Resv messages. The SENDER_TSPEC object was used to indicate a sender's data generation capabilities. The FLOWSPEC object was issued by the receiver and indicated the resources that should be allocated to the associated data traffic. The ADSPEC object was used to inform the receiver and intermediate hops of the actual resources allocated for the associated data traffic. With the introduction of bidirectional LSPs in [RFC3473] the model of communication of bandwidth parameters was implicitly changed. In the context of [RFC3473] bidirectional LSPs, the SENDER_TSPEC object indicates the desired resources for both upstream and downstream directions. The FLOWSPEC object is simply confirmation of the allocated resources. The definition of the ADSPEC object is either unmodified, and only has meaning for downstream traffic, or is implicitly or explicitly (see [RFC4606] and [MEF-TRAFFIC]) irrelevant. This note defines two alternative approaches for extending the existing support for bidirectional LSPs to support asymmetric bandwidth bidirectional LSPs. The intention is to describe the two alternative approaches to sufficient detail to allow the selection of a single approach for standardization. Once a single approach is selected, the other approach will be will be eliminated. Which Berger, et. al. Expires November 8, 2007 [Page 3] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 approach is selected and which is eliminated is a matter for discussion within CCAMP working group. The first approach is specific to Ethernet and uses the [MEF-TRAFFIC] traffic parameters. This approach is not generic and is aimed at providing asymmetric bandwidth bidirectional LSPs for just Ethernet transport. With this extension, the ADSPEC object carries the traffic parameters for the upstream data flow. SENDER_TSPEC object is used to indicate the traffic parameters for the downstream data flow. The FLOWSPEC object provides confirmation of the allocated downstream resources. Confirmation of the upstream resource allocation is a Resv message, as any resource allocation failure for the upstream direction will always result in a PathErr message. Figure 1 shows the bandwidth related objects used in the first approach. |---| Path |---| | I |----------------->| E | | n | -SENDER_TSPEC | g | | g | -ADSPEC | r | | r | | e | | e | Resv | s | | s |<-----------------| s | | s | -FLOWSPEC | | |---| |---| Figure 1: Asymmetric Bandwidth Bidirectional LSPs Using ADSPEC Object The second approach is a generic approach that can be applied to any switching technology supported by GMPLS. In this approach, the existing SENDER_TSPEC, ADSPEC and FLOWSPEC objects are complemented with the addition of UPSTREAM_TSPEC, UPSTREAM_ADSPEC and UPSTREAM_FLOWSPEC objects. The old objects are used in the original fashion defined in [RFC2205] and [RFC2210], and refer only to traffic associated with the LSP flowing in the downsteam direction. The new objects are used in exactly the same fashion as the old objects, but refer to the upstream traffic flow. Figure 2 shows the bandwidth related objects used in the second approach. Berger, et. al. Expires November 8, 2007 [Page 4] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 |---| Path |---| | I |------------------->| E | | n | -SENDER_TSPEC | g | | g | -ADSPEC | r | | r | -UPSTREAM_FLOWSPEC | e | | e | | s | | s | Resv | s | | s |<-------------------| | | | -FLOWSPEC | | | | -UPSTREAM_TSPEC | | | | -UPSTREAM_ADSPEC | | |---| |---| Figure 2: Generic Asymmetric Bandwidth Bidirectional LSPs The two approaches are defined in further detail in Sections 3 and 4 respectively. Section 5 provides a (partial) discussion on the benefits of each of the approaches. Again, as this document progresses, either section 3 or section 4 will be removed. This extensions defined in this document are limited to P2P LSPs. Support for P2MP bidirectional LSPs is not currently defined and, as such, not covered in this document. 2.1. 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]. 3. Asymmetric Bandwidth Bidirectional LSPs Using ADSPEC Object The setup of an asymmetric bandwidth bidirectional LSP is signaled using the bidirectional procedures defined in [RFC3473] together with the inclusion of a new ADSPEC object. The new ADSPEC object is specific to Ethernet and is called the Ethernet Upstream Traffic Parameter ADSPEC object. The Ethernet Upstream Traffic Parameter ADSPEC object uses the Class-Number 13 and C-Type TBA (see IANA Considerations). The format of the object is the same as the Ethernet SENDER_TSPEC object defined in [MEF-TRAFFIC]. Note this extension does not modify behavior of symmetric bandwidth LSPs. Per [MEF-TRAFFIC], such LSPs are signaled without an ADSPEC or with an INTSERV ADSPEC. It should also be noted that the defined approach could be reused to Berger, et. al. Expires November 8, 2007 [Page 5] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 support asymmetric bandwidth bidirectional LSPs for other types of switching technologies. All that would be needed is to define the proper ADSPEC object. 3.1. Procedures The process of establishing an asymmetric bandwidth bidirectional LSP follows the process of establishing symmetric bandwidth bidirectional LSP, as defined in Section 3 of [RFC3473], with two modifications. These modifications MUST be followed with an incoming Path message is received containing an Upstream_Label object and the Ethernet Upstream Traffic Parameter ADSPEC object. The first modification to the symmetric bandwidth process is that when allocating the upstream label, the bandwidth associated with the upstream label MUST be taken from the Ethernet Upstream Traffic Parameter ADSPEC object, see Section 3.1 of [RFC3473]. Consistent with [RFC3473], a node that is unable to allocate a label or internal resources based on the contents of the ADSPEC Object, MUST issue a PathErr message with a "Routing problem/MPLS label allocation failure" indication. The second modification is that the ADSPEC object MUST NOT be modified by transit nodes. 3.2. Compatibility This extension reuses semantics and procedures defined in [RFC3473]. To indicate the use of asymmetric bandwidth a new ADSPEC object c- type is defined. Per [RFC2205], nodes not supporting this extension should not recognize this new C-type and respond with an "Unknown object C-Type" error. 3.3. IANA Considerations: IANA is requested to administer assignment of new values for namespaces defined in this section and reviewed in this subsection. Upon approval of this document, the IANA will make the assignments described below in the "Class Names, Class Numbers, and Class Types" section of the "RSVP PARAMETERS" registry located at: http://www.iana.org/assignments/rsvp-parameters ADSPEC object: Berger, et. al. Expires November 8, 2007 [Page 6] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 This section defines a new ADSPEC object class type: - An Ethernet Upstream Traffic Parameter ADSPEC object: Class = 13, C-Type = TBA (see Section 3). The C-Type value should correspond to the values defined in section 8 of [MEF-TRAFFIC]. 4. Generalized Asymmetric Bandwidth Bidirectional LSPs The setup of an asymmetric bandwidth bidirectional LSP is signaled using the bidirectional procedures defined in [RFC3473] together with the inclusion of the new UPSTREAM_FLOWSPEC, UPSTREAM_TSPEC and UPSTREAM_ADSPEC objects. The new upstream objects carried the same information and are used in the same fashion as the existing downstream objects; they only differ in that they relate to traffic flowing in the upstream direction while the existing objects relate to traffic flowing in the downstream direction. 4.1. UPSTREAM_FLOWSPEC Object The format of an UPSTREAM_FLOWSPEC object is the same as a FLOWSPEC object. This includes the definition of class types and their formats. The class number of the UPSTREAM_FLOWSPEC object object is TBA by IANA (of the form 0bbbbbbb). 4.1.1. Procedures The Path message of a asymmetric bandwidth bidirectional LSP MUST contain an UPSTREAM_FLOWSPEC object and MUST use the bidirectional LSP formats and procedures defined in [RFC3473]. The C-Type of the UPSTREAM_FLOWSPEC Object MUST match the C-Type of the SENDER_TSPEC object used in the Path message. The contents of the UPSTREAM_FLOWSPEC Object MUST be constructed using a consistent format and procedures used to construct the FLOWSPEC object that will be used for the LSP, e.g., [RFC2210] or [RFC4328]. Nodes processing a Path message containing an UPSTREAM_FLOWSPEC Object MUST use the contents of the UPSTREAM_FLOWSPEC Object in the upstream label and resource allocation procedure defined in Section 3.1 of [RFC3473]. Consistent with [RFC3473], a node that is unable to allocate a label or internal resources based on the contents of the UPSTREAM_FLOWSPEC Object, MUST issue a PathErr message with a Berger, et. al. Expires November 8, 2007 [Page 7] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 "Routing problem/MPLS label allocation failure" indication. 4.2. UPSTREAM_TSPEC Object The format of an UPSTREAM_TSPEC object is the same as a SENDER_TSPEC object. This includes the definition of class types and their formats. The class number of the UPSTREAM_TSPEC Object object is TBA by IANA (of the form 0bbbbbbb). 4.2.1. Procedures The UPSTREAM_TSPEC object MUST be included in any Resv message that corresponds to a Path message containing an UPSTREAM_FLOWSPEC object. The C-Type of the UPSTREAM_TSPEC object MUST match the C-Type of the corresponding UPSTREAM_FLOWSPEC object. The contents of the UPSTREAM_TSPEC Object MUST be constructed using a consistent format and procedures used to construct the FLOWSPEC object that will be used for the LSP, e.g., [RFC2210] or [RFC4328]. The contents of the UPSTREAM_TSPEC Object MAY differ from contents of the UPSTREAM_FLOWSPEC object based on application data transmission requirements. 4.3. UPSTREAM_ADSPEC Object The format of an UPSTREAM_ADSPEC object is the same as an ADSPEC object. This includes the definition of class types and their formats. The class number of the UPSTREAM_ADSPEC object is TBA by IANA (of the form 0bbbbbbb). 4.3.1. Procedures The UPSTREAM_ADSPEC object MAY be included in any Resv message that corresponds to a Path message containing an UPSTREAM_FLOWSPEC object. The C-Type of the UPSTREAM_TSPEC object MUST be consistent with the C-Type of the corresponding UPSTREAM_FLOWSPEC object. The contents of the UPSTREAM_ADSPEC Object MUST be constructed using a consistent format and procedures used to construct the ADSPEC object that will be used for the LSP, e.g., [RFC2210] or [MEF-TRAFFIC]. The UPSTREAM_ADSPEC object is processed using the same procedures as the ADSPEC object and as such, MAY be updated or added at transit nodes. Berger, et. al. Expires November 8, 2007 [Page 8] Internet-Draft draft-berger-ccamp-asymm-bw-bidir-lsps-00.txt May 8, 2007 4.4. Packet Formats This section presents the RSVP message related formats as modified by this section. Unmodified formats are not listed. Three new objects are defined in this section: Object name Applicable RSVP messages --------------- ------------------------ UPSTREAM_FLOWSPEC Path and PathErr (via sender descriptor) UPSTREAM_TSPEC Resv and Notify (via flow descriptor list) UPSTREAM_ADSPEC Resv and Notify (via flow descriptor list) The format of the sender description for bidirectional asymmetric LSPs is: ::= [ ] [ ] [ ] [ ] The format of the flow descriptor list for bidirectional asymmetric LSPs is: ::= | ::= [ ]