Internet Draft Don Fedyk, Nortel Category: Informational Lou Berger, LabN Expiration Date: August 13, 2009 Loa Andersson, Ericsson AB February 13, 2009 Generalized Multi-Protocol Label Switching (GMPLS) Ethernet Label Switching Architecture and Framework draft-ietf-ccamp-gmpls-ethernet-arch-04.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/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 August 13, 2009. Copyright and License Notice Copyright (c) 2009 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. Abstract There has been significant recent work in increasing the capabilities of Ethernet switches and Ethernet forwarding models. As a consequence, the role of Ethernet is rapidly expanding into "transport networks" that previously were the domain of other technologies such as Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy (SDH), Time-Division Multiplex (TDM) and Fedyk, et. al. Informational [Page 1] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 Asynchronous Transfer Mode (ATM). This document defines an architecture and framework for a Generalized GMPLS based control plane for Ethernet in this "transport network" capacity. GMPLS has already been specified for similar technologies. Some additional extensions to the GMPLS control plane are needed and this document provides a framework for these extensions. Fedyk, et. al. Informational [Page 2] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 Table of Contents 1 Introduction .............................................. 4 1.1 Terminology ............................................... 6 1.1.1 Concepts .................................................. 6 1.1.2 Abbreviations and Acronyms ................................ 7 2 Background ................................................ 8 2.1 Ethernet Switching ........................................ 9 2.2 Operations, Administration, and Maintenance (OAM) ......... 11 2.3 Ethernet Switching Characteristics ........................ 12 3 Framework ................................................. 12 4 GMPLS Routing and Addressing Model ........................ 14 4.1 GMPLS Routing ............................................. 15 4.2 Control Plane Network ..................................... 15 5 GMPLS Signaling .......................................... 15 6 Link Management .......................................... 16 7 Path Computation and Selection ............................ 17 8 Multiple VLANs ............................................ 18 9 Security Considerations ................................... 18 10 IANA Considerations ....................................... 18 11 References ................................................ 18 11.1 Normative References ...................................... 18 11.2 Informative References .................................... 19 12 Acknowledgments ........................................... 20 13 Author's Addresses ........................................ 21 Fedyk, et. al. Informational [Page 3] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 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]. 1. Introduction There has been significant recent work in increasing the capabilities of Ethernet switches. As a consequence, the role of Ethernet is rapidly expanding into "transport networks" that previously were the domain of other technologies such as SONET/SDH TDM and ATM. The evolution and development of Ethernet capabilities in these areas is a very active and ongoing process. Multiple organizations have been active in extending Ethernet technology. This activity has taken place in the Institute of Electrical and Electronics Engineers (IEEE) 802.1 Working Group, the International Telecommunication Union (ITU) and the Metro Ethernet Forum (MEF). These groups have been focusing on Ethernet forwarding, Ethernet management plane extensions and the Ethernet Spanning Tree Control Plane, but not on an explicitly routed, constraint based control plane. In the forwarding plane context, extensions have been, or are being, defined to support different Ethernet forwarding models, protection modes and service interfaces. Examples of such extensions include [802.1ah], [802.1Qay], [G.8011] and [MEF.6]. These extensions allow for greater flexibility in the forwarding plane and, in some cases, the extensions allow for a departure from forwarding based on Ethernet spanning tree. In the 802.1Qay case, greater flexibility in forwarding is achieved through the addition of a "provider" address space. This document provides a framework for GMPLS Ethernet Label switching (GELS). It will be followed by technology specific documents. GELS will likely require more than one switching type, and the GMPLS procedures that will need to be changed are dependent on switching, and thus will be covered in the technology specific documents. In the new provider bridge model developed in the IEEE 802.1ad project and amended to the IEEE 802.1Q standard [802.1Q], an extra Virtual Local Area Network (VLAN) identifier (VID) is added. This VLAN is referred to as the Service VID, (S-VID and is carried in a Service TAG (S-TAG). In provider backbone bridges (PBB) [802.1ah] a backbone VID (B-VID) and B-MAC header with a Service Instance (I-TAG) Fedyk, et. al. Informational [Page 4] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 encapsulates a customer Ethernet frame or a service Ethernet frame. An example of Ethernet protection extensions can be found in [G.8031]. In the IEEE 802.1Q standard the terms Provider Backbone Bridges (PBB) and Provider Backbone Bridged Network (PBBN) is used in the context of these extensions. Ethernet operations, administration, and maintenance (OAM) is another important area that is being extended to enable provider Ethernet services. Related extensions can be found in [802.1ag] and [Y.1731]. An Ethernet based service model is also being defined within the context of the Metro Ethernet Forum (MEF) and International Telecommunication Union (ITU). [MEF.6] and [G.8011] provide parallel frameworks for defining network-oriented characteristics of Ethernet services in transport networks. The framework discusses general Ethernet connection characteristics, Ethernet User-Network Interfaces (UNIs) and Ethernet Network-Network Interfaces (NNIs). Within this framework, [G.8011.1] defines the Ethernet Private Line (EPL) service and [G.8011.2] defines the Ethernet Virtual Private Line (EVPL) service. [MEF.6] covers both service types. These activities are consistent with the types of Ethernet switching defined in [802.1ah]. The Ethernet forwarding and management plane extensions explicitly allow for the disabling of standard Ethernet spanning tree but do not define an explicitly routed, constraint based control plane. The IEEE 802.1, in [802.1Qay], works on an new amendment that explicitly allows for traffic engineering of Ethernet forwarding paths. The IETF chartered the GMPLS work to specify a common control plane for physical path and core tunneling technologies for the Internet and telecommunication service providers. The GMPLS architecture is specified in RFC3945 [RFC3945]. The protocols specified for GMPLS have been used to control "Transport Networks", e.g. Optical and TDM networks. This document provides a framework for use of GMPLS to control "transport" Ethernet. The GMPLS architecture already handles a number of transport technologies but "transport" Ethernet adds a few new constraints that must be documented. Some additional extensions to the GMPLS control plane are needed and this document provides a framework for these extensions. All extensions to support Eth-LSPs are also expected to build on the GMPLS Architecture and related specifications. This document introduces and explains GMPLS control plane deployment for Ethernet and the concept of the Ethernet Label Switched Path (Eth-LSP). The data plane aspects of Eth-LSPs are outside the scope of this document and IETF activities. Fedyk, et. al. Informational [Page 5] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 The intent of this document is to reuse and align with as much of the GMPLS protocols as possible. For example reusing the IP control plane addressing allows existing signaling, routing, LMP and path computation to be used as specified. The GMPLS protocols support a set of tools for hierarchical LSPs as well as contiguous LSPs. GMPLS specific protocol mechanisms support a variety of networks from peer to peer to UNIs and NNIs. Additions to existing GMPLS capabilities will only be made to accommodate features unique to "transport" Ethernet. 1.1. Terminology 1.1.1. Concepts The following are basic Ethernet and GMPLS terms: o Asymmetric Bandwidth This term refers to a property of a Bidirectional service instance may have differing bandwidth allocation in each direction. o Bidirectional Congruent LSP This term refers to the property of a bi-directional LSP that uses only the same nodes, ports, and links in both directions. Ethernet data planes are normally bi-directional or reverse path congruent. o Contiguous Eth-LSP A contiguous Eth-LSP is an Eth-LSP that maps one to one with an another LSP at a VLAN boundary. Stitched LSP are contiguous LSPs. o Eth-LSP This term refers to Ethernet switched paths that may be controlled via GMPLS. o Hierarchical Eth-LSP Hierarchical Eth-LSPs aggregate Eth-LSPs by creating a hierarchy of Eth-LSPs. Fedyk, et. al. Informational [Page 6] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 o In-band GMPLS Signaling In-band GMPLS Signaling is IP based control messages which are sent on the native Ethernet links encapsulated by a single hop Ethernet header. Logical links that use a dedicated VID on the same physical links would be considered In-band signaling. o Out-of-band GMPLS Signaling Out-of-band GMPLS Signaling is IP based control messages which are sent between Ethernet switches that uses some other links other than the Ethernet data plane links. Out of band signaling typically shares a different fate from the data links. o Point-to-point (P2P) Traffic Engineering (TE) Service Instance An TE service instance made up from two P2P unidirectional Eth- LSPs. o Point-to-multipoint (P2MP) Traffic Engineering (TE) Service Instance An TE service Instance supported by a set of LSPs which comprises one P2MP LSP from a root to n leaves plus a Bidirectional Congruent point-to-point (P2P) LSP from each of the leaves to the root. o Shared forwarding Shared forwarding is a property of a data path where a single forwarding entry (VID + DMAC) may be used for frames from multiple sources (SMAC). Shared forwarding does not change any data plane behavior. Shared forwarding saves forwarding database (FDB) entries only. Shared forwarding offers similar benefits to merging in the data plane. However in shared forwarding the Ethernet data packets are unchanged when using shared forwarding. With shared forwarding dedicated control plane states for all Eth-LSP are maintained regardless of shared forwarding entries. 1.1.2. Abbreviations and Acronyms The following abbreviations and acronyms are used in this document: CCM Continuity Check Message CFM Connectivity Fault Management DMAC Destination MAC Address Fedyk, et. al. Informational [Page 7] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 Eth-LSP Ethernet Label Switched Path I-SID Service Identifier LMP Link Management Protocol MAC Media Access Control MP2MP Multipoint to multipoint NMS Network Management System OAM Operations, Administration and Maintenance PBB Provider Backbone Bridges [802.1ah] PBB-TE Provider Backbone Bridges Traffic Engineering [802.1Qay] P2P Point to Point P2MP Point to Multipoint QoS Quality of Service SMAC Source MAC Address S-TAG A service TAG defined in the 802.1 Standard [802.1Q] TE Traffic Engineering TAG An Ethernet short form for a TAG Header TAG Header An extension to an Ethernet frame carrying priority and other information. TSpec Traffic specification VID VLAN Identifier VLAN Virtual LAN 2. Background This section provides background to the types of switching and services that are supported within the defined framework. The former is particularly important as it identifies the switching functions that GMPLS will need to represent and control. The intent is for this document to allow for all standard forms of Ethernet switching and services. The material presented in this section is based on both finished and on-going work taking place in the IEEE 802.1 Working Group, the ITU and the MEF. This section references and, to some degree, summarizes that work. This section is not a replacement for, or an authoritative description of that work. Fedyk, et. al. Informational [Page 8] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 2.1. Ethernet Switching In Ethernet switching terminology, the bridge relay is responsible for forwarding and replicating the frames. Bridge relays forward frames based on the Ethernet header fields: Virtual Local Area Network (VLAN) Identifiers (VID) and Destination Media Access Control (DMAC) address. PBB [802.1ah] has also introduced a Service Instance tag (I-TAG). Across all the Ethernet extensions (already referenced in the Introduction), multiple forwarding functions, or service interfaces, have been defined using the combination of VIDs, DMACs, and I-TAGs. PBB [802.1ah] provides a breakdown of the different types of Ethernet switching services. Figure 1 reproduces this breakdown. PBB Network Service Types _,,-' | '--.._ _,.-'' | `'--.._ _,.--' | `'--.. Port based S-tagged I-tagged _,- -. _.' `. _,' `. one-to-one bundled _.- =. _.-' ``-.._ _.-' `-.. many-to-one all-to-one | | | Transparent Figure 1: Ethernet Switching Service Types The types are defined in Clause 25 of [802.1ah], and are consistent with the definitions of Ethernet services supported in [G.8011] and [MEF.6]. To summarize the definitions: o Port based This is a frame based service that supports specific frame types, no Service VLAN tagging, with MAC address based switching. o S-tagged There are multiple Service VLAN tag (S-tag) aware services, including: + one-to-one Fedyk, et. al. Informational [Page 9] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 In this service, each VLAN identifier (VID) is mapped into a different service. + Bundled Bundled S-tagged service supports the mapping of multiple VIDs into a single service and include: * many-to-one In this frame based service, multiple VIDs are mapped into the same service. * all-to-one In this frame based service, all VIDs are mapped into the same service. - transparent This is a special case, all frames are mapped from a single incoming port to a single destination Ethernet port. o I-tagged The edge of a PBBN consists of a combined backbone relay (B- component relay) and service instance relay (I-component relay). An I-Tag contains a service identifier (24 bit I-SID) and priority markings as well as some other fields. An I-Tagged service is typically between the edges of the PBBN and terminated at each edge on an I-component that faces a customer port so the service is often not visible except at the edges. However, since the I- component relay involves a distinct relay, it is possible to have a visible I-Tagged Service by separating the I component relay from the B-component relay. Two examples where it makes sense to do this are: an I-Tagged service between two PBBNs and as an attachment to a customer's Provider Instance Port. In general, the different switching type determines which of the Ethernet header fields are used in the forwarding/switching function, e.g. VID only or VID and DMACs. The switching type may also require the use of additional Ethernet headers or fields. Services defined for UNIs tend to use the headers on a hop-by-hop basis. In most bridging cases, the header fields cannot be changed hop-by- hop, but some translations of VID field values are permitted, typically at the edges. While not specifically described in [802.1ah], the Ethernet services being defined in the context of [MEF.6] and [G.8011] also fall into the types defined in Figure 1. Across all service types, the Ethernet data plane is bi-directional congruent. This means that the forward and reverse paths share the exact same set of nodes, ports and bi-directional links. This Fedyk, et. al. Informational [Page 10] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 property is fundamental. The 802.1 group has maintained this bi- directional congruent property in the definition of Connectivity Fault Management (CFM) which is part of the overall Operations Administration and Management (OAM) capability. 2.2. Operations, Administration, and Maintenance (OAM) Robustness is enhanced with the addition of data plane OAM to provide both fault and performance management. Ethernet OAM messages [802.1ag] and [Y.1731], rely on data plane forwarding for both directions. Determining a broken path or misdirected packet in this case relies on OAM following the Eth-LSP. These identifiers are dependent on the data plane so it works equally well for provisioned or GMPLS controlled paths. Ethernet OAM currently consists of: Defined in both [802.1ag & Y.1731]: - CCM/RDI: Connectivity Check, Remote Defect Indication - LBM/LBR: Loopback Message, Loopback Reply - LTM/LTR: Link trace Message, Link trace Reply - VSM/VSR: Vendor-specific extensions Message/Reply Additionally defined in [Y.1731]: - AIS: Alarm Indication Signal - LCK: Locked Signal - TST: Test - LMM/LMR: Loss Measurement Message/Reply - DM/DMM/DMR: Delay Measurement - EXM/EXR: Experimental - APS, MCC: Automatic Protection Switching, Maintenance Communication Channel With some Eth-LSP label formats bi-directional transactions (e.g. LBM/LBR) and reverse direction transactions MAY have a different VID for each direction. Both Y.1731 & 802.1ag assumes that bi- directional transactions (e.g., LBM/LBR) use the same VID in both directions. However in some scenarios, especially with explicitly routed paths [802.1Qay], it is possible that different VIDs are used upstream and downstream. In the context of [802.1Qay] work is ongoing to update [802.1ag] to support such scenarios." Fedyk, et. al. Informational [Page 11] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 2.3. Ethernet Switching Characteristics Ethernet is similar to MPLS it encapsulates many packet and frame types for data transmission. In Ethernet the encapsulated data is referred to as MAC client data. The encapsulation is an Ethernet MAC frame with a header, a source address, destination address, optional VLAN identifier, Type and length on the front of the MAC client data with optional padding and a Frame Check Sequence at the end of the frame. The type of MAC client data is typically identified by an "Ethertype" value. This is an explicit type indication but Ethernet also supports an implicit type indication. Ethernet bridging switches Ethernet based on the Frame destination address and VLAN. The VLAN identifies an active topology. The address is assumed to be unique and invariant within the VLAN. MAC addresses are often globally unique but this is not necessary for bridging. 3. Framework As defined in the GMPLS Architecture [RFC3945], the GMPLS control plane can be applied to a technology by controlling the data plane and switching characteristics of that technology. The architecture includes a clear separation between a control plane and a data plane. Control plane and data plane separation allows the GMPLS control plane to remain architecturally and functionally unchanged while controlling different technologies. The architecture also requires IP connectivity for the control plane to exchange information, but does not otherwise require an IP data plane. All aspects of GMPLS, i.e., addressing, signaling, routing and link management, may be applied to Ethernet switching. GMPLS can provide control for traffic engineered and protected Ethernet service paths. This document defines the term "Eth-LSP" to refer to Ethernet service paths that are controlled via GMPLS. As is the case with all GMPLS controlled services, Eth-LSPs can leverage common traffic engineering attributes such as: - bandwidth profile; - forwarding priority level; - connection preemption characteristics; - protection/resiliency capability; - routing policy, such as an explicit route; - bi-directional service; - end-to-end and segment protection; Fedyk, et. al. Informational [Page 12] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 - hierarchy The bandwidth profile may be used to set committed information rate, peak information rate, and policies based on either under- subscription or over-subscription. Services covered by this framework MUST use a TSpec that follows the Ethernet Traffic parameters defined in [ETH-TSPEC]. In applying GMPLS to "transport" Ethernet, GMPLS may be extended to work with the Ethernet data plane and switching functions. The definition of GMPLS support for Ethernet is multi-faceted due to the different forwarding/switching functions inherent in the different service types discussed in Section 2.1. In general, the header fields used in the forwarding/switching function, e.g. VID and DMAC, can be characterized as a data plane label. In some circumstances these fields will be constant along the path of the Eth-LSP, and in others they may vary hop-by-hop or at certain interfaces only along the path. In the case where the "labels" must be forwarded unchanged, there are a few constraints on the label allocation that are similar to some other technologies such as lambda labels. The GMPLS architecture, per [RFC3945], allowed for control of Ethernet bridges and other layer 2 technologies using the L2SC switching type. Although, it is worth noting that the control of Ethernet switching was not explicitly defined in [RFC3471], [RFC4202] or any other subsequent GMPLS reference document. The characteristics of the "transport" Ethernet data plane are not modified in order to apply GMPLS control. For example, consider the IEEE 802.1Q [802.1Q] data plane: The VID is used as a "filter" pointing to a particular forwarding table, and if the DMAC is found in that forwarding table the forwarding decision is taken based on the DMAC. When forwarding using an Ethernet spanning tree, if the DMAC is not found the frame is broadcast over all outgoing interfaces for which that VID is defined. This valid MAC checking and broadcast supports Ethernet learning. A special case is when a VID is defined for only two ports on one bridge, effectively resulting in a p2p forwarding constraint, in this case all frames tagged with that VID received over one of these ports are forward over the other port without address learning. [802.1Qay]allows for turning off learning and hence the broadcast mechanism providing means to create explicitly routed Ethernet connections. This document does not define any specific format for an Eth-LSP label. Rather, it is expected that service specific documents will define any signaling and routing extensions needed to support a Fedyk, et. al. Informational [Page 13] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 specific Ethernet service. Depending on the requirements of a service, it may be necessary to define multiple GMPLS protocol extensions and procedures. It is expected that all such extensions will be consistent with this document. It is expected that key a requirement for service specific documents will be to describe label formats and encodings. It may also be necessary to provide a mechanism to identify the required Ethernet service type in signaling and a way to advertise the capabilities of Ethernet switches in the routing protocols. These mechanisms must make it possible to distinguish between requests for different paradigms including new, future, and existing paradigms. The Switching Type and Interface Switching Capability Descriptor share a common set of values and are defined in [RFC3945], [RFC3471], and [RFC4202] as indicators of the type of switching that should ([RFC3471]) and can ([RFC4202]) be performed on a particular link for an LSP. The L2SC switching type may already be used by implementations performing layer 2 switching including Ethernet. To support the continued use of that switching type and those implementations, a new switching type MUST be defined for each new Ethernet switching paradigm that is supported. For discussion purposes, we decompose the problem of applying GMPLS into the functions of Routing, Signaling, Link Management and Path Selection. It is possible to use some functions of GMPLS alone or in partial combinations. In most cases using all functions of GMPLS leads to less operational overhead than partial combinations. 4. GMPLS Routing and Addressing Model The GMPLS Routing and Addressing Model is not modified by this document. GMPLS control for Eth-LSPs uses the Routing and Addressing Model described in [RFC3945]. Most notably this includes the use of IP addresses to identify interfaces and LSP end-points. It also includes support for both numbered and unnumbered interfaces. In the case where another address family or type of identifier is required to support an Ethernet service, extensions may be defined to provide mapping to an IP address. Support of Ethernet MUST strictly comply to the GMPLS protocol suite addressing as specific in RFC3471, RFC3473 and related. Fedyk, et. al. Informational [Page 14] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 4.1. GMPLS Routing GMPLS routing as defined in [RFC4202] is IP routing with the opaque TLV extensions for the purpose of distributing GMPLS related TE (router and link) information. As is always the case with GMPLS, TE information is populated with TE resources coordinated with LMP or from configured information. The bandwidth resources of the links are tracked as Eth-LSPs are set up. Interfaces supporting the switching of Eth-LSPs are identified using the appropriate Interface Switching Capabilities. As mentioned in Section 3, the definition of one or more new Interface Switching Capabilities to support Eth-LSPs is expected. The L2SC Interface Switching Capabilities MUST NOT be used to represent interfaces capable of supporting Eth-LSPs. Interface Switching Capability specific TE information may be defined as needed to support the requirements of a specific Ethernet Switching Service Type. GMPLS Routing is an optional piece but it is highly valuable in maintaining topology and distributing the TE database for path management and dynamic path computation. 4.2. Control Plane Network In order for a GMPLS control plane to operate, an IP network of sufficient capacity to handle the information exchange between the GMPLS routing and signaling protocols is necessary. One way to implement this is with an IGP that views each switch as a terminated IP adjacency. In other words, IP traffic and a simple routing table are available for the control plane but there is no requirement for a high performance IP data plane. This IP connectivity can be provided as a separate independent network (out of band) or integrated with the Ethernet switches (in- band). 5. GMPLS Signaling GMPLS signaling, see [RFC3471][RFC3473], is well suited to the control of Eth-LSPs and Ethernet switches. Signaling enables the ability to dynamically establish a path from an ingress node to an egress node. The signaled path may be completely static and not change for the duration of its lifetime. However, signaling also has the capability to dynamically adjust the path in a coordinated fashion after the path has been established. The range of signaling options from static to dynamic are under operator control. Fedyk, et. al. Informational [Page 15] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 Standardized signaling also improves multi-vendor interoperability over simple management. GMPLS signaling supports the establishment and control of bi- directional and unidirectional data paths. Ethernet is bi-directional by nature and the CFM has been built to leverage this. Prior to CFM the emulation of a physical wire and the learning requirements also mandated bi-directional connections. Given this, Eth-LSPs MUST be bi- directional congruent. Eth-LSPs may be either P2P or P2MP (see [RFC4875]). GMPLS signaling also allows for full and partial LSP protection; see [RFC4872] and [RFC4873]. Note that standard GMPLS does not support different bandwidth in each direction of a bi-directional LSP. See [GMPLS-ASYM] if asymmetric bandwidth bi-directional LSPs are required. 6. Link Management Link discovery has been specified for Ethernet in [802.1AB]. However the 802.1AB capability is an optional feature, is not necessarily operating before a link is operational, and it primarily supports the management plane. The benefits of running link discovery in large systems are significant. Link discovery may reduce configuration and reduce the possibility of undetected errors in configuration as well as exposing misconnections. In the GMPLS context, LMP [RFC4204] has been defined to support link management and discovery features. LMP also supports the automated creation of unnumbered interfaces. If LMP is not used there is an additional configuration requirement to add GMPLS link identifiers. For large-scale implementations LMP would be beneficial. LMP also has fault management capabilities that overlap with CFM [802.1ag] and [Y.1731]. It is the goal of the architecture to allow the selection of the best tool set for the user needs so full functionality of Ethernet CFM should be allowed. LMP and 802.1AB are relatively independent. The LMP capability should be sufficient to remove the need for 802.1AB but 802.1 AB can be run in parallel or independently if desired. Figure 2 provides possible ways of using LMP, 802.1AB and 802.1ag in combination. Figure 2 illustrates the functional relationship of link management and OAM schemes. It is intended that LMP would use functions of link property correlation but that Ethernet mechanisms for OAM such as CFM, link trace etc would be used for fault management and fault trace. Fedyk, et. al. Informational [Page 16] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 +-------------+ +-------------+ | +---------+ | | +---------+ | | | | | | | | |GMPLS | | LMP |-|<------>|-| LMP | |Link Property | | | | | | | |Correlation | | (opt) | |IP | | (opt) | | | | | | | | | | Bundling | +---------+ | | +---------+ | | +---------+ | | +---------+ | | | | | | | | | | | 802.1AB |-|<------>|-| 802.1AB | |P2P | | (opt) | |Ethernet| | (opt) | |link identifiers | | | | | | | | | +---------+ | | +---------+ | | +---------+ | | +---------+ | | | | | | | | |End to End -----|-| 802.1ag |-|<------>|-| 802.1ag |-|------- | | Y.1731 | |Ethernet| | Y.1731 | |Fault Management | | (opt) | | | | (opt) | |Performance | | | | | | | |Management | +---------+ | | +---------+ | +-------------+ +-------------+ Switch 1 link Switch 2 Figure 2: Logical Link Management Options 7. Path Computation and Selection GMPLS does not specify a specific method for selecting paths or supporting path computation. GMPLS allows for a wide range of possibilities supported from very simple path computation to very elaborate path coordination where a large number of coordinated paths are required. Path computation can take the form of paths being computed in a fully distributed fashion, on a management station with local computation for rerouting, or on more sophisticated path computation servers. Eth-LSPs may be supported using any path selection or computation mechanism. As is the case with any GMPLS path selection function, and common to all path selection mechanisms, the path selection process should take into consideration Switching Capabilities and Encoding advertised for a particular interface. Eth-LSPs may also make use of the emerging path computation element and selection work; see [RFC4655] Fedyk, et. al. Informational [Page 17] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 8. Multiple VLANs This document allows for the support the signaling of Ethernet parameters across multiple VLANs supporting both contiguous Eth-LSP and Hierarchical Ethernet LSPs. The intention is to reuse GMPLS hierarchy for the support of Peer to Peer models, UNIs and NNIs. 9. Security Considerations The architecture for GMPLS controlled "transport" Ethernet assumes that the network consists of trusted devices, but does not require that the ports over which a UNI are defined are trusted, nor does equipment connected to these ports need to be trusted. Access to the trusted network SHALL only occur through the protocols defined in the UNI or NNI or through protected management interfaces. When in-band GMPLS signaling is used for the control plane the security of the control plane and the data plane may affect each other. When out-of-band GMPLS signaling is used the control plane the data plane security is decoupled from the control plane and therefore the security of the data plane has less impact on overall security. Where GMPLS is applied to the control of VLAN only, the commonly known techniques for mitigation of Ethernet DOS attacks may be required on UNI ports. For a more comprehensive discussion on GMPLS security please see the MPLS and GMPLS Security Framework [SECURITY]. 10. IANA Considerations No new values are specified in this document. 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3471] Berger, L. (editor), "Generalized MPLS Signaling Functional Description", January 2003, RFC3471. Fedyk, et. al. Informational [Page 18] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 [RFC3473] Berger, L. (editor), "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", January 2003, RFC3473. [RFC4202] Kompella, K., Rekhter, Y., "Routing Extensions in Support of Generalized MPLS", RFC 4202, October 2005 11.2. Informative References [G.8031] ITU-T Draft Recommendation G.8031, Ethernet Protection Switching. [G.8011] ITU-T Draft Recommendation G. 8011, Ethernet over Transport - Ethernet services framework. [RFC3945] E. Mannie, Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", RFC 3495. [802.1AB] "IEEE Standard for Local and Metropolitan Area Networks, Station and Media Access Control Connectivity Discovery" (2004). [802.1ag] "IEEE Standard for Local and Metropolitan Area Networks - Virtual Bridged Local Area Networks - Amendment 5:Connectivity Fault Management", (2007). [802.1ah] "IEEE Standard for Local and Metropolitan Area Networks - Virtual Bridged Local Area Networks - Amendment 6: Provider Backbone Bridges", (2008) [802.1Qay] "IEEE standard for Provider Backbone Bridge Traffic Engineering", work in progress. [802.1Q] "IEEE standard for Virtual Bridged Local Area Networks 802.1Q-2005", May 19, 2006 [RFC4204] Lang. J. Editor, "Link Management Protocol (LMP)" RFC4204, October 2005 [MEF.6] The Metro Ethernet Forum MEF 6 (2004), "Ethernet Services Definitions - Phase I". [MEF.10] The Metro Ethernet Forum MEF 10 (2004), "Ethernet Services Attributes Phase 1". Fedyk, et. al. Informational [Page 19] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 [RFC4875] Aggarwal, R. Ed., "Extensions to RSVP-TE for Point to Multipoint TE LSPs", IETF RFC 4875, May 2007 [RFC4655] Farrel, A. et.al., "Path Computation Element (PCE) Architecture", RCF 4655, August 2006. [RFC4872] Lang et.al., "RSVP-TE Extensions in support of End-to-End Generalized Multi-Protocol Label Switching (GMPLS)-based Recovery ", RFC 4872, May 2007. [RFC4873] Berger, L. et.al.,"MPLS Segment Recovery", RFC 4873, May 2007. [Y.1731] ITU-T Draft Recommendation Y.1731(ethoam), " OAM Functions and Mechanisms for Ethernet based Networks ", work in progress. [GMPLS-ASYM] Berger, L. et al., "GMPLS Asymmetric Bandwidth Bidirectional LSPs", work in progress. [ETH-TSPEC] Papadimitriou, D., "Ethernet Traffic Parameters", work in progress. [SECURITY] Luyuan Fang, Ed., " Security Framework for MPLS and GMPLS Networks", work in progress. 12. Acknowledgments There were many people involved in the initiation of this work prior to this document. The GELS framework draft and the PBB-TE extensions drafts were two drafts the helped shape and justify this work. We acknowledge the work of these authors of these initial drafts: Dimitri Papadimitriou, Nurit Sprecher, Jaihyung Cho, Dave Allan, Peter Busschbach, Attila Takacs, Thomas Eriksson, Diego Caviglia, Himanshu Shah, Greg Sunderwood, Alan McGuire, Nabil Bitar. George Swallow contributed significantly to this document. Fedyk, et. al. Informational [Page 20] Internet-Draft draft-ietf-ccamp-gmpls-ethernet-arch-04.txt February 13, 2009 13. Author's Addresses Don Fedyk Nortel Networks 600 Technology Park Drive Billerica, MA, 01821 Phone: +1-978-288-3041 Email: dwfedyk@nortel.com Lou Berger LabN Consulting, L.L.C. Phone: +1-301-468-9228 Email: lberger@labn.net Loa Andersson Ericsson AB Phone:+46 8 632 77 14 Email: loa@pi.nu Fedyk, et. al. Informational [Page 21] Generated on: Fri Feb 13 11:56:46 EST 2009