Internet Engineering Task Force R.Kunze, Ed. Internet-Draft Deutsche Telekom AG Intended status: Informational G.Grammel, Ed. Expires: September 10, 2012 Juniper Networks GMG. G.Galimberti, Ed. Cisco H.Schmidtke, Ed. Juniper Networks March 9, 2012 A framework for Management and Control of G.698.2 optical interface parameters draft-kunze-g-698-2-management-control-framework-02 Abstract This document provides a framework that describes a solution space for the control and management of optical interfaces parameters according to the Black Link approach as specified by ITU-T [ITU G.698.2]. In particular, it examines topological elements and related network management processes to operate this construct. This framework is scoped to address the Optical Channel (OCh)-layer covered by G.698.2. The focus is on enabling the wavelength provisioning process in a black link approach irrespective on how it is triggered i.e. by EMS, NMS or GMPLS. This document covers management as well as control plane considerations in different management cases of a single channel DWDM interface as defined by ITU-G.698.2. The purpose is to identify the necessary information elements and processes to be used by control or management devices for further processing. Hence wavelength routing and selection processes as defined e.g. in WSON are beyond the scope of this document. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." R.Kunze, et al. Expires September 10, 2012 [Page 1] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 This Internet-Draft will expire on September 10, 2012. Copyright Notice Copyright (c) 2012 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. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 2. Terminology and Definitions . . . . . . . . . . . . . . . . . 5 3. Solution Space for optical interfaces using a DWDM Black Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Comparison of approaches for transverse compatibility . . 7 3.1.1. Multivendor DWDM line system with transponders . . . . 7 3.1.2. Black Link Deployments . . . . . . . . . . . . . . . . 9 4. Operational aspects using IUT-T G.698.2 specified single channel DWDM interfaces . . . . . . . . . . . . . . . . . . . 10 4.1. Bringing into service . . . . . . . . . . . . . . . . . . 10 4.2. Configuration Management . . . . . . . . . . . . . . . . . 11 4.3. In service (performance management) . . . . . . . . . . . 11 4.4. Fault Clearance . . . . . . . . . . . . . . . . . . . . . 11 5. Solutions for managing and controlling the optical interface within Black Link scenarios . . . . . . . . . . . . 11 5.1. BL Separate Operation and Management Approaches . . . . . 12 5.1.1. Direct connection to the management system . . . . . . 13 5.1.2. Indirect connection to the DWDM management system . . 15 5.2. Control Plane Considerations . . . . . . . . . . . . . . . 16 5.2.1. Considerations using GMPLS UNI . . . . . . . . . . . . 17 6. Requirements for BL deployments . . . . . . . . . . . . . . . 18 6.1. Interoperability Aspects . . . . . . . . . . . . . . . . . 18 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 9. Security Considerations . . . . . . . . . . . . . . . . . . . 20 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 20 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 11.1. Normative References . . . . . . . . . . . . . . . . . . . 21 R.Kunze, et al. Expires September 10, 2012 [Page 2] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 11.2. Informative References . . . . . . . . . . . . . . . . . . 22 R.Kunze, et al. Expires September 10, 2012 [Page 3] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 1. Introduction The usage of the Black Link approach in carrier applications (which include optical amplifiers) adds further networking option for operators enabling integration of G.698.2 optical interfaces into routers and other types of client devices. Carriers deploy their networks today as a combination of transport and packet infrastructures to ensure high availability and flexible data transport. Both network technologies are usually managed by different operational units using different management concepts. This is the status quo in many carrier networks today. In the case of a black link deployment, where the optical transport interface moves into the client device (e.g. , router), it is necessary to coordinate the management of the optical interface at the client domain with the optical transport domain. There are different levels of coordination, which are specified in this framework. The objective of this document is to provide a framework that describes the solution space for the control and management of single channel interfaces as specified by the ITU-T Recommendation G.698.2 [ITU G.698.2]. In particular, it examines topological elements and related network management measures. From an architectural point of view, the black link is a set of pre-configured/qualified unidirectional, single-fiber, network connections between the G.698.2 reference points S and R. The optical transport network is managed and controlled in order to provide black links of the intended centre frequencies and the optical interfaces are managed and controlled to generate signals of the intended centre frequencies and further parameters as specified in ITU-T Recommendations G.698.2 and G.798. Optical Routing and Wavelength assignment based on WSON is out of scope. Furthermore, support for Fast Fault Detection, to e.g., trigger ODUk Protection Switching is out of scope of this work. Additionally, the wavelength ordering process and the process how to determine the demand for a new wavelength from A to Z is out of scope. Note that the Control and Management Planes are two separate entities that are handling the same information in different ways. This document covers management as well as control plane considerations in different management cases of single channel DWDM interfaces. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this R.Kunze, et al. Expires September 10, 2012 [Page 4] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 document are to be interpreted as described in RFC 2119 [RFC2119]. 2. Terminology and Definitions Current generation WDM netwoks are single vendor networks where the optical line system and the transponders are tightly integrated. The Black Link approach changes this situation by introducing a standardized interface at the level of OCh between the line system and transponders. Black Link: The Black Link [ITU G.698.2] allows supporting an optical transmitter/receiver pair of a single vendor or from different vendors to provide a single optical channel interface and transport it over an optical network composed of amplifiers, filters, add-drop multiplexers which may be from a different vendor. Therefore the standard defines the ingress and egress parameters for the optical interfaces at the reference points Ss and Rs. In that case the optical connection between the two G.968.2 optical interfaces is referred to as a Black Link. G.698.2 provides an optical interface specification ensuring the realization of transversely compatible dense wavelength division multiplexing (DWDM) systems primarily intended for metro applications which include optical amplifiers and leads towards a multivendor DWDM optical transmission network. Single Channel DWDM Interface: The single channel interfaces to DWDM systems defined in G.698.2, which currently include the following features: channel frequency spacing: 50 GHz and wider (defined in [ITU-T G.694.1]); bit rate of single channel: Up to 10 Gbit/s. Future revisions are expected to include application codes for bit rates up to 40 Gb/s. Single channel DWDM interfaces to/from other vendor(s): G.698.2 provides transverse compatibility at the single- channel point, using a direct wavelength-multiplexing configuration, for single channel DWDM interfaces to/from other vendors (but not at the multi-channel point). Forward error correction (FEC): FEC is a way of improving the performance of high-capacity optical transmission systems. Employing FEC in optical transmission systems yields system designs that can accept relatively large BER (much more than 10-12) in the optical transmission line (before decoding). Administrative domain [G.805]: For the purposes of this Recommendation an administrative domain represents the extent of resources which belong to a single player such as a network operator, a service provider or an end-user. Administrative domains of different players do not overlap amongst themselves. Intra-domain interface (IaDI) [G.872]: A physical interface within an R.Kunze, et al. Expires September 10, 2012 [Page 5] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 administrative domain. Inter-domain interface (IrDI) [G.872]: A physical interface that represents the boundary between two administrative domains. Management Plane [G.8081]: The management plane performs management functions for the transport plane, the control plane and the system as a whole. It also provides coordination between all the planes. The following management functional areas are performed in the management plane: performance management; fault management; configuration management; accounting management and security management. Control Plane[G.8081]: The control plane performs neighbour discovery, call control and connection control functions. Through signalling, the control plane sets up and releases connections, and may restore a connection in case of a failure. The control plane also performs other functions in support of call and connection control, such as neighbour discovery and routing information dissemination. Transponder: A Transponder is a network element that performs O/E/O (Optical /Electrical/Optical) conversion. In this document it is referred only transponders with 3R (rather than 2R or 1R regeneration) as defined in [ITU.G.872]. 3. Solution Space for optical interfaces using a DWDM Black Link The management of optical interfaces using the Black Link approach deals with aspects related to the management of single-channel optical interface parameters of physical point-to-point and ring DWDM applications on single-mode optical fibres. The Black Link approach allows the direct connection of a wide variety of equipments using a DWDM link, for example: a. A digital cross-connect with multiple optical interfaces, supplied by a different vendor from the line system b. Multiple optical client devices, each from a different vendor, supplying one channel each c. A combination of the above Table 1 provides a list of BL management tasks regarding the configuration of optical parameters. R.Kunze, et al. Expires September 10, 2012 [Page 6] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 +---------------------------------------+---------+----+----+---+---+ | Task | Domain | a | b | c | d | +---------------------------------------+---------+----+----+---+---+ | determination of centre frequency | optical | R | R | R | R | | configuration of centre frequency at | client | NR | NR | R | R | | optical IF | | | | | | | path computation of wavelength | optical | NR | NR | R | R | | routing of wavelength | optical | NR | NR | R | R | | wavelength setup across optical | optical | ? | ? | R | R | | network | | | | | | | detection of wavelength fault | client | R | R | R | R | | fault isolation, identification of | optical | NR | R | R | R | | root failure | | | | | | | repair actions within optical network | optical | R | R | R | R | | protection switching of wavelength | optical | NR | NR | R | R | | restoration of wavelength | optical | NR | NR | R | R | +---------------------------------------+---------+----+----+---+---+ Note: R = relevant, NR = not relevant Table 1: List of tasks related to BL management Furthermore the following deployment cases will be considered: a. Passive WDM b. P2P WDM systems c. WDM systems with OADMs d. Transparent optical networks supporting specific IPoWDM functions, interfaces, protocols etc. Case a) is added for illustration only, since passive WDM is specified in ITU-T Recommendations G.695 and G.698.1. Case b) and case c)are motivated by the usage of legacy equipment using the traditional connection as described in Figure 1combined with the BL approach. 3.1. Comparison of approaches for transverse compatibility 3.1.1. Multivendor DWDM line system with transponders As illustrated in Figure 1, for this approach interoperability is achieved via the use of optical transponders providing OEO (allowing conversion to appropriate parameters). The optical interfaces labelled "single channel non-DWDM interfaces from other vendor(s)" R.Kunze, et al. Expires September 10, 2012 [Page 7] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 and "Single channel non DWDM interfaces to/from other vendor(s)" can then be any short reach standardized optical interface that both vendors support, such as those found in [ITU-T G.957] [ITU-T G.691], [ITU-T G.693], [ITU-T G.959.1], etc. IrDI IaDI | | . . | +----------------------------|---+ . | + WDM Domain + . | | | |\ /| | | +------+ . | | \ |\ / | . | +------+ | TX/ |-->--+---+--T/-|OM|----|/-------|OD|--+-\T+------->--| RX/ | | RX |--<--+---+--T/-| |----- /|-----| |--.-\T+-------<--| TX | +------+ | | | / \| \ | | | +------+ . | |/ \| . | | | + + | | . +----------------------------.---+ | | TX/RX = Single channel non-DWDM interfaces T/ = Transponder OM = Optical Mux OD = Optical Demux Figure 1: Inter and Intra-Domain Interface Identification In the scenario of Figure 1 the administrative domain is defined by the Interdomain Interface (IrDI). This interface terminates the DWDM domain. The line side is characterized by the IaDI. This interface specifies the internal parameter set of the optical administrative domain. In the case of black link deployment this interface moves into the client devices and extends the optical and administrative domain towards the client node. ITU-T G.698.2 specifies the parameter set for a certain set of applications. This document elaborates only the IaDI Interface as specified in ITU-T G.698.2 as transversely compatible and multi-vendor interface within one administrative domain controlled by the network operator. This administrative domain can contain several vendor domains (vendor A for the DWDM sub-network, and vendors B1 and B2 at the transmitter and receiver terminal side). R.Kunze, et al. Expires September 10, 2012 [Page 8] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 3.1.2. Black Link Deployments In case of a Black Link deployment as shown in Figure 2, through the use of the single channel DWDM interfaces defined in [ITU G.698.2], multi-vendor interconnection can also be achieved while removing the need for one short reach transmitter and receiver pair per channel (eliminating the transponders). Figure 2 shows a set of reference points, for the linear "black-link" approach, for single-channel connection (Ss and Rs) between transmitters (Tx) and receivers (Rx). Here the DWDM network elements include an optical multiplexer (OM) and an optical demultiplexer (OD) (which are used as a pair with the peer element), one or more optical amplifiers and may also include one or more OADMs. |==================== Black Link =======================| +-------------------------------------------------+ Ss | DWDM Network Elements | Rs +---+ | | | \ / | | | +---+ Tx L1----|->| \ +------+ +------+ / |--|--->Rx L1 +---+ | | | | | +------+ | | | | | +---+ +---+ | | | | | | | | | | | | +---+ Tx L2----|->| OM |-|>|------|->| OADM |--|------|->| OD |--|--->Rx L2 +---+ | | | | | | | | | | | | +---+ +---+ | | | | | +------+ | | | | | +---+ Tx L3----|->| / | DWDM | | ^ | DWDM | \ |--|--->Rx L3 +---+ | | / | Link +----|--|----+ Link | \ | | +---+ +-----------+ | | +----------+ +--+ +--+ | | v | +---+ +---+ RxLx TxLx +---+ +---+ Ss = Reference point at the DWDM network element tributary output Rs = Reference point at the DWDM network element tributary input Lx = Lambda x OM = Optical Mux OD = Optical Demux OADM = Optical Add Drop Mux Linear black link as per ITU-T G.698.2 Figure 2: Linear Black Link R.Kunze, et al. Expires September 10, 2012 [Page 9] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 In Figure 2, if the administrative domain consists of several domains (e.g. A for a DWDM network supporting the Black Link, B1 for the DWDM Tx, and B2 for the DWDM Rx), it is typical that there will be a separate Element Management Systems (EMS) will be used for each vendor domain (e.g. EMS-a for domain A, EMS-b1 for domain B1, and EMS-b2 for domain B2). Each EMS may have a common standard north bound management interface to a Network Management System (NMS), allowing consistent end-to-end management of the connection. To facilitate consistent end-to-end network management, the north bound management interface from the EMS to the NMS should be consistent (frome a management information point of view) with the standard protocol-neutral (or protocol-specific) information model used in the EMS south bound management interface to its subtending NEs (TX and/or RX). The [Black-Link-MIB] defines such a protocol- specific information using SNMP/SMI. 4. Operational aspects using IUT-T G.698.2 specified single channel DWDM interfaces A Comparison of the Black Link with the traditional operation scenarios provides an insight of similarities and distinctions in operation and management. The following four use cases provide an overview about operation and maintenance processes. 4.1. Bringing into service It is necessary to differentiate between two operational issues for setting up a light path (a Black Link connection is specific in having defined maximum impairments) within an operational network. The first step is the preparation of the connection if no optical signal is applied. Therefore it is necessary to define the path of the connection. The second step is to setup the Black Link connection. This is done using the NMS of the optical transport network. From the operation point of view the task is similar in a Black Link scenario and in a traditional WDM environment. The Black Link connection is measured by using BER tester which use optical interfaces according to G.698.2. These measurements are carried out in accordance with ITU-T Recommendation M.xxxx. When needed further Black Link connections for resilience are brought into service in the same way. If the optical interface moves into a client device some of changes from the operational point of view have to be considered. The centre frequency of the Black Link connections was determined by the setup process. The optical interfaces at both terminals are set to the centre frequency of the Black Link connection before interconnected R.Kunze, et al. Expires September 10, 2012 [Page 10] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 with the dedicated ports of the WDM network. Optical monitoring is activated in the WDM network after the terminals are interconnected with the dedicated ports in order to monitor the status of the Black Link connection. The monitor functions of the optical interfaces at the terminals are also activated in order to monitor the end to end connection. Furthermore it should be possible to automate this last step. After connecting the client device towards the first control plane managed transport node a control connection may e.g. be automatically established using LMP to exchange configuration information. If tunable interfaces are used in the Black Link scenario it would be possible to define a series of backup wavelength routes for restoration that could be tested and stored in backup profile. In fault cases this wavelength routes can be used to recover the service. 4.2. Configuration Management tbd. 4.3. In service (performance management) tbd. 4.4. Fault Clearance tbd. 5. Solutions for managing and controlling the optical interface within Black Link scenarios Operation and management of WDM systems is traditionally seen as a homogenous group of tasks that could be carried out best when a single management system or an umbrella management system is used. Currently each WDM vendor provides an Element Management System (EMS) that also administers the wavelengths. Therefore from the operational point of view in a pure Black Link or in a mixed setup with transponders there are the following approaches will be considered to manage and operate optical interfaces. 1. Separate operation and management of client device and the transport network a. Direct link between the client device and the management system of the optical network (e.g. EMS, NMS) R.Kunze, et al. Expires September 10, 2012 [Page 11] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 b. Indirect link to the management system of the optical network using a protocol between the client device and the directly connected WDM system node to exchange management information with the optical domain 2. Common operation and management of client device and the Transport network The first option keeps the status quo in large carrier networks as mentioned above. In that case it must be ensured that the full FCAPS Management (Fault, Configuration, Accounting, Performance and Security) capabilities are supported. This means from the management staff point of view nothing changes. The transceiver/receiver optical interface will be part of the optical management domain and will be managed from the transport management staff. The second solution addresses the case where underlying WDM transport network is mainly used to interconnect a homogeneous set of client nodes (e.g. IP routers or digital crossconnects). Since the service creation and restoration could be done by to higher layers (e.g. IP), this may lead to more efficient network operation and a higher level of integration. 5.1. BL Separate Operation and Management Approaches R.Kunze, et al. Expires September 10, 2012 [Page 12] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 5.1.1. Direct connection to the management system As depicted in Figure 3 (case 1a) one possibility to manage the optical interface within the client domain is a direct connection to the management system of the optical domain. This ensures manageability as usual. +-----+ | NMS | |_____| /_____/ | | | +---+---+ +----->+ EMS | / | | / +-------+ / | MI SNMP / | DCN Network --------------------+------------------------------- / +------+-----------------------+ / | +| WDM Domain + | / | |\ /| | +---+--+ | | \ |\ / | | +------+ | CL |-/C------+--- -|OM|----|/-------|OD|--- +-------/C-| CL | | |-/C------+--- -| |----- /|-----| |----+-------/C-| | +------+ | | / \| \ | | +------+ | |/ \| | | + + | +------------------------------+ CL = Client Device /C = G.698.2 Optical Interface OM = Optical Mux OD = Optical Demux EMS = Element Management System MI= Management Interface Figure 3: Connecting G.698.2 optical interfaces to the Transport Management system The exchange of management information between client device and the management system assumes that some form of a direct management R.Kunze, et al. Expires September 10, 2012 [Page 13] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 communication link exists between the client device and the DWDM management system (e.g. EMS). This may be an Ethernet Link or a DCN connection (management communication channel MCC). It must be ensured that the optical network interface can be managed in a standardized way to enable interoperable solutions between different optical interface vendors and vendors of the optical network management application. RFC 3591 [RFC3591] defines managed objects for the optical interface type but needs further extension to cover the optical parameters required by this framework document. Therefore an extension to this MIB for the optical interface has been drafted in [Black-Link-MIB]. In that case SNMP is used to exchange data between the client device and the management system of the WDM domain. Note that a software update of the optical interface components of the client nodes must not lead obligatory to an update of the software of the EMS and vice versa. R.Kunze, et al. Expires September 10, 2012 [Page 14] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 5.1.2. Indirect connection to the DWDM management system The alternative as shown in Figure 4 can be used in cases where a more integrated relationship between transport node (e.g. OM or OD) and client device is aspired. In that case a combination of control plane features and manual management will be used. +-----+ | NMS | |_____| /_____/ | | | +---+---+ | EMS | | | +-------+ | MI | | LMP +------+-----------------------+ +------------+---+ +| + | | | | |\ /| | +---+--+ | +-+ \ |\ / | | +------+ | CL |-/C------+--- -|OM|----|/-------|OD|--- +-------/C-| CL | | |-/C------+--- -| |----- /|-----| |----+-------/C-| | +------+ | | / \| \ | | +------+ | |/ \| | | + + | +------------------------------+ CL = Client Device /C = G.698.2 optical Interface OM = Optical Mux OD = Optical Demux EMS= Element Management System MI= Management Interface Figure 4: Direct connection between peer node and first optical network node For information exchange between the client node and the direct connected node of the optical transport network LMP as specified in RFC 4209 [RFC4209] can (should) be used. This extension of LMP may R.Kunze, et al. Expires September 10, 2012 [Page 15] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 be used between a peer node and an adjacent optical network node as depicted in Figure 4. Recently LMP based on RFC 4209 does not yet support the transmission of configuration data (information). This functionality has to be added to the existing extensions of the protocol. The use of LMP-WDM assumes that some form of a control channel exists between the client node and the WDM equipment. This may be a dedicated lambda, an Ethernet Link, or other signaling communication channel (SCC). 5.2. Control Plane Considerations The concept of black link equally applies to management and control plane mechanisms. The general GMPLS control Plane for wavelength switched optical networks is work under definition in the scope of WSON.One important aspect of the BL is the fact that it includes the wavelength that is supported by the given link. Thus a BL can logically be considered as a fiber that is transparent only for a single wavelength. In other words, the wavelength becomes a characteristic of the link itself. Nevertheless the procedure to light up the fiber may vary depending on the BL implementation. Since the implementation of the BL itself is unknown a priori, different sequences to light up wavelength need to be considered: 1. Transponders first, transponder tuning: The transmitter is switched on and the BL is immediately transparent to its wavelength. This requires the transmitter to carefully tune power and frequency not overload the line system or to create transients. 2. Transponder first, OLS tuning: The transmitter is switched on first and can immediately go to the max power allowed since the OLS performs the power tuning. This leads to an intermediate state where the receiver doesn not receive a valid signal while the transmitter is sending out one. Alarm suppression mechanisms shall be employed to overcome that condition. 3. OLS first, Transponder tuning: At first the OLS is tuned to be transparent for a given wavelength, then transponders need to be tuned up. Since the OLS in general requires the presence of a wavelength to fine-tune it is internal facilities there may be a period of time where a valid signal is transmitted but the receiver is unable to detect it. This equally need to be covered by alarm suppression mechanisms. 4. OLS first, OLS tuning: The OLS is programmed to be transparent for a given Wavelength, then the transponders need to be switched on and further power tuning takes place. The sequencing of R.Kunze, et al. Expires September 10, 2012 [Page 16] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 enabling the link needs to be covered as well. The preferred way to address these in a Control Plane enabled network is neighbour discovery including exchange of link characteristics and link property correlation. The general mechanisms are covered in RFC4209 [LMP-WDM] and RFC 4204[LMP] which provides the necessary protocol framework to exchange those characteristics between client and black link. LMP-WDM is not intended for exchanging routing or signalling information but covers: Control channel manangement Link property correlation Link verification Fault Manangement Extensions to LMP/LMP-WDM covering the code points of the BL definition are needed. Additionally when client and server side are managed by different operational entities, Link state exchange is required to align the management systems. 5.2.1. Considerations using GMPLS UNI The deployment of G.698.2 optical interfaces is leading to some functional changes related to the control plane models and has therefore some impact on the existing interfaces especially in the case of an overlay model where the edge node requests resources from the core node and the edges node do not participate in the routing protocol instance that runs among the core nodes. RFC 4208 [RFC4208] defines the GMPLS UNI that will be used between edge and core node. In case of a black link deployment additional functionalities are needed to setup a connection. It is necessary to differentiate between topology/signalling information and configuration parameters that are needed to setup a wavelength path. RSVP-TE could be used for the signalling and the reservation of the wavelength path. But there are additional information needed before RSVP-TE can start the signalling process. There are three possibilities to proceed: a. Using RSVP-TE only for the signalling and LMP as described above to exchange information to configure the optical interface within the edge node or b. RSVP-TE will be used to transport additional information R.Kunze, et al. Expires September 10, 2012 [Page 17] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 c. Leaking IGP information instead of exchanging this information needed from the optical network to the edge node (overlay will be transformed to a border-peer model) Furthermore following issues should be addressed: a) The Communication between peering edge nodes using an out of band control channel. The two nodes have to exchange their optical capabilities. An extended version of LMP is needed to exchange FEC Modulation scheme,etc. that must be the same. It would be helpful to define some common profiles that will be supported. Only if the profiles match with both interface capabilities it is possible start signalling. b) Due to the bidirectional wavelength path that must be setup it is obligatory that the upstream edge node inserts a wavelength value into the path message for the wavelength path towards the upstream node itself. But in the case of an overlay model the client device may not have fullinformation which wavelength must/should be selectedand this information must be exchanged between the edge and the core node. ...additional points 6. Requirements for BL deployments This section raises requirements from the carrier perspective and will be removed in a separate requirements draft if necessary. 6.1. Interoperability Aspects For carrier network deployments, interoperability is a key requirement. Today it is state-of-the-art to interconnect e.g. client devices from different vendors via a WDM transport system using short-reach, grey interfaces. Applying the Black Link (BL) concept, client devices (e.g. routers) are now directly connected via transport interfaces which must be interoperable to each other. R.Kunze, et al. Expires September 10, 2012 [Page 18] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 A progressive approach addressing interoperability is shown in Figure 5.According to the concept of ITU-T G.698.2 the black link, the single channel (coloured) Tx and the Rx can be provided different vendors. The single-channel reference points Ss and Rs indicate the demarcation between the Tx/Rx and the black link, and the set of optical parameters refers to these reference points according to G.698.2. However, G.698.2 does not give any insight into the client equipment (CL), e.g. routers or switches, containing the optical transmitters and receivers.This is a valid topic which is subject of other standards and multi-source agreement (MSAs) describing electrical interfaces, mechanical properties and environmental conditions. Such topics are out of the scope of this document. <========= Black Link =========> +---------------------------+ | Black Link | +-----------+ | + + | +-----------+ |CL #1 | -+---|\ /|---+- | CL #2 | | +------+-+ | | \ +-------+ / | | +-+------+ | | -+-| Tx | | | | | | | | | | Rx |-+- | | -+-| +--+-+---|OM|-- OADM |--|OD|---+-+--+ |-+- | | -+-| | Ss | | | | | | | | RS | |-+- | | +------+-+ | | / +-------+ \ | | +-+------+ | | | -+---|/ \|---+- | | | | | + + | | | +-----------+ | | +-----------+ +---------------------------+ CL = Client Device OM = Optical Mux OD = Optical Demux Figure 5: Interoperability aspects 7. Acknowledgements The author would like to thank Ulrich Drafz for the very good teamwork during the last years and the initial thoughts related to the packet optical integration. Furthermore the author would like to thank all people involved within Deutsche Telekom for the support and fruitful discussions. R.Kunze, et al. Expires September 10, 2012 [Page 19] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 8. IANA Considerations This memo includes no request to IANA. 9. Security Considerations The architecture and solution space in scope of this framework imposes no additional requirements to the security models already defined in RFC5920 for packet/optical networks using GMPLS, covering also Control Plane and Management interfaces. Respective security mechanisms of the components and protocols, e.g. LMP security models, can be applied unchanged. As this framework is focusing on the single operator use case, the security concerns can be relaxed to a subset compared to a setup where information is exchanged between external parties and over external interfaces. Concerning the access control to Management interfaces, security issues can be generally addressed by authentification techniques providing origin verification, integrity and confidentiality. Additionally, access to Management interfaces can be physically or logically isolated, by configuring them to be only accessible out-of- band, through a system that is physically or logically separated from the rest of the network infrastructure. In case where management interfaces are accessible in-band at the client device or within the optical transport netork domain, filtering or firewalling techniques can be used to restrict unauthorized in-band traffic. Authentication techniques may be additionally used in all cases. 10. Contributors R.Kunze, et al. Expires September 10, 2012 [Page 20] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 Arnold Mattheus Deutsche Telekom Darmstadt Germany email arnold.Mattheus@telekom.de Manuel Paul Deutsche Telekom Berlin Germany email Manuel.Paul@telekom.de Josef Roese Deutsche Telekom Darmstadt Germany email j.roese@telekom.de Frank Luennemann Deutsche Telekom Muenster Germany email Frank.Luennemann@telekom.de 11. References 11.1. Normative References [ITU G.698.2] International Telecommunications Union, "Amplified multichannel dense wavelength division multiplexing applications with single channel optical interfaces", ITU-T Recommendation G.698.2, November 2009. [ITU.G.872] International Telecommunications Union, "Architecture of optical transport networks", ITU- T Recommendation G.872, November 2001. [ITU.G709] International Telecommunications Union, "Interface for the Optical Transport Network (OTN)", ITU- T Recommendation G.709, March 2003. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3591] Lam, H-K., Stewart, M., and A. Huynh, "Definitions of Managed Objects for the Optical Interface Type", R.Kunze, et al. Expires September 10, 2012 [Page 21] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 RFC 3591, September 2003. [RFC4204] Lang, J., "Link Management Protocol (LMP)", RFC 4204, October 2005. [RFC4209] Fredette, A. and J. Lang, "Link Management Protocol (LMP) for Dense Wavelength Division Multiplexing (DWDM) Optical Line Systems", RFC 4209, October 2005. 11.2. Informative References [Black-Link-MIB] Internet Engineering Task Force, "A SNMP MIB to manage black-link optical interface parameters of DWDM applications", draft-galimbe-kunze-g-698-2- snmp-mib draft-galimbe-kunze-g-698-2-snmp-mib, July 2011. [ITU-T G.691] ITU-T, "Optical interfaces for single channel STM-64 and other SDH systems with optical amplifiers", ITU-T Recommendation ITU-T G.691, 2008. [ITU-T G.693] ITU-T, "Optical interfaces for intra-office systems", ITU-T Recommendation ITU-T G.693, 2009. [ITU-T G.8081] ITU-T, "Terms and definitions for Automatically Switched Optical Networks (ASON)", ITU-T Recommendation G.8081", ITU-T Recommendation ITU-T G.8081, September 2010. [ITU-T G.957] ITU-T, "Optical interfaces for equipments and systems relating to the synchronous digital hierarchy", ITU-T Recommendation ITU-T G.957, 2006. [ITU-T G.959.1] ITU-T, "Optical transport network physical layer interfaces", ITU-T Recommendation ITU-T G.959.1, 2009. R.Kunze, et al. Expires September 10, 2012 [Page 22] Internet-Draft draft-kunze-g698-mgnt-ctrl-framework-02 March 2012 Authors' Addresses Ruediger Kunze (editor) Deutsche Telekom AG Berlin, 10589 DE Phone: +49 30 3497 3152 EMail: ruediger.kunze@telekom.de Gert Grammel (editor) Juniper Networks ddddd dddd, 1234 US Phone: +1 45552 EMail: ggrammel@juniper.net Gabriele Galimberti (editor) Cisco Via Philips,12 20052 - Monza Italy Phone: +390392091462 EMail: ggalimbe@cisco.com Hans-Juergen Schmidtke (editor) Juniper Networks dddd, 1234 US Phone: +1 45552 EMail: hschmidtke@juniper.net R.Kunze, et al. Expires September 10, 2012 [Page 23]