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draft-ietf-ccamp-optical-impairment-topology-yang-01wd1214-06r1-g807 (ex G.media).docx 1-12 July 2019: wd12-20-G.807-C1486r9.docxtd369wp3_editor_g876_v0.07.docx 1-12 July 2019: G.876 (ex. G.media-mgmt) wasn’t updated in this meeting, it will be updated based on the consented content of G.807 in next meeting.TAPI
OTSiThe OTSi is defined in ITU-T Recommendation G.959.1, section 3.2.4 [G.959.1]. The YANG model defined below assumes that a single OTSi consists of a single modulated optical carrier. This single modulated optical carrier conveys digital information. Characteristics of the OTSi signal are modulation scheme (e.g. QPSK, 8-QAM, 16-QAM, etc.), baud rate (measure of the symbol rate), pulse shaping (e.g. raised cosine - complying with the Nyquist inter symbol interference criterion), etc.G.807 refers to G.959.1: Optical signal that is placed within a network media channel for transport across the optical network. This may consist of a single modulated optical carrier or a group of modulated optical carriers or subcarriers. The OTSi, defined in [ITU T G.959.1], is the signal that is carried between the output of an OTSi modulator and the input of an OTSi demodulator. The OTSi is carried by a network media channel. Even in the case where the OTSi consists of a group of modulated optical carriers or subcarriers (see [ITU T G.959.1]), these multiple optical carriers or subcarriers are carried in a single network media channel and the OTSi is managed as a single entity within the media network.OTSi represents the signal, i.e. central frequency, modulation technique, application id, laser control, transmit power, etc.OTSi
OTSiGThe definition of the OTSiG is currently being moved from ITU-T Recommendation G.709 [G.709] to the new draft Recommendation G.807 (still work in progress) [G.807]. The OTSiG is an electrical signal that is carried by one or more OTSi’s. The relationship between the OTSiG and the the OTSi’s is described in ITU-T draft Recommendation G.807, section 10.2 [G.807]. The YANG model below supports both cases: the single OTSi case where the OTSiG contains a single OTSi (see ITU-T draft Recommendation G.807, Figure 10-2) and the multiple OTSi case where the OTSiG consists of more than one OTSi (see ITU-T draft Recommendation G.807, Figure 10-3). From a layer 0 topology YANG model perspective, the OTSiG is a logical construct that associates the OTSi’s, which belong to the same OTSiG. The typical application of an OTSiG consisting of more than one OTSi is inverse multiplexing. Constraints exist for the OTSi’s belonging to the same OTSiG such as: (i) all OTSi’s must be co-routed over the same optical fibers and nodes and (ii) the differential delay between the different OTSi’s may not exceed a certain limit. Example: a 400Gbps client signal may be carried by 4 OTSi’s where each OTSi carries 100Gbps of client traffic.The set of OTSi signals that supports a single digital client.Each OTSiG connection consists of one or more OTSi connections, each end-to-end OTSi connection transfers the OTSi signal from the source modulator to the sink demodulator. The signal transferred over each OTSi connection may be only carry part of the client information that is mapped onto the OTSiA, the OTSi connection should be modelled as a FC, as each OTSi is an independent signal that transfers part of the client information stream.Not defined, not relevant for mng purposes, see OTSiAOTSiG
OTSiG-ONot mentionedThe non-associated overhead for an OTSiG.Mentioned jointly with OTSiAOTSiG-O
OTSiANot mentionedThe OTSiG together with the non-associated overhead (OTSiG-O).OTSiA connection is used to transfer client signal from the source to the sink, so an OTSiA connection can be modelled as a FC (Forwarding Construct) for the client signal. One OTSiA connection is consisted of one OTSiG connection and OTSiG-O connection. In this scenario, OTSiG connection and OTSiG-O connection also should be modelled as two separate FC, as they both are used to carry data stream, the traffic carried by the OTSiG is the client data stream, while OTSiG-O is used to carry the OAM information for the OTSi between OSMEs.Layer rate applicable to transponder, likely only MEPOTSiA
NMCNot mentionedA network media channel (is a type of media channel that) is the serial concatenation of all media channels between an OTSi modulator and an OTSi demodulator. The network media channel may exist without an active OTSi. The network media channel must be present to allow the OTSi to be propagated from the OTSi modulator to the OTSi demodulator. NOTE – A network media channel supports a single unidirectional OTSi and an OTSi is supported by a single network media channel. The network media channel cannot be divided into smaller mediachannels (with a narrower slot width) and must be managed as a single entity within the media network. A network media channel cannot be concatenated with another media channel. Two (or more) network media channels can use the same (wider) media channel as a part of the concatenation that forms the network media channel.OTSiMC models some aspects of NMCNMC
OTSiMCNot mentionedNot mentionedNot mentionedOTSiMC represents the bw portion dedicated to an OTSi, i.e. upper/lower frequency, adjustment granularity, grid type. Clarified that OTSiMC does not end in transponder because upper/lower frequency can be different (typically wider) on transponder and likely not relevant for management. Noted that OTSiMC should be uniform end-to-end, i.e. all OTSiMC "cross connections" share same upper/lower frequency, adjustment granularity, grid type, etc. values. The explicit model of OTSiMC Points and Connections is based on the requirement that some management can be performed on the bw portion dedicated to a single OTSi, both at point and cross-connection level (e.g. attenuation, spectrum equalization). Note that network-wide OTSiMC Connection is necessary only in case MC connections are not edge-to-edge.OTSiMC
OTSiMCANot mentionedNot mentionedNot mentionedOTSiMCA represents the set of bw portions that support an OTSiA. Ideally these bw portions shall be routed together in a single MC (Express Channel case). OTSiMCA is relevant for management as it allows proper fault correlation.OTSiMCA
MCThe definition of the MC is currently being moved from ITU-T Recommendation G.872 [G.872] to the new draft Recommendation G.807 (still work in progress) [G.807]. Section 3.2.2 defines the term MC and section 7.1.2 provides a more detailed description with some examples. The definition of the MC is very generic (see ITU-T draft Recommendation G.807, Figure 7-1). In the YANG model below, the MC is used with the following semantics: The MC is an end-to-end topological network construct and can be considered as an "optical pipe" with a well-defined frequency slot between one or more optical transmitters each generating an OTSi and the corresponding optical receivers terminating the OTSi’s. If the MC carries more than one OTSi, it is assumed that these OTSi’s belong to the same OTSiG. The frequency slot of the MC is defined by the n value defining the central frequency of the MC and the m value that defines the width of the MC following the flexible grid definition in ITU-T Recommendation G.694.1 [G.694.1]. In this model, the effective frequency slot as defined in ITU-T draft Recommendation G.807 is equal to the frequency slot of this end-to-end MC. It is also assumed that ROADM devices can switch MCs. For various reasons (e.g. differential delay), it is preferred to use a single MC for all OTSi’s of the same OTSiG. It may however not always be possible to find a single MC for carrying all OTSi’s of an OTSiG due to spectrum occupation along the OTSiG path.A media association that represents both the topology (i.e., the path through the media) and the resource (frequency slot) that it occupies. The size of a media channel is specified by its effective frequency slot, which is described by its nominal central frequency and its slot width [ITU T G.694.1]. The effective frequency slot of a media channel is that part of the frequency slots of the filters along the media channel that is common to all of the filters' frequency slots. For the purposes of management or control when a "wider" media channel is a part of the concatenation that is used to form longer media channels, it may be necessary to record the frequency slots of the longer media channels that are attached at each end.Media Channel (MC): A contiguous spectrum, i.e. a continuous band of frequency bounded by an upper and lower frequency, its width, where that spectrum is defined over some distance, its length. The photonic MC is such that a photon entering the channel at one point may exit, at some other point on the channel, unchanged (clearly there is a potential for loss). In the photonic application: - The MC may be omni-directional, such that photons can travel in any direction, or unidirectional, due to directionally non-linear channel element - The MC may have a complex topology partially meshing many points, via points of channel merge and channel split. In this case a photon entering the channel at one point has a probability of exiting the channel at one of many of the other points on the channel based upon the specific topology. - The MC is available to carry one or more signals where the characteristics of each signal match the characteristics of the MC such that each signal passes through the channel unimpaired. - An MC may be divided into smaller MCs. This may be either a "hard" division through the application of Guard Bands and filter or a conceptual division considering intended use. When a “wide” frequency slot (e.g. those in an OMS media link) is used to support more than on network media channel it is necessary to track the portions of the spectrum that have been allocated. The spectrum allocation is not visible in the media (media channels have no hierarchy). However, from a management/control perspective it may be useful to model spectrum allocation as though it is hierarchical. i.e. a “wide” media channel may support (contain) multiple “narrower” media channels. It may also be necessary to track the “types” of signals that will be assigned to particular media channels since signals that use different modulation schemes (e.g. phase modulation and amplitude modulation) may require a guard band between them to mitigate the effects of destructive interference.MC (Media Channel) is the key construct to represent the Super/Express Channel. MC is the only networking entity, i.e. where FC/Connection is appropriate model; all other entities like OTSiMC, OTSiMCA, MCA can be derived from MC as far as forwarding is concerned. Note that also OMS and OTS are Media Channels. MC
MCGThe definition of the MCG is currently work in progress in ITU-T and is defined in section 7.1.3 of the new ITU-T draft Recommendation G.807 (still work in progress) [G.807]. The YANG model below assumes that the MCG is a logical grouping of one or more MCs that are used to to carry all OTSi’s belonging to the same OTSiG. The MCG can be considered as an association of MCs without defining a hierarchy where each MC is defined by its (n,m) value pair. An MCG consists of more than one MC when no single MC can be found from source to destination that is wide enough to accommodate all OTSi’s (modulated carriers) that belong to the same OTSiG. In such a case the set of OTSi’s belonging to a single OTSiG have to be split across 2 or more MCs. The MCG is relevant for path computation because all end-to-end MCs belonging to the same MCG have to be co-routed, i.e., have to follow the same path. Additional constraints may exist (e.g. differential delay).A media channel group (MCG) management/control abstraction is a unidirectional point to point topological construct that represents a set of one or more media channels, it is bounded by a pair of media ports. The constituent media channels may be atomic media channels or the serial concatenation of multiple media channels. A MCG may be used to represent: - the set of network media channels (NMCG) used to support an OTSiA or; - a line system with optical amplifiers (OMS MCG). - a fibre between two adjacent optical amplifiers (OTS MCG). The constituent media channels are not necessarily in a single contiguous block of the optical spectrum. A bidirectional MCG is formed by a pair of (contra directional) MCGs. The constituent media channels are not necessarily in a single contiguous block of the optical spectrum. A bidirectional MCG is formed by a pair of (contra directional) MCGs.Not defined, not relevant for mng purposes, see MCA.MCG
MCANot mentionedA media channel assembly (MCA) is a management /control abstraction that represents an MCG and its non-associated overhead. Only the OMS MCA and OTS MCA are described in this Recommendation.MCA represents the set of MCs which are correlated for fault&performance management. An MCA can support one or more whole OTSiMCAs, cannot support a fragment of OTSiMCA. Is there only one MEP/MIP per OMS CEP? There is only one MEP/MIP shared by the two OTS CEPs (C/L band).MCA