1. TAPI Photonic Media Model
Stephane St-Laurent, Infinera
September 8, 2019
Updated 004

2. Purpose of this contribution
Explain the Photonic Media define in TAPI
Expose some of the elements that need to be define/augmented

3. Definition: PHOTONIC_LAYER_QUALIFIER
PHOTONIC_LAYER_QUALIFIER_MC:
Media Channel (MC): continuous optical spectrum between end points in the photonic layer intended to transport OTSi
PHOTONIC_LAYER_QUALIFIER_MCA:
Media Channel Assembly (MCA): a group of media channel managed as a single entity
PHOTONIC_LAYER_QUALIFIER_OTSiMC:
OTSi Media Channel (MC): Continuous optical spectrum between end points in the photonic layer to represent the optical spectrum intended to be used by a signal from an OTSi
PHOTONIC_LAYER_QUALIFIER_OTSiMCA:
OTSi Media Channel Assembly (MCA): a group of OTSi media channel managed as a single entity
PHOTONIC_LAYER_QUALIFIER_OTSi:
Optical Tributary Signal: optical signal
Network Medial Channel (NMC): continuous optical spectrum between end points in the photonic layer to represent the optical spectrum intended to carry a signal from an OTSi
Service Media Channel (SMC): continuous optical spectrum between end points in the photonic layer obtain through optical filter that serve NMC (optionally SMC)
Assembly: group of media channel (Network or Service Media Channel) managed as a single entity

4. Overview Media Channel (MC) OTSi Media Channel (OTSiMC)
Continuous optical spectrum define by lower and upper frequency
Could be aligned on ITU grid (could be 6.25 GHz)
Could Include guardband (could be 6.25 GHz and it is technology dependent)
MC could contain 0 to n OTSiMC
MC could be requested at a domain level to represent the contiguous spectrum offered by an optical domain
OTSi Media Channel (OTSiMC)
Continuous optical spectrum to represent the optical spectrum intended to be used by an OTSi
Define by lower frequency and upper frequency
Do no require to be aligned to ITU grid but are technology dependent (medial channel power monitor and transmitter capability)

5. Media Channel (MC)
A media channel (MC) is a spectrum-band define between its lower-frequency and its upper-frequency (in MHz)
It could expose guard bands (read only), a lower-guardband and an upper-guardband, that represent a filter specification (will be define later)
The constraint apply to the possible value for the lower and upper frequency

6. OTSi Media Channel (OTSiMC)
An OTSi media channel (OTSiMC) is a spectrum-band define between its lower-frequency and its upper-frequency (in MHz)
It represent the optical spectrum intended to be used by a signal from an OTSi, for such, it need to be defined in the context of a media channel
It is used to provide information to a system to:
measure power
detect the presence of signal
allocate possible OTSiMC in an MC
The constraint apply to the possible value for the lower and upper frequency

7. OTSi
An OTSi is an optical signal define at a specific center-frequency (in MHz)
It is bounded by its lower-frequency and upper-frequency (in MHz)
The constraint apply to the possible value for the center frequency

8. OTSi and OTSiMC correlation
An OTSi is a signal define at a specific center-frequency (in MHz) based on the constraint and accuracy associated to a transmitter
The measurement of the power at the OTSiMC need to correlate with the measurement done at the transponder
For such, the OTSiMC spectrum-bandwidth should be used in both measurement

9. Multiple OTSiMC in an MC
When multiple OTSiMC could be contained inside one MC, a user should be able to pass information so the OTSiMC could be adjacent, or with some spacing, to each others
Adding some spectrum spacing could improve OSNR of the signal
Note: This provides to the Path Computation Engine (PCE) the information needed to allocate the center frequency to the OTSiMCs. The PCE must still maintain the constraint associated to the center-frequency that is defined by the transponder (OTSi) specification

10. Multiple OTSiMC in an MC
Spacing between OTSiMC could be passed using OTSiMC-additional-spectrum or non-adjacent-OTSiMC-spectrum. One parameter need to be agreed on. The non-adjacent-OTSiMC-spectrum give a better understanding to evaluate non-linear impairment (NLI).

11. Center Frequency Constraint on OTSiMC
The OTSiMC center-frequency constraint is associated to the center frequency adjustment-granularity
The 2 examples on the left show case of granularity of 25 and 12.5 GHz
It is all associated to the equation:
n * adjustment-granularity
Need to add center-frequency constraint in the connectivity-service

12. Lower and Upper Frequency Constraint on OTSiMC
The OTSiMC edge-frequency constraint is associated to the lower and upper frequency adjustment-granularity
The 2 examples on the left show case of granularity of 6.25 and 12.5 GHz
It is all associated to the equation:
n * adjustment-granularity
Note: A monitoring-point on an OTSiMC CEP could be limited, by an implementation, in passband frequency at a granularity specified by the adjustment-constraint. Example: a channel-monitor with a resolution of 12.5 GHz increment on a 12.5 GHz grid
Need to add edge-frequency constraint on OTSiMC

13. frequency-constraint specification
The frequency-constraint of the photonic model is specified using:
grid-type:
[DWDM, CWDM,FLEX, GRIDLESS, UNSPECIFIED]
adjustment-granularity:
[G_100GHZ, G_50GHZ, G_25GHZ, G_12_5GHZ, G_6_25GHZ,
G_3_125GHZ, UNCONSTRAINTED]

14. Min and Max bandwidth constraint of OTSiMC CEP
A node should be able to expose the constraint associated to the minimum and maximum bandwidth of OTSiMC passband of a CEP
It should be presented in MHz
Proposal:
minimum-OTSiMC passband (MHz)
maximum-OTSiMC passband (MHz)
Presented in MC NEP (since the OTSiMC is dynamically created)
Or in the connectivity constraint of the node at the MC layer qualifier

15. Lower and Upper Frequency Constraint on MC
The MC edge-frequency constraint is associated to the lower and upper frequency adjustment-granularity
It is presented by the MC NEP frequency-constraint information using grid-type and adjustment-granularity
The examples show case of granularity of 6.25 and 12.5 GHz
It is all associated to the equation:
n * adjustment-granularity

16. Min and Max bandwidth constraint of MC CEP
A node should be able to expose the constraint associated to the minimum and maximum bandwidth of MC passband of the CEP
It should be presented in MHz
Proposal:
minimum-MC passband (MHz)
maximum-MC passband (MHz)
Presented in MC NEP
Or in the connectivity constraint of the node at the MC layer qualifier

17. Media Channel NEP Specification
The Media Channel NEP specification contain a list that provides the supportable-spectrum and its associated MC CEP frequency-constraint. It also contains available-spectrum and occupied-spectrum
Its passband is specified by tuple of lower-frequency and upper- frequency in MHz
It expose the adjustment-granularity and grid-type (for MC CEP constraint)
As example: a list of 2 entries, one for the C band and one for the L band using flex-grid and an adjustment-granularity of 12.5 GHz

18. Allocation of MC CEP in MC NEP
Assume no stacking for MC

19. Transponder Use Case

20. Disaggregated Use Case: Single OTSi per interface
The OTSiG could contains 1 or multiple OTSi
The OTSiG could be provided to the ROADM using multiple interface
In the case of multiple interface to the ROADM node, the interfaces could be share

21. Disaggregated Use Case: Multiple OTSi per interface
The OTSiG could contains 1 or multiple OTSi
The OTSiG could be provided to the ROADM using multiple interface
Each interface could contain multiple OTSi
In the case of multiple interface to the ROADM node, the interfaces could be share

22. OTSiA
Assuming on OLS system (disaggregated) PCE that allocate the spectrum
In the case of multiple OTSi that form a group, it is possible that:
All the OTSi require the same spectrum bandwidth
Or, the spectrum bandwidth is not be symmetric, example:
225 GHz on OTSi #1 and 200 GHz on OTSi #2
In this case, it may be required to know the bandwidth requirement per interface when doing a connectivity service

23. Disaggregated: Transponder/ Photonic
The OAM channel need to use the OCN and have an OCC between the photonic NE and the Transponder
Needed:
Interface and Protocol to manage:
OTSi TxTransmitPower
OTSi CentralWavelength (For restauration handle by Photonic SDN)
Enable/Disable ???
And to Retrieve Capabilities:
OTSi TxTransmitPower range
OTSi CentralWavelength Tuneability (Range [ lowerFreq,upperFreq]) in MHz

24. ROADM Client Interface (Interface associated to the OTSi)

25. ROADM Interface Client interface in a ROADM node could be shared
For CD architecture, it is common to have interface that are connected internally using a combiner ( 4, 8, 12 ports as example)
Those interface NEP should share the same group id
It is similar for CDC architecture; it is possible for the connection that go to the same direction to share the spectrum through a optical combiner
Those interface NEP should share the same group id

26. TAPI Media Model

27. Defining a network
In its basis configuration, a disaggregated OLS Network could be expressed by a topology that contain node with MC NEP and Link between those NEP
L12
A, B and C are ROADM node
Only MC layer qualifier is required
Link could be unidirectional A 01 02 B
L21 10
L34 11 03 04 07
L43 05
L78
L87
L65
L56 08 C 06
topology = n1 12
topology-context

28. MC Network
Media Channel CEP
{lowerFreq, upperFreq}
Media Channel Assembly
[{lowerFreq, upperFreq},
{lowerFreq, upperFreq}, ..]
Service Interface Point
Node Edge Point
Connection End Point (TTP + CTP)
Connection End Point (CTP only)
Connection End Point (Inverse mux CTP only)
Connection End Point (TTP only)
Node Edge Point Group
MIP
Down MEP
Up MEP
OPM
Connection
Exposing this topology is enough to request service (intent) or even to figure out service request in a declarative manner A B X1 X3 MC MC MC
MC Link MC MC MC X2 X4
MC Link
MC Link
Need to know the connectivity between NEPs
Non Intrusive Monitoring
No Specific OAM signaling
Optical Power Monitoring C MC X5