RI: Clarification about Transitional Links key attributes

italobusi commented 8 years ago

It is not clear how to use the different attributes to qualify the transitional link.

Let's consider as an example the TL in slide 5 of onf2016.303.02.

I think that the two NEPs of this TL should have:

                  {
                      "_layerProtocol": [
                          {
                             "layerProtocolName": "ODU",
                           }
                      ],
                      "uuid": "D1-o-TL"
                   },

                  {
                      "_layerProtocol": [
                          {
                             "layerProtocolName": "ETH",
                           }
                      ],
                      "uuid": "D1-e-TL"
                   },

The transitional link can be defined as follows:

"_link": [ { "_linkPort": [ { "_nodeEdgePoint": ".../D1-o-TL/", }, { "_nodeEdgePoint": ".../D1-e-TL/", } ], "_node": [ ".../D1-o/", ".../D1-e/" ], "uuid": "transitional-link" } ],

In onf2016.355 there are also Total Pool Capacity, supported granularity and Max # instances attributes for the NEPS which are not present in T-API Topology IM. From that description, it seems that the OTN NEP can support 400G but the ETH NEP can only use 200G.

I guess that the TL capacity would then be 200G and we can represent this information using the Link attributes:

` "_link": [ "_transferCapacity": { "totalPotentialCapacity": { "totalSize": "200GBPS" } }, "uuid": "transitional-link" } ],

` Is my understanding correct? If so, why do we need the Total Pool Capacity attribute for the NEPs?

The Link has also the _lpTransition [1] package. This package seems applicable only to TL so why it is [1] and not [0..1]?

From the UML description, it is also not clear what information should be provided in this package:

transitionedLayerProtocolName: Provides the ordered structure of layer protocol transitions encapsulated in the TopologicalEntity. The ordering relates to the LinkPort role.

_nodeEdgePoint: Lists the LTPs that define the layer protocol transition of the transitional link.

How are these attributes used? Since the TL connects an ODU NEP with and ETH NEP, we can understand it is a TL. However, we need some additional information to indicate that the transition is from ETH client to ODU server and not vice-versa.

Also the use of the layerProtocolName [1..*] for the Link is not clear. Should it be ETH, ODU or [ ETH, ODU ]? Why this information cannot be inferrred from the fact that the two NEPs are ETH and ODU?

karthik-sethuraman commented 8 years ago

It would be easier t understand/discuss your questions by drafting an RI network database for the scenario you are describing.