Definitions of "Adaptation", "AdaptationType" and "AdaptationService"
Hello, As agreed on the last OGF, Jeroen and I have worked on the definitions of Adaptation, Adaptation Function and Adaptation Services. We propose four definitions to describe adaptation between network layers: Definitions: * Layer: A collection of Ports with common Characteristic Information (Characteristic Information is defined in ITU-T G800; we envision sublayers to be a separate layer too, but this is really up to technology-specific extensions). * AdaptationType: Abstract type describing the technology of embedding the data of one layer into the data of another layer. * AdaptationService: Adaptation capability in a topology or node. * Adaptation: Actual data transport function where data of one port is embedded in the data of another port. This can be a configured AdaptationService, or a static component. Properties: * AdaptationType is between two Layers (the client and server Layer) * AdaptationService is between two PortGroups (This is a new concept, see below) * Adaptation is between two Ports (the client and server Port) Context: * Adaptation and AdaptationService are part of a Topology or Node. * Adaptation can not be part of a cross-connect in a SwitchMatrix. * AdaptationService can not be part of a SwitchMatrixService. PortGroup concept: * PortGroup: a collection of zero or more Ports in a Node or a Topology. PortGroups can be used to describe between which Ports an Adaptation can be created from an AdapatationService, or similarly between which Ports a cross-connect can be made in a SwitchMatrix. Unidirectional: The above definitions for AdaptationService and Adaptation are for bidirectional adaptations (adaptation one direction and de-adaptation the other direction). We propose the following terms for unidirectional Adaptation and AdaptationService: * AdaptationSource: Embedding of data from a client port into a server port. ("adaptation") * AdaptationSink: Extraction of data out of a server port into a client port. ("de-adaptation") * AdaptationSourceService: AdaptationSource capability in a topology or node. * AdaptationSinkService: AdaptationSink capability in a topology or node. Regards, Freek and Jeroen
Some clarifying questions inline -- On Jan 27, 2010, at 7:02 AM, Freek Dijkstra wrote:
Hello,
As agreed on the last OGF, Jeroen and I have worked on the definitions of Adaptation, Adaptation Function and Adaptation Services.
We propose four definitions to describe adaptation between network layers:
Definitions: * Layer: A collection of Ports with common Characteristic Information (Characteristic Information is defined in ITU-T G800; we envision sublayers to be a separate layer too, but this is really up to technology-specific extensions). can you define sublayer? Is this multiplexing within a layer using labels to encapsulate the sublayer? Or something else?
* AdaptationType: Abstract type describing the technology of embedding the data of one layer into the data of another layer. * AdaptationService: Adaptation capability in a topology or node. I would think this could happen in a port, or at least be specific to a port. Is that possible?
* Adaptation: Actual data transport function where data of one port is embedded in the data of another port. This can be a configured AdaptationService, or a static component.
Properties: * AdaptationType is between two Layers (the client and server Layer) * AdaptationService is between two PortGroups (This is a new concept, see below) * Adaptation is between two Ports (the client and server Port)
Context: * Adaptation and AdaptationService are part of a Topology or Node. * Adaptation can not be part of a cross-connect in a SwitchMatrix. * AdaptationService can not be part of a SwitchMatrixService.
PortGroup concept: * PortGroup: a collection of zero or more Ports in a Node or a Topology. PortGroups can be used to describe between which Ports an Adaptation can be created from an AdapatationService, or similarly between which Ports a cross-connect can be made in a SwitchMatrix.
When a link with multiple labeled sub-links connects to a port with multiple labeled subports on a node -- What is the way that labeled links are concatenated to labeled ports -- is that cross connect? If not, what is it?
Unidirectional: The above definitions for AdaptationService and Adaptation are for bidirectional adaptations (adaptation one direction and de-adaptation the other direction). We propose the following terms for unidirectional Adaptation and AdaptationService: * AdaptationSource: Embedding of data from a client port into a server port. ("adaptation") * AdaptationSink: Extraction of data out of a server port into a client port. ("de-adaptation") * AdaptationSourceService: AdaptationSource capability in a topology or node. * AdaptationSinkService: AdaptationSink capability in a topology or node.
Regards, Freek and Jeroen _______________________________________________ nml-wg mailing list nml-wg@ogf.org http://www.ogf.org/mailman/listinfo/nml-wg
Hi John, Great to hear from you.
Some clarifying questions inline --
Some hopefully-not-too-mystifying answers below.
* AdaptationService: Adaptation capability in a topology or node.
John:
I would think this could happen in a port, or at least be specific to a port. Is that possible?
It certainly can be specific to a port. We introduced the concept of PortGroup to handle the case where only a subset of the Ports in a device can handle some Adaptation. What do you mean with "in a port"? In our proposal, a Port is a *logical* entity, so adaptation happens between Ports. In your question and my sentence above, we refer to Port as a physical Port in a Node (which may have multiple logcial Ports). Would it be useful to introduce another term to distinguish between the two concepts?
* Layer: A collection of Ports with common Characteristic Information (Characteristic Information is defined in ITU-T G800; we envision sublayers to be a separate layer too, but this is really up to technology-specific extensions).
can you define sublayer? Is this multiplexing within a layer using labels to encapsulate the sublayer? Or something else?
Our proposal does not distinguish between layer and sublayer. Do you need this distinction?
When a link with multiple labeled sub-links connects to a port with multiple labeled subports on a node -- What is the way that labeled links are concatenated to labeled ports -- is that cross connect? If not, what is it?
From your NSI work, I presume you are mostly interested in describing multiplexing. Are you interested to create a proposal for NML to cover
I'm not entirely sure if I follow you here. Concatenation of labeled subports in a port (which may or may not be connected to a link) seems multiplexing to me. A I would describe a cross-connect (with these terms) as the connection between a labeled subport in one port and a labeled subport in another port. However, this is all speculation on my side: we have not defined subports or labels. In fact, you have a good point with label: our current proposal does not discuss multiplexing (or inverse multiplexing), although we certainly intend to support that. In my view, labels are used for two specific purposes: 1) To distinguish between channels in a link (multiplexing) 2) To switch data in a Node (cross connects) this one or both of these topics (multiplexing and/or cross connects)? If so, I offer you my help. Regards, Freek
Hi all, just one question inline On Jan 27, 2010, at 4:02 AM, Freek Dijkstra wrote:
Hello,
As agreed on the last OGF, Jeroen and I have worked on the definitions of Adaptation, Adaptation Function and Adaptation Services.
We propose four definitions to describe adaptation between network layers:
Definitions: * Layer: A collection of Ports with common Characteristic Information (Characteristic Information is defined in ITU-T G800; we envision sublayers to be a separate layer too, but this is really up to technology-specific extensions).
So to describe a Layer you have to describe all the Ports that the Layer includes? How would we use that exactly? Will the tagged ethernet layer (to name an example) include all the Ports in the topology that support that functionality?
Evangelos Chaniotakis wrote:
* Layer: A collection of Ports with common Characteristic Information
So to describe a Layer you have to describe all the Ports that the Layer includes?
No, we indeed should define Layer as a property of each Port. A Layer should stands on it's own, and the word "collection" is probably not the correct word to use. If you have a suggestions for a better definition, please do let us know! (Here are the ITU definitions, I'm certain you can do better than this. Characteristic information (CI): This is the combination of the adapted information with additional information (layer information) that is transported across the network. Some of the layer information can remain unchanged across the network, though it can be read within the network, while other layer information may be altered within the network. Adapted information: Adapted information is the information that is transported transparently across a server layer network. Adapted information is the client information encoded in such a manner that it is transportable across the layer network. This encoding can include labelling of the client information in order to distinguish the client information within the context of a single instance of adapted information. Adapted information is the construct that allows independence between client and server. The termination sink function extracts layer specific information (e.g., encoding, labelling, fields for sublayer OAM) to create the layer adapted information. The extracted information is the layer information (LI), such that the adapted information is equal to the characteristic information minus the layer information. The operation of the termination function is independent of the client layer network. ) Regards, Freek
It feels strange to reply to myself, but I like to make the progress clear to all on the list, so here it goes :)
As agreed on the last OGF, Jeroen and I have worked on the definitions of Adaptation, Adaptation Function and Adaptation Services.
The discussion has faded. The two comments were: - The word "collection" in the Layer definition is not clear. (It seems to imply that *all* ports in a Layer need to be listed in order to define a layer). - The current definitions do not cover multiplexing and sublayers. - The current definitions do not cover channels and named links. I propose that the authors (Jeroen and me) improve the first two items. However, channels and links seem distinct issues, for which the NSI group may have some requirements. I will shortly call for volunteers who like to propose definitions on the issue of links and paths. Regards, Freek
participants (3)
-
Evangelos Chaniotakis -
Freek Dijkstra -
John Vollbrecht