Data Plane and Control Plane

Extracted from : RFC 5212

"A data plane layer is a collection of network resources capable of terminating and/or switching data traffic of a particular format [RFC4397]. These resources can be used for establishing LSPs for traffic delivery. For example, VC-11 and VC4-64c represent two different layers. 

From the control plane viewpoint, an LSP region is defined as a set of one or more data plane layers that share the same type of switching technology, that is, the same switching type. For example, VC-11, VC-4, and VC-4-7v layers are part of the same TDM region. The regions that are currently defined are: PSC, L2SC, TDM, LSC, and FSC.

Hence, an LSP region is a technology domain (identified by the ISC type) for which data plane resources (i.e., data links) are represented into the control plane as an aggregate of TE information associated with a set of links (i.e., TE links). For example, VC-11 and VC4-64c capable TE links are part of the same TDM region.

Multiple layers can thus exist in a single region network. Note also that the region may produce a distinction within the control plane. Layers of the same region share the same switching technology and, therefore, use the same set of technology-specific signaling objects and technology-specific value setting of TE link attributes within the control plane, but layers from different regions may use different technology-specific objects and TE attribute values.

This means that it may not be possible to simply forward the signaling message between LSRs that host different switching technologies. This is due to changes in some of the signaling objects (for example, the traffic parameters) when crossing a region boundary even if a single control plane instance is used to manage the whole MRN (Multi Region Network)."

Shiomoto, K.; Papadimitriou, D.; Le Roux, J. & Vigoureux, M. (2008), 'D. Brungard," Requirements for GMPLS-Based Multi-Region and Multi-Layer Networks (MRN/MLN)', Technical report, RFC 5212, July 2008.