[Teas-ns-dt] Proposed text for section "Transport Slice Endpoint"

["Rokui, Reza (Nokia - CA/Ottawa)" <[e-mail]>]

All,

Following is the modified version of the transport slice endpoint section. Please provide your comments.

Cheers,

Reza


4.2.  Transport slice endpoints

   As discussed in section 3, the transport slice consists of a set of connections between multiple endpoints with a specified connectivity type and one or more SLOs associated with it.

   The transport slice endpoints are the logical identifier to identify the head-end and tail-end points of a transport slice and to perform the forwarding of the user traffic. The characteristics of the transport slice endpoints (TSE) are:

   - They are conceptual point of connection of a network function, device or application to the transport slice.
   - They are logical identifier and requested by the customer of transport slice during the creation of the transport slice
   - They are associated with (hosted by) exactly one application, device, network function (ADN)
   - The cardinality between a TSE and ADN is many:1, i.e. a single device or application can host multiple transport slice endpoints
   -  A TSE is identified by its hosted ADN (its IP address, name , ID etc), TSE unique identifier, TSE unique name and other data. Non-exhaustive list of other data is IP address v4 and v6, VLAN, port, connectivity type (i.e. P2P, P2MP, MP2MP) etc.). TDB to add more

   Note that the concept of the transport slice endpoint is similar to the Link Termination Point (LTP) defined in [draft-ietf-teas-yang-te-topo-18] and access points (AP) defined in [RFC8453] with an important difference. The main difference between them is that both LTP and AP are associated to traffic engineering (TE) whereas TSE is not. In other words. the AP (See section 2.1 RFC8453) is a common identifier for the TE link and LTP is a conceptual point of connection of a TE node to one of the TE links, terminated by the TE node (see section 3.5 draft-ietf-teas-yang-te-topo-18) whereas TSE is a logical head-end and tail-end of the transports slice connections. The TE characteristic of the network might be taken into consideration during the realization of a transport slice.

   There is another type of the endpoints called "Transport Slice Realization endpoints (TSRE)". These endpoints are allocated  and assigned by the network controller during the realization of a transport slice and are technology-specific, i.e. they depends on the network technology which is used during the transport slice realization. They are identified by a hosted node and some associated data. A non-exhaustive list of devices containing TSRE are routers, switches, firewalls, WAN, application acceleration, Deep Packet Inspection (DPI), server load balancers, NAT44 [RFC3022], NAT64 [RFC6146], HTTP header enrichment functions, and TCP optimizers

4.2.1.  Connectivity patterns within Transport Slice

   The transport slices are a set of connections among the set of  endpoints.  These connections can be point to point (P2P), point to
   multipoint (P2MP), multi-point to point (MP2P), or multi-point to  multi-point (MP2MP) based on the connectivity type requested by the customer.