playing with md, some more text

documentation/design/05-implementation.md

@@ -6,10 +6,40 @@ Because it rocks, but let's see afterwards what can be written here.
 
 ## Storing Information
 
-Section XXX (Conceptual Design of a SDN Controller as Net- work Supervisor)
+Section XXX (Conceptual Design of a SDN Controller as Network Supervisor)
 discusses the need to store information about for element inventories and
 topology inventories.
 
+### Element Inventories
+
+Storing information about network elements and their properties is a relative
+static process, at least when one considers potential changes over time.
+Typically such network elements are added to a network and they will remain in
+the network for a longer time, i.e., multiple minutes or even longer.
+
+### Topology Inventories
+
+Every network has one given physical topology and on top of this at least one
+logical topology. There may be multiple logical topologies on top logical
+topologies, i.e., a recursion.
+
+A topology consists out of interfaces, which are attached to their respective
+network elements, and links between these interfaces.
+
+Mathematically, such a topology can be described as a directed graph, whereas
+the interfaces of the network elements are the nodes and the links are
+the edges.
+
+G <sub>physical</sub> ist a superset of G <sub>logical1</sub>. 
+
+
+### Potential other Inventories
+
+There may be the potential need to store information beyond pure topologies,
+actually about network flows, i.e., information about a group of packets
+belonging together.
+
+
 ## YANG to code
 
 The base of the development of goSDN are YANG modules. The RESTful API used for RESTCONF is defined in an OpenAPI 2.0 file. This API documentation is generated from the YANG module. The YANG module description is also used to generate code stubs for the goSDN RESTCONF client.
@@ -18,7 +48,7 @@ The base of the development of goSDN are YANG modules. The RESTful API used for
 
 ### YANG
 
-YANG defines an abstract netwoprk interface. It is the foundation of the RESTCONF protocol. Several code generators exist to generate code stubs from a given definition.
+YANG defines an abstract network interface. It is the foundation of the RESTCONF protocol. Several code generators exist to generate code stubs from a given definition.
 
 ### OpenAPI