4.2 Draw initial diagrams

In the Raster tool, create a diagram tab for each telecom service (see Service tabs). When two services have a lot of components in common, it may be more convenient to combine those services into a single diagram. This avoids components from appearing in more than one diagram, but does tend to make the diagram more complex.

Then, for each telecom service, draw an initial diagram based on the information that is currently available. The diagrams will likely not be very detailed yet. At the very least all actors involved with the service must be drawn. Note that it is always possible to create a diagram; if absolutely no information is available beyond the actors involved then the actors can simply be connected using an unknown link (“cloud” symbol). Drawing and editing diagrams using the Raster tool is explained in Workspace.

When creating diagrams, the following guidelines may be helpful:

• A cable containing multiple fibers or strands should be modelled as a single wired link. Two cables in the same duct should be modelled by two wired links in the diagram.
• Point-to-multipoint connections should be modelled using a single wireless link, but may sometimes be more conveniently modelled using separate wireless links to each receiving node. If you know in advance that the link to each individual node is subject to identical risks, then for simplicity a single wireless link should be used.
• Equipment components can be a single device, or an entire installation. For example, a small telephone exchange may be modelled as a single equipment node. However, installations such as these contain multiple cables and sub-components. Often it is not necessary to model these cables and equipment items separately. When an installation is separated over multiple rooms or when wireless links are used then the sub-components should be modelled separately. Alternatively, an unknown link may be used instead of an equipment item.