1-21. Mesh Connectivity.
This form of connectivity allows a nodal unit to communicate with up to four other nodal units (simplified
sketch shown above).
The facing page illustration is a more detailed example of the above simplified sketch. In this example,
each nodal unit is shown receiving eight group inputs. Therefore, the rate of each group input is 576
kb/s or less. Remember that group input rates of 1024 kb/s or 1152 kb/s require the use of two ports.
The mux in each nodal unit multiplexes the group inputs together into an output SG. These output SG'S
have been designated F1 through F5. Each output SG is broadcast to the other four nodal units via
In the return direction, each nodal unit receives four SG'S. Each incoming SG is demultiplexed by a separate
demux to obtain group data for those groups connected to that unit. Data for each group is routed to
its assigned output port.
For example, data from group K enters at mux input port 5 of nodal unit No. 2 and is multiplexed into
SG F2. Demux 2 of nodal unit No. 5 demultiplexes received SG F2 to obtain data for group K and
routes it to output port 1. Similarly, data from group K' enters at mux input port 1 of nodal unit No.
5 and is multiplexed into SG F5. Demux 4 of nodal unit No. 2 demultiplexes SG F5 to obtain data for
group K' and routes it to output port 5. Thus, user K communicates with user K'.
In summary, the following should be noted:
The same numbered port is used to input and output data for a given group. For example, if
data from a given group enters at mux input port 4, then return data for that group must exit
at output port 4,
Each demux has a port assignment capability controlled by operator entered configuration data.
That is, data for a given group is demultiplexed out of a received SG and routed to its assigned