Use text with significant entities, relations and arguments.
Fictive example:
(internetz)
WAN eth0;
|
| cat5e straight;
|
WAN eth1; static 89.205.25.230/24;
[router-x] gw 89.205.25.1; WAN NAT 192.168.0.1/24; DNS1 89.205.127.77;
LAN eth0; static 192.168.0.1/24; DHCP-Server 192.168.0.2-192.168.0.254;
|
| cat5e cross;
|
LAN eth0; DHCP 192.168.0.2/24;
[PC] gw 192.168.0.1; DNS1 89.205.127.77;