I found a convenient program to view the current load on the network. Called iptraf. The most interesting thing for me in this program is the detailed load on a specific interface, indicating the outgoing and incoming traffic, the number of packets, etc.
As you can see, here is the total number of packets, separately the number of incoming, outgoing. As well as the size of packets in bytes, incoming, outgoing and total current speed.
You can view this graph by typing iptraf -d eth0 on the console. Eth0 corresponds to the name of the network interface, a complete list of which is displayed by the ifconfig command.
There is a TCP / UDP traffic monitor that displays current connections. Called by the iptraf -s eth0 command.
Iptraf is available in Debian repositories.
aptitude install iptraf