Quality of service: a call and a backup on one slow line

The idea

A phone on a call and a laptop running a backup share an office Router and one slow line, through a modem, to a cloud server. When the line is full a queue forms; QoS decides what waits and what is dropped, and only where the queue is.

Steps

1. One line, one queue

   A full line is where calls go bad, so first see what one does to a call. The phone's call and the laptop's backup, a big TCP upload, share one 8 Mbit/s line. Ping cloud from the phone, idle, then during the backup.

   phone:~# ping -c 10 10.0.3.10
   laptop:~# iperf3 -c 10.0.3.10 -t 120 --forceflush
   phone:~# ping -c 10 10.0.3.10

2. Marking packets: DSCP

   To put voice first, a router must tell it apart. Ping from the phone, then the laptop, while officeRouter records.

   phone:~# ping -c 1 10.0.3.10
   laptop:~# ping -c 1 10.0.3.10