VMG1312-B10A: QoS
The ZyXEL VMG1312 has QoS enabled by default with a set of default rules giving priorities to various protocols.
Initial findings show that the default settings may not ideal.
The affect of disabling QoS
Here we are running a backup job, an rsync (over ssh). Just after 7am QoS is disabled for around 30 minutes. The latency (blue) immediatly jumps up to an average of 350ms. It was less than 20ms with QoS enabled.
Problems with default settings
With the default settings, running an rsync over ssh backup, kills DNS lookups completely! SSH has a higher priority than DNS, and with all the SSH traffic DNS lookups can't get a word in edgeways.
AA Default Settings
We set the QoS be simply based on packet size. We deactivate the various default Classes and Queues and rely on the setting to let small packets jump the queue. This typically gives VoIP, DNS and other 'real time' protocols priority. This is similar to the way that the core routers at the AAISP side work.
QoS on our CQM Monitoring
Customer Feedback
We welcome any customer feedback as to these QoS settings. We're happy for customers to modify their config if they would like, but these settings would get overwritten if a config is ever send from the AAISP side to the router.