Cisco router priority group

1

I found this old configuration in a cisco router:

interface Serial0
  priority-group 1

priority-list 1 protocol ip high udp ntp
priority-list 1 protocol ip medium udp 6075
priority-list 1 protocol ip low tcp ftp-data
priority-list 1 protocol ip low tcp smtp

I do not know what are the default values, NTP may be included.

If I remember well the number of interface buffers is small for the high priority packets, those buffers are rather meant for real time traffic, no point to buffer them long with relatively big delays. If there is NTP packet flood, routers may start easily droping NTP packets.