XG QoS Help


I am having a few issues with QoS settings in a XG450 (SFOS 17.5.5 MR-5). To be honest I can't really find a good explanation about how the different QoS settings interact with each other. So these are all the questions i have, thanks in advance.

  • First question is a bit basic and i thought i knew the answer until i started searching online
    • Is 1Mbps = 128KB/s or 125KB/s
    • I thought it 128KB/s you know because 1024/8 = 128 but i found calculators that say something different.
  •  A few things regarding the Traffic Shaping (QoS) Settings in System services -> traffic shaping settings:
    • If i have a symmetric ISP connection of 100Mbps down and 100Mbps up, do i need to put 200Mbps as the total available WAN bandwidth? 
    • I was doing some testing with the Enforce guarantee bandwidth value, which seems to work as advertised but even if i disable the setting, when i click on Show bandwidth usage it keeps counting the Default Policy.
      • In the picture my Application based QoS rule seems to be added to the Default Policy, even though it is disabled. 


  • Application based QoS policy
    • If i want to create a shaping rule that will apply to multiple apps (i.e. OneNote, Teams, etc) to guarantee and limit the bandwidth should i use Individual or Shared?
      • Lets say i want to guarantee 50Mbps and limit at 80Mbps for all O365 related apps. 
    • if i don't want to limit the upload/download separately do i need to give the total bandwidth?
      • Lets say i want to limit 50Mbps down and 50 Mbps up, do i put 100Mbps.

The final question i have is more general regarding the priority of the QoS policies. If multiple policies are applying how will they be prioritized? It seems you can give a priority to the Default Policy and then to every other individual traffic shaping policy you create.

At the moment we are only looking to implement traffic shaping to certain apps but i wouldn't be surprised if in the future we will need to implement QoS for web categories, users, etc.

Thanks in advance.