They are always based on the value set on the WAN interface. So to clarify further: the 4/7, 2/7, 1/7 are minimal guarantees. So if a lower class traffic needs more and upper classes don't the upper bw will be yielded to a lower class. So in case of no congestion, the priority values will not have any effect but the bw limitations will. From a logic standpoint you will have to look at it this way. Only when there are packets buffered and waiting to be sent over the WAN connection due to a lower upload speed the packest will be serviced according to their queues. So realtime queue gets serviced first until empty. Then the bandwidth queues start with first high queue. If that queue doesn't need 4/7th of the bw to be serviced fully then it will yield the rest to the medium queue. Then the medium queue gets the 2/7 + extra it got from the high queue. If that isn't necessary, all the rest goes down to the low queue which then has 1/7 + what it received from the medium queue. I don't think there are formal best practices on Meraki perse but Cisco itself has documents explaning the 4, 8 and 12 class documents and associated design guides if you want to geek out. What I personally use in Meraki MX are the following: My first rule is matching in the Category Voice and Video conferencing but matching each AUDIO category inside. And set that one to ignore bw limit + DSCP EF. (Btw WiFi also has a traffic shaping page and there you can also set the L2 PCP tag which whould be set to 6). My second rule is matching ALL Voice and Video conferencing. Setting that prio to high, ignore bw limit and giving it AF41. If you want to allow fluent streaming video like Youtube then my next rule matches on streaming where I set prio to high, limit to either per client limit or custom limit and DSCP to AF31. Then I match all business relevant traffic like databases, work apps, also remote management for us networking guys 😉 That gets medium, ignore bw and AF21. Then we get to bulk data where email, filetransfers are put. There you can optionally set bw limit but priority is medium or low with AF11. Then finally we get the undesired category that contains advertising, online filetransfers etc. Those also get low prio, have a strict bw limit and get the CS1 tag.
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