> On 29 May 2020, at 11:06, Kevin Darbyshire-Bryant 
> <[email protected]> wrote:
> 
> I’m trying to create a ‘diffserv5’ for the purposes of implementing a 'Least 
> Effort’ class: something like LE=Bittorrent, BK=Backups/long term 
> down/uploads, BE=Best Effort/Normal, VI=Streaming media/facetime/zoom, 
> VO=VOIP/SIP.  Not too hard you’d think, take diffserv4 and add a tin.
> 
> I did this with tin allocation: 0=LE, 1=BE, 2=BK, 3=VI, 4=VO.  BW allocation 
> relative to base rate = LE>>8, BE>>0, BK>>4, VI>>1, VO>>2.  Tin display order 
> = 0, 2, 1, 3, 4.  In theory I don’t mind LE being starved hence the above 
> order.  This pretty much ‘jammed' the shaper as soon as any traffic went into 
> LE with other higher priority tins seeing huge latencies, lots of drops and 
> general bad news all over.
> 
> I tried again with a slightly different tin allocation: 0=BE, 1=LE, 2=BK, 
> 3=VI, 4=VO more in keeping with the existing arrangement and display order 1, 
> 2, 0, 3, 4. The shaper doesn’t appear to obviously wedge, though I have seen 
> some latency spikes that I don’t normally see, so it feels like there’s still 
> a corner case being hit.
> 
> Does anyone have any ideas?

Pondering out loud:  Is setting different (i.e. increased) codel intervals & 
targets sensible for ‘artificially’ reduced bandwidths, especially in ingress 
mode?  If I have a 100mbit link and I wish to have a minimum reservation for a 
low bandwidth, low priority tin e.g. 1mbit. Does it make sense to make that tin 
respond slower as if it were a 1mbit link whereas it’s a minimally reserved 
portion of a 100mbit link and it could burst up 100 times quicker than I think? 
 Egress I suspect is less of a problem in that we’ll queue the packets and 
eventually throw them in the floor, but ingress???

Kevin
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