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Computers & Hardware => Networking => Topic started by: neil on July 20, 2022, 04:29:10 AM

Title: High ping even with openwrt SQM
Post by: neil on July 20, 2022, 04:29:10 AM
So, I reset my modem a few weeks ago and was using it without any changes. Today during the game update, I noticed I was getting high ping, even with sqm enabled on my openwrt router. 
router and modem are in bridge mode.

So, I tested it with different sqm settings, setting my speeds 85% and 90% of actual speed, but still ping was all over the place during the game update. I checked my modem settings and QoS in modem settings was off, I turned it on and DSCP value to AF11. And all of sudden ping drops normal.

Can anyone explain why I need to also turn on QoS and DSCP marking in the modem settings? Even when SQM is enabled in openwrt router.

In the attached screenshot. flat line is with DSCP marking.
Title: Re: High ping even with openwrt SQM
Post by: neil on September 16, 2022, 04:26:37 AM
It was an issue with my config.
I was creating ptm interfaces with vlan config in the modem settings, separate vlan for IPTV and internet.
You just need to create a single PTM interface.
And create separate vlans in the router. In my case it's openwrt router.
After creating separate vlans in the router, IPTV is working fine without stream stopping every few minutes and stuttering.

Title: Re: High ping even with openwrt SQM
Post by: burakkucat on September 16, 2022, 05:16:49 PM
That makes sense . . . now you have explained it.

Have the modem doing just the minimum (acting as the VDSL2 end-point) and have all other configuration requirements fulfilled by the router.
Title: Re: High ping even with openwrt SQM
Post by: neil on September 16, 2022, 07:19:43 PM
That makes sense . . . now you have explained it.

Have the modem doing just the minimum (acting as the VDSL2 end-point) and have all other configuration requirements fulfilled by the router.

Yes, in the modem just single PTM vdsl bridge interface without any vlans.

In the router, separate vlan for pppoe wan connection and separate vlan for IPTV.
It took me a long time to figure it out. I was using it like that for more than a year with IPTV stream stopping after few mins.
Now in openwrt router SQM is working flawlessly even when people are using internet and streaming content. No ping spikes in online games.

and now my MTU for pppoe wan is 1490 bytes, before it was 1492. 2 bytes taken by vlan.