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vanburen

I recently bought an Ubiquiti EdgeRouter X [1]. Which has a smart queue function that utilises fq_codel.

Results from the DSLReports speed test [2], using the same router, the only difference being turning smart queue on:

Smart queue off: https://i.imgur.com/zeY4rTd.png

Smart queue on: https://i.imgur.com/jfHpiFb.png

Notice the improvement in bufferbloat score from D to A+.

Subjectively, I have noticed the connection seems more responsive and there no longer seem to be latency spikes when utilising all the upload bandwidth.

It’s certainly worth considering bufferbloat, if you suffer from latency spikes when using all your upload bandwidth (I used to suffer from this a lot more, when I had an ADSL connection, with only 1 megabit upload).

[1] https://www.ubnt.com/edgemax/edgerouter-x/

[2] http://www.dslreports.com/speedtest

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I love the ER-X because it's cheap, generally available and a fine router with SQM. Just keep in mind that with smart queue enabled it will top out at about 150-170Mbit. If you're on a faster connection the Edgerouter ER4 with its faster quad core CPU should be able to handle up to about 300-350Mbit.

When you need to shape even more bandwidth, routers based on the Marvel XP Armada chipset do very well. I flashed a Linksys WRT1900ACS with OpenWRT and was able to shape about 600-750Mbps before it ran out of horsepower.

> I love the ER-X because it's cheap

I love my ER-X, but once I got my gigabit connection it can't quite keep up compared to plugging directly into the modem. It's close enough that I'm not looking to replace it, but the next time I need a router I may go the NUC build your own route.

How does one go about building a router from a NUC? Don't you need two NIC's for a router? (One for the modem, one to connect a switch for the LAN.) Or have enough people given up on wired networking that they just build routers where the entire LAN is on WiFi?

If you have a VLAN capable switch and appropriate network card with the right drivers, then you can have all the logical ports you could possibly want.

I have done this at my parents place with a cheap Intel Celeron based computer with a single network port, but 2 logical networks with vlanning. One is for their personal network and the other is for their guest suite they offer through Airbnb.

It’s only 20MB/s fibre, so not much cpu power needed. The no name computer cost less than $250, came with a 60gb SSD and I put pfsense on it.

You can get NUCs with dual NICs or just use one of the mini PCs out there. Ars has few articles building a home brew router with speed comparisons.

Turn on hwnat to keep up with gigabit. (It won't keep up with simultaneous gigabit down and up).

For anyone else looking, there's quick-and-dirty notes on how to configure this back in the 1.7 release notes. (Search for "smart queue") https://community.ubnt.com/t5/EdgeMAX-Updates-Blog/EdgeMAX-E...

Note the comment "the actual rate limits will be set to 95% of the specified value". That explains why I saw a 5-10% dropoff in throughput when I enabled it with honest numbers.

Note that if you have gigabit or faster it's usually cheaper to build a router box with a really fast CPU. Most/all reasonably priced network applicances can't do FQ in hardware offload and their CPU's are pretty weak. Never managed to get over 200mbps on any network box besides a super beefy PC.

An APU2 running OpenBSD with codel and a reasonable pf ruleset gets 450.

I'm currently behind a Linux router with basically nothing but firewall rules configured; I still get an A on that test (meaningful?). I guess this sort of thing is just the default nowadays?

You're one of the lucky ones with an ISP with properly configured buffers. A+ is the goal on that test though, which basically means no extra latency under load.

What router? what ISP? What link technology? What bandwidth? A pointer to your dslreports result? There are plenty of small ISPs that have adopted this stuff... and a few router makers.

I am always happy to hear of a bloat free connection.

doesn't the smart queue feature reduce the maximum bandwidth the router can handle?

In some cases, your connection speed may be fast enough that your router's CPU can't keep pace when doing traffic shaping. But if your router is powerful enough, then properly configured SQM will not result in any meaningful reduction in throughput (and can lead to better real-world throughput, by allowing congestion control to work properly). The more you know about the properties of your WAN connection, the more accurately you can configure SQM to account for the true limits of your connection. If you have an ADSL connection, then it helps to tell SQM to take into account ATM framing overhead, for example.

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