Source
r/Ubiquiti•
_Sigma

QoS at >100Mbps?

I have 120/6 Internet and would like to do ingress and egress traffic shaping QoS.

I currently have an EdgeRouter-Lite which I have configured with priority queue. Enabling the traffic shaping reduces my down speed to 60mbps or so. This is obviously undesirable.

Is there any option other than going up to an er8(pro)? Can the edge switches do the QoS I want? It's unclear from the docs.

Is there some way to do traffic shaping without disabling the hardware offload and maintaining my down speed?

Posted Feb 28, 2016, 5:04 AM UTC · edited

1215
hlmtre•

They CAN do this kind of downspeed if you allow them to offload the packets to the hardware. If you enable QoS or traffic shaping, I believe that must be done in software, which means the ERL is just a wee dual-core 500Mhz box attempting to push a shitton of bandwidth through its dinky processor.

I'm running into the same issue. I'm probably going to get a different device to do the QoS.

3
_SigmaOP•

This was my understanding. I just wanted to make sure I wasn't missing something. What else are you looking at? I really like Ubiquiti , but ER8 is expensive in Canada.

1
Cheeze_It•

So I am not 100% sure on this as I don't have an ERL, but I believe if you enable any sort of deeper packet inspection (like matching packets and such) or queuing then you automatically disable hardware offloaded forwarding.

The next question to ask is, are you pushing so many small packets that in which you are hitting the PPS limit of the router? I almost can guarantee you that you aren't. It sounds like something else is afoot.

When you enable QoS/CoS and get everything working and downloading....are you checking your CPU utilization? Are you maxing it out?

2
maddnes•

So I am not 100% sure on this as I don't have an ERL, but I believe if you enable any sort of deeper packet inspection (like matching packets and such) or queuing then you automatically disable hardware offloaded forwarding.

That's 100% correct, you can be sure now!

are you pushing so many small packets that in which you are hitting the PPS limit of the router?

Not possible at that bandwidth: 120Mbps ≈ 235,000pps @64B packets. ER-L does 1,000,000pps @64B (offloaded).

are you checking your CPU utilization? Are you maxing it out?

Definitely maxed for the ER-L at that bitrate without offload.

1
_SigmaOP•

This my understanding, thanks!

1
maddnes•

Is there some way to do traffic shaping without disabling the hardware offload and maintaining my down speed?

Nope!

Enabling the traffic shaping reduces my down speed to 60mbps or so. This is obviously undesirable.

The dual core 500MHz MIPS CPU in the ER-L is certainly underpowered for the job. However, the ER-X has a dual core (with SMP) 880MHz CPU which can easily push 120Mbps (I have mine running at 130 since that's my dl speed). I think it'll hit ~150Mbps consistently, but above that I'm unsure.

I actually use an ER-L for offloaded inter-VLAN traffic and an ER-X for QoS'd WAN traffic. No NAT on the ER-L so I can still do src/dst based policies for QoS. Not super ideal, but it's still relatively cheap.

If you don't have VLANs, the ER-X would more than suffice.

EDIT: See this post on the forums(v1.7.0beta1):

* ERLite-3 and ERPoe-5: below 60 Mbps most likely will work, above 200 Mbps most likely will not work.
* ER-8: below 160 Mbps most likely will work, above 450 Mbps most likely will not work.
* ERPro-8: below 200 Mbps most likely will work, above 550 Mbps most likely will not work.
* ER-X and ER-X-SFP: below 100 Mbps most likely will work, above 250 Mbps most likely will not work.
1
_SigmaOP•

I had seen those numbers, but it is nice to hear someone else confirm those speeds.

How complex is the traffic-shaper policy that you use?

1
maddnes•

As far as I'm aware, the traffic-control policies (i.e. Smart-Queue and Advanced Queue) are more CPU intensive than the older traffic-policy options (such as Shaper). I haven't used traffic-policy shaper with the ER-X (I used it when I just had the ER-L for upload only).

I'm only using smart-queue right now, as I wanted to see if more thorough queueing was even necessary. For me, it doesn't seem to be. Smart-queue on upload and download is phenomenal. I can have several downloads going, consuming all available download bandwidth, and still be able to browse, stream video, game, skype, etc, with no noticeable performance degradation.

I use just the default settings on smart-queue, except for upload I have ECN disabled (i.e. - I want it to drop packets instead of mark for upload). But ECN is enabled on download.

2
_SigmaOP•

Thanks for the details. Smart queue on the erl reduces me. To 60 or so down. So you're saying you get 130+ down with smart queue enabled on the erx?

1
maddnes•

So you're saying you get 130+ down with smart queue enabled on the erx?

Yes indeed!

Like I said, though, I use an ER-L (as my internal router) as well as an ER-X (as my WAN router), because I want the hardware offloaded inter-vlan traffic from the ER-L, as well as the QoS performance (and PoE/switch) from the ER-X. If you used an ER-X only, and have vlans, the inter-vlan routing performance will be significantly reduced.

My 'dream' device would be something with SFP(s), PoE (24v passive and af) on all ports, all ports able to be configured as a switch, as well as a really beefy CPU. I'd shell out twice as much as an ER-L for that..

1
Networkian•

Probably a stupid question since you said you're using priority-queue and not a shaper policy - but could you double-check that there are no bandwidth limits? What shows up if you run a show traffic-policy? Or even show, and see if there are any config references to 60Mbps.

Here's an example from one of my EdgeRouters - note bandwidth limit set:

admin@er-8# show traffic-policy
 shaper Down {
     bandwidth 100mbps
     class 10 {
         ...
     }
     class 20 {
         ...
     }

As u/Cheeze_It mentioned, the Edgerouters should be able to do this without breaking a sweat. Maybe at some point, try backing up the config, then resetting the router and restoring it?

Ninja edit: which model are you using? I assume the ER-Lite?

0
_SigmaOP•

ERL, yes

No, there is no limit in the traffic-policy.

1