Balance 20 overwhelmed by single client download

I have a Balance 20, 8.3.0 build 5106 in a simple home setup. Dual WAN, one WAN is fiber ISP with advertised 500Mb/sec bandwidth, second WAN is mobile internet on standby connected via USB. No VPN and simple firewall rules.

I have had several episodes where the device becomes unresponsive when performing a file download over the WAN. My son starts downloading a game and it appears that all of the router’s resources are given to the download. The device effectively no longer functions as a switch, it does not respond consistently to pings, and I cannot log into the console without very long delays. If I do manage to login to the console, the dashboard shows CPU at 100%. Basically my entire home internet is down, except for the download.

I understand that the max throughput of the Balance 20 is 150Mbp/sec, and it is possible to exceed this with a 500Mb/sec WAN connection. Typically large downloads are throttled by the download server and never reach the point of overwhelming resources on the receiving end. But it appears that some download servers can deliver a volume of traffic enough to exceed the throughput of the router.

I am surprised that the the router does not handle this volume of traffic more gracefully, i.e. it doesn’t throttle the WAN traffic in order to allow other router functions adequate CPU to be at least usable.

Is this expected behavior, or is there a setting that can configure the router to better manage this situation?



Get a router properly sizes for your WAn

The Balance 20 is not the best fit for your application. All of the activities you mention require resources and B20 simply cannot do “everything at once.” And, the GUI is not prioritized. So, to answer your question I’d say the behavior you see is indeed expected.
A device such as the Balance 20X would be more appropriate for your situation.

Thanks Rick,

My application is an ordinary home internet setup. I’m not even using the advanced features of the PepLink 20, except for the ability to fail over to another WAN. No load balancing, VPN, VLANs, etc. Just routing and switching.

The interesting part is that I cannot control my WAN internet speed. My ISP doesn’t offer anything lower than 500Mb/sec. These high speeds are becoming more common in many areas.

I don’t want or need more than the 150Mb/sec that the Balance 20 can handle, but it seems there is no way to configure it so that it is not overwhelmed by ordinary activity. Why can’t it just throttle the WAN at 150Mb/sec and keep doing everything else it’s supposed to do, like operate as a switch?

I’m having a hard time believing that a company that has been building routers for years would design a product in such a way that it would simply fall over under these circumstances, with no way it can be configured to avoid this problem.

Hoping someone from PepLink can confirm that my $400 router cannot handle an ordinary activity on an ordinary home broadband connection.

The Balance 20 is undersized for your WAN connection. It’s drinking out of a firehose. This is a common problem for all routers, not just your specific one. I replace routers all the time for my clients when they upgrade to faster connections, to prevent exactly this sort of issue.

Try this: go to your WAN settings for your fiber connection, and set the Upload Bandwidth setting to 120 Mbps. That will throttle the WAN interface.

You can also use group bandwidth limits to rate limit downloads on the client side, but give the WAN rate limit a try first.

balance 20 is not $400. balance 20x is $400. i highly suggest you upgrade.

It’s drinking out of a firehose.

I understand that. I’m just really surprised that cannot detect the flow of a firehose and close the valve to a manageable rate. I mean the product is named “balance” which suggests it knows how to manage resources.

In practice it would be difficult to size a router that cannot throttle to a fast broadband connection, since broadband connections often do not adhere to advertised bandwidths. If I have a 500Mb connection that rarely achieves over 200Mb in real-world conditions, but could periodically spike to faster than 500Mb, do I have to buy a 1 Gb router so that my entire network doesn’t randomly stop working?

A proper router should just manage the bandwidth and limit throughput to its spec, but not fall over.

Try this: go to your WAN settings for your fiber connection, and set the Upload Bandwidth setting to 120 Mbps. That will throttle the WAN interface.

Thanks for the tip. There is a setting for Upload Bandwidth, and Download Bandwidth. I will change both and see if I can reproduce the problem (outside of working hours…) The specific problem I am experiencing occurs when a client on the LAN downloads, so I think that Download Bandwidth would be the key setting.

The help tip next to the Download bandwidth has the following text:

This field refers to the maximum download speed.

Default weight control for outbound traffic will be adjusted according to this value.

I would interpret that as meaning the values are only used for balancing multiple WAN traffic. It’s not clear that it would also apply throttling if there is only one WAN, but I’ll give it a try. (also note that that the Download bandwidth setting mentions outbound traffic, is that a typo?)

Peplink’s use of the name “Balance” refers to load balancing for inbound and WAN connections, within the limits of its processing power. The spec sheets “stateful firewall throughput” also isn’t a true measure of actual capacity, it is only a measure of raw throughput under ideal conditions. With all features enabled, I find actual throughput to be about 1/3rd of the raw firewall through.

Peplink could certainly do way better about listing specs and real world throughput, in order to make better sizing decisions. Even the “1Gbps” Balance 20x taps out at around 350Mbps with everything enabled. On anything 500Mbps over over, I use a Balance 310 or BR1 Pro as the minimum, and I have really great results.

Set the upload bandwidth only, leave the download alone. I should have mentioned that the WAN rate limiting using that method isn’t really documented and the tool tip’s refer only to their use in load balancing calculations.

You are likely experiencing Bufferbloat. Some routers support the fq_codel or CAKE algorithms (CAKE is the latest and greatest). Peplink has fq_codel working under the Mitigate Bufferbloat setting for uploads. It doesn’t currently work for downloads, but my information is that is expected to be fixed in version 9.

I and others wish that this was a higher priority for Peplink, but will be very happy if it is finally fixed in version 9 which hopefully will be out later this year. See my long 2018 thread. The 2nd to last response is from Peplink where they say: “Balance 20/30 doesn’t have this feature at the moment due to some limitations. We have filed this and hopefully it is available in the future firmware release.”
reply more_vert Need Active Queue Management for Bufferbloat (fq_codel)

The most recent Bufferbloat user community request was a few days ago from @Andrew_Williams: “+1 for cake. I’ve been using it on my cellular enabled openWRT boxes with great success. If Peplink would get on the ball with this it would be a huge win for everyone.”
Queue management - fq_codel implementation - Mitigate Bufferbloat

While we wait for fq_codel in version 9 for the Peplink routers which will support it, you may want to experiment with enabling the “DSL cable optimization” feature, which my understanding is prioritizes ping, DNS and TCP ACK packets on uplink and can give you a somewhat better Bufferbloat result: Network->QoS Application, DSL cable optimization.

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Experiences vary, I guess. We have 20X routers on 1Gbps fiber connections, and they routinely run at a symmetric pace of 900+ Mbps TCP traffic across the WAN from LAN clients to off-site servers .

If anything, I have found Peplink devices to run slightly faster than the announced throughput limit.



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Followup on this issue: I set the WAN upload and download bandwidth settings to match the broadband connection and was not able to reproduce the issue, so I believe that was a resolution.

It would be helpful if Peplink was more clear on the documentation for these settings. The documentation suggests that the values used as a weight for balancing, and not as a maximum for throttling. I’m not 100% convinced that it actually is throttling based on this setting since I don’t know of a consistent way to create that much traffic on the broadband connection, but so far so good, and I’m optimistic.

Thanks to all for your suggestions.