Limiting bandwidth per WAN

I have a Peplink 20.

I want to reduce jitter, and notice that when traffic on a WAN goes up, jitter on that WAN goes up too.

To test this, I just started downloading tons of files and watching a couple videos. Then I noticed that my download bandwidth on my primary WAN went far higher than what I set as the download bandwidth (set from the Network > WAN page). I assumed that this setting was also used for QoS (what difference does QoS make if we are overflowing our connection?), but now when I look at the manual again I am thinking that maybe this is only used for load balancing? If that is the case, then how does QoS work?

My outbound policy has several rules (using the Enforced algorithm) simply for me to monitor jitter from within the LAN (so that I can test this every 5 minutes, and I know which WAN is used so I can compare the jitter).

Then I have a rule of algorithm Priority with WAN 1 as the top priority.

My expected behavior on this would be that WAN 1 is used exclusively (aside from those enforced rules that are set solely from one-to-one from an IP in my LAN to an IP out on the internet) up to the speed settings I set from the Network > WAN page and roll over to WAN 2 if WAN 1 fails. Is that not correct?

If not, how do I configure my Peplink 20 to do that (use WAN 1 exclusively aside from those few enforced rules up to a speed I set, and fail over to WAN 2 if WAN 1 fails)?


— David

Hi David,

The bandwidth settings in WAN interface are needed if you had configured Qos. Voice traffics will be prioritized automatically based on the settings.

Since you have 2 WAN links, can I suggest in this way?

  1. Create Outbound Policy for Voice. Used Priority Algorithm (Priority Order: WAN2, WAN1)
  2. Change Default Outbound Policy (Https Persistence and Default rules). Used Priority Algorithm (Priority Order: WAN1, WAN2)

Hope this help.


> The bandwidth settings in WAN interface are needed if you had configured Qos.

But I did configure QoS. Under Network > QOS > Application I had set in the first rule “All Supported VOIP Protocols” as High (I also have three other QoS rules there). Do I also have to create a matching outbound policy?

Just to clarify, the peplink also controls download speed per WAN link with QoS (for example by slowing down the rate of requests when downloading a large file), right?

If I understand correctly (and there’s a good chance I don’t!), if I only had your two suggested outbound rules in place then the only traffic on WAN 2 would be voice (unless of course WAN 1 went down)?


— David

jadvidhobbs brings up an issue I don’t understand.

In other dual WAN routers, limiting the WAN speed in the device settings serves as a type of QoS. For example, if I have 60/4 HSI connection on WAN1 I would put 55/3 in the Peplink settings to prevent any QoS from occurring at the ISP level. Is this not the case with Peplink? Like jdavidhobbs, I have noticed I’m able to exceed upload and download setting levels on my Balance 20 device.

I hate to add any additional info to this thread, but since it seems to be topical I will: A few moments ago I noticed that a wireless device began consuming our entire upload connection and then some (4.5 out of 4 advertised) on WAN1. I believe an active SIP call that was registered over WAN1 failed over to WAN2 as a QoS feature response as I heard the employee saying “hello? hello?” for about 5 seconds, the normal failover time I have experienced with our set up. Is that correct behavior for the Balance 20 or is it possible something else happened? I have QoS for voice set as highest priority. I don’t have outbound policies set at this time.

Thanks cyclops for adding your experience too.

Will anyone from Peplink respond? Is there a fix being made to the firmware? Are cyclops and I configuring the Peplink incorrectly? As of now it looks to me like QoS does not work on the Peplink 20, and I should return the device.


— David

Here are the answers to your questions:

  1. Configuring the upload speed does throttle a WAN link so it is important to configure this for QOS. The Balance will use all of the available bandwidth for downloading regardless of this setting.

  2. Correct. The only traffic on WAN2 would be voice unless WAN1 went down. There are other ways to configure the load balancing, but if you have VoIP phones it is important for them to stay on the same WAN link they registered on. The priority algorithm works well for this.

  3. As mentioned, the Balance will not throttle the download speed but it should indeed throttle the upload. If there is a one way audio problem, you may need to use compatibility mode for SIP under: Network> Service Passthrough Support. I would use outbound policy rules for the phones using the priority algorithm.

  4. QOS does work in the Peplink. For most applications selecting “All Supported VoIP Protocols” is all that is needed. Some VoIP phones use a separate RTP session for the audio. In this case you can select the category “Audio Video Streaming” and from there you can select “RTP”.

Thank you for all the answers to my questions. In my case, the upload speed is not a limiting factor, so I don’t think there are many cases where the Peplink’s QoS would kick in. The best I can do to limit my VOIP traffic from increased jitter due to increased download demands is to try to separate out the VOIP traffic (getting back to TK Liew’s suggestion of those two outbound rules) so that high-download-bandwidth traffic doesn’t use that WAN. The Peplink does not do traffic shaping to attempt to control download bandwidth.


Peplink do supports traffic shaping for Balance 305 and above. You can set or reserve bandwidth for certain IP or IP segment.