How does SpeedFusion handle intermittent packet loss and connection "flapping"?


#1

I have a client with geographically distant call centers. We need to ensure reliable inter-site connectivity for 1. VoIP and 2. virtual desktops. Our sites are connected via MPLS, but this bandwidth is limited due to cost, and its reliability is not significantly better for us than much cheaper “business-grade” internet connections. So, we supplement the MPLS with additional ISPs at each site. We are looking at SpeedFusion VPN to make best combined use of these connections.

I would like to know how SpeedFusion VPN handles each of the following cases. We see these frequently with both fiber and coaxial cable ISPs.

  • Intermittent packet loss (let’s say 10-15%) on a given WAN connection. It is not totally down, but lossy enough to disrupt VoIP traffic. Can Peplink’s health checks detect this and disable the interface until packet loss returns to near 0%?

  • A WAN connection is “flapping”, that is, rapidly changing state between up and down (every few seconds/minutes). In this case, we want to suppress the interface until it stops flapping and stays up for a while. Cisco has IP event dampening, which uses an exponential decay algorithm that suppresses an interface if it changes state too frequently. What is Peplink’s solution to this problem?

To state these questions a different way: It sounds like a health check consists of one ICMP echo packet. Does SpeedFusion technology consider the results of many consecutive health checks when deciding which interfaces to use? If so, what are those decision parameters, and can we modify/tweak them?

Also, what is the historical uptime of Peplink’s DNS service used for inbound load balancing? Does Peplink publish outage reports/statistics anywhere?

Thank you!


#2

Hi,

Look like WAN links reliability is your top priority. Since intermittent packet loss is happening there, WAN Smoothing is a right solution to counter this.

SpeedFusion will keep track the health status of each path, and will take this as one of the element when determining the outgoing path.

If you’d like to fine tuning the behavior on how SpeedFusion handle packet loss and latency, you can refer to the following post for some hidden advanced features (Cut-off latency / Suspension Time after Packet Loss):-
https://forum.peplink.com/threads/3740-Technical-notes-about-advanced-SpeedFusion-features-in-firmware-6-2-0

Hope this help.


#3

Hi TK,

That answers part of one of my questions. Your link describing hidden features doesn’t explain how Peplink detects and quantifies intermittent packet loss, or what you consider to be the threshold of “too much” packet loss. When we see this happening, we typically want the interface to be disabled until the problem resolves and the WAN link is reliable again. This may be minutes or hours, not milliseconds.

Also, what exactly is WAN Smoothing and how does it work?

Chris


#4

Hi Chris,

Please refer here for WAN Smoothing description.

I do advise to enable WAN Smoothing first to counter the problem of intermittent packet loss. The hidden advanced features are manual way to fine tuning the behavior on how SpeedFusion handle packet loss and latency.