Bigleaf uses a tunnel overlay to provide SD-WAN and internet optimization features, such as Same IP Address Failover and intelligent load balancing. As with any tunnel and overlay network, there is protocol overhead for the tunnel encapsulation. The Bigleaf service does not have an MTU requirement for end user traffic.

In addition, our circuit monitoring and managed network services consume a set amount of bandwidth depending on the circuit usage configuration.

Refer to our Glossary of Terms to familiarize yourself with the terms used throughout this article.

Bandwidth usage and data rates

All monthly calculations are based on 31 days. In networking and telecommunications, bits per second (bps) is a common measure of speed or bandwidth for circuits and connections. For example, a modern dial-up connection would operate at 56Kbps, or a gigabit fiber circuit could be 1Gbps.

A byte is a unit of data, which commonly consists of 8 bits. Files stored on a computer have a file size expressed in bytes. It is very common for cellular circuits to be metered or have data usage caps. They usually have some language describing the data cap as “4GB of data per month.”

When thinking about bits and bytes and overhead and utilization, it’s important to be aware of the units and value conversions between the two. For example, if you download a file, it will show the data transfer rate in bytes per second (Bytes/s or B/s). A 40MB file downloads in 10 seconds at an average rate of 4MB/s, which is 32Mbps. See this Wikipedia article for details about data-rate units.

Tunnel overhead

The Bigleaf tunnel overlay will impose additional protocol overhead on customer traffic traversing the network between our on-premises routers (CPE) and our Tunnel Endpoint (TE) servers in our Points of Presences (POPs). Overhead is different for various potential types of traffic. The maximum throughput for a customer UDP flow over a 100Mbps circuit is approximately 94.3Mbps when using Bigleaf.

TCP

Bigleaf clamps TCP traffic to 1380 bytes to avoid fragmentation of TCP traffic across our tunnel overlay. The final overhead is 8%. (This is standard practice, normally this overhead is ~2.7% on the internet with 1500 MTU.)

Most speed test and cloud file transfer applications utilize TCP, so consider this overhead with speed test expectations.

Non-TCP traffic, such as UDP or ESP

There is a 5.7% overhead for non-TCP traffic traversing Bigleaf’s tunnel overlay, such as UDP or ESP.

Bigleaf service metrics and management utilization

Bandwidth rate (Kbps): 14Kbps

Per month data usage (GB): 3.9GB

Bigleaf’s zero touch provisioning, configuration services, and logging and metrics collection require internet connectivity to communicate with our infrastructure. A small amount of this communication is “out-of-band” directly on the WAN circuits, while the rest is “in-band” inside the Bigleaf overlay tunnels. The in-band network flows are identified as “SD-WAN Mgmt” traffic type in our Dynamic QoS, as seen in the Performance page charts in Bigleaf Cloud Connect. 

If your Bigleaf site has a data capped cellular circuit in Backup Only, none of these described services will utilize that Backup Only circuit unless there are connectivity issues with the other circuits.

Circuit monitoring utilization

Bigleaf’s circuit monitoring evaluates circuits in each direction to determine latency, loss, jitter, and capacity. Different circuit usage or load balancing types have different levels of utilization. Load Balance is the default setting. You can read more load balancing in our article Load Balancing options for WAN circuits.

The data usage and rates for the circuit monitoring seen below include ethernet headers (+14bytes) per circuit. The very small amount of out-of-band management traffic described in the previous section is also included in the calculations below.

Examples

Note: The usage calculations in the examples don’t account for any failover events if the Backup Only circuit were to become active and routing end user internet traffic.

Example 1: ACME branch office

100Mbps Bigleaf Service Plan

WAN circuit is from Fiber ISP with 100Mbps speed. WAN2 circuit is from 5G cellular provider with 10Mbps speed.

WAN1 is configured as Load Balance, WAN3 is Backup Only.

Total Bigleaf utilization: 48.9Kbps on the 100Mbps service plan or .05% utilization

45.7Kbps = 30Kbps (WAN1 utilization) + 4.9Kbps (WAN2 utilization) + 14Kbps (service usage)

Total Bigleaf data usage: 22.38GB, but only 2.7GB on Backup Only circuit

22.38GB = 15.8GB (WAN1 usage) + 2.7GB (WAN2 usage) + 3.88GB (in-band service usage)

Example 2: ACME HQ office

1Gbps Bigleaf Service Plan

WAN1 circuit is from Fiber ISP with 1Gbps speed. WAN2 circuit is from Cable ISP with 1Gbps download and 35Mbps upload. WAN3 circuit is a 5G cellular circuit with 10Mbps.

WAN1 is configured as Load Balance, WAN2 is Load Balance, WAN3 is Backup Only.

Total Bigleaf utilization: 78.9Kbps on the 1Gbps service plan or .0079% utilization.

Total Bigleaf data usage: 38.18GB in total. 35.48GB is between WAN1 and WAN2 Load Balance circuits, then +2.7GB, which is only on the Backup Only WAN3 circuit.

Need help?

If you’re troubleshooting a usage issue and you require additional assistance or have questions about this content, contact Bigleaf Support.