Multapplied SD-WAN is able to adjust leg download and upload speeds when increases in leg latency or packet loss are detected. This minimizes latency and loss on each leg and maintains the performance of both latency-sensitive and bulk applications.
How Does it Work?
Our SD-WAN is continually monitoring latency on each leg of your data’s journey. When a circuit comes online, a test is performed to determine idle latency and jitter. These become the baseline values.
When the circuit is idle, the baseline values are updated using regular heartbeat packets sent between the CPE and aggregator. This ensures both have an accurate picture of the leg’s normal latency. If packet loss detection is enabled, the CPE and aggregator will also track the circuit’s loss rate to detect issues.
High latency or packet loss is caused by sending faster than the leg’s available bandwidth?
The latency or loss rate will return to baseline after the circuit speed is reduced to within available bandwidth levels. After finding the speed that results in normal latency or packet loss, the leg speed is gradually increased until it can resume full sending speed. (If high latency or packet loss occurs again, the speed is reduced against and the acceleration returns to the initial pace.)
High latency or loss is due to traffic from other devices on the local or ISP network?
Latency will not return to baseline and packet loss will not change when the leg speed is reduced. In this case, leg speed will settle at a default of 50% of the configured speed until latency returns to baseline or packet loss returns to the acceptable threshold. If leg traffic returns to idle, the speed slowly increases until it reaches the full configured speed.
Uses for Bandwidth Adaptation
Leg latency can increase for a number of reasons. Environments that bandwidth adaptation can handle include:
- Leg download or upload speeds have been set higher than the bandwidth provided by the ISP and the leg is approaching 100% load
- Leg speeds have been set properly for normal use, but equipment failure or environmental issues have reduced the bandwidth available from the ISP
Bandwidth adaptation can help in the above situations because reducing the sending speed decreases the leg’s latency and packet loss rate.
Bandwidth adaptation is not designed to handle:
- The leg is sharing bandwidth with one or more other devices. For example, if the CPE and another router are connected to the same cable modem via a switch, the CPE can’t fully control the bandwidth used on the Internet connection and the router’s traffic may induce latency.
- The load on the ISP’s cable network, DSL central office, or wireless backhaul is greater than the network’s available bandwidth. At some sites, this occurs regularly at the same time every day, such as during heavy residential use every evening.
- The leg regularly experiences packet loss above the configured threshold, even though the throughput of the leg is low
In the above situations, latency or packet loss are caused by factors beyond the control of Multapplied SD-WAN, and bandwidth adaptation will have no effect.