High latency on low bandwidth

When we restrict users to low bandwidth, e.g. 2 Mbps, we see a very high latency on that connection, e.g. 630 ms. Whereas if we have users on high bandwidth, e.g. 100 Mbps, we see a very low latency, e.g. 8 ms.

We have a 1 Gb Synchronos connection coming into our business. We think this is due to Bandwidth Manager, can you help?

That is probably the result of the queue build-up, where network packets from multiple connections are placed in the queue to conform to the 2 Mbps restriction.

Let's say, even if the user opens just a web-page in the browser, it will establish 5-10 connections to fetch images and related resources. Each connection will try to occupy all bandwidth available, so to keep the rate under 2 Mbps, the extra packets will be placed in the queue until more can be sent. As any new packet stays in the queue until all preceding packets are sent, the latency will increase.

If you try measuring latency with ping without any other data transfers running at the same time, the added latency should be near zero.