Paths showing data loss but internet provider does not recognise it. How to prove it?

Products

• AppNeta

Issue/Introduction

Have setup paths to Azure targets, from local office AppNeta M50 which show consistent data loss inbound to this M50:

The internet circuit provider, does not recognize AppNeta monitoring results, maintaining that there is no issue to their circuit. Checking our router, firewall, etc shows nothing wrong with them.

How can we confirm that the Internet Provider's circuit is where the issue lies?

Resolution

Looking at the data loss graph, overlay it to the Voice Loss for the same time frame and if you find that when the data loss occurred, i.e. there was no voice loss and vice-versa such as:

Then this is consistent with a problem in the MTU settings, as per:

TechDocs : AppNeta : Investigating Violation Events - Data Loss

Most likely, an MTU mismatch so take a look at that to see if there is anything incorrect with it.

When reviewing diagnostic tests run during the time this data loss event occurs, check the Data Loss column on the Data Details tab:

As per the TechDocs guide, look for a hop reporting non-zero data loss that continues for all subsequent hops along the route.

Also, the cause of data loss can be at the first hop reporting that data loss, the previous hop, or any infrastructure in between the two.

The only other option is to use trace route to identify all the hops in between and see which is dropping packets or has latency. If those hops are on the Internet Service Provider's circuits then you will be able to present that as additional evidence to the AppNeta findings.