Codec Receive statistics on IPort

Updated by Bryan Jones


This document applies to the Telos iPort High density when using dual path senders and receiver. While the screen shots are from an iPort High Density, this would also apply to the previous version iPort PLUS.


Customer reports that Received packetss A and Received packets B do not match with the total packets A + B

An explanation

In this case, multicast is used as a transmission mechanism. This is only important to the extent that multicast is UDP, so no guaranteed path is used, as would be the case if TCP was used as a transport mechanism. In iPort, TCP is rarely used.

Upon analyzing the screenshot, it becomes evident that both paths A and B experienced significant stream interruptions. This could imply that packets were disabled on path A but continued on path B and were later re-enabled, or some combination of both. Despite this, the A/B receiver maintained a 99% reception rate, indicating that the impact of lost samples was minimal.

In this instance, the counters are functioning as intended, although their behavior might be perplexing at first glance. Understanding their function is crucial to comprehending the system's operation.

Each decoder has two receivers, paths A and B. If there are no packets for more than 2 seconds, the receiver resets its state, including the packets received counter.

The combined A/B counter is not cleared as long as the packets on at least ONE path are active. Therefore, you could get combined A/B counter values that are much higher than the sum of separate A and B counters.

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