iPAD network capture using the RVI

Quantifying Packet Loss from an iPAD


In order to measure the packet loss of the RTP stream from the Fusion Media Broker to a Fusion Enabled iOS Application the ipad will need to be connected to a Macintosh with wireshark installed.  

The following commands are taken from The Mac Developer Library (https://developer.apple.com/library/mac/qa/qa1176/_index.html#//apple_ref/doc/uid/DTS10001707-CH1-SECRVI) and they describe how the mac can be used used listen to wireless network traffic received by the iPAD:

rvictl -s IPAD_UUID

Where IPAD_UUID is the Identifier for the IPAD, which can be obtained from XCode’s Organizer view:

STEP1: Taking a Capture using RVI

Using Wireshark there is now an additional Interface that can be monitored.

Make a call using the IPAD and allow the Call to establish and run for a few minutes, before stopping the capture and processing the results.

This capture will determine how much packet loss there is from the Fusion Media Broker to the Ipad.  This is because the UDP packets will either be missing or out of sequence.

RVI Captures Introduce Erroneous Skew Measurements

It must be remembered that the capture being taken using the RVI is not at the IPAD but the Mac which it is tethered to.  We have witnessed significant discrepancies in timings values taken using the RVI when compared to a network router.  Notably the skew values can be seconds out within a few minutes.  It is preferable to capture IPAD traces at a wifi access point or network router.

If possible a local wifi-router network capture is also helpful, when determining where packet loss occurs.

Capture taken from a Mavericks Mac +

Wireshark cannot understand the packets captured from Mavericks because Apple chose to use an unknown packet format.  This can be resolved by Opening EditPreferences then Protocols-->DLT_USER and editing the Encapsulations Table to add the following Entry:

DLT = User 2 (DLT=149)

Payload Protocol = eth

Header Size = 108

Header Protocol = <leave blank>

Trailer Size = 0

Trailer Protocol = <leave blank>







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