Goals and Symptoms

There are often questions to evaluate the network activity of the ION Meters. This articles gives a worst case calculation for the bandwidth required by the meters to operate correctly on the network.

Facts and Changes

Bandwidth, network, ION

Causes and Fixes

There are two contributors to data traffic between the Log Inserter and a meter:

1.  Periodic polling by the Log Inserter to check if there are any new records to upload
2.  Uploading data records


1. The periodic polling consists of a request from the server to the meter and a response from the meter. Log inserter polling to meter occurs every 5 seconds.

• The size of the request (in bytes) will follow the formula:
  54 (TCP/IP overhead) + 46 (ION packet overhead) + 3 * # recorders (data and waveform, whether enabled or disabled) + 3 (for the event log controller)
• The size of the response (in bytes) will follow the formula:
  54 (TCP/IP overhead) + 47 (ION packet overhead) + 5 * # recorders (data and waveform, whether enabled or disabled) + 5 (for the event log controller)

NOTE: allocating 5 bytes for the log positions of the data recorder and the event log controller assumes that the log position is > 65535.  This is a worst-case assumption.


2. Uploading data records also consists of a request and a response.  Log Inserter sends one request per recorder.

• The maximum possible size of this request would be 113 bytes (including TCP/IP overhead).
• The size of the response depends on the number of values being logged and their data type.  The formula is:
  
  54 (TCP/IP overhead) + 61 (ION packet overhead) + [logged value data]
  For a 32-bit float the size of the logged data would be 6 bytes (4 bytes for the float, 2 bytes overhead - worst case).

Example in the case of the ION7650:

There are 29 recorders (13 data rec and 16 waveform rec).

1. The default polling period is 5 seconds. The packet sizes would be:

• Request size = 54 + 46 + 3 * 29 + 3 = 190 bytes
• Response size = 54 + 47 + 5 * 29 + 5 = 249 bytes

So that's 439 bytes over the link every 5 seconds.


2. If you are logging only 32-bit floats in the 13 data recorders (worst case), the packet sizes would be:

• Request size = 113 bytes
• Response size = 54 + 61 + 16 inputs * 13 recorders * 6 bytes = 1363 bytes

So that's another 1476 bytes every 15 minutes.

Maximum network activity over 24h: 7.36 MB

More Information:
This calculation makes the assumption that you are using an ION meter with a default template, and no power quality events. Downloading waveforms will add some considerable network activity.
Be aware that this calculation is valid only for the communications between Loginserter and the meter. This doesn't take into account the activity generated by Vista, Designer, or anything else that can access the meter over the network.

This is the network activity. This is NOT the amount of data logged in the database.