HVR's network communication initiated through the HVR remote listener is optimized for high latency, low bandwidth network configurations so we recommend customers always use it – especially in Wide Area Network (WAN) scenarios.
If the customer uses our recommended approach with an HVR installation on the database server then HVR will capture transactions from the tables requested, compress the data, and then send it across the wire. Compression ratios vary depending on the data types used but may be as high as 10 to 1. HVR will always try to transport the data as quickly as possible and may be using all of the available network bandwidth. There is an action LocationProperties with options /ThrottleKbytes and /ThrottleMillisecs to prevent HVR from using all available network resources if the available bandwidth and one point in time would not be sufficient to keep up with the transaction volume.
If customers run HVR to capture or integrate changes on a remote server then HVR can not optimize network traffic and a much higher bandwidth may be used, and also the setup may then be a lot more sensitive to high network latency.
Refresh and row-by-row compare may use a lot of bandwidth in a short period of time simply because a lot of data is transferred between systems. If the HVR protocol is used then network communication is optimized relative to using database connectivity across the network.