What is the bandwidth required to send video over IP with an AVN Encoder?

That depends upon the AVN encoder. See the complete AVN Comparison Chart here.

The AVN420 and VSiCasterā„¢ have total bandwidth between 100 kbps and 4 Mbps, which makes them well suited for stream transmissions over the public Internet or any LAN.

AVN4XXHD encoder blades (AVN422, AVN441, AVN443) have a configurable total bandwidth between 5 and 20 Mbps.

The AVN2XX encoders (AVN200, AVN210 and AVN220) have different bitrate/bandwidths dependent upon type. See the link at the top for a complete AVN comparison chart.

Once a specific bitrate is set, a sustained bandwidth of the same value is required to pass clean video (i.e. Bitrate = 3.8Mbps requires at least a sustained 3.8Mb pipeline).