+.SH "NOTES"
+.IX Header "NOTES"
+.SS "Block I/O statistics"
+.IX Subsection "Block I/O statistics"
+This I/O value is the amount of I/O since the previous iteration
+of virt-top. To calculate speed of I/O, you should divide
+the number by delay secs.
+.SS "\s-1NETWORK\s0 \s-1RX\s0 \s-1BYTES\s0 \s-1AND\s0 \s-1PACKETS\s0"
+.IX Subsection "NETWORK RX BYTES AND PACKETS"
+Libvirt/virt\-top has no way to know that a packet transmitted to a
+guest was received (eg. if the guest is not listening). In the
+network \s-1RX\s0 stats, virt-top reports the packets transmitted to the
+guest, on the basis that the guest might receive them.
+.PP
+In particular this includes broadcast packets. Because of the way
+that Linux bridges work, if the guest is connected to a bridge, it
+will probably see a steady \*(L"background noise\*(R" of \s-1RX\s0 packets even when
+the network interface is idle or down. These are caused by \s-1STP\s0
+packets generated by the bridge.