This is a cumulative count of frames transmitted out this port since the last reset, the outbound counterpart to cdx6500allportsFrameInTot. Comparing this against the port's outbound packet count over time helps an admin judge framing efficiency on that circuit, since a large frame-to-packet ratio suggests unnecessary link-layer overhead worth investigating. For example, if FrameOutTot grows nearly 1:1 with PktOutTot, each packet is being sent in its own frame with little batching.