mac_track_ips empty ???

[friedel]

Hi;
I've installed CactiEZ with mactrack plugin.
I'm wondering whether table mac_track_ips is empty.
I've a few Cisco Devices in mactrack, and Im suprised that the mac<->ip is shown on a few ports (Cisco 2960), but unly on those ports where vendor_mac is NULL, on all other Ports no IP is listed ???

Is this maybe the reaseon that I get no IP on a Cisco Router (Cisco 3750) ??

Any idea ??
Thanks in advance !