This value identifies the aggregable physical interface, radio or LAN port, that the connection table shows is actually receiving traffic from a source, referencing radioTable or ifTable depending on interface type. Admins use it to see real traffic-forwarding relationships, including 1+1 radio-protection pairs where the same traffic reaches two aggregable radios simultaneously. This index pointing to the radioTable entry for one ODU, alongside a matching connection row for a second ODU sharing the same aggregator index, would reveal a 1+1 protected radio pair.