This counter reports how many times Layer 1 has qualified a Remote Alarm Indication, also known as a Yellow alarm, on this WAN line. A Yellow alarm is sent by the far-end equipment to indicate it is having trouble receiving from this side, so a rising lsLayer1RAI count tells an admin the problem may actually be with the local transmit path or cabling rather than this device's receiver. If a technician sees lsLayer1RAI incrementing while lsLayer1LOS stays at zero locally, it suggests the far-end device isn't receiving a clean signal from this router, prompting a check of the outgoing cable or transmitter.