SoftwareErrors is a read-only Counter32 counting the number of software errors, described in the MIB as protocol errors, recorded for this IP-to-IP conversation. Because these are protocol-level rather than physical errors, an admin seeing this counter increase for a IP-to-IP conversation should suspect malformed frames or a protocol mismatch rather than a cabling fault, and — since this ipsb table duplicates the row layout of the MIB's iplb table but is sampled and indexed independently — a given pair can show different collection intervals in ipsb than it does in iplb. A steady trickle of software errors for the pair 10.4.12.30/198.51.100.7 alongside a zero HardwareErrors count for the same row narrows the problem down to how the endpoints are speaking, not the wire between them.