The Authenticator field in an Accounting-Response packet is called
the Response Authenticator, and contains a one-way MD5 hash
calculated over a stream of octets consisting of the Accounting-
Response Code, Identifier, Length, the Request Authenticator field
from the Accounting-Request packet being replied to, and the response
attributes if any, followed by the shared secret.
32-bit unsigned integer representing the number of
packets that were lost by the system that created the
packet file between the first packet record in the
file and this one.