I can't believe after all these years, this question is still unanswered. I saw a similar post here from 2003 unanswered on the subject as well.
How come nobody knows who this network is in our stats ?
It's like nobody has an answer, but when I did some google researching about a year ago, I saw it referencing to mobile cop car units. (maybe the internet cops have in their cars?)
My buddy still gets them in his stats sometimes & asked me to post here.
For instance, one from illinois -
pppox pool - rback16.emhril
With some numbers after...that I left blank.