PPPoE connection problems + Reset state == fixed?

I have been having intermittant connection problems with Bellsouth PPPoE 
DSL service using m0n0wall as my router. Occasionally, in my system logs 
I will notice something like this:

Aug 5 12:47:05  mpd: [pppoe] LCP: no reply to 1 echo request(s)
Aug 5 12:47:15  mpd: [pppoe] LCP: no reply to 2 echo request(s)
Aug 5 12:47:25  mpd: [pppoe] LCP: no reply to 3 echo request(s)
Aug 5 12:47:35  mpd: [pppoe] LCP: no reply to 4 echo request(s)
Aug 5 12:47:45  mpd: [pppoe] LCP: no reply to 5 echo request(s)
Aug 5 12:47:45  mpd: [pppoe] LCP: peer not responding to echo requests
Aug 5 12:47:45  mpd: [pppoe] LCP: LayerFinish
Aug 5 12:47:45  mpd: [pppoe] LCP: LayerStart
Aug 5 12:47:45  mpd: [pppoe] LCP: state change Opened --> Starting
Aug 5 12:47:45  mpd: [pppoe] LCP: phase shift NETWORK --> DEAD
Aug 5 12:47:45  mpd: [pppoe] setting interface ng0 MTU to 1500 bytes
Aug 5 12:47:45  mpd: [pppoe] up: 0 links, total bandwidth 9600 bps
Aug 5 12:47:45  mpd: [pppoe] IPCP: Down event
Aug 5 12:47:45  mpd: [pppoe] IPCP: state change Opened --> Starting
Aug 5 12:47:45  mpd: [pppoe] IPCP: LayerDown

After a while, and a series of failed attempts to establish connection, 
the connection is re-established.

The past couple of times this has happened, after resetting the NAT 
table and Firewall state table in the m0n0wall GUI, connection has 
almost immediately been re-established. I haven't done a formal 
investigation to find out if this is just a coincidence or something is 
happening to the state of m0n0wall that eventually causes connections to 
fail. Does anyone have any insight into this situation? How might I be 
able to further diagnose the problem and analyze the NAT/firewall tables 
to figure out what's happening? Thanks.