Intermittent outages via tserv13.ash1

[altadenamd]

My connections through tserv13.ash1 go silent for minutes at a time, long enough to stop ssh with 400s timeouts.  During this nothing on v6 (outside my local network) pings (even www.he.net), the tunnel's v4 address does ping pretty much at all times through these outages.  This appears to happen fairly regularly, different times around hourly or a bit more often.  Possibly could be my router, though I have another tacked-up vpn (vti, though) that keeps up through these and doesn't seem to go bad.  I could switch to New York (adds 15ms or so) but don't want to change addresses if possible.
Is the server maybe running out of RAM or maybe a bad interface on a LAG?  I presume this doesn't hit everyone or I would have seen notes here already.

Actually wish VZ would get with the program and offer native V6 for business fios...  (some residential accounts have it already).  About once a month for several years now I listen for RADV packets and never see any :-(, and once in a while try configure dhcp-pd to no avail either. And of course when I call tech support they say "what's that" about ipv6.

-- Pete