[ale] Cablemodem problems (Charter); DSL maybe

Ken Cochran kwc at TheWorld.com
Mon Aug 20 23:17:22 EDT 2007


>From: "James P. Kinney III" <jkinney at localnetsolutions.com>
>Date: Mon, 20 Aug 2007 17:23:22 -0400
>Subject: Re: [ale] Cablemodem problems (Charter); DSL maybe
>
>
>For reasons best left to <rant> formatting, cable modems are apparently
>very picky about grounding. To add to that, they are also very poorly
>installed in most situations. The best thing _you_ can do is to get a
>groundrod from the hardware store and pound it in yourself. Then run
>appropriately sized bare copper from the ground in your power breaker
>box to it. Repeat for the ground connection from the cable feed. Be sure
>to use solid mechanical connection and use the anti corrosion grease.

Both telco & cable enter the house by "their" NIDs, each on the
outside wall nearby the electrical service/meter.  All are
common-grounded (per code) to a single deep-driven rod directly
below the power box (constructed in early 1970s).  It's on a
lake, so there is a high water table; I'd think that would make
for very good grounding.  (?)  Grounding has been inspected
before, by both telco & cableco techs & by me & my electrician(s)
and they report no problems.  And it looks good to me now.  {shrug}

Services are underground in plastic conduit from the house to a
pole, about 75 feet, and from that pole to the street pole, in
the air about another 75-80 feet.  The "middle" pole is *not*
grounded, neither for phone nor cable nor power; also, it's on
"their" side of any NIDs, so any grounding there is utilities'
responsibility.  I think the "street" pole is grounded for
everything.  (Hmm, it'd have to be, it has a power transformer
too and the power people here *always* ground transformers.)

Internal house cabling is RG-6 with "snap'n seal" conectors.
>From the house to the street is RG-11, with similar connectors.

Any other ideas?  I just can't believe the cableco's outside
plant is so temperature sensitive that they have to have a
crew "retune" it seasonally.  But right now I'm not getting
more than about 30 minutes at a time of ip-connectivity.
Then it's out for roughly another 30 minutes, "cycling" like
this all the time.

-kc

>On Mon, 2007-08-20 at 16:21 -0400, Ken Cochran wrote:
>> Hi ALErs:
>>
>> Sort of a 2-part question/problem, cablemodem problems vs DSL:
>> (Lesser of 2 evils?)
>>
>> 1.  (Charter) Cablemodem service problems:  You folks in the
>>     cableco/outside plant world can maybe help me with this?
>>
>> I've been having problems with Charter (cablemodem) for a long
>> time now (a couple of years or more, I track the tickets) and I'm
>> wondering if now that I can get dsl at my location, it might be
>> time to change.
>>
>> At roughly regular intervals of every few months, I get sporadic
>> loss & restart of IP, TV works fine, usually the cablemodem
>> itself (& subsequently the dispatched tech) reports good signal
>> levels/s:n ratios, etc.  What happens is a loss of Internet
>> communications every few minutes, lasting for a few minutes.
>> Netstat reports non-zero send-Qs when this is "underway."
>> Traceroute doesn't even make it as far as the 1st hop.  A little
>> while later, things resume as if nothing ever happened.  This
>> repeats all the time.  Currently, this has been happening since
>> Friday afternoon and has not been corrected.  Last time (mid-May
>> 2007) also took several days to correct.  The cablemodem itself
>> reported a borderline signal level; repair took a line tech.
>>
>> Last couple of times (& now, still experiencing this), the
>> visiting (house services) tech says he has to dispatch a "line
>> tech" to "rebalance" (?) the neighborhood lines (along the
>> street).  He says it is because of the change in (weather)
>> seasons and/or ambient temperatures (going either hot or cold)
>> that causes this & line techs have to come out & rebalance these
>> a few times per year (roughly seasonally).  Any idea(s) as to
>> just what is happening here?  Sounds like BS to me; I find it
>> hard to believe that a cableco has to go out & redo its outside
>> plant 2-4 times a year to correct for what sounds to me like
>> design deficiencies in said outside plant.
>>
>> Some local setup details:
>> Cablemodem is a Motorola SurfBoard SB4101.  Distance from service
>> entrance to the "node" (coax to fiber converter) is about 2000
>> feet via coax that's about as big around as my thumb.  Outside
>> plant is from Scientific Atlanta.
>>
>> 2.  DSL:  Location, Alexander City, Alabama (east central AL),
>>     ILEC & my local service is Bellsouth/ATT and DSL has only
>>     recently become available at my location.  It looks like my
>>     pickins' are slim wrt carriers.  I'm about 6500 feet from the
>>     "remote" box (or pair-gain mux or whatever they're calling
>>     that thing nowadays...) that serves my area.
>>
>> a.  Recommended (or not) carriers
>>     Unless some things have changed/added, I think Bellsouth/ATT
>>     might be my only option for DSL but I need to check further.
>>     Any recommendations for/against alternatives?  I think my
>>     available options *might* be HiWaay (hq in Huntsville AL) or
>>     maybe SpeakEasy (but last time I checked, they don't serve
>>     here) or EarthLink/Mindspring (also an unknown right now).
>>     Looks like I *can* get the $10/month DSL here (with the 1yr
>>     committment of course); anyone besides Bellsouth/ATT doing
>>     anything similar?  Naturally I have problem(s) with ATT's
>>     customer monitoring but I may have to put up with this
>>     nastiness just to have Internet access that works at all. :-(
>>
>> b.  NAT issues
>>     I see the little Westell modems from Bellsouth at customers'
>>     homes & notice the following:
>>     -  The modem itself handles the PPPoE/PPPoA stuff nowadays,
>>        so no need for that on the client computer.
>>     -  The client computer gets a gets an RFC1918 private
>>        address, 192.168.100.x iirc.
>>
>>     My own internal private network is also RFC1918 & 192.168.x.y.
>>     If I change to DSL with its required PPPo{EA}, it appears
>>     that I'll become "double-NAT"ed; is this a problem?  If so,
>>     how do I deal with it?



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