[ale] Cable modem recommendation

[scott mcbrien]

No we do not use Comcast VoIP.

-Scott

On Mon, Apr 2, 2012 at 12:33 PM, Michael H. Warfield <mhw at wittsend.com> wrote:
> On Mon, 2012-04-02 at 10:31 -0400, mike at trausch.us wrote:
>> On 04/02/2012 10:08 AM, Michael H. Warfield wrote:
>> > On Mon, 2012-04-02 at 09:47 -0400, mike at trausch.us wrote:
>> >> On 04/02/2012 08:33 AM, Lightner, Jeff wrote:
>> >>> Does anyone know if there is a special device required for Comcast
>> >>> telephone and if so would they be charging an extra monthly fee and
>> >>> if so if one can buy one rather than rent as they can with cable
>> >>> modem?
>> >
>> >> It is indeed some form of VoIP.  That said, just like many of the VoIP
>> >> providers, they typically require that you use an MTA that is provided
>> >> by them and therefore provisioned through them.
>> >
>> > Well, there's some variation in the degree of "required".  AT&T Uverse
>> > very strongly wants you to use their RG (Residential Gateway) to provide
>> > HPNA network over coax, video over IP, phone VoIP, wired networking and
>> > wireless networking.  But their RG is a serious POS.  It goes dain
>> > bramaged every once in a while requiring a reset, sometimes loses
>> > setting like static mappings, has a dhcp server that's total junk, and
>> > doesn't support a lot of things I would personally consider mandatory in
>> > a modern device.  (The set top boxes - STBs - even run Windows ME for
>> > crying out loud - stone knives and bearskins.)  You CAN replace it with
>> > one you buy off the shelf I read on article on a person's experience
>> > getting it up and running.  It wasn't a pleasant experience since the
>> > AT&T people are not familiar with provisioning the devices and are not
>> > encouraged or encouraging to pursue it.  But they will, if forced.  He
>> > got his running.  It can be done.  It likely won't be easy.
>
>> DSL networks are very different from cable networks.
>
> Oh, I'm well aware of how they both work.
>
>> In DSL networks, authentication occurs using your personal credentials,
>> usually over some form of PPP (PPPoE is what AT&T uses, if memory
>> serves).
>
> That is correct.
>
>> It is a PITA, but it is possible to do absolutely anything you
>> want; they cannot make you use a particular device, all they can say is
>> that your device must not interfere with the telco's network.
>
>> OTOH, cable networks use MAC addresses for authentication (wonderful,
>> isn't it?).  A residential Comcast customer that has no services other
>> than Internet (or Internet and TV, the important thing here being that
>> they do not have the Voice package) can go out to the store, pick up a
>> cable modem, install it, and then call Comcast.  Comcast will require
>> that you read the MAC address of the device, and then they will
>> "provision" it, which involves sending a configuration file to your
>> local node or hub or whatever it is on their network that your modem
>> actually talks to.  Then, the cable modem will be able to grab a
>> configuration file and you'll be out of the walled garden.
>
> Yeah, I have a couple of DOCSIS 2 cable modems laying around from the
> last time I was with Comcast.  I've had my own cable and DSL modems for
> a very long time.  Even had a couple of the Comcast ones tftp booting
> from my server to play with them.  :-P  Actually, I might have given one
> of those to my son Scott, since he's still with Comcast.
>
> AFA the link layer authentication goes, that's one thing.  In general,
> in principle, the VoIP is at least semi-independent.
>
> The cable companies have to walk a fine line or run a foul of the FCC
> regulations in this area.  At one point the FCC was even requiring cable
> companies support "cable cards" for consumer purchased equipment but
> that turned into an abject failure as nobody bought them.  The biggest
> stick in the mud with cable companies is encrypted content such as
> premium TV channels, movies, and view on demand.  DTV channels sort of
> complicated that a bit but there were cable TV tuner / capture cards
> that worked really well with the Comcast channels if they weren't
> encrypted.  That's what the cable cards were SUPPOSE to address by
> allowing consumers to provide their own STBs while still allowing the
> cable companies control over their premium content.  While cable cards
> are still a failure, there's still teeth in some of those FCC regs
> mandating some level of support for consumer purchased equipment, which
> is really where the standardized DOCSIS modems and devices have come in,
> which Comcast does support.
>
>> Now, I have been told that the business class side works a little
>> differently; they use some form of PKI to provide authentication for the
>> routed tunnel that you obtain through them.
>
> Yeah, I have never dug deeply into that but, talking with a couple of
> people who have, there's some sort of tunneling involved in there.
>
>> In the case of AT&T and having a routed block, they will just send your
>> routed block over your PPPoE session, once established.
>
> Correct.
>
>> I have no clue how to determine what my current cable modem is doing,
>> because I haven't the ability to capture or monitor the coax side of the
>> network.  If I could only do that...
>
> I used to be able to do that (in fact, that's what the second DOCSIS
> modem was for).  Never really got anything useful out if it and I never
> played around with it on the RF level.
>
> There's a couple of styles of adapters out there too which allow you to
> piggyback ethernet over 75 ohm coax together with cable.  AT&T settled
> in on HPNA which is NOT compatible with a coexisting cable TV signal but
> they run everything over IP so they don't need it.  HPNA boasts 200Mb
> over standard grade 75 ohm CATV coax (RG-59) with upgraded connectors.
> All the AT&T Uverse STBs are actually HPNA bridges and you can bridge
> twisted pair off the back of them down the coax runs.  The MoCA adapters
> will actually interface Cat 5/5e/6 to your cable TV cable and are
> suppose to be compatible with the Comcast signal (they occupy different
> parts of the spectrum).  I think there's a third standard which is also
> suppose to be compatible with standard broadband CATV but I'm not
> familiar with it.
>
>> >> I don't know what Comcast's rules are; I'm not sure if they allow you to
>> >> swap out for your own dedicated devices or not.  I know that many other
>> >> providers do not, because of the recent requirements that they provide
>> >> certain services in the same way as landlines (e.g., 911 service).
>> >> Therefore, they likely require that you use their own device so that
>> >> they can control the configuration and such.
>> >
>> >> The advantage to Comcast's MTAs (which are built-in to the cable modem
>> >> itself) is that they have a battery back-up contained in the box, too.
>> >> This makes them bigger and heavier, of course, but it means that during
>> >> short power outages, you still have telephone service.
>> >
>> > The AT&T unit has an external battery backup that includes it's DC
>> > supply.  I would consider that a plus to having a built in one.  As most
>> > of us know all too well, those gel cells go bad after a few years and
>> > are worthless.  Then you replace the battery or the UPS or the device.
>> > I would much MUCH rather have a separate UPS that alerts you when the
>> > battery is failing or needs replacement.  The one on the AT&T unit isn't
>> > anything to brag about but it doesn't have anything serious to carry.
>> > If it died, they could easily replace it without swapping my whole RG or
>> > ripping it apart to replace.
>>
>> Agreed.
>>
>> All-in-one devices are horrible.  Evil.
>>
>> The current cable modem that I have is also a router/gigabit switch.  I
>> cannot disable most of its functionality, and I can't do complex things
>> with my address space, because this thing sucks so horribly.  If only I
>> had control of my own IPv4 network... oh, well, that's what IPv6 is for!
>>  :-)
>>
>>       --- Mike
>
> Mike
> --
> Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
>   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
>   NIC whois: MHW9          | An optimist believes we live in the best of all
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>
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