[ale] Diagnostic help needed

Sat Jan 14 19:00:10 EST 2012

Ah! I remember that, we called it Switched Digital Video, was not data so I
am not too knowledgeable about it either but heard about it through
coworkers... It was added to support more HD channels than could otherwise
be added to the same amount of bandwidth. Only problem was on nodes with
too many subscribers they'd sometimes get a message on their TV saying
something like 'This channel cannot be displayed right now, try again
later', especially on less popular channels. (Yikes!)

On Sat, Jan 14, 2012 at 6:34 PM, Jim Kinney <jim.kinney at gmail.com> wrote:

>
>
> On Sat, Jan 14, 2012 at 5:36 PM, Kirsa <kirsa.thierry at gmail.com> wrote:
>
>> I would not be surprised if you experienced a similar speed issue next
>> Friday though... On almost any residential cable node Friday 5-12pm is peak
>> time and has the most utilization of the entire week. So that you were down
>> to 4mbit/s on Friday evening and 2mbit/s by Friday night sounds
>> suspiciously like congestion to me, despite the faulty equipment.
>>
>> I used to work for a big cable company as a Network Engineer and took the
>> calls from techs in the field who had (supposedly) exhausted their
>> troubleshooting steps. They are handed a stack of trouble calls every
>> morning to complete before the end of the day. Faced with the option of
>> either not getting home by dinner, or not doing a thorough job it is
>> not surprising that some of them lie to the customer or to their support
>> about what troubleshooting steps have been taken (simply to get out the
>> door faster). Not saying it is necessarily the case here, but it is not
>> uncommon for the problem to continue or to come back even after it has been
>> blamed on customer equipment and/or modems have been replaced and/or
>> improvements made. In other words, you might want to do some speed testing
>> next Friday and make sure your problem is fixed.
>>
>> Regarding video/internet use, video and data services
>> use separate frequency ranges on the wire and do not share bandwidth
>> between them. So have no fear if people start watching more of HD video
>> because it will not affect your internet service, unless it is HD video
>> delivered through via the internet... One day we will probably start seeing
>> television sets or cable boxes which receive video streams via DOCSIS but
>> it's still a few years off.
>>
>
> <DOH!> I worked (briefly) in the cable co world and totally forgot that
> the spectrum used was preallocated on the wire/pipe. Thanks for the
> correction. Supposedly, the migration to all digital cable makes it
> possible to have a tiny hard-coded spectrum for control (channel mapping,
> upgrades, boot ups, etc) and the rest is allocated "on the fly" based on
> need. The receivers will be remapped for the channel stream based on
> control signalling. So channel 46 may be on one frequency now and another
> next hour so on-demand and data can be split out over additional
> frequencies as needed. I'm not sure if this is accurate as I only worked
> with the data end reading DOCSIS 3 data usage and mostly ignored the
> meeting sections not directly related to my job.
>
>>
>> -Kirsa
>>
>>
>>
>>
>> On Sat, Jan 14, 2012 at 2:39 PM, Drifter <drifter at oppositelock.org>wrote:
>>
>>> Update:
>>> Most issues fixed and problem has been identified as a slowly failing
>>> hub/switch.
>>>
>>> Some cable problems I really don't have.  I live in a condo with 74
>>> units,
>>> 71 occupied at this time.  (Anyone want a really good deal on a nice
>>> house
>>> in a nice location? :)  ) But only 51 of them have a computer installed.
>>> And many of the cable users have not opted to get Comcast's HighDef
>>> service.  So the relative demand on the cable here is fairly light.
>>>
>>> As to my problems.  I finally isolated the various parts of the problem.
>>> Primary choke on download speeds was the router itself.  A power cycle
>>> fixed that.  Rest of the problem is the hub/switch that splits out the
>>> signal at my office to serve two computers and the printer.  One or more
>>> ports on the switch apparently have problems.  Five minutes ago, this box
>>> is getting >20 down and >4 up while the other computer, plugged into the
>>> hub was only getting 12 down and 3.7 up.  Checked and this varies with
>>> the
>>> port on the hub.  So time to get another hub/switch.
>>>
>>> Sean
>>>
>>>
>>> -------------------------------------------------------------------------------------------------------
>>>
>>> On Saturday, January 14, 2012 02:06:06 pm Jim Kinney wrote:
>>> > Keep in mind that cable modem speed is heavily impacted by subscriber
>>> > count use on your cable leg.  100 users watching tv is the same
>>> > bandwidth as 100 users watching netflix or downloading DVDs.  The
>>> > advantage of dsl is your speed is mostly constant.  With cable it can
>>> > vary wildly based on your neighbors activity.  Watch your speeds drop
>>> > when school gets out @ 3pm! On Jan 14, 2012 12:48 PM, "Ron Frazier"
>>> > <atllinuxenthinfo at c3energy.com>
>>> >
>>> > wrote:
>>> > > Hi Sean,
>>> > >
>>> > > I'm have Comcast service.  I just ran a test at
>>> > > http://www.speedtest.net.  You can use them but I would stick to
>>> > > speed testing and not use their PC optimization tests, etc.  I got
>>> > > 21 Mbps down and 4 Mbps up, which is pretty typical for me.
>>> > > Regarding your last sentence, the technician should KNOW where to
>>> > > look when he comes.  Once he's gone, you can do some further testing
>>> > > yourself.  One basic strategy is to eliminate everything between
>>> > > your PC and the cable modem.  First make sure you have a software
>>> > > firewall running in your PC.  I would never recommend connecting a
>>> > > PC DIRECTLY to the internet without a firewall running.  Take the PC
>>> > > down near the modem if possible.  Turn off or disconnect any
>>> > > wireless connections.  Using the prefab LAN cable (as opposed to
>>> > > homemade) that came with the cable modem, connect the cable modem
>>> > > DIRECTLY to your PC.  Your PC should get an IP address from the
>>> > > modem and have direct unfettered access to the internet.  Then, run
>>> > > your speed test.  You may also wish to check that the coaxial cable
>>> > > running from the cable modem to the wall outlet is tight on both
>>> > > ends, not crimped, etc.  Actually, the connectors should be crimped
>>> > > on, the wire should not be crimped or severely bent.  If the speed
>>> > > test works then, you can start moving your PC further away from the
>>> > > modem.  Try connecting it with a LAN cable to a port on your router.
>>> > >  Then, try wireless, etc.  If, at some point, performance suffers
>>> > > dramatically, you may have found the culprit.  Be aware that cable
>>> > > internet performance will vary depending on how many users in the
>>> > > area are online.  However, in general, you should get numbers
>>> > > similar to mine if you're on the same pricing package.  Also, be
>>> > > aware that the speed may drop down to about 16 Mbps for long
>>> > > downloads and that depends on whether the remote server can keep up
>>> > > that speed.  I've downloaded many Ubuntu ISO's where the remote
>>> > > server could only send 1-2 Mbps and I knew my system was working
>>> > > fine.  (In that case, find a better mirror server.)
>>> > >
>>> > > By the way, I had a scenario once where my download speed was
>>> > > fluctuating widely and occasionally dropping badly.  It took 4 visits
>>> > > from the techs and me INSISTING that something was wrong.  Finally,
>>> > > they found a nail had been driven through the cable out on the power
>>> > > pole. Depending on the wind, it would either work or not.  Once that
>>> > > was replaced, everything was fine.
>>> > >
>>> > > Hope this helps.
>>> > >
>>> > > Sincerely,
>>> > >
>>> > > Ron
>>> > >
>>> > > On 1/14/2012 9:27 AM, Drifter wrote:
>>> > > > Abandoned Speakeasy and its DSL connection through Covad and AT&T.
>>> > > > Went with Comcast as the (slightly) lesser of evils -- the other
>>> > > > being AT&T.
>>> > > > Comcast technician was scheduled to arrive between 9-11 am on
>>> > > > Thursday. He arrived at 10:55 and insisted he was on time.
>>> > > > I was not amused.
>>> > > > Technician did his job: installed a cable "modem" that provides
>>> > > > internet and VOIP, thus allowing us to cut all our ties to Ma
>>> > > > Bell.  When the installer left Thursday at 1 pm  Speed tests
>>> > > > showed 20 mbs down and 3.7 mbs up. Much better. :)  That was
>>> > > > Thursday afternoon.
>>> > > >
>>> > > > Friday morning a friend came over and helped me rewire the cat-5
>>> > > > cable as I needed to move the router down next to the cable
>>> > > > "modem." (Friend is MUCH better at wiring new plugs on the end of
>>> > > > cat-5 cable than I will
>>> > >
>>> > > ever
>>> > >
>>> > > > be.)  When my friend left Friday afternoon a speed test still
>>> > > > showed similar numbers throughout the house. All seemed good.
>>> > > >
>>> > > > After lunch Friday I noticed that download speeds seemed to be
>>> > > > lagging so I ran another test (using Speakeasy's test). Speeds had
>>> > > > dropped to<3 coming down but had increased to>4 going out.  WTF?
>>> > > > By Friday night download speeds had dropped to<2 and uploads were
>>> > > > humming ~4.
>>> > > >
>>> > > > I am clueless.  I whined and Comcast is sending out another
>>> > > > technician late this afternoon.  Only guess I have is that the
>>> > > > "modem" has a fubar component.
>>> > > >
>>> > > > Thoughts would be appreciated.  It would be nice if I knew where to
>>> > > > tell the Comcast guy where to look.
>>> > > >
>>> > > > Sean
>>> > >
>>> > > --
>>> > >
>>> > > (PS - If you email me and don't get a quick response, you might want
>>> > > to call on the phone.  I get about 300 emails per day from alternate
>>> > > energy mailing lists and such.  I don't always see new messages very
>>> > > quickly.)
>>> > >
>>> > > Ron Frazier
>>> > >
>>> > > 770-205-9422 (O)   Leave a message.
>>> > > linuxdude AT c3energy.com
>>> > >
>>> > > _______________________________________________
>>> > > Ale mailing list
>>> > > Ale at ale.org
>>> > > http://mail.ale.org/mailman/listinfo/ale
>>> > > See JOBS, ANNOUNCE and SCHOOLS lists at
>>> > > http://mail.ale.org/mailman/listinfo
>>> _______________________________________________
>>> Ale mailing list
>>> Ale at ale.org
>>> http://mail.ale.org/mailman/listinfo/ale
>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>> http://mail.ale.org/mailman/listinfo
>>>
>>
>>
>> _______________________________________________
>> Ale mailing list
>> Ale at ale.org
>> http://mail.ale.org/mailman/listinfo/ale
>> See JOBS, ANNOUNCE and SCHOOLS lists at
>> http://mail.ale.org/mailman/listinfo
>>
>>
>
>
> --
> --
> James P. Kinney III
>
> As long as the general population is passive, apathetic, diverted to
> consumerism or hatred of the vulnerable, then the powerful can do as they
> please, and those who survive will be left to contemplate the outcome.
> - *2011 Noam Chomsky
>
> http://heretothereideas.blogspot.com/
> *
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://mail.ale.org/mailman/listinfo/ale
> See JOBS, ANNOUNCE and SCHOOLS lists at
> http://mail.ale.org/mailman/listinfo
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.ale.org/pipermail/ale/attachments/20120114/92721ee5/attachment-0001.html 