[Tech] Need help with the Internet at the Mentone ("slow" ... latency? and/or connectivity?)

Christian Einfeldt einfeldt at gmail.com
Fri Jun 24 13:46:25 PDT 2016


Hi, Thanks for your thoughts, Michael.

On Fri, Jun 24, 2016 at 1:44 PM, Michael Paoli <
Michael.Paoli at cal.berkeley.edu> wrote:

> Sounds like you've got latency issue, not necessarily bandwidth
> issue(s).  The very long times on ping to Google would
> reflect latency issues.  It's not uncommon for ISPs to support
> large buffering - this gives 'em a slight edge in most typical
> bandwidth tests ... and the cost of latency - as/when the
> bandwidth is quite saturated, buffers fill, and hence latency
> can be quite to even exceedingly high.  This can then trigger various
> errors, such as DNS timeouts - which might well be why your
> "speed tests" failed - but can't really tell from the limited output
> that check provided (the CLI tool may have options for more details,
> and/or one may use additional diagnostics to check what's happening
> when the speed test is attempted - which may then make clear why the
> test is failing).  Shared usage of bandwidth can be an issue, e.g.
> multiple computers, etc., and single "pipe" of some fixed limited
> bandwidth to Internet.  If one machine is hogging it all, or even
> multiple are together trying to use all the bandwidth, that will
> make it "slow" for them, and anything else attempting to share that
> bandwidth.
>
> Anyway, realized and understand that bandwidth (speed), and latency
> (how long does the trip take) are not the same thing.  Either may
> be perceived as "slow", depending upon the nature of the usage.
>
> If, as you mention, you're having problems even doing the updates,
> it's likely either issues with latency causing issues with DNS,
> and/or more general connectivity issues (which may also be caused
> by latency issues).  "Slow" - as in low bandwidth, will not
> in-and-of-itself break "speed"tests or getting updates on-line ...
> were it only a bandwidth issue, things would just take longer ...
> possibly *much* longer.
>
> From: "Christian Einfeldt" <einfeldt at gmail.com>
>> Subject: [Tech] Need help with the Internet at the Mentone
>> Date: Fri, 24 Jun 2016 11:50:55 -0700
>>
>
> Hi,
>>
>> Here are my questions:
>>
>>    1. Why did my speed tests fail in this situation?
>>    2. Are the ping speeds normal for this situation?
>>    3. What diagnostic tests can I run to isolate the slowness on this
>>    system?
>>
>> As most people on this list know, Partimus is volunteering for a low
>> income
>> housing shelter in here in SF.  I have put in some quality legacy Lubuntu
>> machines in the lobby for the residents to use.  These machines all have
>> Intel Core 2 duo chips with 2 GB of RAM and are running Lubuntu 14.04.  I
>> use a similar machine at home, and have no problems with it.  This email
>> is
>> being written on such a machine at one of the other two homeless shelters.
>> The residents routinely use these machines to watch YouTube video and use
>> LibreOffice, etc., all without issue.  The machines are proven good.
>>
>> This is the third shelter to which we have given machines.  They don't
>> have
>> a budget for either the equipment or the tech support for these machines.
>>
>> Two of the three shelters have good speed on the Internet that goes to the
>> machines.  (The shelters provide the Internet service).
>>
>> However, the third shelter, called the Mentone, has slow Internet speeds
>> in
>> the lobby.  I am not able to even do anything as basic as run sudo apt-get
>> update, as the machine chokes on downloading the updates.
>>
>> The wiring is put in place by a company I will call the Maintenance Group
>> (MG).  I have called both the MG and the ISP.  Both of them claim that
>> they
>> have no problems.  The ISP says that they are providing the usual 2 Mbit /
>> second that we expect here in the US for a configuration like this.  The
>> MG
>> says that they have run a test on the wiring from the server to the lobby,
>> and are not seeing any problems.
>>
>> The ISP is a good company that does not hate GNU-Linux.
>>
>> The ISP asked me to give them a speed test directly from the switch, which
>> is located in the basement.  So I ran speed tests in the basement and in
>> the lobby, and was unable to get the speed test to work.  Speed test has
>> worked on this machine before.  Here are the two results:
>>
>> Lobby, where the Lubuntu machine is to be located:
>>
>> cje at cje-ultralap440:~$ speedtest-cli
>>
>> Retrieving speedtest.net configuration...
>>
>> Could not retrieve speedtest.net configuration: timed out
>>
>> cje at cje-ultralap440:~$ ifconfig
>>
>> eth0      Link encap:Ethernet  HWaddr 20:1a:06:04:64:42
>>          inet addr:172.16.2.121
>>
>> basement, directly from the switch:
>>
>> cje at cje-ultralap440:~$ speedtest-cli
>>
>> Retrieving speedtest.net configuration...
>>
>> Could not retrieve speedtest.net configuration: timed out
>>
>> cje at cje-ultralap440:~$
>>
>> *My first question:  *I am not sure why this speed test failed.  Does
>> anyone know?
>>
>> Since I couldn't run speedtest, I pinged google instead.  Here are the
>> results from the lobby:
>>
>> cje at cje-ultralap440:~$ ping www.google.com
>>
>> PING www.google.com (216.58.192.4) 56(84) bytes of data.
>>
>> 64 bytes from nuq04s29-in-f4.1e100.net (216.58.192.4): icmp_seq=1 ttl=52
>> time=8.24 ms
>>
>> 64 bytes from nuq04s29-in-f4.1e100.net (216.58.192.4): icmp_seq=2 ttl=52
>> time=7.31 ms
>> <snip>
>>
>> --- www.google.com ping statistics ---
>>
>> 16 packets transmitted, 12 received, 25% packet loss, time 15037ms
>>
>> rtt min/avg/max/mdev = 6.962/7.497/8.198/0.366 ms
>>
>> Here is the test from the basement:
>>
>> cje at cje-ultralap440:~$ ping www.google.com
>>
>> PING www.google.com (216.58.192.4) 56(84) bytes of data.
>>
>> 64 bytes from nuq04s29-in-f4.1e100.net (216.58.192.4): icmp_seq=1 ttl=52
>> time=8.24 ms
>>
>> 64 bytes from nuq04s29-in-f4.1e100.net (216.58.192.4): icmp_seq=2 ttl=52
>> time=7.31 ms
>> <snip>
>>
>> --- www.google.com ping statistics ---
>>
>> 11 packets transmitted, 11 received, 0% packet loss, time 10015ms
>>
>> rtt min/avg/max/mdev = 7.022/7.816/8.519/0.451 ms
>>
>> cje at cje-ultralap440:~$
>>
>> *My second question*: Are these ping speeds normal?
>>
>> My third question: What can I do to find the problem with the system?
>>
>> Thanks!
>>
>> --
>> Christian Einfeldt
>>
>
>


-- 
Christian Einfeldt
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