[lug] DSL OR CABLE MODEM

Ferdinand Schmid fschmid at archenergy.com
Tue Jun 18 12:34:50 MDT 2002


A satellite link is even slower than terrestrial wireless due to the distance that your 
signal needs to travel.  Sprint may have an exceptionally high latency and other wireless 
providers may be faster.  But a difference between wireless and wired even shows when you 
compare a wired LAN link with ping times in the 0.5ms .. 1ms range to an 802.11b link with 
ping times in the neighborhood of 5ms (and the initial ping requiring about 50ms).
I can see this with my Sprint connection as well - if I keep a connection active (e.g. a 
dummy shell continuously sending a small quantity of data back and forth) then the latency 
goes down.

Ferdinand

Harris, James wrote:
> Hmm, you say wireless is rather high latency too?  Hmmm... That could be
> problem.  I had heard that average satellite was around 300ms, so that's
> what I was shying away from.  If that's untrue, or out of date, then, I
> guess it's just the cost that would kick me.  (As gross as it would be, I
> could run a 2k server with ICS... *GACK, choke, gag, sputter, hack*.)
> 
> Is wireless up over the 100+ms latency mark also?  I can deal with up to
> about 150, but after that, unless it's super cheap, I can't justify it since
> most of what I'm doing is more dependant on low latency than it is on super
> high bandwidth.  Thus, replacing my super good 49k to 51k ppp connection
> with something more expensive just wouldn't be justified.
> 
> 
>>-----Original Message-----
>>From: Ferdinand Schmid [mailto:fschmid at archenergy.com] 
>>Sent: Tuesday, June 18, 2002 09:41
>>To: lug at lug.boulder.co.us
>>Subject: Re: [lug] DSL OR CABLE MODEM
>>
>>
>>Fred Robinson wrote:
>><snip>
>>
>>>Transmit and receive rates are fairly good, as high as 500K 
>>
>>download and up
>>
>>>to 125K upload.  However, the effective rate seems more 
>>
>>like 100K, and
>>
>>>upload at 50K, steady stream, but satellite isn't steady, 
>>
>>it's bursty.  The
>>
>>>network roundtrip delay is approx. 50ms (or half a second), 
>>
>>so content comes
>><snip>
>>A minor correction: 500ms is 0.5seconds.  50ms is 0.05seconds.
>>
>>Just to put the ping results into the right perspective.  
>>Even the land based wireless 
>>systems have fairly high latency times.  My Sprint Broadband 
>>connection ranges between 
>>50ms and 500ms with rare but occasional multi second delays.  
>>Wired services do much 
>>better in this department.  Downloads however are usually 
>>around 300kB/s and up.  So for 
>>web browsing wireless is great but for ssh takes getting used to.
>>
>>Ferdinand
>>-- 
>>Ferdinand Schmid
>>Architectural Energy Corporation
>>Celebrating 20 Years of Improving Building Energy Performance
>>http://www.archenergy.com
>>
>>_______________________________________________
>>Web Page:  http://lug.boulder.co.us
>>Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
>>Join us on IRC: lug.boulder.co.us port=6667 channel=#colug
>>
> 
> _______________________________________________
> Web Page:  http://lug.boulder.co.us
> Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
> Join us on IRC: lug.boulder.co.us port=6667 channel=#colug


-- 
Ferdinand Schmid
Architectural Energy Corporation
Celebrating 20 Years of Improving Building Energy Performance
http://www.archenergy.com




More information about the LUG mailing list