Subject: RE: [lemonade] Wireless latencies

From: "Vaudreuil, Greg M (Greg)" <[email-masked]>
Date: Fri, 13 Jun 2003 13:35:58 -0500

OK, I have run a different test, skipping my corporate network gunk... maybe something about back-to-back modems.

Using my LG CDMA phone (qualcomm chipset) on the Verizon 1xRTT network using the 14.4 data channel (not the high-speed data) and pinging the first router after the wireless link with 100 byte packets, over 100 samples, I measured a high of 598, a low of 441, and an average of 532 milliseconds.  This was with "five bars" of signal strength.

End-to-end round-trips to the likes of a www.yahoo.com site are some 60 ms or so higher.

Greg V.

-----Original Message-----
From: Mark Crispin [mailto:[email-masked]]
Sent: Friday, June 13, 2003 12:08 PM
To: Randall Gellens
Cc: Vaudreuil, Greg M (Greg); IETF LEMONADE (E-mail)
Subject: Re: [lemonade] Wireless latencies

On Thu, 12 Jun 2003, Randall Gellens wrote:
> > My measured experience using a CDMA
> > data network has an average RTT of 1200 milliseconds
> The round-trip times can vary considerably, depending on a number of
> factors, including the specific options supported by the
> infrastructure, the service options requested by the handset, the
> packet sizes, the amount of interference, etc.  However, 1200 ms
> seems quite high.  It should be more like 120-140 ms.

I have to agree.  If this is the performance of CDMA data networks, then I
think that I'll stick with CDPD!  :-)

For what it's worth, PC Pine (using full IMAP and SMTP) works quite well
over CDPD.  I use it all the time.  The only time I have a problem is when
the ferry boat makes its turn and I lose the signal...

-- Mark --

http://staff.washington.edu/mrc
Science does not emerge from voting, party politics, or public debate.
Si vis pacem, para bellum.
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From: Mark Crispin <[email-masked]>
Date: Fri, 13 Jun 2003 13:43:35 -0700 (Pacific Daylight Time)

On Fri, 13 Jun 2003, Vaudreuil, Greg M (Greg) wrote:
> Using my LG CDMA phone (qualcomm chipset) on the Verizon 1xRTT network
> using the 14.4 data channel (not the high-speed data) and pinging the
> first router after the wireless link with 100 byte packets, over 100
> samples, I measured a high of 598, a low of 441, and an average of 532
> milliseconds.  This was with "five bars" of signal strength.

I averaged 516ms (min of 455ms, max of 756ms but I think Pine may have
been doing a NOOP over IMAP at that time) pinging www.yahoo.com with 100
byte packets via CDPD from a ferry boat (not optimal characteristics...).
This suggests that something is wrong with your CDMA facility for you to
be getting 75ms worse with a full-strength connection, especially since
CDMA is superior technology.

Of course, at 14.4 it isn't unreasonable see a few hundred ms of ping
times for 100 byte packets.

-- Mark --