TCP/IP at 70 MPH
I've been giving my Sprint card a serious work out this past week. We're on a 2,800 mile round-trip taking my oldest son to school in Oklahoma. Sprint coverage is pretty consistent along the Interstates across VA/TN/AR/OK. Though the rougher the terrain, the more variable the signal. Overall throughput is decent as long as I have at least 2 bars, though I'm having to get accustomed to modem speeds all over again. I did an 8M download as we drove through several cells as the signal waxed and waned, and even dropped off the Sprint network altogether at points, and then automatically re-established a little further down the road. (When this happens, the Novatel Connection Manager shows "Searcing for network" and then "Connected" again, with no intervention on my part.)
During these "brown outs" existing TCP connections simply stall until the air link comes back, (which can be for several minutes). Then packets just silently resume. (It's under these conditions that TCP/IP really shines.) New connection attempts fail on the DNS lookup... It might be nice if the adapter did some automatic retries, or even delayed sending the request when it realizes that the air link is not viable.
A nice feature of the Novatel Connection Manager is that it automatically establishes a new session after Standby or Hibernate.
Browsing
It's been a while since I've done much browsing at ~modem speeds. I am finding that open-in-new-tab really helps here. Ctrl-click a link to start it loading in a new tab, and continue reading on the current page until you can see that the new page has finished. Pages with excessive embedding are the most painful.
It can be frustrating trying to browse when coverage is spotty. Not only does your whole flow come to a halt, but you get popup DNS errors from the loading tab. This error leaves the new tab window an empty zombie - F5 doesn't attempt a reload, but you can go to the address bar and press enter, again and again...
Google Maps
It is very cool to be able to search "restaurant" in the "current map view". Much better than having to watch for those little Interstate signs that are posted just before the exits where you have to make high-speed culinary/lane-change decisions. The trick though is to find and zoom to your current location before you're no longer there! Hey Google: is GPS integration on the way!?
The drag-panning feature works surprising well. Google seems to have optimized the amount of data that flows across those Ajax connections to accomplish the map tiling. One glaring definciency of Google Maps for this task is the lack of mile markers. Now I need a "Show This Location in Mapquest" extension for Firefox. (Zeroing in on a location in Mapquest is MUCH more bandwidth-intensive than Google Maps.)
Instant Messaging
Instant messaging works great even at the lowest signal levels, but the "brown out" transparency can definitely interfere with the assumed immediacy. For example, I was talking back and forth with my niece for a while, then it seemed like she stopped talking. Several minutes later a bunch of her messages came across all at once, (and I assume mine pushed across to her). Even though her screen name continually to show as active in the buddy list.
Thunderbird/Sauce Reader
Not surprisingly, these make very effective use of the low-bandwidth connection.
VPN
I know from prior experience that my AT&T Network Cient on the IBM corporate VPN is fairly sensitive to intermitten connectivity. The heartbeat will timeout the session pretty easily in the presence of limited connectivity, so the fact that it stayed connected for long periods of time tells me that even when the air link is poor, the adapter maintains sockets and keeps packets moving. The actual usability of the VPN connection is another matter, however. The VPN overhead, plus Lotus Notes in my case, is like a scene out of The Matrix!
Google Earth
As expected it takes a lot of bandwidth to load the rich imagery. Using the tilt feature I was able to get an idea of what the landscape was going to look like around our hotel stop. It works, but I didn't find a really compelling reason to sit through the long streaming process.
Speed Tests (broadbandreports.com)
Because the signal fluctuated quite a bit as we drove along, it's hard to really say how many bars. (Kbps up/down):
0-1 bars: 21/22 (lots of connection stalling)
1-2 bars: 43/58
2-3 bars: 58/50
3-4 bars: 60/82
I see a little better throughput on terra firma:
2 bars 62
3 bars 73
4 bars 81
Whether moving or standing still, the correlation between signal strengh and throughput appears to be fairly linear, though the slope is much steeper when you're in motion; and has a lot more variance, of course.
The main thing here is that all this experimentation has been instrumental in distracting me from the separation anxiety. Stuart is going to do very well in the environs of Oklahoma Christian University. Lots of hard work, lots of caring people... Get a jump kido.
During these "brown outs" existing TCP connections simply stall until the air link comes back, (which can be for several minutes). Then packets just silently resume. (It's under these conditions that TCP/IP really shines.) New connection attempts fail on the DNS lookup... It might be nice if the adapter did some automatic retries, or even delayed sending the request when it realizes that the air link is not viable.
A nice feature of the Novatel Connection Manager is that it automatically establishes a new session after Standby or Hibernate.
Browsing
It's been a while since I've done much browsing at ~modem speeds. I am finding that open-in-new-tab really helps here. Ctrl-click a link to start it loading in a new tab, and continue reading on the current page until you can see that the new page has finished. Pages with excessive embedding are the most painful.
It can be frustrating trying to browse when coverage is spotty. Not only does your whole flow come to a halt, but you get popup DNS errors from the loading tab. This error leaves the new tab window an empty zombie - F5 doesn't attempt a reload, but you can go to the address bar and press enter, again and again...
Google Maps
It is very cool to be able to search "restaurant" in the "current map view". Much better than having to watch for those little Interstate signs that are posted just before the exits where you have to make high-speed culinary/lane-change decisions. The trick though is to find and zoom to your current location before you're no longer there! Hey Google: is GPS integration on the way!?
The drag-panning feature works surprising well. Google seems to have optimized the amount of data that flows across those Ajax connections to accomplish the map tiling. One glaring definciency of Google Maps for this task is the lack of mile markers. Now I need a "Show This Location in Mapquest" extension for Firefox. (Zeroing in on a location in Mapquest is MUCH more bandwidth-intensive than Google Maps.)
Instant Messaging
Instant messaging works great even at the lowest signal levels, but the "brown out" transparency can definitely interfere with the assumed immediacy. For example, I was talking back and forth with my niece for a while, then it seemed like she stopped talking. Several minutes later a bunch of her messages came across all at once, (and I assume mine pushed across to her). Even though her screen name continually to show as active in the buddy list.
Thunderbird/Sauce Reader
Not surprisingly, these make very effective use of the low-bandwidth connection.
VPN
I know from prior experience that my AT&T Network Cient on the IBM corporate VPN is fairly sensitive to intermitten connectivity. The heartbeat will timeout the session pretty easily in the presence of limited connectivity, so the fact that it stayed connected for long periods of time tells me that even when the air link is poor, the adapter maintains sockets and keeps packets moving. The actual usability of the VPN connection is another matter, however. The VPN overhead, plus Lotus Notes in my case, is like a scene out of The Matrix!
Google Earth
As expected it takes a lot of bandwidth to load the rich imagery. Using the tilt feature I was able to get an idea of what the landscape was going to look like around our hotel stop. It works, but I didn't find a really compelling reason to sit through the long streaming process.
Speed Tests (broadbandreports.com)
Because the signal fluctuated quite a bit as we drove along, it's hard to really say how many bars. (Kbps up/down):
0-1 bars: 21/22 (lots of connection stalling)
1-2 bars: 43/58
2-3 bars: 58/50
3-4 bars: 60/82
I see a little better throughput on terra firma:
2 bars 62
3 bars 73
4 bars 81
Whether moving or standing still, the correlation between signal strengh and throughput appears to be fairly linear, though the slope is much steeper when you're in motion; and has a lot more variance, of course.
The main thing here is that all this experimentation has been instrumental in distracting me from the separation anxiety. Stuart is going to do very well in the environs of Oklahoma Christian University. Lots of hard work, lots of caring people... Get a jump kido.
posted by Chris Noé at 4:15 PM
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