The DSL service (and perhaps other net access) is moody. The weather page now loads OK when the connection is good. It takes about 8 seconds now; that's OK. It was seldom OK when I first wrote. I took my Mac (laptop) into the shop and that may be the difference. The ‘genius’ stipulated that WiFi access was unsteady. Perhaps the laptop is fixed. Sometimes hours go by with no problems.

Just now, as I write I am doing the shell command:
ping -a 172.16.0.1 on two Macs, one connected by WiFi and the other by Ethernet, to the same 2Wire modem. The -a options provides audible feedback and I can thus ‘watch’ two computers and connections at once. The WiFi version (my laptop) is getting few responses. The IP address 172.16.0.1 belongs to the modem, and is the address used to configure the modem. I am getting 79% packet loss over periods of about one minute, I am 7 feet from the modem. The signal strength indicated in the modem icon in the menu bar is three of four bars. I change channel with no effect. A period of about one minute passed with no ping response via WiFi. I power cycled the 2Wire. After about 35 seconds both ping sequences recommence. I do not understand how this can be my laptop. After 20 minutes ping reports 6% packet loss and 24 duplicates. After about 30 minutes the packet loss is back to about 80%. After another 10 minutes it is working fine; no loss in 5 minutes.

Another phenomenon is that ping reports duplicate packets. This is not in itself damaging but may be a clue, but I cannot understand that clue. The duplicates are sometimes more frequent during periods of lost packets, but also happen during long periods of no lost packets. I have seen no duplicate or lost packets ever Ethernet, except as I power cycled the 2Wire. I do not recall seeing duplicate packets when I first reported these problems.

I called AT&T and got a very knowledgeable engineer who was polite almost to a fault. He made several reasonable suggestions, some of which I had not thought of. He told me of this URL which gets me to parts of the web site built into the 2Wire modem that I had not found before. If you have a 2Wire modem and click on that link you will presumably find the page in your modem, not mine. So much for naming in the “universal scope”. There are many pages accessible starting from there that I have not yet explored. There is a statistics page there that counts wireless messages transmitted and received. With this I may be able to distinguish which transmission direction is losing the ping packets. The problem is not yet resolved but it was fun talking to someone knowledgeable and indeed helpful.

Current Theory

All of the problems are between my laptop and the 2Wire modem. Lost packets, especially when the carry http requests, cause excessive delay; the browser waits 10 seconds (I speculate and depending on browser) before resending request. On pages where several sequentially dependent links must be followed before display, such as the above weather page, lost packets can easily cause a minute or more delay.

Packets can be lost in either direction but I think lost packets from my Mac cause the biggest problem. I am not sure how to prove this. It can be a weak transmitter, or receiver, and on either side of the wireless link. A signal strength meter would cut the uncertainty by 2. A UDP trader between two network machines could determine which direction was losing packets.

Here are traceroutes to www.wunderground.com via these two ISPs: I am now of the firm opinion that the packets are lost in my house and that the rest of the internet path is not part of the malfunction. 

 1  homeportal.gateway.2wire.net (172.16.0.1)  2.728 ms  1.436 ms  1.628 ms
 2  bras27-l0.pltnca.sbcglobal.net (151.164.184.107)  17.690 ms  15.319 ms  15.631 ms
 3  64.164.107.2 (64.164.107.2)  13.749 ms  17.445 ms  15.704 ms
 4  151.164.93.239 (151.164.93.239)  15.733 ms  16.596 ms  15.796 ms
 5  69.220.8.31 (69.220.8.31)  17.642 ms  18.930 ms  17.405 ms
 6  po5-3.core01.sjc04.atlas.cogentco.com (154.54.13.97)  17.838 ms  17.290 ms  17.646 ms
 7  te9-2.mpd01.sjc04.atlas.cogentco.com (154.54.0.173)  18.514 ms  18.764 ms  17.375 ms
 8  te8-2.mpd01.sfo01.atlas.cogentco.com (154.54.2.165)  17.827 ms te9-1.mpd01.sfo01.atlas.cogentco.com (154.54.0.169)  18.759 ms te8-2.mpd01.sfo01.atlas.cogentco.com (154.54.2.165)  18.746 ms
 9  vl3855.na21.b001865-1.sfo01.atlas.cogentco.com (38.20.34.86)  17.823 ms  19.321 ms  19.582 ms
10  wunderground.demarc.cogentco.com (38.99.207.50)  17.723 ms  18.552 ms  17.594 ms
11  64.243.174.100 (64.243.174.100)  17.778 ms  18.694 ms  17.659 ms
12  64.243.174.100 (64.243.174.100)  33.628 ms  17.846 ms  39.169 ms

 1  dsl017-054-185.sfo1.dsl.speakeasy.net (69.17.54.185)  3.241 ms  2.603 ms  3.676 ms
 2  dsl017-054-001.sfo1.dsl.speakeasy.net (69.17.54.1)  116.012 ms  33.455 ms  46.788 ms
 3  220.ge-0-1-0.cr2.sfo1.speakeasy.net (69.17.83.177)  17.732 ms  17.747 ms  15.274 ms
 4  unknown.Level3.net (209.247.156.221)  18.968 ms  15.829 ms  15.208 ms
 5  vlan89.csw3.SanJose1.Level3.net (4.68.18.190)  26.640 ms  25.472 ms  18.490 ms
 6  ae-82-82.ebr2.SanJose1.Level3.net (4.69.134.217)  18.349 ms  16.468 ms  15.440 ms
 7  ae-1-6.bar2.SanFrancisco1.Level3.net (4.69.140.153)  46.484 ms  17.320 ms  16.283 ms
 8  ae-4-4.car2.SanFrancisco1.Level3.net (4.69.133.157)  16.982 ms  17.799 ms  16.695 ms
 9  WBS-CONNECT.car2.SanFrancisco1.Level3.net (4.78.242.62)  15.114 ms  17.355 ms  21.001 ms
10  64.243.174.100 (64.243.174.100)  17.175 ms  16.656 ms  17.684 ms
11  64.243.174.100 (64.243.174.100)  27.144 ms  16.284 ms  17.165 ms
This is an older problem which has perhaps been fixed or may be merely part of the current and better diagnosed problem.