WRT54G + Comcast = random cutouts?

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Two days ago my WRT54G V6 started cutting out the internet connection
for no reason.
I updated the firmware and that didn't help.  Per Google I changed the
MTU from auto to 1492, I thought that worked until just now it cut out
on me.
The cable modem is a Linksys BEFCMU10 version 4.
When I go to its diagnostic page http://192.168.100.1/ this is what I get:
Modem
Standard Specification Compliant      DOCSIS 2.0
  Hardware Version      v2.0
  Software Version      2.0.3.4.2-1212
  Cable Modem MAC Address      <removed>
  Cable Modem Serial Number      <removed>
  CM certificate      Installed

CONNECTION:

   Startup Procedure
                          
              
        Status      Comment
  Acquire Downstream Channel      723000000 Hz      Locked
  Connectivity State      Operational      Operational
  Boot State      OK      Operational
  Security      Enabled      BPI+
        

Downstream Channel
                          
              
  Lock Status      Operational
  Modulation      256QAM
  Channel ID      45
  Provisioned Rate      6600 kbps
  Symbol Rate      5360.537 Ksym/sec
  Downstream Power      1.2 dBmV
  SNR      38.2 dB
        

Upstream Channel
                          
              
  Lock Status      Operational
  Modulation      16QAM
  Channel ID      2
  Provisioned Rate      1100 kbps
  Symbol Rate      5120 Ksym/sec
  Upstream Power      37.2 dBmV



and the log

Time      Priority      Description
  2009-12-02 01:13:12      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-02 01:13:08      critical      No Ranging Response received - T3
time-out
  2009-12-02 01:13:03      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-02 01:12:30      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 22:56:19      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-01 22:55:47      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 20:57:49      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-01 20:57:16      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:58:03      critical      No Ranging Response received - T3
time-out
  2009-12-01 00:57:58      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-01 00:57:57      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:26      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:24      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:23      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:21      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:21      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:18      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:16      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:15      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:14      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:12      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:11      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:09      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:07      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:06      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:04      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:03      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:57:02      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:57:00      critical      DHCP FAILED - Request sent, No response
  2009-12-01 00:56:59      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-01 00:56:57      critical      DHCP FAILED - Request sent, No response
  1970-01-01 00:00:06      critical      No Ranging Response received - T3
time-out

Re: WRT54G + Comcast = random cutouts?


On Wed, 02 Dec 2009 01:23:10 -0500, Justin

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Maybe your router is getting hot or going bad? I have Comcast and the
same router and it works just fine. Have you tried an alternative
software for the router?

Re: WRT54G + Comcast = random cutouts?


f/fgeorge wrote:
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Its not getting hot, it has been sitting in the same place for the last
year without a problem.  There's no dust.


I heard about alternative firmwares for the Linksys...
Which one should I try?

Re: WRT54G + Comcast = random cutouts?


On Wed, 02 Dec 2009 17:00:50 -0500, Justin

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All the reviewers like Tomato, I use HyperWrt 2.0, it works fine for
me.

Re: WRT54G + Comcast = random cutouts?


f/fgeorge wrote:
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Both of which I can't use due to version 6.0.

Re: WRT54G + Comcast = random cutouts?


On Wed, 02 Dec 2009 23:16:47 -0500, Justin

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I use and recommend dd-wrt. You can check if your device is supported
here:  http://www.dd-wrt.com/wiki/index.php/Supported_Devices

--
Bill

Re: WRT54G + Comcast = random cutouts?



"Justin" wrote:
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     Try changing the frequency band that your wireless router uses.
I had a Linksys WRT54GS wireless router that worked for a couple
months, and then the connection started getting iffy.  I suffered for at
least 6 months, thinking that "it's that flaky Wi-Fi crap".  I finally tried
changing to a different frequency band, and then the connection became
rock solid.  A neighbor had probably gotten a wireless router, too, and
chose the same band.  Or someone nearby got a wireless telephone.

*TimDaniels*



Re: WRT54G + Comcast = random cutouts?


Timothy Daniels wrote:
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Do you mean channel, or band?  For example I have it on channel 11,
using G.  Should I go back to b?

Re: WRT54G + Comcast = random cutouts?


On Thu, 03 Dec 2009 02:57:37 -0500, Justin

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I think he meant channel. Going from G to B (or vice versa) will not
help. Changing to another channel MAY help, assuming you find a
channel without interference. Note that there are only 3
non-overlapping channels: 1, 6, and 11. Try doing a site survey to see
which channels are in heavy use, and then avoid them.

--
Bill

Re: WRT54G + Comcast = random cutouts?


Bill M. wrote:
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I went from 11 to 1 - no change.  I used kismac to see what channels are
open, there is one other wireless network on channel 6 - very weak
signal.  He has wpa2 enabled just like me.

Re: WRT54G + Comcast = random cutouts?


On Thu, 03 Dec 2009 19:42:38 -0500, Justin

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With that info, I think you can probably rule out interference from
other wireless networks. Unfortunately, wireless networks aren't the
only thing that use that band.

By the way, if I were going to manually set the router's MTU, I'd
probably use 1500 rather than 1492 bytes, but that's based on an
experience I had quite a few years ago so it may not apply now.

When your Internet connection goes down, have you pinpointed whether
the culprit is the router, cable modem, or other?

--
Bill

Re: WRT54G + Comcast = random cutouts?


Bill M. wrote:
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I confirmed it is not the wireless - the ethernet machines go down as well.
It has been OK for the day so maybe it healed itself....
I had a problem with the MTU back around 2004, I would connect to a
friend's dyndns.org site.  When I tried to upload a file it would
transfer the first byte and quit.
Once I set the MTU from 1,500 to 1,492 it worked.
I never understood what the problem was.  That was with a different
router, though.

Re: WRT54G + Comcast = random cutouts?


On Thu, 03 Dec 2009 22:51:28 -0500, Justin

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So it could still be the router, the cable modem, or the ISP. If it
happens again, try to narrow it down further.

--
Bill

Re: WRT54G + Comcast = random cutouts?


Bill M. wrote:

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Thanks for the tip.
Yes, it keeps happening now.  I can get about two nimutes of internet
usage and then it craps out.

I unplug the modem and router, plug the modem back in, and then the router.
I can get an external IP address.
Once it craps out, I still have the ip address.
I CAN get to the router setup fine.
I have to hit renew several times before I get an IP, but its always
been like that.

Here's the log from 192.168.100.1
Time      Priority      Description
  2009-12-04 00:48:01      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-04 00:45:19      critical      No Ranging Response received - T3
time-out
  2009-12-04 00:45:15      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-04 00:44:42      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-04 00:42:54      critical      REG RSP not received
  2009-12-04 00:42:38      critical      No Ranging Response received - T3
time-out
  2009-12-04 00:42:33      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-04 00:42:00      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-04 00:29:15      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-04 00:28:42      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out
  2009-12-04 00:26:58      critical      No Ranging Response received - T3
time-out
  2009-12-04 00:26:52      critical      Received Response to Broadcast
Maintenance Request, But no Unicast Maintenance opportunities received -
T4 timeout
  2009-12-04 00:26:20      critical      Started Unicast Maintenance Ranging -
No Response received - T3 time-out

Re: WRT54G + Comcast = random cutouts?


Justin wrote:
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I think it's time to remove the router from the equation and
connect one of your PCs direct to the modem and see how that
goes.  I'm guessing it will work fine.

Re: WRT54G + Comcast = random cutouts?


On Fri, 04 Dec 2009 00:50:14 -0500, Justin

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You mean the router can get an external IP address assigned to its WAN
interface, right?

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This part seems to refer to getting a non-routed IP address assigned
to your PC by the router. It's normal for this assignment to take
10-20 seconds, so perhaps you're being impatient? You shouldn't have
to hit renew to make this happen after a router/PC reboot.

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<snip>

I didn't see anything interesting in the modem log, but I wouldn't
mind seeing the numbers from the Signal page, specifically the
Downstream level and SNR, and the Upstream level.

And like $Bill said, simply (temporarily) removing the router and
connecting a PC directly to the cable modem might be a quick way to
rule the router in or out. Note that you'll have to reboot the modem
and reboot or renew the PC when you make the cabling change.

I assume the modem's various lights remain on and normal. I also
assume you've done a hard reset of the router, not the quick reset.
With the router powered up, you'll need to press and hold the reset
button for about 30 seconds to do a full reset and return everything
to factory defaults.

When you see your next outage, verify that you can access the router's
setup pages, if the router is still in the mix at that time. (Checks
the router's LAN side and its internal web server.) Then check to see
if you can access the modem's web pages. (Checks the router's WAN side
and checks the modem's LAN side and internal web server.) If all of
that works, what _exactly_ do you see when you try to access anything
on the Internet? Have you tried pinging your ISP's gateway address and
perhaps a known Internet address such as 4.2.2.2? (easy to remember IP
of a DNS server)

--
Bill

Re: WRT54G + Comcast = random cutouts?


Bill M. wrote:
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Correct.


Downstream Channel          
  Lock Status      Operational
  Modulation      256QAM
  Channel ID      45
  Provisioned Rate      6600 kbps
  Symbol Rate      5360.537 Ksym/sec
  Downstream Power      -1.7 dBmV
  SNR      37.6 dB
Upstream Channel          
  Lock Status      Operational
  Modulation      16QAM
  Channel ID      1
  Provisioned Rate      1100 kbps
  Symbol Rate      2560 Ksym/sec
  Upstream Power      38.8 dBmV

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I understand.


If I do that I'll have to reenter all the WPA keys... Ugh.
But yes, that's one thing I have not tried.

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I do have access to the router's setup page, I confirmed that.  When it
goes out, the first thing I do is release and renew the router's WAN ip
address - via the setup page.

Re: WRT54G + Comcast = random cutouts?


On Fri, 04 Dec 2009 16:22:35 -0500, Justin

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Thanks.



Modem signal levels all look good. Thanks for posting this.


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There's only one key, and heck, you can use Copy/Paste if it's hard to
type. :)


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Ok, don't do that. :)

I would suggest a slightly different mindset next time it happens.
Instead of focusing on fixing the issue, focus on troubleshooting the
issue. Once you know what the real issue is, the permanent solution
will likely become obvious.

--
Bill

Re: WRT54G + Comcast = random cutouts?


Bill M. wrote:

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Yeah, right.
Thanks for all the "help."
I am switching to Comcast's triple play so I will end up with a new
cable modem.
The connection has been working all day.

Re: WRT54G + Comcast = random cutouts?


On Fri, 04 Dec 2009 23:48:22 -0500, Justin

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You're welcome.


I didn't see any issues with your current modem, so I don't expect to
see any major changes as a result of getting a new one. I know you
need it to support the triple play, but I'm just saying.

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Cool. Hope it stays that way. :)

--
Bill

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