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View Full Version : Router losing connection to modem every few days

Rich99
28-09-2009, 19:16
I recently had my modem changed under warranty to a linksys wrt610n. Since then I've been having intermittent problems with the internet connection on it. 3 times in the last 3 weeks I've lost the internet. The modem shows the ethernet light & the occassional blink on the send light, whereas normally both the send & receive lights blink quite a lot. When this happens I can access the router (192.168.1.1) but cannot access the modem (192.168.100.1). If I renew the wan ip address of the router, it all comes back to life & I can access both the modem & the internet. Since it onlt started happenning since I got the new router, I'm tempted to blame that. However the last time it happenned I checked the log on the modem. Normally there is very little in the modem logs, but the internet failure happened sometime during the day at ~13.30 there were loads of entries. This makes me wonder if it's the modem or the virign network? (I renewed the wan ip at 17.20). Any thoughts? What is the modem doing when all these log entries are made? Is that causing my problems?

Mon Sep 28 17:20:33 2009 Mon Sep 28 17:20:33 2009 Information (7) Map Reject - Downstream Traffic Flow Not Mapped to BPI+ SAID ...
Mon Sep 28 17:20:33 2009 Mon Sep 28 17:20:33 2009 Information (7) SA Map State Machine Started
Mon Sep 28 17:20:26 2009 Mon Sep 28 17:20:26 2009 Information (7) Map Reject - Downstream Traffic Flow Not Mapped to BPI+ SAID ...
Mon Sep 28 17:20:26 2009 Mon Sep 28 17:20:26 2009 Information (7) SA Map State Machine Started
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) The s/w filename specified in the config file is the same as ...
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) A software upgrade filename was specified in the config file.
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) Authorized
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) Registration complete!
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) We registered with a DOCSIS 1.1 config file!
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) Received a REG-RSP message from the CMTS...
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) Sending a REG-REQ to the CMTS...
Mon Sep 28 13:34:34 2009 Mon Sep 28 13:34:34 2009 Information (7) CableModem SNMP configure complete
Mon Sep 28 13:34:33 2009 Mon Sep 28 13:34:33 2009 Information (7) IP init completed ok
Mon Sep 28 13:34:33 2009 Mon Sep 28 13:34:33 2009 Information (7) CableModem TFTP init ok
Mon Sep 28 13:34:33 2009 Mon Sep 28 13:34:33 2009 Information (7) CableModem DHCP client init ok
Mon Sep 28 13:34:33 2009 Mon Sep 28 13:34:33 2009 Critical (3) DHCP WARNING - Non-critical field invalid in response.
Mon Sep 28 13:34:28 2009 Mon Sep 28 13:34:28 2009 Information (7) MAP w/initial maintenance region received
Mon Sep 28 13:34:27 2009 Mon Sep 28 13:34:27 2009 Information (7) Downstream sync ok
Mon Sep 28 13:34:27 2009 Mon Sep 28 13:34:27 2009 Information (7) Beginning initial ranging...
Mon Sep 28 13:34:27 2009 Mon Sep 28 13:34:27 2009 Information (7) downstream time sync acquired...
Mon Sep 28 13:34:27 2009 Mon Sep 28 13:34:27 2009 Information (7) Downstream sync ok
Mon Sep 28 13:34:26 2009 Mon Sep 28 13:34:26 2009 Information (7) starting ds time sync acquisition...
Mon Sep 28 13:34:25 2009 Mon Sep 28 13:34:25 2009 Information (7) Locked on the downstream. Waiting for UCDs...
Mon Sep 28 13:34:25 2009 Mon Sep 28 13:34:25 2009 Information (7) Downstream lock ok
Mon Sep 28 13:34:24 2009 Mon Sep 28 13:34:24 2009 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/Q...
Mon Sep 28 13:32:32 2009 Mon Sep 28 13:32:32 2009 Information (7) Failed to establish downstream FEC lock. Restart error.
Mon Sep 28 13:32:32 2009 Mon Sep 28 13:32:32 2009 Information (7) Downstream lock failed
Mon Sep 28 13:32:32 2009 Mon Sep 28 13:32:32 2009 Information (7) Sync Start
Mon Sep 28 13:32:32 2009 Mon Sep 28 13:32:32 2009 Critical (3) Received Response to Broadcast Maintenance Request, But no Un...
Mon Sep 28 13:32:32 2009 Mon Sep 28 13:32:32 2009 Information (7) Reset downstream scanning state!
Mon Sep 28 13:32:32 2009 Mon Sep 28 13:32:32 2009 Information (7) Downstream lock failed
Mon Sep 28 13:32:33 2009 Mon Sep 28 13:32:33 2009 Critical (3) SYNC Timing Synchronization failure - Failed to acquire FEC f..
Sephiroth
28-09-2009, 20:42
I don't think the log file shows anything unusual. I have these entries any time I look at the log and my 20Mb/s service is fine.

The acid test of whether you have a cable modem problem is whether or not you lose the internet when directly connected to the modem.

It is unlikely (in my experience) for the modem to be a problem with the router unless there is a DHCP wobbly. Your modem and router settings would be of interest.
Ignitionnet
28-09-2009, 20:47
The symptom of not being able to reach the modem sounds like the modem lost its' connection. They tend to become unreachable when they lose connectivity.

The logs you've provided show you losing downstream sync, it happens every so often. Right now it would likely be a long and painful investigation to try and find the issue. I have had similar connection issues here and there over both upstream and downstream and am not much wiser as to what has happened.
Rich99
28-09-2009, 21:12
The acid test of whether you have a cable modem problem is whether or not you lose the internet when directly connected to the modem.



The trouble is I have a house of machines needing the internet & the problem may only happen once a week - I can't leave only 1 machine online for that long :(
Sephiroth
28-09-2009, 21:15
Then we have to do this the hard way - with possible inconclusive results.

What are your router WAN settings?
Mick Fisher
28-09-2009, 21:28
I have 2 machines on a LAN, 1 wired and the other wireless. The wired machine was configured to a static IP and DHCP was switched on in the router. The result was I lost the WAN connection every day or so. A DHCP release/renew would fix it. The LAN remained up.

The fix was to configure the wireless machine to a static IP and switch off DHCP in the router.

Don't know if that will help you?

Maybe worth a try.
Sephiroth
28-09-2009, 21:32
I have 2 machines on a LAN, 1 wired and the other wireless. The wired machine was configured to a static IP and DHCP was switched on in the router. The result was I lost the WAN connection every day or so. A DHCP release/renew would fix it. The LAN remained up.

The fix was to configure the wireless machine to a static IP and switch off DHCP in the router.

Don't know if that will help you?

Maybe worth a try.

Yes - there are a few such issues here that were resolved via the static IP solution.
Rich99
28-09-2009, 23:04
Yes - there are a few such issues here that were resolved via the static IP solution.

It seems wierd that that would be the issue, since all the machines behind the router stay up & working. The WAN connection is just DHCP - what specific info were you after?
Sephiroth
28-09-2009, 23:16
A readout of all your WAN settings on the router.
Rich99
29-09-2009, 08:20
Settings are just DHCP, status is as follows:

Connection Type: Automatic Configuration - DHCP
Internet IP Address: 86.25.145.xxx
Subnet Mask: 255.255.252.0
Default Gateway: 86.25.144.1
DNS1: 194.168.4.100
DNS2: 194.168.8.100
DNS3:
MTU: 1500
DHCP Lease Time: 5 Days 1 Hour 36 Min 36 Sec
Sephiroth
29-09-2009, 09:15
I presume you've done the usual of switching the modem off for 5 minutes (to clear your session), also the router, then power on the modem and a minute or so later the router and look again at the WAN values served.

Something doesn't square up here. I would have expected thr subnet mask to be 255.255.255.0 and the Default Gateway to be 86.25.145.1.

Better brainios than me might comment - but with these values in fronto of me, I would consider taking it off automatic and putting the static values I've suggested in. You can always revert to automatic which I vastly prefer.
Ignitionnet
29-09-2009, 09:32
I presume you've done the usual of switching the modem off for 5 minutes (to clear your session), also the router, then power on the modem and a minute or so later the router and look again at the WAN values served.

Something doesn't square up here. I would have expected thr subnet mask to be 255.255.255.0 and the Default Gateway to be 86.25.145.1.

Better brainios than me might comment - but with these values in fronto of me, I would consider taking it off automatic and putting the static values I've suggested in. You can always revert to automatic which I vastly prefer.

Using /24s as subnets is inefficient and is largely gone as there's no need.

For a while now VM have used cable bundling, binding multiple cable interfaces to a single IP scope. Makes for more efficient use of IP addresses as less wastage on network and broadcast addresses and more control, instead of having to throw a series of /24s at a single interface putting the whole CMTS into a bigger subnet.

/22s / .252.0 are the weapon of choice on the next generation kit, my own IP address for example is 94.172.192.x and subnet 255.255.252.0 - I just happened to be the first person to connect to this CMTS apart from test modems so got a very early IP in the scope :)