RT-N56U losing internet connection every 30 minutes

[dismas]

Today I started losing the internet connection on my router. It is not a wi-fi issue since I am connected through ethernet. The internet would suddenly stop working, but it would come back in a minute or so. This seems to happen every 30 minutes. It just started happening today. Is it a router issue or is it my ISP? I have a RT-N56U with firmware 3.0.0.4.374_979. I have not experienced any issues with this router before today.

This is the router's system log for today: http://pastebin.com/TmgrZeeE

 

[RMerlin]

The following line indicates that either your modem is crashing/rebooting, or there is a problem with the Ethernet cable between the modem and the router.

Jun 17 23:12:41 WAN Connection: Ethernet link down.

 

[dismas]

Thanks Merlin. Looks like the modem (Motorola SB6121) was having issues every 30 minutes:

Jun 18 2014 15:16:05	6-Notice	D106.0	DHCP Renew - lease parameters tftp file-?BExV7kGkeqRy+IwK8k40@CvJONPRYo5oy63Hy1QSpbH3K2XAxhFDA modified;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 15:16:05	4-Error	D103.0	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 14:46:05	6-Notice	D106.0	DHCP Renew - lease parameters time server-76.85.237.73;tftp file-?BExV7kGkeqRy+IwK8k40@CvJONJymedP0Gi7VtdFEXOCrsrpeVFu7 modified;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 14:46:05	4-Error	D103.0	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 14:16:26	6-Notice	I401.0	TLV-11 - unrecognized OID;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 14:16:26	5-Warning	Z00.0	MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13	6-Notice	N/A	Cable Modem Reboot due to IP loss ;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 13:45:47	6-Notice	D106.0	DHCP Renew - lease parameters tftp file-?BExV7kGkeqRy+IwK8k40@CvJONEkwGJYbGBombgLZS6WXbmVcbTRR modified;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 13:45:47	4-Error	D103.0	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 13:16:07	6-Notice	I401.0	TLV-11 - unrecognized OID;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 13:16:07	5-Warning	Z00.0	MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13	6-Notice	N/A	Cable Modem Reboot due to IP loss ;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 12:45:49	6-Notice	I401.0	TLV-11 - unrecognized OID;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 12:45:49	5-Warning	Z00.0	MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:13	6-Notice	N/A	Cable Modem Reboot due to IP loss ;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 12:15:11	6-Notice	D106.0	DHCP Renew - lease parameters tftp file-?BExV7kGkeqRy+IwK8k40@CvJONObGluBLrxUoiKjoUvWqcT5TIh6I modified;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;
Jun 18 2014 12:15:11	4-Error	D103.0	DHCP RENEW WARNING - Field invalid in response v4 option;CM-MAC=a4:7a:a4:72:f8:8c;CMTS-MAC=00:01:5c:69:2a:53;CM-QOS=1.1;CM-VER=3.0;

I restarted the modem and will see if that helps.