modem keeps switching from gigabit (blue led) to 100mb (amber)

[nightmarevoid]

Hello everyone. I just moved and was lucky enough to get a free modem and router. The modem is a Motorola Surfboard SB6120 and the router is a WNDR3800 and I'm using Xfinity for my provider. Not exactly cutting edge, but for two people and a minecraft server it's more than enough imo. The issue I keep running into is that for some reason the modem keeps switching from gigabit connection to the router (blue LINK led) to 100MB (amber LINK led). I realize that at a max of 160MB I'm not losing a whole lot but it's still really annoying. I've tried updating my router firmware to no avail, and there doesn't seem to be a setting to force gigabit connection. Does anyone have some advice?

 

Spec sheet for the modem and router:
https://www.cnet.com/products/motorola-surfboard-sb6120-cable-modem/

 

https://www.cnet.com/products/netgear-wndr3800-premium-edition-wireless-router-802-11-a-b-g-n-desktop-series/

[Escapenz]

They both keep blinking ? Or does it go from blue to amber and stay on amber?

[Dutch_Master]

It's most likely a wiring issue. See if you can get another Cat5E or Cat6 cable and if that fixes the problem.

[nightmarevoid]

1 minute ago, Escapenz said:

They both keep blinking ? Or does it go from blue to amber and stay on amber?

If I fully power cycle the router, the modem will be Blue for a while and then switch to amber and stay on amber.

[nightmarevoid]

1 minute ago, Dutch_Master said:

It's most likely a wiring issue. See if you can get another Cat5E or Cat6 cable and if that fixes the problem.

Thanks, will try this.

[Boomwebsearch]

2 minutes ago, nightmarevoid said:

Hello everyone. I just moved and was lucky enough to get a free modem and router. The modem is a Motorola Surfboard SB6120 and the router is a WNDR3800 and I'm using Xfinity for my provider. Not exactly cutting edge, but for two people and a minecraft server it's more than enough imo. The issue I keep running into is that for some reason the modem keeps switching from gigabit connection to the router (blue LINK led) to 100MB (amber LINK led). I realize that at a max of 160MB I'm not losing a whole lot but it's still really annoying. I've tried updating my router firmware to no avail, and there doesn't seem to be a setting to force gigabit connection. Does anyone have some advice?

 

Spec sheet for the modem and router:
https://www.cnet.com/products/motorola-surfboard-sb6120-cable-modem/

 

https://www.cnet.com/products/netgear-wndr3800-premium-edition-wireless-router-802-11-a-b-g-n-desktop-series/

 

Usually green or blue represents a gigabit connection and amber would represent a sub-gigabit connection (typically a 10/100 MBPS link connection). What speeds are you paying for from your ISP and could you please take a look at the ethernet cables going between your modem and router (it should be a Cat 5.e or Cat 6 cable to get the gigabit link connection speeds)?

[Bananasplit_00]

I'd start with trying another cable

[Boomwebsearch]

Just now, Bananasplit_00 said:

I'd start with trying another cable

2 minutes ago, Dutch_Master said:

It's most likely a wiring issue. See if you can get another Cat5E or Cat6 cable and if that fixes the problem.

 

If you see either Cat 5.e or Cat 6 written on the cable then that means that the ethernet cable isn't likely going to be the issue and it's able to support the gigabit speeds.

 

10 minutes ago, nightmarevoid said:

I've tried updating my router firmware to no avail

Try updating the firmware of the modem as well to the latest version available.

[Bananasplit_00]

2 minutes ago, Boomwebsearch said:

 

If you see either Cat 5.e or Cat 6 written on the cable then that means that the ethernet cable isn't likely going to be the issue and it's able to support the gigabit speeds.

Ethernet cables break when abused. It's an easy first step to try.

[nightmarevoid]

5 minutes ago, Boomwebsearch said:

 

Usually green or blue represents a gigabit connection and amber would represent a sub-gigabit connection (typically a 10/100 MBPS link connection). What speeds are you paying for from your ISP and could you please take a look at the ethernet cables going between your modem and router (it should be a Cat 5.e or Cat 6 cable to get the gigabit link connection speeds)?

I have the 200MB plan from Xfinity. As far as the cable goes, as far as I know it's a regular Cat 5.e cable. That being said I have no idea what the health of the cable is. I just found it at work wrapped up behind the server cabinet and took it with me so it wouldn't be tossed in landfill. For all I know it was there because it was broken.

[Dutch_Master]

1 minute ago, Boomwebsearch said:

If you see either Cat 5.e or Cat 6 written on the cable then that means that the ethernet cable isn't likely going to be the issue and it's able to support the gigabit speeds.

True, but wires break. Using a different cable could eliminate the broken wire from the connection. Remember, Gbit networking requires all 4 wire-pairs in the cable, 100Mbit only needs 2 pairs. If one pair has a broken core, it could display the error symptoms described by the OP. (intermittent contact)

[Boomwebsearch]

18 hours ago, Bananasplit_00 said:

Ethernet cables break when abused. It's an easy first step to try.

18 hours ago, Dutch_Master said:

True, but wires break. Using a different cable could eliminate the broken wire from the connection. Remember, Gbit networking requires all 4 wire-pairs in the cable, 100Mbit only needs 2 pairs. If one pair has a broken core, it could display the error symptoms described by the OP. (intermittent contact)

18 hours ago, nightmarevoid said:

I have the 200MB plan from Xfinity. As far as the cable goes, as far as I know it's a regular Cat 5.e cable. That being said I have no idea what the health of the cable is. I just found it at work wrapped up behind the server cabinet and took it with me so it wouldn't be tossed in landfill. For all I know it was there because it was broken.

 

If you aren't sure about the health of your ethernet cable and know/think that it may have been damaged from abuse (ex. sharp bends, excessive connecting and disconnecting, tangling, etc) then I would consider getting another Cat 5.e cable to see if the issue was your old cable. Although most home users will just connect it once to from the modem to the router (a new cable) and not mess with it, that's why I said that it isn't likely to be the cable, although it could be the case if the cable is possibly damaged and is not functioning correctly.

[nightmarevoid]

I tried a different cable and the modem has stayed in gigabit mode for over 24 hours. So everyone who said it was the cable wins!