TonyMan
join:2002-10-01
Lisle, IL
| SB6120 Connection Speed - LAN side
So, I took the whole Comcast package a couple weeks back & they installed the SB6120. The bottom LED (LAN) was orange meaning 10/100 Meg connection. I updated my router to a Lynksys N with a Gig switch in it & the LED turned blue meaning 1 Gig LAN connection. Two days ago Comcast had a fairly significant outage for a few hours and when things came back the LED is now orange again. That makes no sense to me since it was a network outage, not something here. Anyway, my speed tests still show the same speed I had after getting a Gig connection. I don't see anything in the modem via a browser that tells me whether it's connecting at a Gig or not. I have repowered both devices, but still the same results.
Any way I can verify the LAN side connection speed other than the LED?
Thanks |
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Cjaiceman
Premium,MVM
join:2004-10-12
Parker, CO
 ·Comcast Workplace
·Comcast
| The only way would be if the router tells you the connection speed on the WAN port, which would most likely be on the status page in the router. »192.168.1.1 username and password are admin unless you changed them.
Have you tried resetting and restarting the modem? Go to »192.168.100.1 go to the configuration tab, then click on Reset All Defaults and then once the page has reloaded click on Restart Cable Modem. Let us know how that works for you... 
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Duct tape is like The Force – it has a light side and a dark side, and it binds the Universe together |
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koitsu
Premium
join:2002-07-16
Mountain View, CA
| reply to TonyMan
Sounds like the SB6120 may be incompatible with auto-negotiation/duplex on whatever Linksys switch you have. It may be intermittent as well; this is a known problem. Given that neither of your devices are managed devices, you're out of luck.
Replace the Linksys with something that negotiates correctly with the SB6120. I'd recommend one of the HP ProCurve desktop switches, or a D-Link DGS-2205 or DGS-2205.
Finally, are you using anywhere near gigabit capacity through your cable modem? If not, then won't 100mbit full-duplex be sufficient? That's 100mbit up, 100mbit down by the way.
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Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer. |
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TonyMan
join:2002-10-01
Lisle, IL
| reply to TonyMan
I guess I could call it intermittent, but it was working fine for a couple weeks. Before I switched to the 1Gig connection I had download speed of about 40meg. After the switch I saw in the low to mid 60's. I still see that which almost makes me think it's just the LED. When no one else is using the Net I will plug my PC directly to the modem since that has a Gig interface and see what that does. I can also try different ports on the switch.
I will post my findings, thanks. |
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TonyMan
join:2002-10-01
Lisle, IL
| Well, I'll be! I unplugged the router & connected the modem to my PC and the LED turned blue. So, I figure, good old Lynksys router isn't negotiating properly. I plug the router back into the modem & the LED comes back on blue. Don't quite get is all, but, as one of my favorite comedians, 'Uncle Larry" Reeb says, "It's a sick world, I'm a happy guy". |
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koitsu
Premium
join:2002-07-16
Mountain View, CA
| reply to TonyMan
It could also be that a soft reset of the cable modem doesn't properly re-negotiate speed/duplex with your Linksys device, which would mean either the SB6120 or the Linksys is incompatible (with regards to auto-negotiation) with one another.
You could try doing a software reset on the SB6120 (available via the web interface, e.g. »192.168.100.1/) and see if after that reset the LED on the cable modem doesn't come back up blue.
Either way, this kind of problem -- even sporadic -- is almost always the sign of vendor compatibility problems, specifically with regards to auto-negotiation. Even enterprise-level hardware has this problem, which is why many environments prefer managed switches where you can administratively set the speed/duplex on *both ends* (required! You can't set it on one end and expect the other end to work properly) to avoid this kind of situation. In other environments, auto-neg is the only way to get things to work. Go figure. 
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Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer. |
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TonyMan
join:2002-10-01
Lisle, IL | reply to TonyMan
Yep, I hear you. Soft reseting didn't help. It does look like once it renegotiated with the PC, the modem was ok, or maybe it was the router needed a rest. I agree, auto negotiation can be fun. |
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