Using a swith with the Asus RT-N66U

[socaljazzdude]

Hi all,

I just received my brand new Asus RT-N66U today which I intend to replace my EA4500 as my primary router. Everything went great with the setup with one minor exception, the N66U does not seem to want to allow my Linksys Cisco SE2800 switch to receive a LAN signal. The SE2800 is essentially just a dumb gigabit switch so I am at a complete loss for why these two devices are not communicating.

Note that I have verified that all four ports on the N66U are functioning by plugging in my main desktop to port 1 and my laptop to the rest of the ports, so I believe at this point that it is safe to rule out a defective port on the new N66U.

When I disconnect the N66U and plug my EA4500 back in(along with the switch connected to the EA4500) everything works fine.

Is there a special setting that I have to enable on the N66U to allow the use of connected Ethernet switches? I noticed under Advanced settings--->LAN a switch control function that was set to OFF. I enabled this to ON but this has no effect on the connected switch.

I am very new to the world of Asus routers so I would appreciate any guidance that any of you could suggest.

 

[Asmodian]

I don't think it is a compatibility problem, at least I have used a switch connected to both the RT-AC66U and the AC68U without issue. No special settings.

I suggest a bad or partially bad cable as something to rule out at least.

 

[joegreat]

I suggest a bad or partially bad cable as something to rule out at least.

Hi,

The RT-N66U is very sensitive on cabling: You have to use CAT5e or CAT6 cables. Otherwise you will get issues!

With kind regards
Joe

 

[sm00thpapa]

Enable Jumbo frames and see what happens.

 

[PrivateJoker]

Enable Jumbo frames and see what happens.

Whoa! That has nothing to do with it, this is a dumb switch.

@socal if you plug your Cisco switch into the Asus do you get LEDs that indicate cable connectivity?

If so, when you plug a PC directly into new switch do the PC & Switch get LED link lights that verify the cable is connected on both ends?

You are testing this by plugging something into one of the cisco's ports *and* plugging the Cisco into the Asus, right? The Asus won't see a dumb unmanaged switch without anything plugged into it (and even with stuff plugged into it), it gets no IP address and has no MAC address. But you will (should) see anything that flows through it and gets an IP address.

 

[socaljazzdude]

Whoa! That has nothing to do with it, this is a dumb switch.

@socal if you plug your Cisco switch into the Asus do you get LEDs that indicate cable connectivity?

If so, when you plug a PC directly into new switch do the PC & Switch get LED link lights that verify the cable is connected on both ends?

You are testing this by plugging something into one of the cisco's ports *and* plugging the Cisco into the Asus, right? The Asus won't see a dumb unmanaged switch without anything plugged into it (and even with stuff plugged into it), it gets no IP address and has no MAC address. But you will (should) see anything that flows through it and gets an IP address.

Well I must say that yesterday's setup of my new N66U was quite an experience due to the switch issue. To answer your question, yes I verified that everything was connected at both ends. Originally my Linksys Cisco switch was directly connected to my EA4500. So when I unplugged the EA4500 and hooked up the N66U, all I did was plug in all the wired clients(including the bridge) that were originally connected to the EA4500.

This issue really confused me because I have two other switches that connected without any problems over a MoCa connection. Both my D-Link switch in a bedroom and a Cisco(non Linksys) switch in my den successfully received the LAN signal from the N66U and all devices connected to those respective switches had no problems.

Surprisingly, this ended up being what you and Asmodian suggested, which was a bad cable. Whereas the cat 6 cable in question was accepted without any problems by the EA4500, the N66U didn't like it. Oh well, problem solved. Thanks for your help!

 

[socaljazzdude]

I don't think it is a compatibility problem, at least I have used a switch connected to both the RT-AC66U and the AC68U without issue. No special settings.

I suggest a bad or partially bad cable as something to rule out at least.

It's funny how with technology the simplest and sometimes most unlikely things are the cause of problems. You were absolutely right. I couldn't believe it but a trusty cat 6 cable of mine must have been going bad and the N66U did not like it. Thanks for responding, this helped save me several hours of pulling my hair out lol!

 

[savagehenry]

Which is why when you are troubleshooting network issues you start at layer 1 (physical layer) and work your way up the OSI model. Typical network problems will be resolved in the first 3 layers, physical (bad cabling, bad nic...), data link (ethernet, speed/duplex mismatch...), and network (IP address, subnet mask, routing...). Keep that in mind next time and I promise you will save a lot of time and hair pulling.

 

[socaljazzdude]

Which is why when you are troubleshooting network issues you start at layer 1 (physical layer) and work your way up the OSI model. Typical network problems will be resolved in the first 3 layers, physical (bad cabling, bad nic...), data link (ethernet, speed/duplex mismatch...), and network (IP address, subnet mask, routing...). Keep that in mind next time and I promise you will save a lot of time and hair pulling.

Definitley, good advice savagehenry! I'll keep that in mind as well as to note that just because an Ethernet cable worked without any problems with one device, doesn't mean it will work fine with another device. Thanks for your help!

 

[sm00thpapa]

Whoa! That has nothing to do with it, this is a dumb switch.

@socal if you plug your Cisco switch into the Asus do you get LEDs that indicate cable connectivity?

If so, when you plug a PC directly into new switch do the PC & Switch get LED link lights that verify the cable is connected on both ends?

You are testing this by plugging something into one of the cisco's ports *and* plugging the Cisco into the Asus, right? The Asus won't see a dumb unmanaged switch without anything plugged into it (and even with stuff plugged into it), it gets no IP address and has no MAC address. But you will (should) see anything that flows through it and gets an IP address.

That's why I said to see what happens. My D-Link DGS-2205 gigabit switch mentions this and supports jumbo frames when enabled.