RB450G, ROS 4.6, link speed

RouterOS General
1

I have a customer using a RB450G to connect two networks together. Ether1 is WAN, Ether2 is LAN-A and Ether3 is LAN-B.

Ether1 (WAN) is connected to our cable modem at 100mbit (we have a 28mbit service) without issues.
Ether3 (LAN-B) is connected to a D-Link DGS-1248T switch at 1gbit without issues.

The issue I’m having is with Ether2 (LAN-A). It was originally connected to an old Dell PowerConnect 5224 (24-port 1gbit) switch but would only link at 100mbit (full duplex). If I disabled auto-negotiation and forced it to 1gbit, the link would fail. At first I thought it was a cabling issue but when I plugged it into another wall jack (which had a PC connected at 1gbit on it), it did the same thing so I figured it had to be some compatibility issue between the RB450G and the switch. I explained this to the customer and they agreed it was time to replace the switch.

I replaced the switch with a D-Link DGS-3120-24 (24-port 1gbit) switch. However, Ether2 will only link at 10mbit to it! (If I plug it back into the Dell switch, it links at 100mbit, same as before). If I try to force 100mbit or 1gbit, the link fails. This leads me to think it must be something on the RB450G.

Any idea on why it won’t link at 1gbit to either the original Dell switch or the new D-Link switch? The only thing i haven’t tried is upgrading to ROS 4.17 or 5.6, which I may do this weekend.

mez

2

Try upgrading to latest v5.6. Test with another cable and other ports.

3

I’ve upgraded the router to 5.6 and also plugged ether4 into a different wall jack. Neither made any difference. It links at 10mbit to the new D-Link switch and 100mbit to the old Dell switch. The wall jack I tried had a computer on it which links at 1gbps so I’m confident the cable is good.

Any other ideas?

4

Gigabit speed can only be auto-negotiated and there will be no link if you force it. Is it problem only with ether2 or other ports as well?

5

I tried both ether2 and ether4 with the same results. I ended up forcing 1gbps in the switch which seems to be working.

Mez