I have RB2011UiAS-IN wired router as a heart of my home network. Its ports:
ether1 - internet goes here
ether2, ether3... - go to PCs
ether5 - goes to separate WiFi Router's WAN port
current Firmware: 6.49.15
I didn't do any specific configuration and used the initial one as is.
But all the time of the router usage I experience issues with Internet connection. Periodically ether1 link is down and then in a few seconds (5-15) it is up.
Log fragment:
13:56:19 interface,info ether1 link down
13:56:19 dhcp,info dhcp-client on ether1 lost IP address XXX.XXX.XXX.XXX - lease stopped locally
13:56:23 interface,info ether1 link up (speed 1G, full duplex)
13:56:30 dhcp,info dhcp-client on ether1 got IP address XXX.XXX.XXX.XXX
14:10:19 interface,info ether1 link down
14:10:19 dhcp,info dhcp-client on ether1 lost IP address XXX.XXX.XXX.XXX - lease stopped locally
14:10:23 interface,info ether1 link up (speed 1G, full duplex)
14:10:27 dhcp,info dhcp-client on ether1 got IP address XXX.XXX.XXX.XXX
How to fix this annoing behavior? Does anybody face the same issue?
Re: RB2011UiAS-IN random 'ether1 link down' happens
I assume you already tried replacing the cable attached to ether1.
Which kind of "internet" goes to ether1?
I presume is a ISP device or your own modem/adapter, and the only connection to it from LAN is the Mikrotik router.
And then all your network devices are connected to the RB4011.
The default configuration on most Mikrotik devices have a DHCP client enabled on ether1, and your log shows how there is some time lost in dealing with lost and re-assigned DHCP client IP address.
If you can (it depends on the type of connection to the ISP), you may want to assign a static IP address to ether1 and disable the DHCP client and see if the down links continue (at least it should be faster to resume).
Then try experimenting with settings for port speed disabling auto-negotiation (default should be speed auto-negotiation that in some cases has been found as being involved in port flapping).
Which kind of "internet" goes to ether1?
I presume is a ISP device or your own modem/adapter, and the only connection to it from LAN is the Mikrotik router.
And then all your network devices are connected to the RB4011.
The default configuration on most Mikrotik devices have a DHCP client enabled on ether1, and your log shows how there is some time lost in dealing with lost and re-assigned DHCP client IP address.
If you can (it depends on the type of connection to the ISP), you may want to assign a static IP address to ether1 and disable the DHCP client and see if the down links continue (at least it should be faster to resume).
Then try experimenting with settings for port speed disabling auto-negotiation (default should be speed auto-negotiation that in some cases has been found as being involved in port flapping).
Re: RB2011UiAS-IN random 'ether1 link down' happens
Hi @jaclaz
Thank you for your suggestions. I tried them.
My Internet provider provides the connection through ethernet RJ45 with dynamic IP. So simple attempt to make it static just on router's side was not successful. It seems that in order to switch the router to static IP I need to speak with the provider in order to add the static IP feature to my account. I'll keep in mind that idea. At the moment I search for the solution on my side.
And trying auto negotiation I find out the following:
switching off auto negotiation I can select only one rate. So I choose 1Gbps (this is the speed I pay for, and seems it is supported most of the time). An once I did that I got 'ether1 link down' message in the log and that's all. Connection simply gone.
Then I switched to 100Mbps and connection was established. I didn't check yet if the connection is stable in this mode. I was upset with that idea that I need to have 10 times less service than I pay for. But at least in this mode I got functional connection.
So it seems that the key reason is found. As I understand the picture I have: randomly router sees that connection doesn't fit 1Gbps full duplex and link goes down. Then in 3s the router restores the link and then DHCP client receives the configuration.
But if I connect internet cable directly to my laptop then there are no that disconnections. So laptop seems to be able to overcome such issues without disconnections.
Thus the questions are:
Thank you for your suggestions. I tried them.
My Internet provider provides the connection through ethernet RJ45 with dynamic IP. So simple attempt to make it static just on router's side was not successful. It seems that in order to switch the router to static IP I need to speak with the provider in order to add the static IP feature to my account. I'll keep in mind that idea. At the moment I search for the solution on my side.
And trying auto negotiation I find out the following:
switching off auto negotiation I can select only one rate. So I choose 1Gbps (this is the speed I pay for, and seems it is supported most of the time). An once I did that I got 'ether1 link down' message in the log and that's all. Connection simply gone.
Then I switched to 100Mbps and connection was established. I didn't check yet if the connection is stable in this mode. I was upset with that idea that I need to have 10 times less service than I pay for. But at least in this mode I got functional connection.
So it seems that the key reason is found. As I understand the picture I have: randomly router sees that connection doesn't fit 1Gbps full duplex and link goes down. Then in 3s the router restores the link and then DHCP client receives the configuration.
But if I connect internet cable directly to my laptop then there are no that disconnections. So laptop seems to be able to overcome such issues without disconnections.
Thus the questions are:
- can the router be configured in order not to loose the link? Is there a way to configure the router be less demanding?
- what could be reasons that auto negotiation cannot be switched off with fixed 1Gbps full duplex?
Re: RB2011UiAS-IN random 'ether1 link down' happens
Yep, but it is a complex setting:switching off auto negotiation I can select only one rate.
https://help.mikrotik.com/docs/display/ROS/Ethernet
and what happens may depend on both sides of the ethernet link.
I would try re-setting autonegotiation on but reduce the list to only one advertised speed and see what happens, like:
Code: Select all
/interface ethernet
set [ find default-name=ether1 ] autonegotiation=yes advertise=1G-baseT-full
Code: Select all
/interface ethernet
set [ find default-name=ether1 ] autonegotiation=yes advertise=1G-baseT-half
I don't think there is a documented "simple way out", it seems like these connection mismatches are rather common, if you search on the forum for port flapping or ether1 link down you will find many similar reports,
In some cases putting a (otherwise unneeded) unmanaged switch between the two devices solves (in a "wrong" way, still if it solves it ...) the issue, if you have a spare GB capable switch around or you can borrow one it is something to try, buying one only for the test is probably not worth it, as there are no guarantees that it will have any effect. Though a (say) TP-Link 5 ports unmanaged switch should be under 15 Euro and (still say) a Zyxel managed one below 25 Euro.
It could also be *something* in your configuration, improbable since you are running a default one, but still possible.
No idea if upgrading the software to a later (stable) 7.xx would make any difference, there are reports of newer versions being worse than 6.4x.x, then the next 7.xx version is reported as fixing the issue, and then a later 7.xx version is reported of being worse (a regression bug of some kind?).