FCS RX CCR1036 to Juniper when set to manual negotiation (auto is fine)

RouterOS General
1

I have a CCR1036 connected to my IP transit via ethernet, the provider on hte other side is a Juniper device (from Wireshark traces i can see is a Juniper MAC).

The provider tells me to set manually (not auto-neg) the speed to 100Mbps (tx/rx flow control set to off).

However, when set manually i start getting logs in the console and FCS RX errors on the interface stats. Traffic passes however, but logs 4 to 5 times a minute.

When i set to automatic it negotiates to 100Mbps automatically and no errors/logs, no FCS RX etc. Pipe has ran fully saturating @ 100Mbps no issues for months, not one CRC or checksum error when set to auto negotiation.

Is this a bug i am seeing? Surely if it negotiates to 100Mbps automatically, when can i not set to 100Mbps manually - its the same speed so why would one get FCS RX for one but not the other?

Has anyone else seen this? Do i need to be worried?!

2

I’d set it to auto, then adjust the bandwidth setting on the interface to 100Mb.

Come to think of it you can do the above, call into your ISP and have them check for errors on their interface. If none are found, leave as is. If they are taking errors, then you will need to manually set yours.