Whenever we adjust the MTU or L3MTU on a 10G port to 9000 for jumbo frames, the entire traffic on the router goes down and the only way to connect to the router is via Winbox MAC.
The Mikrotik MTU support table indicates that that the CCR2216 supports MTU of up to 9570.
Changing MTU has to be done carefully … and on all devices in same L3 network (subnet) as every member of eubnet has to be able to receive jumbo packets (MRU usually closely follows MTU). and this relies on all devices being able to use large L2MTU.
If you are using OSPF, all OSPF neigbours (of that interface) will also need to have an mtu of 9000.
Thought not sure why you can’t connect to it via IP.
My thinking is packets, transmitted by CCR, are too big for management station if that one is not set for jumbo frames as well. Wireshark might tell (probably not), some diagnostic counters on management station’s NIC as well.
Thank you all for the replies.
We resolved this by first changing the L2MTU across the network, then once that was done we set the MTU (L3).
Also, sometimes the devices will lose connectivity for up to a minute. Don’t panic.
If on a live network schedule a downtime with your customers as MTU behaviour can be complicated especially if you are not an expert like me 