I have a new CRS317 with the last SwOS. Connecting different other switches on SFP+ ports all the traffic is OK. The problem is with an WiFi access point: when connected through the CRS317 there is no HTTP(S) traffic to internet, while there is some traffic, such ping. I tried to modify the MTU on the router card where the WiFi access point connects (through the CRS317) but no success. Of course when there is no CRS317 to connect the router with the access point, all the traffic is normal.
It’s obvious a MTU problem of the switch, different sizes of ping pass, also sometimes HTTP packets, but never HTTPS. I changed the MTU of the router interface but after the switch let through smaller packets, and so on. Is there any way to change MTU in SwOS?
Switch never changes MTU as it can’t fragment L3 (IP) packets. You have to deal with MTU on IP devices (end devices, router). MTU settings on various devices in same L2 domain (IP subnet) have to match.
I can’t explain the difference when all the rest of config is identical (i.e. without changing anything on any other device, just by replacing CRS317 with CSS326, things start to work).
Finally I booted RouterOS, upgraded to last stable, setup in bridge mode, setup VLANs and the same wireless access point works normally, there is data traffic. Of course first I tested without any VLAN settings and worked. So no hardware problem, most probably SwOS bug.
Please someone confirm that in bridge mode there is full speed, 10GB on all 16 SPF+ ports.