Crs310-8g+2s+in Possible Buffer Issue with 2.5 Gb Ports

Hardware MikroTik hardware general
1

Hello everyone,

I purchased a CRS310-8g+2s+in back in January. I am currently running RouterOS 7.15.2. I have noticed that file transfers as well as iperf3 traffic from 2.5Gb be devices to 1 Gb devices results in high retries, and in some cases lowered transfer speeds. According to iperf3, traffic between two 2.5 Gb devices will yield me ~2.35 Gb/s in each direction with 0 retries. Traffic from 1 Gb devices to 2.5 Gb devices will yield ~940 Mb/s with close to 0 retries. These are both normal and what I would expect. However, when transferring from 2.5 Gbe to 1 Gbe the retries increase into the hundreds.
I am not certain if the issue is related to auto-negotiation or the switch’s buffer. The buffer rings a bell because I am aware of this same issue occurring with the RB5009. See http://forum.mikrotik.com/t/rb5009-slow-speed-2-5g-bug-report-as-requested/155362/1 For background info, I am using i225 Rev 3 NICs in my machines for 2.5 Gbe connectivity. These speed/reliability issues also exist when using SwOS 2.16.

Before I submit a ticket, I’d like to reach out to the forum and see if anyone else is experiencing these issues. Any feedback would be greatly appreciated.

Thank you,

RoR

2

since ros 7.15 QoS Hardware Offloading (QoS-HW) is avaliable

documentation
https://help.mikrotik.com/docs/pages/viewpage.action?pageId=189497483

official topic about it
http://forum.mikrotik.com/t/qos-hardware-offloading-qos-hw/166573/1

enabling QoS Hardware Offloading you can monitor buffer status and also tune and monitor some settings related to buffers in a global way and also specific to each interface, i think this can help you

off course this features are available using RouterOS not SWOS

3

Thank you for your help and prompt response. I may try to configure QoS, but from my reading of available options, it looks like it’s mainly helpful for a port’s egress traffic generally. I’d need to tailor it to vary the buffer according to destination. I think it’s interesting that the RB5009 seemed to have this same issue that was patches by RouterOS