Pass through / Media Converter

RouterOS Beginner Basics
1

Hi! I am looking to use Mikrotik CRS305 as a media converter.

What I want to achieve: the fastest, low latency, unprocessed, pass-through possible of 2 SFP ports.

I’m using a 2.5GB SFP ONU in sfp-port1, and my router/firewall connected to sfp-port2 via SFP 10GB.

My router/firewall is handling everything, but doesn’t support 2.5GB SFP.
The only task the Mikrotik should do is passing through traffic between 2 SFP ports with different speed (2.5/10).

This is my current config - are there any improvements I can make?

name="bridge" mtu=auto actual-mtu=1500 l2mtu=1592 arp=enabled arp-timeout=auto mac-address=XX:XX:XX:XX:XX:XX protocol-mode=none fast-forward=yes igmp-snooping=no auto-mac=no 
     admin-mac=XX:XX:XX:XX:XX:XX ageing-time=5m vlan-filtering=no dhcp-snooping=no port-cost-mode=long

name="sfp-sfpplus1" default-name="sfp-sfpplus1" mtu=1500 l2mtu=1592 mac-address=XX:XX:XX:XX:XX:XX orig-mac-address=XX:XX:XX:XX:XX:XX arp=enabled arp-timeout=auto loop-protect=off 
      loop-protect-status=off loop-protect-send-interval=5s loop-protect-disable-time=5m auto-negotiation=no tx-flow-control=on rx-flow-control=on speed=10G-baseCR bandwidth=unlimited/unlimited 
      switch=switch1 sfp-rate-select=high sfp-shutdown-temperature=95C 

name="sfp-sfpplus2" default-name="sfp-sfpplus2" mtu=1500 l2mtu=1592 mac-address=XX:XX:XX:XX:XX:XX orig-mac-address=XX:XX:XX:XX:XX:XX arp=enabled arp-timeout=auto loop-protect=off 
      loop-protect-status=off loop-protect-send-interval=5s loop-protect-disable-time=5m auto-negotiation=no tx-flow-control=on rx-flow-control=on speed=2.5G-baseX bandwidth=unlimited/unlimited 
      switch=switch1 sfp-rate-select=high sfp-shutdown-temperature=95C
      
name="switch1" type=Marvell-98DX3236 mirror-source=none mirror-target=none l3-hw-offloading=yes qos-hw-offloading=no
2

try media converter FTC11XG from mikrotik

3

I don’t see any. You’ve got the main thing there, being the Ethernet flow control, needed with the speed mismatch and protocols like UDP that don’t have their own flow control, such as a WG tunnel out to a peer elsewhere on the Internet. Ethernet flow control won’t transit the Internet, but it’s the fast-to-slow transition that needs flow control, not the slow-to-fast one.

4

Can you elaborate the benefits of that device? Is the switch-chip better?
Looks like it runs on SwitchOS which the CRS305 is also capable. Another concern is if that SFP port supports 2.5GB, since they only mention 1/10GB.


Thank you. Do you suggest disabling flow control in the slow-to-fast direction?

5

I would expect it to have no effect either way, but how about you do the test and tell us?