First of all, thanks for taking the time to read my post.
I recently bought a CRS310-8G+2S+IN switch. I chose this model because my old gigabit connection was getting a bit saturated, and I’m also planning to split my network into VLANs to isolate my IoT devices.
My issue is that when I connect my PC—an MSI X870 Tomahawk motherboard with a Realtek® 8126-CG 5G LAN chip—at 2.5Gbps, game streaming (using Moonlight or Steam Link) performs very poorly. However, it worked better with my old gigabit switch. I found that if I manually limit my PC’s port to 1Gbps, the performance improves significantly. Also, if I connect my PC directly to the network, bypassing the CRS310-8G+2S+IN at 2.5Gbps, it works perfectly.
I’m not sure if this is a configuration issue or something else. Could someone take a look at my setup? I’m new to the MikroTik ecosystem.
Thanks in advance!
# 2025-03-04 16:09:13 by RouterOS 7.18.1
# software id = WFJL-JHUJ
#
# model = CRS310-8G+2S+
# serial number = HGXXXXXXXXXX
/interface bridge
add comment=defconf name=bridge protocol-mode=none vlan-filtering=yes
/interface ethernet
set [ find default-name=ether1 ] comment=UpLink
set [ find default-name=ether2 ] comment="Device 1"
set [ find default-name=ether3 ] comment="Device 2"
set [ find default-name=ether4 ] comment="Device 3"
set [ find default-name=ether5 ] comment="Device 4"
set [ find default-name=ether6 ] comment="Device 5"
set [ find default-name=ether7 ] comment="Device 6"
set [ find default-name=ether8 ] comment="PC Port"
/interface list
add name=WAN
add name=LAN
/interface bridge port
add bridge=bridge comment=defconf interface=ether1
add bridge=bridge comment=defconf interface=ether2
add bridge=bridge comment=defconf interface=ether3
add bridge=bridge comment=defconf interface=ether4
add bridge=bridge comment=defconf interface=ether5
add bridge=bridge comment=defconf interface=ether6
add bridge=bridge comment=defconf interface=ether7
add bridge=bridge comment=defconf interface=ether8
/ip firewall connection tracking
set udp-timeout=5s
/ip neighbor discovery-settings
set discover-interface-list=all lldp-med-net-policy-vlan=1 lldp-vlan-info=yes
/interface ethernet switch
set 0 l3-hw-offloading=yes
/interface list member
add interface=ether2 list=LAN
add interface=ether3 list=LAN
add interface=ether4 list=LAN
add interface=ether5 list=LAN
add interface=ether6 list=LAN
add interface=ether7 list=LAN
add interface=ether8 list=LAN
add interface=sfp-sfpplus1 list=LAN
add interface=sfp-sfpplus2 list=LAN
add interface=ether1 list=WAN
/ip address
add address=192.168.1.6/24 comment=defconf interface=bridge network=192.168.1.0
/ip dns
set servers=192.168.1.2
/ip route
add disabled=no distance=1 dst-address=0.0.0.0/0 gateway=192.168.1.1 pref-src="" routing-table=main scope=30 suppress-hw-offload=no target-scope=10
/system clock
set time-zone-name=Europe/Madrid
/system identity
set name="MikroTik CRS310-8G+2S+IN"
/system note
set show-at-login=no
Are you sure the used cable between PC and switch is at least CAT6 ?
Can you try another one ?
What port do you use for connecting your PC ?
Which one goes towards you ISP modem ?
Have you also tried to manually set the port on the switch connecting to your PC to 2.5Gbps ? What does that give ?
Sometimes you can run into a border condition with port - cable - port which for some combinations is just enough to make it work but for others not.
Auto-negotiation of speeds being flaky might be an indication of such a problem, I think.
Just a question:
why are both SFP ports part of LAN but not member of bridge ?
I’ve tested using a CAT6 cable (previously, I was using a CAT5) with the same results. However, I’ve ordered a CAT8 cable that will arrive tomorrow so I can perform further tests.
“Which port do you use for connecting your PC?”
It’s ether8.
“Which port connects to your ISP modem?”
It’s ether1.
“Have you tried manually setting the switch port connecting your PC to 2.5Gbps? What result does that yield?”
It’s currently synchronizing at 2.5Gbps.
“Why are both SFP ports included in the LAN but not added to the bridge?”
I’m not using the SFP ports at the moment; I can either remove them from the LAN or add them to the bridge. Perhaps it’s just a misconfiguration.
Other questions:
why do you have VLAN filtering activate on bridge but no further VLAN config on that device ?
When you see the poor performance on your PC, can you run /tools/profile - all to see if one or all cores are at maximum performance ?
Also, how do you define “poor performance” ? Not getting the required bandwidth or latency issues ?
I see you have l3-hw offloading active for switch but not for the ports ?
To enable full hardware routing, enable l3hw on all switch ports:
/interface/ethernet/switch set 0 l3-hw-offloading=yes
/interface/ethernet/switch/port set [find] l3-hw-offloading=yes
" why do you have VLAN filtering activate on bridge but no further VLAN config on that device ?"
I enabled it because I plan to use VLANs in the near future.
" When you see the poor performance on your PC, can you run /tools/profile - all to see if one or all cores are at maximum performance ?"
All values are either 0 or very close to it (around 2–3%).
“Also, how do you define “poor performance” ? Not getting the required bandwidth or latency issues ?”
I believe the issue is related to bandwidth, as I’m experiencing frame drops, although latency remains below 1ms (almost negligible per my performance overlay).
You have provided zero context here. What is the CRS310 connected to…an ISP router, another switch, an ISP modem???
What is the speed of the incoming internet?
Internet speed is not a factor here since I’m streaming within a local network. I enabled VLAN filtering because I plan to use it soon.
I’ve attached a diagram illustrating three topology scenarios:
When my PC syncs with the CRS310 at 2.5G, game streaming to the Apple TV is slow.
When my PC syncs with the CRS310 at 1G, game streaming to the Apple TV works fine.
When I bypass the CRS310 and sync my PC with the Fritz!Box at 2.5G, game streaming to the Apple TV is perfect.
My concern isn’t that my PC can’t maintain a 2.5G connection with the CRS310 for game streaming (I only use this setup for scenarios requiring high bandwidth and extremely low latency); rather, I suspect there’s an issue with syncing the PC at 2.5G with the CRS310 compared to using the Fritz!Box.
Interesting so you have a fritzbox device that is NOT providing anything other than one flat subnet. No vlan capability, no port forwarding capability? No real firewall rules to speak of.
Assuming its fiber cable IN and using 2.5Ghz out for max throughput.
It would seem that you want to use the Mikrotik switch as a router, in which case the top speed you should expect with some firewall rules is about 300Mbps.
Stick a 5009 router in between with the 2.5gig to the Fritz and the 10+ to the switch and you would be in business.
Yes, I have a plan to achieve that—potentially using another CRS310-8G+2S+IN or maybe the 5009 ( it only have one 2.5G port, not sure if will be future proof or maybe yes ) —but first, I need to confirm that the CRS310-8G+2S+IN is capable of handling the job.
If the plan is to use the CRS328 as a switch NO routing, no creation of VLANS on switch, then it will work ( one flat subnet from fritz ).
If you intend to have a network of vlans behind the fritz, then put a router after the fritz like the 5009 so at least you maximize the throughput of the system.
From the config, all i see is a flat bridge, with some unnecessary “WAN” / “LAN” descriptors, but there is no routing actually happening
all ethernet interfaces are in the bridge, with the same pvid=1 (default)
you state that in addition to the router (ether1) and the PC(ether8), there are other “devices” connected to the switch
if those other devices are operating at different rates than 2.5gb/s (say 1G, or in extreme cases 10m/half for some cheap IOT stuff)
this can put the switch-chip in a contention state, and cause packet-drops between ports 1–>8 when servicing say, a crusty old 100mb/s device on port 5
some tests to run:
1- disconnect all other devices from the switch, see if there is an improvement with only ports 1 and 8 running
2- run “/interface/ethernet/print stats”
look for FCS errors, TX-errors, RX/TX drops, etc
3- reset and simplify your configuration:
for the dumbest possible bridge:
this will make troubleshooting much easier with a cleaner config (technically and functionally the same as what you have today, but much simpler to understand)
That’s the desired state, but it’s not what the /export shows
OP hasn’t even introduced vlans yet , and is observing some weird (presumably L1/L2) effect
so my thinkig goes:
start with a naked L2 bridge (not vlan aware)
test that
then introduce vlans, set up inter-vlan routing , ant only then deal with possible L3 HW-offloading working/not working correctly
in theory i don’t see any fundamental flaw in what OP wants to do
except maybe for the fact that the Marvell switch-chips appear to be a little fragile when dealing with big rate-differences between interfaces
what i would do, is break the scenario into steps, and diagnose/validate those steps one at a time, beggining with the simplest possible one
I tried that, but it didn’t improve the situation. Besides, I had a printer connected at 10Mbps, so I’ll disconnect it and switch to Wi-Fi instead.
Here are my stats: it seems the printer on ether7 might be generating rx-fragment errors, and there’s a noticeable rx-broadcast metric on ether8—though I’m not sure if that could be related to game streaming.
I tried it without any luck.
Today, I tested the connection using a CAT8 cable, but unfortunately, it didn’t resolve the issue.
After doing some additional research, I’ve started to suspect that the issue might be related to the Fritz!Box 5590 Fiber. I found a review (in Spanish) at this link which indicates that the 2.5G port can have performance problems when many connections are active. This could very well be the cause of the issues I’m experiencing. I’ll test it with iperf, but it’s strange because it worked fine jumping the Mikrotik switch.
Maybe I’ll need to buy a MikroTik RB5009UG+S+IN or another CRS310-8G+2S+IN, but both have stock problems in my country ( Spain ), and also read some problems with 2.5G port on RB5009UG+S+IN and not sure if they’re resolved.
Anyway, thank you all for your help, what an amazing community!
This is the PoE version, which is more expensive and not available on Amazon and it’s sold through an external vendor, which is a red flag for me. ( Bad experiences in the past )
