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Daisy Chain on Wire Speed

Posted: Fri Oct 04, 2019 11:05 pm
by kanuns
Hi everyone.

I need to ask you a question. I have a need to daisy chain 3 mikrotik routers. I want to use them as access points, it will be like the following.

Main Router-------->Router One's Port 3 [Bridge port (port 3,4,wlan)] --------> Router two's Port 3 [Bridge port (port 3,4,wlan)] --------> Router three's Port 3 [Bridge port (port 3,4,wlan)]

Users will be using Wlan to access the network.

I want to use the ports as switch. But I see that when converting this to bridge, it will not be working on wire/switch speed. Instead they will work as CPU Speed. So, each router will have more and more load on the CPU, with last one have the least and router one having the most load. I am using hap ac lite.

Is there any way I can make them work on wire speed so that I can avoid the CPU load? I heard that Vlan setup can do that but I am not able to understand that.

Any ideas?

Re: Daisy Chain on Wire Speed  [SOLVED]

Posted: Fri Oct 04, 2019 11:31 pm
by xvo
Passing data between bridged ethernet ports will be automatically done on wirespeed using switch chip (of course if you leave hw-offload option on).
Passing data from wlan to ethernet will be done by CPU as it's just the way it works, nothing can be done about it.

So you actually don't need to do anything, it will work the way you want it out of the box.

Re: Daisy Chain on Wire Speed

Posted: Fri Oct 04, 2019 11:33 pm
by mkx
Almost all routerboards can work wirespeed with ports in bridge ... if there's a switch chip in the routerboard, all used ports are connected to same switch chip (you can check the block diagram for your routerboards) and no fancy functionality is used. If you are not going to use VLANs then it should be fine.

Re: Daisy Chain on Wire Speed

Posted: Fri Oct 04, 2019 11:43 pm
by kanuns
Wow, many thanks for the quick replies.

So, there is no issue when it comes to Wire, but when the users get connected to Wlan then the CPU will be used - and nothing can be done about it.

Meaning:

Main Router-------->Router One's Port 3 [Bridge port (port 3,4,wlan)] --------> Router two's Port 3 [Bridge port (port 3,4,wlan)] --------> Router three's Port 3 [Bridge port (port 3,4,wlan)]

Router 3 will cause load on the CPU of Router 2 because of the Wlan, and Router 2 will cause load on Router 1 because of Wlan and the data from the single port of main router, the load will be on
CPU of it.

Am I right ?

Re: Daisy Chain on Wire Speed

Posted: Sat Oct 05, 2019 12:00 am
by xvo
No, wlan <-> eth traffic will cause CPU load only on the device where this wlan is, not on any others.

Re: Daisy Chain on Wire Speed

Posted: Sat Oct 05, 2019 12:45 am
by kanuns
Ok, thanks,
I learned something new just now that hardware offloading can be done on only 1 bridge port at a time. I made 2 bridges HWoffload didnt activate on the second one. So deleted the first and it started working on the second.

Any more advice that can make storms like broadcast etc ??

Moreover, i have made a hotspot on the main router and when I connect to the 3rd routers wifi, the page loads all the way from the main router to the 3rd router's wifi. If this approach right? or should I make the wifi's independent on each router and start hotspot on them and put the data server on the main router in walled garden ?

Best Regards

Re: Daisy Chain on Wire Speed

Posted: Sat Oct 05, 2019 1:18 am
by xvo
1) Yes, only one hw-offloaded bridge per switch chip: that means that on devices with one switch chip you can have hw-offload only on one bridge, on devices like RB4011/RB3011 - total of two hw-offloaded bridges, one for each port group, and on devices without the switch chip - no hw-offload obviously.

2) Nothing specific here. If you are afraid of possible loops - run STP or RSTP on bridges.

3) One hotspot server will be enough :)

You are welcome!

Re: Daisy Chain on Wire Speed

Posted: Sat Oct 05, 2019 2:05 am
by kanuns
Again many thanks for your reply and time.

Last question, if I leave it the way it is, I am not able to login to any of the APs (or the router with wifis).
how about i give the bridge port's ethernet port an IP and make bridge on just the WIFI ports. That is how the routers will have independent - but that will be routing not switching ?

Any other way I can make those AP router reach internet via that bridged switch ports that are daisy chained together?

Thanks in advance

Re: Daisy Chain on Wire Speed

Posted: Sat Oct 05, 2019 11:34 am
by xvo
I think I didn't completely get this one.

If the question is about connecting to the routers themselves, then you just need to assign an address (or DHCP client) to the bridges on each router.
Not to the ports belonging to the bridge, but the bridge itself.

And once again:
Separate bridges = Routing = CPU load
Having in mind this exact devices are not very powerful, that can become a bottleneck.

Re: Daisy Chain on Wire Speed

Posted: Mon Oct 07, 2019 10:03 pm
by kanuns
Hi,
thank you for your reply
what i meant was, that if I give an IP to the bridge i will be able to login to the routers which are working as a switch, but i guess this will make it routing, not switching.

I guess that the only option I have is to run 2 cables, 1 just to access the router just to see whats going on and other for bridging which i described earlier.

I highly appreciate your time for the replies.

Re: Daisy Chain on Wire Speed

Posted: Mon Oct 07, 2019 11:14 pm
by mkx
what i meant was, that if I give an IP to the bridge i will be able to login to the routers which are working as a switch, but i guess this will make it routing, not switching.

Nope, it's not like that. On devices with switch chip (that can do wirespeed switching between ether ports) router's CPU is yet another port off switch chip. So even if you configure device with IP address this doesn't automatically disable switching between ether ports.
Which means there's no need whatsoever to use separate ether cable for managerial connections ...

Re: Daisy Chain on Wire Speed

Posted: Mon Oct 07, 2019 11:17 pm
by xvo
Connecting to the router itself won't make that traffic "routed", just "switched to the router's CPU".
Obviously such traffic can't avoid CPU in any scenario - because CPU is its destination :)
And it won't affect the other traffic in any way.

Re: Daisy Chain on Wire Speed

Posted: Mon Oct 07, 2019 11:25 pm
by IPANetEngineer
Also, if you use the following page, it will tell you what features are supported in 'hw-offload'

https://wiki.mikrotik.com/wiki/Manual:I ... Offloading