CRS MAC address learning problem

Hardware MikroTik hardware general
1

Hello,
Anybody else having issues with MAC learning on CRS series?

I’ve just deployed a CRS125-24G-1S and at first everything seemed fine, but after a few minutes we started noticing a communication problems.

There seems to be a limit for the number of MAC addresses the CRS can learn. We couldn’t reach 2000 addresses in the FDB unicast table, while the RB1100AHx2 this CRS was supposed to replace have about 2700 host entries on the bridge hosts table.

Can anyone confirm this?

2

also the latest routerboard firmware ?

the 1100 is more powerfull than a CRS, is it used for routing ?

3

Router OS 6.20 with firmware 3.18 (latest stable version for both).

No L3 at all, we are just using it as a VLAN enabled switch.

The RB1100 has a more powerful CPU, but the L2 forwarding on the CRS is done in the switch chip (at wire-speed if you belive the datasheet).

4

I’ve been digging the CRS documentation and may have found the problem:

learn-override (yes | no; Default: !learn-override)
learn-limit (1..1023; Default: !learn-limit)
Enable or disable MAC address learning and set MAC limit on the port. By default, when !learn-override and !learn-limit, MAC learning is enabled with max allowed limit - 1024.


Can anyone confirm the CRS supports at most 1024 MAC address per port? It’s kind of a deal breaker…

5

maybe lowering de fdb time out can help to reduce the count of mac??

6

Hello,
There are new CRS switch improvements in RouterOS v6.32rc5 which allow to overcome 1023 MAC learning limit per port.

Here are command examples to unset it on CRS ether1 port, similarly they apply to other ports

/interface ethernet switch port unset ether1 learn-limit

or

/interface ethernet switch port set ether1 !learn-limit
7

Becs,

What about 6.32 released yesterday. I tried

/interface ethernet switch port set ether1 !learn-limit

and it errors..

/interface ethernet switch port set ether1 !learn-limit
no such item

Will this fix be in the 6.32 final as its listed in the changelog but clearly isn’t…

From the changelog posted yesterday…

*) crs switch - allow to unset port learn-limit, new default is unset to allow more than 1023 hosts per port;

8

Check the interface names on your CRS. Perhaps, there is not an interface called exactly “ether1” on your switch.

9

Thanks Becs it was the longer default names forgot as I’m always on CCR or RB

But it accepted

/interface ethernet switch port set ether1-master-local !learn-limit

But if I look in the switch / port against ether1 or the rest of the slaves they still all have the max of 1023 in the Max number of connections..

Is the 6.32 final that was released yesterday is this based on RC5 or RC6

I then backed up a second CRS125 made the changes the backup is the same size. I then dumped the backup as a script there’s no change.

Can you confirm its in this release?

Thanks!

10

It works from command line interface, but the input field in Winbox is not fixed yet. It will be done soon.

11

Thanks Becs :slight_smile:

Could you pass this for winbox addition please? There’s no time period shown or available in winbox (I’m using winbox 3 but it’s not in 2 either) but in

IPv6 firewall / address lists

There’s no timer field only ip and name

Most annoying on IPv6 lists you have no idea of the remaining time…

Thanks!

12

Any chanse this comming to CRS317 but I want to set the limit to say 5 per port?