This post underlines the mac-address limitation. For more information, please read further down this topic.
The customer has set a limit of 5000 addresses with the action of discard and at one side it's not working. On LF4.1, everything is working well, but on LF1.1 there has been seen mac-addresses pass the 5000 limit.
Both devices are CE6880 and the version is V200R005C10SPC800.
<L.1.1>display mac-address summary
Summary information of slot 1:
Capacity of this slot : 98304
-----------------------------------
Static : 0
Blackhole : 0
Dyn-Local : 0
Dyn-Remote : 0
Dyn-Trunk : 1
OAM : 0
Sticky : 0
Security : 0
Authen : 0
Guest : 0
Mux : 0
Tunnel : 2149
Snooping : 0
Evn : 5000
Ovsdb : 0
In-used : 7150
-----------------------------------
As we can see, the EVN learned that mac-addresses are limited to 5000 (which is OK), but we can see that the tunnel learned that mac-addresses are overpassing the limit.
The 2149 Tunnel addresses consists of the number of MAC address entries learned by Layer 2 tunnel.
The EVN mac-address entries are learned through the EVPN tunnel. EVN uses MP-BGP to transmit the MAC address entries between Layer 2 networks.
Solution
The difference between them is that the EVN / EVPN mac-address entries are coming from the forwarding plane and the 'tunnel' mac-address entries are coming from the control plane. These are the mac-addresses learned through the BGP, so that is why they are separate from the addresses learned through the EVPN tunnel.
The mac-address limit command is limiting the addresses through the forwarding plane. This is the reason for the mac-addresses through the control plane to overlap the 5000 limit; also, it would not be recommended to limit the addresses learned through the control plane.
