526 | Layer 2w w w . d e l l . c o m | s u p p o r t . d e l l . c o m Per-VLAN MAC Learning LimitPer-VLAN MAC Learning Limit is available only on platform: eAn individual MAC learning limit can be configured for each VLAN using Per-VLAN MAC LearningLimit.One application of Per-VLAN MAC Learning Limit is on access ports. In Figure 24-1, an InternetExchange Point (IXP) connects multiple Internet Service Provider (ISP). An IXP can provide several typesof services to its customers including public an private peering. Public peering means that all customers areconnected to one VLAN, and if one ISP wants to peer with another ISP, it establishes a BGP peeringsession over this VLAN. Private Peering means that the IXP sets up a separate VLAN between twocustomers that want to peer privately; only the ports of these two ISPs would belong to this VLAN, andthey would peer via BGP. In Figure 24-1, Per-VLAN MAC Learning Limit is used on the access ports forthe ISPs that have subscribed to private and public peering since these access ports are members ofmultiple VLANs.Figure 24-1. Per-VLAN MAC Learning LimitTask Command Syntax Command ModeConfigure a MAC learning limit on aVLAN.mac learning-limit limit vlan vlan-id INTERFACEDisplay the MAC learning limitcounters for a VLAN.show mac learning-limit [interface slot/port [vlanvlan-id]]EXEC Privilegeinterface GigabitEthernet 1/1...mac learning-limit 1 vlan 10mac learning-limit 1 vlan 20ISP AISP BISP CISP A, B, and C are all public peers through VLAN 10.In addition, ISP A and C are private peers on a separateVLAN, VLAN 20. Since the access ports for ISP Aand C are members of multiple VLANs, Per-VLAN MACLearning Limit can be applied to those ports.Internet Exchange Point802.1QTagged
