(Optional) MAC address to be declared a permit or deny MAC address. (Optional) Adds the specified MAC address as a deny MAC address for the Ethernet service instance. (Optional) Adds the specified MAC address as a permit MAC address for the Ethernet service instance. (Optional) Sets up a MAC address to be permitted or denied. To return to the default MAC security setup on the service instance, use Mac security command in service instance configuration mode. To configure MAC security and the various MAC security elements on an Ethernet service instance, use the If flooding is disabled, when the packet’s MAC address destination is unknown, Mac limit action flooding disable command to prevent flooding the destination. Will always be flooded, which results in system degradation. When this limit is reached, the system cannot learn the new destination. However, there is a limit to the number of MAC address entries that can be included in the MAC address table. The next timeĪ packet with that destination is received, the packet is simply forwarded to the correct interface. To learn that the destination belongs to a specific interface and an entry in the MAC address table is created. This is known as “flooding.”Įventually, the packet reaches the correct interface destination and that destination replies. If the system does not find a match, copies of the packets are forwarded to each interface associated If the system finds a match (for example, bridge-domain ID), the packets are forwarded to the appropriate interface associated Each MAC address table contains information and attributes such as the following:

When a Layer 2 device receives a packet, the destination MAC address is examined and the device looks at the MAC address table. If a MAC ACL does not exist on the Ethernet service instance, all packets are passed. If the MAC ACL permits the address, the software continues Software checks the source MAC address of the packet against the ACL. After a networking device receives a packet, the Cisco IOS The mac access-group in command is used to apply MAC ACLs on Ethernet service instances. This command was integrated into Cisco IOS XE Release 3.5S.

Service instance configuration (config-if-srv) Name of a MAC ACL to apply to an interface or subinterface (as specified by the macĪ MAC ACL is not applied to the Ethernet service instance. No mac access-group access-list-name in Syntax Description

Mac access-group in command in service instance configuration mode.

To use a MAC access control list (ACL) to control inbound traffic on an Ethernet service instance, use the port-channel load-balance weighted rebalance.mac limit maximum addresses (service instance).

Mac address flooding cisco