Layer 2 Learning and Forwarding Overview
On MX Series routers only, you can configure Layer 2 MAC address and VLAN learning and forwarding properties in support of Layer 2 bridging. The router learns unicast media access control (MAC) addresses to avoid flooding the packets to all the ports in a bridge domain. The MX Series router creates a source MAC entry in its source and destination MAC tables for each MAC address learned from packets received on ports that belong to the bridge domain.
By default, Layer 2 address learning is enabled. You can disable MAC learning for the router or for a specific bridge domain or logical interfaces. You can also configure the following Layer 2 forwarding properties for an MX Series router:
- Timeout interval for MAC entries
- MAC accounting
- A limit to the number of MAC addresses learned from the logical interfaces
For more information about how to configure bridge domains and virtual switches, see Configuring a Bridge Domain and Configuring a Layer 2 Virtual Switch.
