Terms and Acronyms

• integrated routing and bridging (IRB)—IRB provides simultaneous support for Layer 2 bridging and Layer 3 routing on the same interface. Packets arriving on the interface are Layer 2 switched or Layer 3 routed based on the destination MAC address: packets with frames addressed to the router interface's MAC address are routed to other Layer 3 interfaces.
• bridge domain—A set of logical ports that share the same flooding or broadcast characteristics. As in a virtual LAN, a bridge domain spans one or more ports of multiple devices. By default, each bridge domain maintains its own forwarding database of MAC addresses learned from packets received on ports belonging to that bridge domain. See alsobroadcast domain and VLAN.
• virtual switch—A routing instance that can contain one or more bridge domains.
• VLAN—A switched network that defines a broadcast domain. VLANs are logically segmented by function, application, or team, without regard to the physical location of the users. Users on the same VLAN share a common VLAN tag. See also bridge domain.
• VLAN ID—VLAN tag for ports switched within a single bridge domain.