Bridge Domain Interface (2024)

FAQs

What is a bridge domain interface? ›

Bridge domain interface is a logical interface that allows bidirectional flow of traffic between a Layer-2 bridged network and a Layer-3 routed network.

All the bridge domain interfaces on the Cisco ASR 1000 chassis share a common MAC address. The first bridge domain interface on a bridge domain is allocated a MAC address. Thereafter, the same MAC address is assigned to all the bridge domain interfaces that are created in that bridge domain.

A bridge domain is a set of logical ports that share the same flooding or broadcast characteristics. Like a virtual LAN (VLAN), a bridge domain spans one or more ports of multiple devices.

A Bridge Group is essentially a Layer 2 domain where you can group together a set of related endpoints. Bridge Domain Interfaces (BDIs) and Bridged Virtual Interfaces (BVIs) are both concepts related to Bridge Groups.

The bridge interfaces send traffic with Layer 2 addressing. On the same device, you can configure some interfaces as bridge interfaces, while other interfaces work as Layer 3 interfaces. Traffic between bridge interfaces is inspected at Layer 2.

To locate your domain URL you will want to open Bridge in your normal web browser. In the address bar you will see your site's address.

About Bridge Domains

A bridge domain (BD) represents a Layer 2 forwarding construct within the fabric. One or more endpoint groups (EPGs) can be associated with one bridge domain or subnet. A bridge domain can have one or more subnets that are associated with it.

The bridge domain defines the unique Layer 2 MAC address space and a Layer 2 flood domain if such flooding is enabled. While a VRF instance defines a unique IP address space, that address space can consist of multiple subnets.

Bridging divides a single physical LAN (now called a single broadcast domain) into two or more virtual LANs, or VLANs. Each VLAN is a collection of some of the LAN nodes grouped together to form individual broadcast domains.

Why use VLAN instead of a router? ›

Here are some reasons why you would use a VLAN: VLANs are very cost-effective. This is because workspaces communicate via VLAN switches rather than routers, which are only needed when data is being transferred outside the VLAN. This reduces the need for physical devices, hardware, and cabling.

A Bridge domains (BDs) provide layer 2 forwarding within the fabric as well as a layer 2 boundary. A Bridge Domain is not a VLAN but it can accommodate multiple subnets. There are following Forwarding Option for packet Type in BD, a summary is given here. A Bridge Domain can have more than one subnets.

Bridges allow us to logically segment the network and to lessen the size of collision domains, lessening the chances of a collision. Bridges do nothing to segment broadcast domains. Switches bring us one-host collision domains (“microsegmentation”) and the capability to logically segment the broadcast domain.

Bridging virtual network interfaces allows a virtual interface to connect to an outside network through a physical interface, such as Ethernet or Thunderbolt, making it appear as a normal host to the rest of the network. Note: You can't use bridging if the physical network device used for bridging is a wireless device.

A bridge group is a virtual group. It can forward packets only after interfaces have been added to the group. As shown in Figure 15-15, the following methods can be used to add users to a bridge group: Directly add users to the bridge group. User 3 uses this method.