You can configure one or more bridge domains on MX Series routersto perform Layer2 bridging. The Layer2 bridging functionsof the MX Series routers include integrated routing and bridging (IRB)for support for Layer2 bridging and Layer3 IP routingon the same interface, and virtual switches that isolate a LAN segmentwith its spanning-tree protocol instance and separate its VLAN IDspace.
A bridge domain is a set of logical ports that share the sameflooding or broadcast characteristics. Like a virtual LAN (VLAN),a bridge domain spans one or more ports of multiple devices.
On Juniper Networks MX Series 5G Universal Routing Platformsonly, you can configure one or more bridge domains to perform Layer2bridging. Thus, MX Series routers can function as Layer2 switches,each with multiple bridging, or broadcast, domains that participatein the same Layer2 network. You can also configure Layer3routing support for a bridge domain. Integrated routing and bridging(IRB) provides support for Layer2 bridging and Layer3IP routing on the same interface. IRB enables you to route packetsto another routed interface or to another bridge domain that has aLayer3 protocol configured.
You can also group one or more bridge domains within a singleinstance, or virtual switch. The MX Series routers also support multiplevirtual switches, each of which operates independently of other virtualswitches on the router. Virtual switches isolate a LAN segment withits spanning-tree protocol instance. .Thus, each virtual switch can participate in a different Layer2network.
In Junos OS Release9.2 and later, bridge domains providesupport for a Layer2 trunk port. A Layer2 trunk interfaceenables you to configure a single logical interface to represent multiple VLANs on a physical interface. You can configurea set of bridge domains and VLAN identifiers that are automaticallyassociated with one or more Layer2 trunk interfaces. Packetsreceived on a trunk interface are forwarded within a bridge domainthat has the same VLAN identifier. A Layer2 trunk interfacealso supports IRB within a bridge domain. In addition, you can configureLayer2 learning and forwarding properties that apply to theentire set of bridge domains.
In Junos OS Release9.3 and later, you can configure VPLSports in a virtual switch instead of a dedicated routing instanceof type vpls so that the logical interfaces of the Layer2bridge domains in the virtual switch can handle VPLS routing instancetraffic. Packets received on a Layer2 trunk interface are forwardedwithin a bridge domain that has the same VLAN identifier.
FAQs
Understanding Layer 2 Bridge Domains on MX Series
What is the difference between bridge domain and VLAN? ›
A bridge domain and broadcast domain are synonymous in definition and can be used interchangeably with each other. He even says that a bridge domain is synonymous with a broadcast domain. So according to Cisco, a VLAN is a Broadcast Domain. According to Reynolds, a Broadcast Domain is synonymous with a Bridge Domain.
What is bridge domain in Vxlan? ›
Bridge domain—It is a Layer-2 flood broadcast domain that maps/connects VLANs of a Layer-2 virtual network on the tenant side of a ToR switch to a Layer-2 VNI on the fabric side of the switch. There is a 1:1 mapping between the bridge domain ID and the L2 VNI (one BD for each L2 virtual network).
What is Layer 2 traffic? ›
Layer 2 is equivalent to the link layer (the lowest layer) in the TCP/IP network model. Layer2 is the network layer used to transfer data between adjacent network nodes in a wide area network or between nodes on the same local area network.
What is the L2 interface? ›
In a Layer 2 deployment, the firewall provides switching between two or more networks. Devices are connected to a Layer 2 segment; the firewall forwards the frames to the proper port, which is associated with the MAC address identified in the frame.
How does a bridge domain work? ›
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 traffic. Bridge domain interfaces are identified by the same index as the bridge domain. Each bridge domain represents a Layer 2 broadcast domain.
What are bridge domains? ›
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.
Why use bridge domain? ›
Yes thats correct , 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 traffic. BDI is used to "bundle" one or more physical L2 interfaces and link it to a L3 logical interface for routing.
What is Layer 2 bridging? ›
Layer 2 VPN bridging creates a virtual Ethernet switch that connects devices on different networks as if they were on the same LAN. This allows devices to use their native protocols and addresses, and to broadcast and multicast traffic.
What is the difference between bridge domain and VNI? ›
Summary: VNI is a VXLAN-specific identifier for traffic segregation in VXLAN overlays. Bridge domains are broader, used for Layer 2 forwarding and isolation in various network virtualization technologies.
Layer 2 refers to a secondary framework or protocol that is built on top of an existing blockchain system. The main goal of these protocols is to solve the transaction speed and scaling difficulties that are being faced by the major cryptocurrency networks.
Can a layer 2 switch do VLANs? ›
Layer 2 switches offer limited to no routing capabilities within network segments such as VLANs. Layer 3 switches offer routing between different network segments. Limited scalability. Higher scalability enabled by layer 3 switches' cross network segment routing capabilities.
Are VLANs layer 2 or 3? ›
Since VLANs exist in their own layer 3 subnet, routing will need to occur for traffic to flow in between VLANs. This is where a layer 3 switch can be utilized.
Can VLANs talk to each other? ›
Virtual Local Area Networks (VLANs) separate an existing physical network into multiple logical networks. Thus, each VLAN creates its own broadcast domain. Communication between two VLANs can only occur through a router that is connected to both. VLANs work as though they are created using independent switches.
What network device is used in Layer 2 of the OSI model? ›
Switch: A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model.
What is the difference between Vxlan and VLANs? ›
VLANs operate with a 12-bit network identifier. This means that you can only create 4096 administrative domains within your network using VLANs. On the other hand, VXLANs operate with a 24-bit network identifier. With this, you can theoretically create as many as 16 million administrative domains.
What is VLAN and bridge? ›
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.
What is a VLAN domain? ›
A virtual local area network (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer (OSI layer 2). In this context, virtual refers to a physical object recreated and altered by additional logic, within the local area network.
Is a VLAN a domain of its own? ›
In a network with a single switch without VLANs, the broadcast domain is that entire switch. In a network with multiple interconnected switches without the use of VLANs, the broadcast domain includes all of those switches. When using VLANs, each VLAN is typically its own broadcast domain.
What is the difference between bridge domain and bridge group? ›
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.
