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Technical Overview


This technical overview provides high-level information about some of the key technologies used in this use case.

It contains the following sections:

Junos Fusion Enterprise

Junos Fusion provides a method of significantly expanding the number of available network interfaces on a device—called an aggregation device—by allowing the aggregation device to add interfaces through interconnections with satellite devices. The entire system—the interconnected aggregation device and satellite devices—is called a Junos Fusion. A Junos Fusion simplifies network topologies and administration because it appears to the larger network as a single, port-dense device that is managed using one IP address.

Junos Fusion Enterprise brings the Junos Fusion technology to enterprise switching networks. In a Junos Fusion Enterprise, EX9200 switches act as aggregation devices while EX2300, EX3400, EX4300 or QFX5100 switches act as satellite devices.

In a Junos Fusion Enterprise, each satellite device has at least one connection to the aggregation device. The aggregation device acts as the single point of management for all devices in the Junos Fusion Enterprise. The satellite devices provide network interfaces that send and receive network traffic.

An EX9200 switch acting as an aggregation device in a Junos Fusion Enterprise is responsible for almost all management tasks, including interface configuration for every satellite device interface in the topology. The aggregation device runs Junos OS software for the entire Junos Fusion Enterprise, and the network-facing interfaces on the satellite devices—called extended ports—are configured from the aggregation device and support features that are supported by the version of Junos OS running on the aggregation device.

The satellite devices and the aggregation device maintain the control plane for the Junos Fusion Enterprise using multiple internal satellite management protocols. Network traffic can be forwarded between satellite devices through the aggregation device. Junos Fusion Enterprise supports the IEEE 802.1BR standard.

Figure 1: Junos Fusion Enterprise Example Topology
Junos Fusion Enterprise Example Topology

Junos Fusion Enterprise provides the following benefits:

  • Simplified network topology—You can combine multiple devices into a topology that appears to the larger network as a single device, and then manage the device from a single IP address.

  • Port density—You can configure a large number of network-facing interfaces into a topology that operates as a single network device.

  • Manageability—You can manage a Junos Fusion that supports a large number of network-facing interfaces from a single point. The single point of management, the aggregation device, runs Junos OS software for the entire Junos Fusion.

  • Flexibility—You can easily expand the size of your Junos Fusion by adding satellite devices to the Junos Fusion as your networking needs grow.

  • Investment protection—In environments that need to expand because the capabilities of the existing hardware are maximized, a Junos Fusion can be a logical upgrade option because it enables the network to evolve with minimal disruption to the existing network and without having to remove the existing, previously purchased.

For additional information on Junos Fusion Enterprise, see Example: Enabling Junos Fusion Enterprise on an Enterprise Campus Network and Junos Fusion Enterprise Feature Guide.


Ethernet VPN (EVPN) is a standards-based protocol that provides virtual multipoint bridged connectivity between different domains over an IP or IP MPLS backbone network. This control-plane technology uses Multiprotocol BGP (MP-BGP) for MAC and IP address endpoint distribution, with MAC addresses being treated as routes. EVPN enables MPLS devices to exchange reachability information with each other about their endpoints. Ethernet VPN (EVPN) provides the ability to connect dispersed campus buildings using a Layer 2 overlay. As with other types of VPNs, an EVPN consists of customer edge (CE) endpoint devices connected to provider edge (PE) routers. In this example, the EX9208 switches function as aggregation devices in the Junos Fusion Enterprise and as PE routers in the MPLS topology.

Figure 2: EVPN-MPLS Topology
EVPN-MPLS Topology

EVPN functions by exchanging routes and there are many EVPN route types. See Defining EVPN-VXLAN Route Types.

Most VLANs in campus networks are confined to a single building. VLANs or subnets that are confined to a single building do not have a need to extend layer 2 connectivity across buildings or to Junos Fusion Enterprises in other buildings. EVPN type 5 routes, which are commonly called IP prefix routes, can be used to create communication paths between campus buildings for these VLANs. The procedures to enable EVPN type 5 routes for VLANs that are not extended across campus buildings are provided in this network configuration example.

For additional information on EVPN-MPLS, see EVPN Feature Guide.

For additional information on EVPN Type 5 routes, see Understanding EVPN Pure Type-5 Routes.