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MX Series Router Architecture

The key components of the Juniper Networks MX Series 5G Universal Routing Platforms are:

  • Dense Port Concentrators (DPC)

  • Modular Port Concentrators (MPC)

  • Modular Interface Cards (MIC)

  • Control Board and Routing Engine (CB-RE)

  • Switch Control Board (SCB)

  • Switch Fabric Board (SFB)


The MX80 Universal Routing Platform leverages the technology used in the MPCs, common across the MX Series, and can accommodate multiple combinations of Modular Interface Cards (MICs) for increased flexibility. The MX80 is a single board router with a built-in RE and one Packet Forwarding Engine (PFE). The PFE has two “pseudo” Flexible PIC Concentrators (FPC 0 and FPC 1). Because there is no switching fabric, the single PFE takes care of both ingress and egress packet forwarding.

The MX Series router has been optimized for Ethernet services. Examples of the wide range of Ethernet services provided by the MX Series include:

  • Virtual private LAN service (VPLS) for multipoint connectivity—Native support for VPLS services

  • Virtual leased line (VLL) for point-to-point services—Native support for point-to-point services

  • RFC 2547.bis IP/MPLS VPN (L3VPN)—Full support for MPLS VPNs throughout the Ethernet network

  • Video distribution IPTV services

  • Ethernet aggregation at the campus/enterprise edge—Supports dense 1-Gigabit Ethernet, 10-Gigabit Ethernet, and 100-Gigabit Ethernet configurations, and provides full Layer 3 support for campus edge requirements

  • Ethernet aggregation at the multiservice edge—Supports up to 480 1-Gigabit Ethernet ports or 48 10-Gigabit Ethernet ports for maximum Ethernet density along, with full Layer 2 and Layer 3 VPN support for MSE applications


You can configure MX Series routers to provide simultaneous support for Layer 2 and Layer 3 Ethernet services. In many cases, Layer 2 protocols run on some interfaces, and Layer 3 protocols run on others.

The Junos OS Layer 2 Switching and Bridging Library topic discusses Layer 2 configurations on supported routers, including Layer 2 statement summaries and configuration statement examples. For more complete Layer 2 configuration examples for MX Series routers, see the Ethernet Networking User Guide for MX Series Routers.

For more information about configuring Layer 3 features and functions (such as class of service), see the relevant Junos configuration guides.