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MX240 System Overview

The MX240 router is an Ethernet-optimized edge router that provides both switching and carrier-class Ethernet routing. The MX240 enables a wide range of business and residential applications and services, including high-speed transport and VPN services, next-generation broadband multiplay services, high-speed Internet and data center internetworking.

Benefits of the MX240 Router

  • System Capacity—MX240 provides 3 Tbps of system capacity for space-constrained cloud, enterprise, data center, service provider, cable, and mobile service core deployments.

  • Always-on infrastructure base—MX Series routers ensure network and service availability with a broad set of multilayered physical, logical, and protocol-level resiliency aspects. Junos OS Virtual Chassis technology on MX Series routers supports chassis-level redundancy and enables you to manage two routers as a single element. Multichassis link aggregation group (MC-LAG) implementation supports stateful chassis, card, and port redundancy.

  • Application-Aware Networking—On MX Series routers you can use deep packet inspection to detect applications, and by using the user-defined policies, you can determine traffic treatment for each application. This feature enables highly customized and differentiated services at scale.

  • Programmable Chipset—The chipset implemented in the MX Series routers has a programmable forwarding data structure that allows fast microcode changes in the hardware itself, and a programmable lookup engine that allows inline service processing. the chip’s programmable QoS engine supports coarse and fine-grained queuing to address the requirements of core, edge, and aggregation use cases.

  • Junos Continuity and Unified In-Service Software Upgrade (Unified ISSU)—With the Junos continuity plug-in package, you can perform a smooth upgrade when new hardware is installed in your MX Series router.

    Unified in-service software upgrade (unified ISSU) enables software upgrades and changes without disrupting network traffic.

  • Junos Telemetry Interface—Using the Junos telemetry interface data, you can stream component-level data to monitor, analyze, and enhance the performance of the network. Analytics derived from this streaming telemetry can identify current and trending congestion, resource utilization, traffic volume, and buffer occupancy.

  • Integrated Hardware-Based Timing—You do not need to use external clocks because MX Series routers support highly scalable and reliable hardware-based timing, including Synchronous Ethernet for frequency, and the Precision Time Protocol (PTP) for frequency and phase synchronization. Synchronous Ethernet and PTP can be combined in a hybrid mode to achieve a high level of frequency (10 ppb) and phase (<1.5 uS) accuracy.

MX240 Hardware Overview

The MX240 router is five rack units (U) tall. Several routers can be stacked in a single floor-to-ceiling rack, for increased port density per unit of floor space.

Fully populated, the MX240 provides a maximum aggregate switch fabric capacity of up to 1.92 Tbps and line-rate throughput for up to 48 10-Gigabit Ethernet ports, or four 100-Gigabit Ethernet and eight 10-Gigabit Ethernet ports, or twelve 40-Gigabit Ethernet ports.

Table 1 lists the MX240 router capacity.

Table 1: MX240 Router Capacity



System capacity

1.92 Tbps full-duplex

Switch fabric capacity per slot

480 Gbps

MPCs and DPCs per chassis

2 or 3


Apart from one dedicated slot for the SCB, another multifunctional slot is available for either one DPC, MPC, or SCB.

Chassis per rack


The router provides two dedicated line card slots for Dense Port Concentrators (DPCs), Modular Port Concentrators (MPCs), or Flexible PIC Concentrators (FPCs). DPCs and MPCs each install into a single line-card slot. The FPC installs into both slots. The router also provides one dedicated slot for a Switch Control Board (SCB), and one multifunction slot for either one DPC, MPC, or SCB. Optionally, an FPC can be installed in both the multifunction slot and lowest dedicated line card slot.

An FPC supports up to two PICs. An MPC supports up to two Modular Interface Cards (MICs).

Each DPC includes two or four Packet Forwarding Engines. Each Packet Forwarding Engine enables a throughput of 10 Gbps.

Several types of line cards, are available. For a list of the supported line cards, see the MX Series Interface Module Reference.

Four SCBs are available for the MX240 routers—SCB-MX, the SCBE-MX, SCBE2-MX, and SCBE3-MX.

Table 2 compares the fabric bandwidth capacities of SCBs per MX-series router.

Table 2: Switch Control Board Capacities for MX Series 5G Universal Routing Platforms (Full-Duplex)


Fabric Bandwidth Per Slot

MX240 Fabric Bandwidth

MX480 Fabric MBandwidth

MX960 Fabric Bandwidth

Enhanced MX Switch Control Board (model SCBE3-MX)

Up to 1.5 Tbps (non-redundant fabric configuration with MPC10E line cards); 1 Tbps (redundant fabric configuration with MPC10E line cards)

Up to 6 Tbps

Up to 18 Tbps

Up to 33 Tbps

Enhanced MX Switch Control Board (SCBE2-MX)

Up to 480 Gbps (non-redundant fabric configuration); 340 Gbps (redundant fabric configuration)

Up to 1.92 Tbps

Up to 5.76 Tbps

Up to 10.56 Tbps

Enhanced MX Switch Control Board (SCBE-MX)

Up to 240 Gbps (non-redundant fabric configuration); 160 Gbps (redundant fabric configuration)

Up to 930 Gbps

Up to 2.79 Tbps

Up to 5.25 Tbps

Switch Control Board (SCB-MX)

Up to 240 Gbps (non-redundant fabric configuration); 120 Gbps (redundant fabric configuration)

Up to 465 Gbps

Up to 1.39 Tbps

Up to 2.6 Tbps

The connections between line cards and SCBs are organized in three groups:

  • Switch fabric—Connects the line cards and provides for packet transport between the line cards.

  • Control plane—Gigabit Ethernet links between the combined SCBs/Routing Engines and each DPC, MPC, or FPC. All board-to-board information is passed over Ethernet except for low-level status and commands.

  • Management signals—Provide low-level status diagnostic support.