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MX2000-SFB2-S Enhanced Switch Fabric Board Description

MX2000-SFB2-S enhanced switch fabric boards (SFB2) create a highly scalable and resilient “all-active” centralized switch fabric that delivers up to 2 Tbps of full-duplex switching capacity to each Modular Port Concentrator (MPC) in an MX2000 series router. Each SFB2 hosts one switch fabric plane made of three fabric chipsets. You can install up to eight SFB2s in an MX2000 series router. Only seven SFB2s are required for line rate operation.

Note that you can’t mix switch fabric board models (SFB, SFB2, SFB3) in a single MX2000 series router chassis. If you upgrade from an SFB to an SFB2, the MX2000 routers will support both the SFB and SFB2 at the same time but only for the duration of the upgrade.

The MX2000-SFB2-S switch fabric board straddles the two backplanes. It has connectors connecting to both backplanes.


The MX2000 SFB and the MX2000 SFB2 Enhanced Switch Fabric Board are the same except that the SFB has two PF fabric chips per card whereas the SFB2 has three XF fabric chips per card.

Figure 1 shows the MX2000 Enhanced Switch Fabric Board (SFB).

Figure 1: MX2000-SFB2-S Enhanced Switch Fabric BoardMX2000-SFB2-S Enhanced Switch Fabric Board

Software release

  • Junos OS Release 11.4 and later

  • Name in CLI: Switch Fabric Board

Features and Components

The MX2000-SFB2-S provides:

  • PCIe control of three XF fabric chips per card.

  • I2C bus logic interface for managing component managements and monitoring temperature and voltage

  • Switching functions for MPCs

  • 2 Tbps per slot with eight SFB2s and 1.7 Tbps per slot with seven SFB2s

SFB2 Slots

You can install up to eight SFB2s in an MX2000 router. The SFB2s install vertically into the front of the chassis in the slots labeled 0 through 7. If any slots are empty, you must install a blank panel.

Slot 0 must always have a functioning SFB2. If the SFB2 in slot 0 fails, replace it with a functioning SFB2 from another slot, and then install a blank panel in the other slot. If slots 1 through 7 are empty, install a blank panel in them. You cannot install a blank panel in slot 0.


If an SFB2 fails, don’t remove it until you have a replacement SFB2 or blank panel ready to install.

SFB2 Redundancy

For line rate operation, the MX2000 series router must have at least seven SFB2s installed. Although MX2000 routers can operate with fewer than seven SFB2s, packet forwarding performance is impacted.

Weight and Dimensions

  • Weight: 16 lb (7.2 kg)

  • Width: 1.7 in. (4.31 cm)

  • Depth: 23.6 in. (59.94 cm). With ejector handle: 26.14 in. (66.39 cm)

  • Height: 16.225 in. (41.21 cm)

Maximum Power Requirements (without MICs)


  • Typical: 250 W

  • At different temperatures:

    295 W at 55° C

    280 W at 40° C

    270 W at 25° C


  • Typical: 220 W

  • At different temperatures:

    265 W at 55° C

    250 W at 40° C

    240 W at 25° C


See MX2000 Switch Fabric Board LED for a description of the SFB2 LED functions.

Each SFB2 also has a set of bicolor LEDs on the craft interface that indicate its status. The SFB2 LEDs, labeled 0 through 7, are located along the bottom center of the craft interface.


During an upgrade from SFB to SFB2, MX2000 series routers support both SFB and SFB2 at the same time for the duration of the upgrade.

Interoperabilitly with MPC Line Cards

The MX2000-SFB2 interoperates with these MPCs:

  • MPC2E

  • MPC2E NG (with ethernet MICs only)

  • MPC3E

  • MPC3E NG (with ethernet MICs only)

  • MPC4E

  • MPC5E

  • MPC6E

  • MPC7E

  • MPC8E

  • MPC9E

  • MS-MPC