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T1600 Component Redundancy


The T1600 Core Router is designed so that no single point of failure can cause the entire system to fail. The following major hardware components are redundant:

  • Switch Interface Boards (SIBs)—The T1600 router has five SIBs.

    See T1600 Switch Interface Board (SIB) Description.

  • Host subsystem—The host subsystem consists of a Routing Engine functioning together with a control board. The router can have one or two host subsystems. If two host subsystems are installed, one functions as the master and the other functions as the backup. If the master host subsystem (or either of its components) fails, the backup can take over as the master. To operate, each host subsystem requires a Routing Engine installed in an adjacent slot to a control board.

    If the Routing Engines are configured for nonstop active routing, the backup Routing Engine automatically synchronizes its configuration and state with the master Routing Engine. Any update to the master Routing Engine state is replicated on the backup Routing Engine. If the backup Routing Engine assumes mastership, packet forwarding continues through the router without interruption. For more information about nonstop active routing, see the Junos OS High Availability Library for Routing Devices.


    Nonstop active routing is supported for standalone T1600 routers in Junos OS Release 8.5 and later. Nonstop active routing is supported for T1600 routers in a routing matrix in Junos OS Release 10.0 and later.

    See T1600 Host Subsystem Description

  • SONET Clock Generators (SCGs)—The router has a standard configuration of one SCG. A second can be purchased to function as backup. If one SCG fails, the other becomes the master SCG. Mastership of the SCGs is independent of the host subsystem, so routing functions are not affected.

    See T1600 SONET Clock Generators Description.

  • Power supplies—The router has two power supplies, which share the load evenly. If one power supply fails, the other power supply can provide full power to the router indefinitely.

    See T1600 Power System Description.

  • Cooling system—The cooling system has redundant components, which are controlled by the host subsystem. If one of the fans fails, the host subsystem increases the speed of the remaining fans to provide sufficient cooling for the router indefinitely.

    See T1600 Cooling System Description.