MX10003 Component Redundancy
A fully congured router is designed so that no single point of failure can cause the enre system to fail.
Only a fully congured router provides complete redundancy. All other conguraons provide paral
redundancy. The following major hardware components are redundant:
• Host subsystem—The host subsystem consists of two Roung and Control Boards (RCBs). The RCB is
an integrated board and a single FRU that provides Roung Engine and Control Board funconality.
The router can have one or two host subsystems. If two host subsystems are installed, one funcons
as the primary and the other funcons as the backup. If the primary host subsystem (or either of its
components) fails, the backup can take over as the primary. The RCB installed in slot 0 funcons as
the default primary.
• Power supplies—The router supports six power supplies. Table 4 on page 7 shows the power
redundancy supported on the AC and DC powered router for minimum operaon. Minimum power
supplies required for non-redundant operaon is 2 for AC (high), 3 for DC, and 4 for AC (low). With
addional power supplies, it provides
N
+1 and
N
+
N
redundancy for the system. Both AC and DC
systems can withstand the failure of a single power supply without system interrupon in
N
+1
redundancy mode. If one power supply fails in a fully redundant system, the other power supply can
provide full power to the router indenitely.
Table 4: Power Supply Redundancy
Power Supply PSM Redundancy Feed Redundancy
AC (250 V; high) 2+1 2+2
AC (110 V; low) 4+1 Not allowed
DC 3+1 3+3
• Cooling system—The cooling system has a total of four fan modules, which are controlled and
monitored by the host subsystem. A fully congured router needs all the four fan modules to operate
normal. The fan modules are at the rear and are used to cool the router. If a fan fails or the
temperature rises above the temperature threshold, the speed of the remaining fans is automacally
adjusted to keep the temperature within the acceptable range.
7