Ptx5000 System Architecture Description; Ptx5000 Packet Transport Router Description; Ptx5000 Hardware Component Overview - Juniper PTX5000 Hardware Manual

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PTX5000 System Architecture Description

Copyright © 2017, Juniper Networks, Inc.
Routing Engine. If the backup Routing Engine assumes mastership, packet forwarding
continues through the packet transport router without interruption. For more information
about nonstop active routing, see Nonstop Active Routing Concepts and Nonstop Active
Routing System Requirements.
Centralized Clock Generators (CCGs)—The PTX5000 has a standard configuration of
one CCG. If two CCGs are installed, the second CCG functions as backup. If one CCG
fails, the other becomes the master CCG. Mastership of the CCG is independent of the
host subsystem, so routing functions are not affected. See
Clock Generator Description" on page
Power system—The PTX5000 has two redundant, load-sharing power distribution
units (PDUs), located at the lower rear of the chassis in slots
on the left. The PDUs are hot-removable and hot-insertable. When the PTX5000
PDU1
is operating normally and both PDUs are switched on, load sharing between them
occurs automatically. If one PDU fails in a fully redundant power system, the other
PDU can provide full power to the PTX5000 indefinitely.
NOTE: Redundant PDUs must be the same model number during normal
operations.
The PDUs provide connections for the DC power cables or AC power cords; configure
the output voltages produced by the power supply modules (PSMs); and connect to
the midplane, which distributes the different output voltages to PTX5000 components,
depending on their voltage requirements. The number of PSMs required for full
redundancy varies depending on the configuration of the chassis.
NOTE: The normal-capacity power system distributes power into three
different output zones. The high-capacity power system does not use power
zones. See the
Zones" on page 71
system power zones.
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 packet transport router
indefinitely. See "PTX5000 Cooling System Description" on page
PTX5000 Packet Transport Router Description on page 3
PTX5000 Hardware Component Overview on page 5
The PTX5000 has two main architectural components:
Chapter 1: System Overview and Architecture
23.
"Understanding Normal-Capacity Power System Power
for more information about normal-capacity power
"PTX5000 Centralized
on the right and
PDU0
27.
9