Specifications

Page 20 /148
2.3 The M40 Hardware System
The M40 Internet Backbone Router provides high-speed interfaces for large
networks and network applications, such as those supported by Internet
backbone service providers. Application-specific integrated circuits (ASICs), a
definitive part of the router design, enable the router to achieve data forwarding
rates that match current fiber-optic capacity.
The router accommodates up to eight Flexible PIC Concentrators (FPCs), each of
which can be configured with a variety of network media types—all together
providing up to 128 physical interface ports per system.
The router architecture cleanly separates control operations from packet
forwarding operations. This design eliminates processing and traffic bottlenecks,
permitting the router to achieve full line-rate performance. Control operations in
the router are performed by the Routing Engine, which runs JUNOS Internet
software to handle routing protocols, traffic engineering, policy, monitoring,
policing, and configuration management. Forwarding operations in the router are
performed by the Packet Forwarding Engine, which consists of hardware,
including ASICs, designed by Juniper Networks.
The router’s maximum aggregate throughput is 40 Gbps. The router can forward
traffic at line rate for any combination of Physical Interface Cards (PICs) that does
not exceed 3 Gbps on a single FPC. Any combination that exceeds 3 Gbps is
supported, but constitutes oversubscription.
The router is a modular, rack-mountable system. The chassis is 35 in. high, 19 in.
wide, and 23.5 in. deep (91 cm high, 48 cm wide, and 60 cm deep). The chassis
mounting system installs into standard 19-in. equipment racks or Telco center-
mounted racks and allows two routers to be installed into one standard, 78-in.
rack. A fully populated router weighs approximately 250 lbs. (90 kg).
Component Replaceability
Most of the major router hardware components are field-replaceable. Field-
replaceable components fall into two categories:
§ Hot-removable and hot-insertable—You can remove and replace these
components without powering down the system and disrupting routing
functions. Power supplies, fan assemblies, and Flexible PIC
Concentrators (FPCs) are hot-removable and hot-insertable.
§ Hot-pluggable—You can remove and replace these components without
powering down the system, but the system either stops forwarding
packets or switches to a warm shutdown mode as long as the
component is removed. The System Control Board (SCB) and the
Routing Engine are hot-pluggable.