Overview Of The M120 Router; M120 Router Description - Juniper Networks Hardware Manual

Multiservice edge router

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CHAPTER 1

Overview of the M120 Router

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M120 Router Description on page 3

The M120 Multiservice Edge router is a complete routing system that provides

SONET/SDH, ATM, Ethernet, and channelized interfaces for large networks and network

applications, such as those supported by Internet service providers (ISPs) and large

enterprise customers. Application-specific integrated circuits (ASICs), a definitive part

of the router design, enable the router to forward data at the high speeds demanded by

current network media.

The router provides multiple redundancy options and chassis configurations, enhanced

ASIC features, and chassis and Packet Forwarding Engine (PFE) scaling. PFE routing

functionality is performed by Forwarding Engine Boards (FEBs) which separate routing

ASICs from Flexible PIC Concentrators (FPCs) to provide high availability and redundancy

of the forwarding engine. The router utilizes the I-chip ASIC, which supports up to 32,000

logical interfaces depending on your configuration. The base chassis provides 120 gigabits

per second (Gbps) of midplane bandwidth between the interfaces and FEBs, and 144

Gbps, half duplex, of fabric bandwidth between the FEBs.

The router is a quarter-rack chassis that supports up to six FPCs. Four slots accept FPCs

of Types 1, 2, and 3 and two slots accept Compact FPCs (CFPCs). Each FPC can be

configured with a variety of network media types, altogether providing up to 130 physical

interface ports per system. The CFPC slots are identical to the Type 1, 2, and 3 FPC slots,

but feature a smaller form factor to provide higher density 10-Gigabit interfaces. The

router height of 20.75 in. (52.71 cm) enables stacked installation of four routers in a single

floor-to-ceiling rack, for increased port density per unit of floor space. In a standalone

configuration, the router's maximum aggregate throughput is 60 Gbps, full duplex.

The router architecture separates control operations from packet forwarding operations,

which helps to eliminate processing and traffic bottlenecks. Control operations in the

router are performed by the Routing Engine, which runs Junos OS to handle routing

protocols, traffic engineering, policy, policing, monitoring, and configuration management.

Forwarding operations in the router are performed by the Packet Forwarding Engine

(PFE), which includes ASICs, designed by Juniper Networks contained on the FEBs. The

redundant FEBs provide route lookup and forwarding functions from the PICs and CFPCs

with fast switchover times and higher bandwidth PFEs provide support for larger numbers

of PICs.

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