T640 Packet Forwarding Engine Architecture; Figure 2: Control Packet Handling For Routing And Forwarding Table Updates - Juniper T640 Hardware Manual

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T640 Packet Forwarding Engine Architecture

Copyright © 2013, Juniper Networks, Inc.
The Routing Engine constructs and maintains one or more routing tables (see
Figure 2 on page 7). From the routing tables, the Routing Engine derives a table of active
routes, called the forwarding table, which is then copied into the Packet Forwarding
Engine. The design of the ASICs allow the forwarding table in the Packet Forwarding
Engine to be updated without interrupting forwarding performance.
Figure 2: Control Packet Handling for Routing and Forwarding Table
Updates
Replacing a T640 Routing Engine on page 265
T640 Routing Engine Description on page 33
Maintaining the T640 Routing Engines on page 183
The Packet Forwarding Engines provide the Layer 2 and Layer 3 packet switching,
forwarding, and route lookup functions. In a maximum configuration with eight Type 3
FPCs installed, the Packet Forwarding Engines can forward up to 640 million packets
per second (Mpps) for all packet sizes. The maximum aggregate throughput rate for the
T640 router is 320 Gbps (full duplex). The Packet Forwarding Engines are implemented
in ASICs that are physically located on the FPCs and the PICs.
Each Packet Forwarding Engine consists of the following components (see
page 8):
Layer 2/Layer 3 Packet Processing ASIC, which performs Layer 2 and Layer 3
encapsulation and de-encapsulation, and manages the division and reassembly of
packets within the T640 router.
Queuing and Memory Interface ASICs, which manage the buffering of data cells in
memory and the queueing of notifications.
T-series Internet Processor, which provides the route lookup function.
Chapter 2: T640 Router System Architecture Overview
Figure 3 on
7