Data Flow Through The T640 Router; Figure 3: Data Flow Through The T640 Router - Juniper T640 Hardware Manual

T640 Core Router Hardware Guide

Data Flow Through the T640 Router

Figure 3: Data Flow Through the T640 Router

10
Replacing T640 Packet Forwarding Engine Components on page 219
To ensure the efficient movement of data through the T640 Core Router, the router is
designed so that ASICs on the hardware components handle the forwarding of data.
Data flows through the T640 router in the following sequence (see Figure 3 on page 10):
Packets arrive at an incoming PIC interface.
1.
The PIC passes the packets to the FPC, where the Layer 2/Layer 3 Packet Processing
2.
ASIC performs Layer 2 and Layer 3 parsing and divides the packets into 64-byte cells.
The Switch Interface ASIC extracts the route lookup key, places it in a notification and
3.
passes the notification to the T-series Internet Processor. The Switch Interface ASIC
also passes the data cells to the Queuing and Memory Interface ASICs for buffering.
The Queuing and Memory Interface ASICs pass the data cells to memory for buffering.
4.
The T-series Internet Processor performs the route lookup and forwards the notification
5.
to the Queuing and Memory Interface ASIC.
The Queuing and Memory Interface ASIC sends the notification to the Switch Interface
6.
ASIC facing the switch fabric, unless the destination is on the same Packet Forwarding
Engine. In this case, the notification is sent back to the Switch Interface ASIC facing
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