EX Series Architecture
This section provides a high-level overview of typical EX Series platforms to prepare the reader for upcoming detailed discussions of packet flow in this chapter, as well as in Chapters 4 and 11.
The EX-PFE ASIC
The heart of the EX platform is the EX-PFE ASIC. This Juniper-developed chip offers extreme network and VCP/fabric flexibility, which allows it to be used in a number of different modes within a particular switch model. As with other Juniper designs, this PFE mechanism can be replicated as needed to provide increased switch capacity through a multichip PFE complex. For example, an EX3200-24 is based on a single PFE ASIC, whereas the EX4200-48 uses three. Meanwhile, a single 8200 series LC uses four PFE chips to support 8×10 GE front panel ports, along with the necessary switch fabric connections. Each EX-PFE chip can forward more than 102 Mpps at wire rate, whether all Layer 2, all Layer 3, or any mix.
EX-PFE effectively offers some 88 Gbps of switching/communications capacity, which can be carved up and delegated to 1×GE, 10×GE, or VCP/fabric ports as each hardware application requires. For example, each EX-PFE can provide 24×1 Gigabit ports + 2 VCP ports, or alternatively can provide 24×1 Gigabit + 1×10 Gigabit + 1 VCP port, or in yet another application, 2×10 Gigabit + 2 VCP ports.
We highlight the flexibility of the EX-PFE ASIC in the next section, where you can see it operating in a number of the aforementioned modes.
EX3200 Architecture
Our hardware ...
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