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Ethernet Network Access Module
Plexus 9000 Planning and Engineering Guide
Issue 2, April 23, 2004
Section 130-120-810
5-210
Telica,
Inc.
5.19.3.2
Media Access Controllers (MACs)
The ENA module has three Ethernet media access controllers (MACs) for
interfacing via the PHYZITs and midplane to an Ethernet transceiver on the
rear module. There are two gigabit Ethernet MACs and one octal 10/100
MAC. IP packets from the rear module must be segmented in the
forwarding engine before being sent to the SF module. Cells coming from
the switch fabric must be reassembled in the forwarding engine and packets
sent to the PHYZIT for transmission through the rear card Forwarding
Engine
The main function of the forwarding engine is to examine incoming packets
or cells and based on the incoming IP address and the UDP source or
destination address, and make a forwarding/routing decision. Because the
ENA supports many Voice Server modules, it must determine the module
slot for the incoming packets.
5.19.3.3
ATM Port Controllers (APCs)
The APCs maintain and manage the ATM Virtual Connections. They
perform the scheduling and policing of ATM functions on the data flowing
through the module.
5.19.3.4 PHAZITs
The PHAZIT’s main function is a 4:2 switch fabric multiplexer for the
APCs and links the SERDES devices to the APCs. In the egress direction,
the Phazits switch the active switch fabric ports to the APCs, synchronize
transfers between the SERDES and the APCs and check the integrity of the
data from the midplane.
In the ingress direction from the network, it is designed to interface each
APC to both A and B SF modules. Ingress data will be sent from an APC to
the Phazit, where the Phazit will then pass the cell data to both A and B
Serdes for SF A and B modules.
5.19.3.5 Serializer/Deserializer
(SERDES)
The SERDES provide the data interface to the SF. They take the 1.0GHz
embedded clock/data stream from the SF and extract a clock from it and
provide 8-bit-wide data to the PHAZIT circuitry or take the 8-bit wide data
from the PHAZIT and embed the clock and send the clock/data stream to the
SF module.