User`s guide

1-8 StorageWorks Fibre Channel Storage Switch Service Guide
System Components
The Switch architecture separates the switching function from the ports,
resulting in three basic board modules: the motherboard, its CPU daughter
board, and plug-in interface cards.
The CPU daughter board module holds the CPU, memory, and an Ethernet
port.
Components are enclosed in an air-cooled chassis, which can be mounted in a
standard rack or used as a tabletop unit.
The chassis has a local user interface via four push buttons and a Vacuum
Fluorescent Display (VFD) for local access to the Switch’s internal functions.
Switching Function
The switching function is based on a central memory bank associated with its
data path control. Each Switch port stores received frames in this memory,
passing a buffer pointer to the forwarding port’s transmitter. The Switch uses
cut-through routing to route frames from the receiving port to the transmitting
port - providing the transmit port is free - without waiting for the end of the
frame to be received. This provides a low-latency data path within the Switch.
The frame may be temporarily stored in the memory bank but only if the
transmit port is busy.
Embedded Port
The embedded port, which is a logical N_Port, is based on a microcontroller
and is responsible for:
■
Fibre Channel link control
■
Switch management
■
Routing table management
■
Address assignment and management functions
■
Management of Class F services and the related protocols as defined in
the Fibre Channel Standard.
The embedded port also functions as an SNMP agent, a Fibre Channel Name
Server, and an Alias Server to manage multicast and broadcast functions.