User guide

FN100 Architecture
Fast Network 100 User Guide Page 1-7
1.5 FN100 ARCHITECTURE
The FN100 is based on an architecture that utilizes a high speed switch
engine coupled with an AMD 29200 RISC processor for management
functions. This architecture provides an efficient mix of optimal
performance and intelligence.
The non-blocking design of the FN100 provides wire-speed filtering and
forwarding rates for all Fast Ethernet ports, allowing the device to keep up
with incoming packets even when the packet rates on all LANs are at the
maximum possible rate.
The high speed scalable switch fabric at the core of the FN100 allows
packets to be forwarded through the FN100 at very high rates with
minimal latency. The switch fabric in the FN100 supports data rates up to
2.56 Gbps - more than enough for sixteen 100 Mbps ports.
The Address Database Engine is used by the FN100 to make filtering and
forwarding decisions. Each time a packet is received, it is placed into
packet memory, analyzed for errors, compared against the MAC address
and filtering entries in the database, and sent to the appropriate destination
port.
1.5.1 Store and Forward Switching
The FN100 is an intelligent Fast Ethernet switch that uses full store and
forward switching. Store and forward switching allows the FN100 to
temporarily store packets until network resources, typically an unused
link, are available for forwarding. This allows for complete error
checking, and limits the amount of time between when a device requests
access to the network and when it is granted permission to transmit. In
addition, full store and forward switching ensures data integrity and
prevents error conditions from being generated throughout the network.