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Operation
All data packets destined for a front panel port, the INB, or the i960 are converted
into the canonical format before forwarding to the SmartSwitch ASIC. Network
Interface Blocks (NIBS) check for valid data packets entering the system. If an
errored data packet is found, the SmartSwitch ASIC flags the error and does not
forward the errored data packet to any outbound ports. Once in this common
format, the SmartSwitch ASIC decides (from header information) the port
destination of data packets. Data packets are then converted from the canonical
format to the proper format for the interface destination, whether it is a front
panel port or connection to the INB.
ENIB
The Ethernet Network Interface Block (ENIB) converts Ethernet data packets
received through front panel ports into a common canonical format that allows
the SmartSwitch ASIC Engine to determine the proper destination port. The ENIB
also converts data packets from the common canonical format back to Ethernet
data packets for transmission out front panel ports.
SmartSwitch ASIC
The SmartSwitch ASIC is a hardware-based switch design that is the key building
block of the SmartSwitch 9000 hub. The SmartSwitch ASIC makes all filtering/
forwarding decisions in custom hardware, as opposed to software like in
traditional bridges. This custom hardware enables the SmartSwitch ASIC to
process over 750K frames per second. The SmartSwitch ASIC is designed to
support up to 64 ports, shared between the host processor, the INB backplane,
and LAN/WAN interfaces on the front panel of SmartSwitch 9000 modules. The
SmartSwitch ASIC can operate in two modes:
• Traditional Switch - When operating as a traditional switch, the SmartSwitch
ASIC makes filtering/ forwarding decisions based on Destination Address
(DA), with standard IEEE 802.1d learning.
• SecureFast Switch (SFS) - When operating as a SecureFast Switch switch, all
filtering/forwarding decisions are made based on a Destination Address-
Source Address (DA-SA) pair and the associated receive/transmit port to
deliver virtual circuit capabilities using traditional packet technologies
i960 Core
The i960 core provides the SNMP protocol stacks to support industry standard
MIBs. Additionally, Cabletron enterprise extension MIBs are supported for each
media type. Advanced management services, such as the Distributed LAN
Monitor, telnet and network address to MAC address mapping, are also provided
by the i960 core.
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