User`s guide

3-3
Operation
INB Interface
Each module that attaches to the INB has an INB Network Interface Block (NIB).
The INB NIB converts canonical frames to fixed length data blocks for
transmission onto the INB. For data blocks received from the INB, the INB NIB
reassembles the data blocks received from the INB back into canonical frames for
transmission to the SmartSwitch ASIC then from the SmartSwitch ASIC to the
front panel ports.
SecureFast Switch
The SmartSwitch ASIC is a hardware-based switch design that is the key building
block of the SmartSwitch 9000. All filtering/forwarding decisions are made in
hardware as opposed to software, as in traditional switches. This custom
hardware allows the SmartSwitch ASIC to process over 750K frames per second.
The SmartSwitch ASIC is designed to support up to 64 ports that are 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 in traditional switch mode, it makes
filtering/forwarding decisions based on Destination Address (DA), with
standard IEEE 802.1d learning.
• SecureFast Switch (SFS) - When operating in SecureFast Switch mode, all
filtering/forwarding decisions are made based on a DA-SA pair and its receive
port. These DA-SA pairs with the associated receive port are programmed into
the switch using Cabletron’s SecureFast Virtual Network Server (SecureFast
VNS). This provides the network administrator with the ultimate network
security without the performance degradation found when using routers or
traditional switches with special filtering capabilities.
The SmartSwitch 9000 hub can support modules operating in traditional switch
mode and SecureFast Switch mode simultaneously providing security
when/where needed and ease of configuration where security is not required.