Cabletron Systems 9E428-36, Руководство пользователя

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3-3
Operation
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 an SFS switch, the SmartSwitch
ASIC makes all filtering/forwarding decisions based on a Destination
Address-Source Address (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 bridges
with special filtering capabilities. The SmartSwitch 9000 hub can support
individual modules operating in the traditional switch mode or SFS mode
providing security where needed.
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.
The Host engine sends and receives packets via the CPU’s SmartSwitch ASIC
Interface. This allows the bridge to perform spanning tree protocol and other
bridging functions. The SMB Interfaces provide communication to the Host
Engine for management functions.
INB NIB
Each module that attaches to the Internal Network Bus (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.