Cabletron Systems 9A426-01, Руководство пользователя

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3-5
Operation
INB Network Interface Block
The 9A426-01 Module’s INB Interface includes a Network Interface Block
(INB NIB). Canonical frames processed by the module’s SmartSwitch ASIC core
that are destined for the INB on the SmartSwitch 9000s’ backplane are converted
by the INB NIB into fixed length data blocks and then transmitted on the INB.
Conversely, data blocks received by the module from the INB are converted by
the INB NIB into canonical frames and forwarded to the SmartSwitch ASIC core
for processing.
FDDI Network Interface Block
The 9A426-01 Module’s FNB Interface includes an FDDI Network Interface Block
(FNIB). Canonical frames processed by the module’s SmartSwitch ASIC core that
are destined for one of the two FNBs on the SmartSwitch 9000s’ backplane are
first converted by the FNIB into FDDI packets and then transmitted onto the
selected FNB. Conversely, FDDI packets received by the module from an FNB are
converted by the FNIB into canonical frames and forwarded to the SmartSwitch
ASIC core for processing.
ATM Network Interface Block
The 9A426-01 Module’s ATM Interface includes an ATM Network Interface Block
(ANIB). ATM cells that enter the module’s front panel port are converted by the
module’s ANIB into canonical frames. The ANIB uses hardware (ASICs) to
perform its conversions. The canonical frames are then forwarded to the
SmartSwitch ASIC core (a separate set of ASICs on the module) for processing.
Conversely, canonical frames processed by the module’s SmartSwitch ASIC core
that are destined for front panel ATM ports are converted via ASICs in the ANIB
into fixed length (53 byte) ATM cells and then transmitted to the ports. The ANIB
uses encapsulation techniques in accordance with the ATM Forum LAN
Emulation Specification. These techniques include the capability to encapsulate
ATM data in either Ethernet or Token Ring frame formats.