3Com EtherLink 3C985B-SX Installation And User Manual - page 12
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About the NIC
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Standard Ethernet frame size (up to 1,518 bytes)
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Supports 32 multicast addresses
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Adaptive interrupt frequency (maximizes network throughput; adapts to traffic load)
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Dual DMA channels
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33/66 MHz, 32-bit or 64-bit PCI bus master with adaptive DMA
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PCI Local Bus Rev 2.2 compliant: 17.3 cm x 10.7 cm (6.8" x 4.2")
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ASIC with on-chip MAC and dual RISC processors
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Universal dual voltage signaling (3.3V and 5V)
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Status LEDs
Key Protocols and Interfaces
Each NIC is interoperable with existing Ethernet equipment assuming standard Ethernet minimum and maximum
frame size (64 to 1518 bytes), frame format, and compliance with the following standards and protocols:
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Gigabit Ethernet (IEEE 802.3-1999)
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Logical Link Control (IEEE 802.2)
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Flow Control (IEEE 802.3x)
Adaptive Interrupt Frequency
The NIC driver intelligently adjusts host interrupt frequency based on traffic conditions, in order to increase overall
application throughput. In light traffic, the NIC driver interrupts the host for each received packet, minimizing
latency. When traffic is heavy, the NIC issues one host interrupt for multiple, back-to-back incoming packets,
preserving host CPU cycles.
Dual DMA Channels
The PCI interface on each of the 3Com Gigabit EtherLink Server Adapters contains two independent DMA
channels for simultaneous read and write operations.
32-bit or 64-bit PCI Bus Master
Compliant with PCI Local Bus Rev 2.1, the PCI interface on each of the 3Com Gigabit EtherLink Server Adapters is
compatible with both 32-bit and 64-bit PCI buses. As a bus master, each NIC requests access to the PCI bus
instead of waiting to be polled.
ASIC with Embedded RISC Processor
The core control for the NIC resides in a tightly integrated, high-performance ASIC. The ASIC includes dual RISC
processors. This provides the flexibility to add new features to the card and adapt it to future network
requirements via software download. This also enables the NIC drivers to exploit the built-in host off-load
functions on the NIC as host operating systems are enhanced to take advantage of these functions.