T

T

C

9

0

2

1

T

C

9

0

2

0

e-mail:service@tmi.com.tw

website:www.tmi.com.tw

Interrupt Coalescence

While receiving frames, the TC9021/TC9020 can be configured to operate with adaptive interrupts to maximize the

host CPU efficiency. For heavy traffic, the TC9021/TC9020 issues a single interrupt for a series of back-to-back

receive frames which reduces CPU interrupt overhead significantly. For light traffic, the TC9021/TC902 issues an

interrupt when frame arrives to minimize the latency. On the transmit side, the frequency of interrupt is

programmable on a frame by frame basis. An “interrupt-less” transmit operation is provided to further reduce

interrupt to the host CPU.

IEEE 802.1p Priority Support

The TC9021/TC9020 supports transmit packet priority queuing, allowing the host to insert higher priority frames

into the front of the transmit queue for lower latency transfer. The TC9021/TC9020 also examines the IEEE standard

priority field of appropriately tagged receive frames and generates a host system interrupt according to a user

programmable priority threshold. This mechanism provides immediate notification to the host of high priority frame

arrivals.

IEEE 802.1Q VLAN Support

The TC9021/TC9020 can be programmed to insert VLAN tags automatically into outgoing frames on a global or

individual frame basis. On the receive side, the TC9021/TC9020 examines all incoming frames for 802.1Q compliant

VLAN tags. Once a VLAN tag is detected, the TC9021/TC9020 will optionally remove the VLAN tag before uploading

the frame into system memory. The TC9021/TC9020 also offers a receive filtering mode based on either a VLAN ID

exact or hashed match.

Jumbo Frame Support

The TC9021/TC9020 can be configured to use a maximum frame size of up to 9,018 bytes. This Jumbo Frame size

reduces packet-processing overhead on the host CPU as much as 85 percent. In systems that are CPU bound, it can

provide for layer 4 throughput increases of greater than 100%.

Network Management

The TC9021/TC9020 implements management statistic counters based on IEEE 802.3 MIB and IETF RMON statistic

register sets, providing a powerful management capability

Power Management

The TC9021/TC9020 is fully compliant with PCI Power Management v1.1 and ACPI Power Management

specification v1.0. It implements multiple wakeup events including Wakeup packets, Magic Packets, and Link Status

change. The TC9021/TC9020 also supports legacy Wake-On-LAN and Magic packet power management

mechanisms.