DM9302 datasheet(52/64 Pages) DAVICOM

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DM9302

10/100Mbps Ethernet Fiber/Twisted Pair Media Converter with Local bus

Preliminary datasheet

DM9302-15-DS-P01

July 30, 2009

Strict Priority Queuing. Weighted Round-Robin

Queuing (WRR) based on their priority and queue

weight. Queues with larger weights get more service

than smaller. This mechanism can get highly efficient

bandwidth and smooth the traffic. Strict Priority

Queuing (SPQ) based on priority only. The Packet on

the highest priority queue is transmitted first. The next

highest-priority queue is work until last queue empties,

and so on. This feature can be set in bit 5 of register

6Dh.

9.2.14.1 Port-Based Priority

Port based priority is the simplest scheme and as

default. Each port has a 2-bit priority value as index

for splitting ingress packets to the corresponding

transmit queue. This value can be set in bit 0 and 1 of

9.2.14.2 802.1p-Based Priority

802.1p priority can be disabled by bit 2 of register

6Dh, it is enabled by default.

The DM9302 extracts 3-bit priority field from

received packet with 802.1p VLAN tag, and maps this

field against VLAN Priority Map Registers (D0h~D1h)

to determine which transmit queue is designated. The

VLAN Priority Map is programmable.

9.2.14.3 DiffServ-Based Priority

DiffServ based priority uses the most significant

6-bit of the ToS field in standard IPv4 header, and

maps this field against ToS Priority Map Registers

(C0h~CFh) to determine which transmit queue is

designated. The ToS Priority Map is programmable

too. In addition, User can only refer to most

significant 3-bit of the ToS field optionally, see bit 7 of

DM9302 датащи(PDF) 52 Page - Davicom Semiconductor, Inc.