DM8603EP DAVICOM [Davicom Semiconductor, Inc.], DM8603EP Datasheet - Page 77

• Manufacturer Part Number: DM8603EP
• Description: 10/100 Mbps 3-port Ethernet Switch Controller with MII / RMII Interface
• Manufacturer: DAVICOM [Davicom Semiconductor, Inc.]

9.2.15 Priority Support
and video conferencing.
See next section for more detail. The DM8603 offers four level queues for transmit on each port.
Priority Queuing (SPQ). WRR based on their priority and queue weight, the priority weight 8, 4, 2 and 1 for
queue 3, 2, 1, and 0 respectively by default. 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 packets 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 REG 08h/09h/0Ah.17h.[5].
9.2.15.1
splitting ingress packets to the corresponding transmit queue. This value can be set in REG
08h/09h/0Ah.17h.[1:0].
9.2.15.2
against VLAN Priority Map Registers (REG 10h.17h) to determine which transmit queue is designated. The
VLAN Priority Map is programmable.
9.2.15.3
this field against ToS Priority Map Registers (REG 10h.18h~1Fh) 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 REG 11h.1Eh.[7].
Preliminary datasheet
DM8603-12-DS-P01
November 8, 2010
The DM8603 supports Quality of Service (QoS) mechanism for multimedia communication such as VoIP
The DM8603 provides three priority classifications: Port-based, 802.1p-based and DiffServ-based priority.
The DM8603 provides two packet scheduling algorithms: Weighted Round Robin (WRR) and Strict
Port based priority is the simplest scheme and as default. Each port has a 2-bit priority value as index for
The DM8603 extracts 3-bit priority field from received packet with 802.1p VLAN tag, and maps this field
DiffServ based priority uses the most significant 6-bit of the ToS field in standard IPv4 header, and maps
Port-Based Priority
802.1p-Based Priority
DiffServ-Based Priority
10/100 Mbps 3-port Ethernet Switch Controller with MII / RMII Interface
DM8603
77