DM9302 View Datasheet(PDF) - Davicom Semiconductor, Inc.

Part Name

Description

Manufacturer

DM9302

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

Davicom Semiconductor, Inc. 

DM9302

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

9.2.13 VLAN Support

9.2.13.1 Port-Based VLAN

The DM9302 supports port-based VLAN as

default, up to 16 groups. Each port has a default VID

called PVID (Port VID, see register 6Fh). The

DM9302 used LSB 4-bytes of PVID as index and

mapped to register B0h~BFh, to define the VLAN

groups.

9.2.13.2 802.1Q-Based VLAN

Regarding IEEE 802.1Q standard, Tag-based

VLAN uses an extra tag to identify the VLAN

membership of a frame across VLAN-aware

switch/router. A tagged frame is four bytes longer

than an untagged frame and contains two bytes of

TPID (Tag Protocol Identifier) and two bytes of TCI

(Tag Control Information).

Dest.

Src. Length/Type

Data

Standard frame

Dest.

Src. TPID TCI Length / Type

Data

Tagged frame

0x8100

2 bytes

Priority CFI VID

3 bits

1 bits 12 bits

port.

The DM9302 also supports 16 802.1Q-based

The DM9302 will remove the tag from the

VLAN groups, as specified in bit 1 of register 53h. It’s packet and recalculate CRC before sending it out.

obvious that the tagged packets can be assigned to

(3). Receive untagged packet and forward to Tag

several different VLANs which are determined port.

according to the VID inside the VLAN Tag. Therefore,

The DM9302 will insert the PVID tag when an

the operation is similar to port-based VLAN. The untagged packet enters the port, and recalculate

DM9302 used LSB 4-bytes VID of received packet CRC before delivering it.

with VLAN tag and VLAN Group Mapping Register

(4). Receive tagged packet and forward to Tag

(B0h~BFh) to configure the VLAN partition. If the port.

destination port of received packet is not same VLAN

Received packet will forward to destination port

group with received port, it will be discarded.

without modification.

9.2.13.3 Tag/Untag

User can define each port as Tag port or Un-tag

port by bit 7 of register 6Dh in 802.1Q-based VLAN

mode. The operation of Tag and Un-tag can explain

as below conditions:

(1). Receive untagged packet and forward to

Un-tag port.

Received packet will forward to destination port

without modification.

(2). Receive tagged packet and forward to Un-tag

9.2.14 Priority Support

The DM9302 supports Quality of Service (QoS)

mechanism for multimedia communication such as

VoIP and video conferencing.

The DM9302 provides three priority classifications:

Port-based, 802.1p-based and DiffServ-based priority.

See next section for more detail. The DM9302 offers

four level queues for transmit on per-port based.

The DM9302 provides two packet scheduling

algorithms: Weighted Round-Robin Queuing and

Preliminary datasheet

51

DM9302-15-DS-P01

July 30, 2009

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