dm9302 Davicom Semiconductor, Inc., dm9302 Datasheet - Page 51

• Manufacturer Part Number: dm9302
• Description: 10/100mbps Ethernet Fiber/twisted Pair Media Converter With Local Bus
• Manufacturer: Davicom Semiconductor, Inc.

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.
VLAN groups, as specified in bit 1 of register 53h. It’s
obvious that the tagged packets can be assigned to
several different VLANs which are determined
according to the VID inside the VLAN Tag. Therefore,
the operation is similar to port-based VLAN. The
DM9302 used LSB 4-bytes VID of received packet
with VLAN tag and VLAN Group Mapping Register
(B0h~BFh) to configure the VLAN partition. If the
destination port of received packet is not same VLAN
group with received port, it will be discarded.
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:
Un-tag port.
without modification.
Preliminary datasheet
DM9302-15-DS-P01
July 30, 2009
9.2.13 VLAN Support
9.2.13.1 Port-Based VLAN
9.2.13.3 Tag/Untag
The DM9302 supports port-based VLAN as
The DM9302 also supports 16 802.1Q-based
User can define each port as Tag port or Un-tag
(1). Receive untagged packet and forward to
Received packet will forward to destination port
(2). Receive tagged packet and forward to Un-tag
Dest.
Dest.
Src.
Src.
0x8100
2 bytes
10/100Mbps Ethernet Fiber/Twisted Pair Media Converter with Local bus
TPID
Length/Type
TCI
Priority
3 bits
Length / Type
1 bits
CFI
VLAN uses an extra tag to identify the VLAN
membership
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).
port.
packet and recalculate CRC before sending it out.
port.
untagged packet enters the port, and recalculate
CRC before delivering it.
port.
without modification.
mechanism for multimedia communication such as
VoIP and video conferencing.
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.
algorithms: Weighted Round-Robin Queuing and
9.2.13.2 802.1Q-Based VLAN
9.2.14 Priority Support
Regarding IEEE 802.1Q standard, Tag-based
(3). Receive untagged packet and forward to Tag
(4). Receive tagged packet and forward to Tag
Received packet will forward to destination port
The DM9302 supports Quality of Service (QoS)
The DM9302 provides three priority classifications:
The DM9302 provides two packet scheduling
VID
12 bits
The DM9302 will remove the tag from the
The DM9302 will insert the PVID tag when an
Data
of
a
Data
frame
across
DM9302
Standard frame
Tagged frame
VLAN-aware
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