ACD82224 Datasheet, PDF (15/77 Pages) List of Unclassifed Manufacturers – 24 Ports 10/100 Fast Ethernet Switch

VLAN. Frames from the source port will only be forwarded to destination ports within the same
VLAN domain. A broadcast/multicast frame will be forwarded to all ports within the VLAN(s) of
the source port. A unicast frame will be forwarded to the destination port only if the destination
port is in the same VLAN as the source port. Otherwise, the frame will be treated as a frame with
unknown DA. Each VLAN can be assigned with a dedicated dumping port. Multiple VLANs can
also share a dumping port. Unicast frames with unknown destination addresses will be forwarded
to the dumping port of the source port VLAN.
A Leaky VLAN can be enabled by setting the corresponding bit in the system configuration
register (bit-8 of register-16). A VLAN becomes a broadcast domain. Each broadcast domain
VLAN can still be assigned with a dedicated dumping port.
Port Trunking
Security VLAN can be disabled by setting the corresponding bit in the system configuration
register (bit 8 of Register 16, see Table 7.15). When security VLAN is disabled, each VLAN
becomes a Leaky VLAN and is equivalent to a broadcast domain. Four dumping ports of four
different Leaky VLANs can be grouped together to form a fat pipe uplink (for example, port 0,
port 1, port 2, and port 3 can be grouped to form an 800 Mbps uplink port). When multiple
dumping ports are grouped as a single pipe, each port has to be assigned to one and only one
VLAN. A unicast frame with a matched DA will be forwarded to any destination port, even if the
VLAN ID is different. All unmatched DA packets will be forwarded to the designated dumping
port of the source port VLAN. The broadcast and multicast packets will only be forwarded to the
ports in the same VLAN of the source port. Therefore, a 200 to 800 Mbps pipe can be
established by carefully grouping the dumping ports, and directly connecting with any
segmentation switches.
Dumping Port
Each VLAN can be assigned with a dedicated dumping port. Multiple VLANs can share a single
dumping port. Each dumping port can be used for an up-link connection or for a DTE connection.
That is, the dumping port can be used to connect the switch with a computer repeater hub, a
workgroup switch, a router, or any type of interconnection device compliant with IEEE 802.3
standard. ACD82224 will direct the following frames to the dumping port:
(1) A frame with unknown unicast destination address.
(2) A frame with a unicast destination address that does not match with any port’s source
address within the VLAN of the source port.
(3) A frame with a broadcast/multicast destination address (See Spanning Tree Support).
If the device is configured to work under Flood-to-All-Port mode (Register 25, bit 12), the frames
with unknown DA will be forwarded to all the ports in the VLAN(s) of the source port except the
source port itself.
Mode of Operation
Each port can be configured or auto-sensed to work under either half-duplex or full-duplex mode.
Under half duplex mode, the CSMA/CD will be enforced, and the flow control is achieved
through backpressure. Under full duplex mode, the receiving process and the transmitting
process of the port are independent, and the flow control is done by pause-frame based flow
control scheme specified by the IEEE 802.3x.
Page 14 of 77
Confidential
Page 14