T71L6816A Taiwan Memory Technology, T71L6816A Datasheet - Page 10

• Manufacturer Part Number: T71L6816A
• Description: Sixteen-port 10/100 Switch
• Manufacturer: Taiwan Memory Technology

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By set the “FlowCtrl_En” in EEPROM for any specific port, The T71L6816A will check the
DA field of every incoming 64 -byte packet from the specific port to see if it is the address
“0x0180c2000001” or not. If it is the legal pause frame, the T71L6816A will hold the
data forwarding to the specific port for a time period depended on the value defined in
the pause timer field, otherwise the pause frame will be dropped if its format is illegal.
Also, if fl ow control is enabled for one port, the T71L6816A will automatically send out
one pause frame with pause timer “0xffff” to that port if the free pages of T71L6816A
drop below the low watermark.
3.12.1 Flow Control in Half Duplex Mode
The T71L6816A support the back pressure congestion control scheme in half duplex mode
with two different way, force-collision and force-carrier.
By set the “BackPress_En” in EEPROM, the T71L6816A will enable the back -pressure scheme
while the free pages of T71L6816A drop belo w the low watermark. If the internal resources
is low, The T71L6816A will force collision on the incoming packet if “BackMode” is set
to be ‘0’ and will occupy the carrier signal to stop packets receiving if “BackMode” is
set to be ‘1’.
3.13 Port-based VLAN
Sometimes users want to divide some segments on their network for some reasons such as
security or traffic. The T71L6816A provide the port -based VLAN(Virtual LAN) scheme to
divide the attached devices into maximum three different segments defined by con figuring
the EEPROM. Once different VLANs
within the same VLAN segment and prevent them from flowing into ports not belong to the
same VLAN. So, users can isolate traffics between any two different VLANs but the common
port.
The T71L6816A use the VLAN_1/VLAN_2 fields defined in EEPROM to determine the effective
VLANs. That is, if any bit is set to ‘1’ in VLAN_1/VLAN_2, the corresponding port is
belonging to the VLAN group 1 or 2 and all other ports without inclusion in VLAN_1 or
VLAN_2, if exists, will form the third VLAN group. If one port belongs to more than one
VLAN group, it can receive all of the traffic within those VLAN groups.
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Change to products or specifications without notice.
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were defined, the T71L6816A will forward the traffic
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P. 10
Preliminary T71L6816A
Publication Date:Jun. 2001
Revision:0.A