VT6516 ETC, VT6516 Datasheet - Page 34

• Manufacturer Part Number: VT6516
• Description: 16/12 PORT 10/1000 ASE T/TX
• Manufacturer: ETC

When request transfer to or from SDRAM through scheduler, the input control need to derive each burst
starting address to bank0 or bank1 information for scheduler to utilize SDRAM bandwidth efficiently. When
input FIFO is filled to 12x64 or page boundary or end of frame, the input port control will request DRAM access
to write packet. Input FIFO size is 64 bits by 24.
After receiving the grant of queueing (cut-through or store-and-forward), even the bad packet has to be
forwarded.
While cut-through, the input control will request the grant of cut-through counter bus for passing the cut
through packet count from input port to output port as the whole packet has received.
server ports configuration by set the register of server port mask(14A0H~14A1H), and server ports only enable
after the VLAN enabled. The multicast or broadcast frames received from one VLAN group will forward to any
server ports and only forward to the ports with same VID.
4.3 Network Management Features
4.2.1 Cross VLAN Server Port support
Flow control
the dedicated register XXXX, Register-XXXX is used to specify the upper and lower thresholds of reserved
buffer slot for whole switch.
threshold and the permanent buffer has been used up, a flow control with a predefined pause time value will
be sent to the source port to stop the input traffic. If flow control mechanism is not enabled, the public buffer
will exhausted so that the further incoming frames will be dropped.
and the permanent buffer has been used up, the port will perform back-pressure based flow control by
sending a jam pattern on each incoming frame. If backpressure flow control of the port is not enable, the
frame will be dropped.
Sniffer port
be set for any individual port of sixteen ports. And each sniffer port can set to monitor the traffic coming
from any others fifteen port(monitor port). Any packets sent to the monitor ports or transmitted out of
monitor port will be forwarded to sniffer port.
Spanning tree support
frames from the CPU port having a DA value equal to reserved Bridge Management Group Address for
BPDU will be forwarded to the port specified by the CPU. Frames from other port with a DA equal to
reserved Bridge Management Group Address for BPDU will be forwarded to the CPU port.
The VT6516 support Cross VLAN server port configuration, the following illation show the sample of
The flow control activity is triggered when the buffer utilization exceeds certain thresholds specified by
Under full-duplex mode operation, if the buffer utilization of whole switch has exceeded the upper
Under half duplex operation, if the buffer utilization of whole switch has exceeded the upper threshold
The VT6516 support sniffer function for user to monitor the network traffic. The Sniffer port enable can
The VT6516 support the spanning tree protocol (STP). When spanning tree protocol support is enabled,
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Preliminary VT6516 Datarsheet