KS8993F Micrel Inc, KS8993F Datasheet - Page 30

• Manufacturer Part Number: KS8993F
• Description: IC CONV MED 10/100 3PORT 128PQFP
• Manufacturer: Micrel Inc

Specifications of KS8993F

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 128-MQFP, 128-PQFP
• Number Of Primary Switch Ports: 3
• Internal Memory Buffer Size: 32
• Operating Supply Voltage (typ): 1.8/2.5/3.3V
• Fiber Support: Yes
• Integrated Led Drivers: Yes
• Phy/transceiver Interface: MII/SNI
• Power Supply Type: Analog/Digital
• Package Type: PQFP
• Data Rate (typ): 10/100Mbps
• Vlan Support: Yes
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Pin Count: 128
• Mounting: Surface Mount
• Jtag Support: No
• Operating Supply Voltage (max): 1.89/3.465V
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: KS8993F-EVAL - EVAL KIT EXPERIMENTAL KS8993F
• Lead Free Status / RoHS Status: Not Compliant, Lead free / RoHS Compliant

2.4.2 Learning
The internal look up engine will update its table with a new entry if the following conditions are met:
The look up engine will insert the qualified Source Address into the table, along with the port number and time stamp.
If the table is full, the last entry of the table will be deleted to make room for the new entry.
2.4.3 Migration
The internal look up engine also monitors whether a station has moved. If so, it will update the table accordingly.
Migration happens when the following conditions are met:
The look up engine will update the existing record in the table with the new source port information.
2.4.4 Aging
The look up engine will update the time stamp information of a record whenever the corresponding Source Address
appears. The time stamp is used in the aging process. If a record is not updated for a period of time, the look up
engine will remove the record from the table. The look up engine constantly performs the aging process and will
continuously remove aging records. The aging period is 200 seconds. This feature can be enabled or disabled
through Global Register 3 (0x03).
2.4.5 Forwarding
The KS8993F will forward packets using an algorithm that is depicted in the following flowcharts.
one of the forwarding algorithm where the search engine looks up the VLAN ID, static table, and dynamic table for the
destination address, and comes up with “port to forward 1” (PTF1). PTF1 is then further modified by Spanning Tree,
Port Mirroring and Port VLAN processes to come up with “port to forward 2” (PTF2) as shown in
where the packet will be sent.
Micrel, Inc.
June 2009
1. The received packet's Source Address (SA) does not exist in the look up table.
2. The received packet is good, has no receiving errors, and is of legal length.
1. The received packet's Source Address (SA) is in the table but the associated source port information is
2. The received packet is good, has no receiving errors, and is of legal length.
different.
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Figure 4
Figure 5
or [phone]
M9999-062509
KS8993F/FL
shows stage
. PTF2 is