IP1726LF-DS-R01 datasheet(15/33 Pages) ETC2

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IP1726 LF

Preliminary Data Sheet

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Jun 15, 2005

IP1726 LF-DS-R06

The first in first out method will override the CoS setting and is not recommended when the CoS function

is enabled. When the strict priority is enabled, the data packets stored in low priority queue will not be

sent out until all data packets in high priority queue are sent out. When the weighted round robin function

is enabled, the IP1726 LF will send the data packet in an order switching between high priority queue

and low priority queue with ratio defined by pin 109,110 setting (without EEPROM) or Register 2CH(with

EEPROM/CPU)

4.2.8 Broadcast Storm Control

To prevent the broadcast storm, the IP1726 LF implement a broadcast storm control mechanism. When

this function is enabled, the IP1726 LF will monitor the number of the broadcast packet and take the

proper action to prevent the broadcast packet from reaching the pre-defined buffer level. The behavior of

handling the broadcast packet is dependent on the operating mode of the IP1726 LF.

Drop the broadcast packet when the flow control is disabled

4.2.9 Handling the Higher Layer Protocol

The IP1726 LF can handle two categories of data packet, the configuration related and the TCP/IP

related. The configuration-related protocol concerns the network configuration such as, the VLAN group,

the link aggregation and the spanning tree. Unlike the configuration-related protocol, the TCP/IP related

data has nothing to do with the network.

Four forwarding schemes can be selected to handle the protocol mentioned above, dropping the packet,

sending to a specified port(commonly connected to a CPU), and broadcasting to all ports. The protocol

handling scheme is programmed by writing the corresponding bit in register 02H.

4.2.10 Port Security

In some cases, it is required to disable the address learning mechanism and specify the MAC address.

This function is useful for the application which will prevent the unauthorized user from intruding the

network. The typical application is the Ethernet to the Home(ETTH).

Programming the registers 31H and 32H will enable/disable the address learning function. The LSB of

the register 31H corresponds port 1.

The register 33H handles the forwarding rule. A data packet will be either forwarded or dropped

depending on the setting of this register.

IP1726LF-DS-R01 数据表(PDF) 15 Page - List of Unclassifed Manufacturers