AL103 Revision 1.0
1. AL103 Overview
The AL103 provides eight 10/100 Mbit/s Ethernet ports. Each port supports both 10 and 100
Mbit/s data rate. The operation mode is auto-negotiated by the PHY. All ports are full-duplex
capable. The device also supports VLAN for workgroup and segment switching applications.
The AL103 also supports trunking applications. The chip provides two optional load-balancing
schemes, explicit and dynamic. With trunking, it is possible to group up to four full-duplex links
together to form a single 800 Mbit/s link.
Data received from the MAC interface is stored in the external memory buffer. The AL103 utilizes
cost effective SGRAM to provide 8-Mbit or 16-Mbit of buffer memory.
During transmission, the data is obtained from the buffer memory and routed to the destination
port’s output buffer. If a collision occurs in half-duplex operation, the MAC control will back off
and retransmit in accordance to the IEEE 802.3 specification.
The AL103 provides two flow control methods. For half-duplex operations, an optional jamming
based flow control (known as backpressure) is available to prevent loss of data. With this method of
flow control, the switch will generate a jam signal when the receive buffer is full and the sending
station will not start to transmit until the line is clear. In the full-duplex mode, the AL103 utilizes
IEEE 802.3x as the flow control mechanism.
All ports support multiple MAC addresses. The switch chip supports 1K MAC addresses internally.
These MAC addresses are shared among all eight ports.
The initialization and configuration of the switch is programmed by an external EEPROM. Field
reconfiguration can be achieved by using a parallel interface to reprogram the EEPROM.
The AL103 also supports port based VLAN. The VLAN register set is used to configure the
destination ports for multicast and broadcast frames.
The device also provides two levels of security for intrusion protection. Security can be
implemented on a per port basis.
The AL103 operates only in the store and forward mode. The entire frame is checked for error and
any frames with errors are automatically filtered and will not be forwarded to the destination port.
The AL103 also features port monitoring and broadcast storm throttling.
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