The RTL8304E-CG is a 4-port Fast Ethernet switch controller that integrates memory, four MACs, and two physical layer transceivers for 10Base-T and 100Base-TX operation into a single chip.
The RTL8304E supports two MII/RMII interface for external devices to connect to the 3rd and 4th MACs. The external device could be a routing engine, HomePNA, HomePlug, or another processor depending on the application.
The RTL8304E supports several advanced QoS functions with four-level priority queues to improve multimedia or real-time networking applications, including:
· Multi-priority assignment
· Differential queue weight
· Port-based and queue-based rate limitation
· 16-entry ACL for advanced packet control application
For multicast applications, the RTL8304E supports IGMPv1/v2/v3 and MLDv1/v2 snooping.
To meet security and management requirements, the RTL8304E supports IEEE 802.1x Port-based/MAC-based Access Control, MAC Address Limits, Port Isolation, Port Mirroring, and also supports five 32-bit MIB Counters on each port.
The RTL8304E supports 16 VLAN groups. These can be configured as port-based VLANs and/or 802.1Q tag-based VLANs. The RTL8304E also supports VLAN translation and QinQ.
The RTL8304E contains a 2K-entry address lookup table. Two 4-way associative hash algorithms avoid hash collisions and maintain forwarding performance. The 2K-entry table provides read/write access from the SMI interface, and each of the entries can be configured as a static entry that does not automatically age out and can only be controlled by the external management processor. For IGMP/MLD snooping application, each of the 2K entries can be configured as a multicast entry that indicates the matched packets will be forwarded to specific multi ports. For IEEE 802.1x application, each of the 2K entries can be configured as an authorized or unauthorized entry.
Maximum packet length can be 2047 bytes. Two types of independent storm filter are provided to filter packet storms, and an intelligent switch engine prevents Head-of-Line blocking problems. The filtering function is supported for IEEE 802.1D specified reserved multicast addresses (01-80-C2-00-00-02 and 01-80-C2-00-00-04 to 01-80-C2-00-00-0F).
The RTL8304E provides flexible LED functions for diagnostics. An externally managed processor can control the LEDs via SMI.
The RTL8304E supports Realtek’s Green Ethernet power saving mode, as well as Energy-Efficient Ethernet mode (EEE; defined in IEEE 802.3az) to minimize system power consumption. When the Green Ethernet Feature is enabled, the RTL8304E provides link-on and dynamic detection of cable length and dynamic adjustment of power required for the detected cable length. This feature provides high performance with minimum power consumption.
Energy-Efficient Ethernet (EEE) supports Low Power Idle Mode. When Low Power Idle Mode is enabled, systems on both sides of the link can disable portions of the functionality and save power during periods of low link utilization.
For whole system power saving, the RTL8304E supports the Wake-on-LAN (WOL) function and provides control signals to manage the system power based on the port linkage and the traffic loading of the CPU port.
To simplify the peripheral power circuit, the RTL8304E can use a low-cost PNP transistor to generate 1.8V from a 3.3V power supply.