Texas Instruments TNETX3270 With 24 10-MBIT/S Ports and 3 10-/100-MBIT/S Ports, Description

TNETX3270

ThunderSWITCH 24/3 ETHERNET SWITCH

WITH 24 10-MBIT/S PORTS AND 3 10-/100-MBIT/S PORTS

SPWS043B ± NOVEMBER 1997 ± REVISED APRIL 1999

description

The TNETX3270 provides highly integrated switching solutions that allow network designers to lower overall system costs. Based on Texas Instruments (TI ) ThunderSWITCH architecture, the TNETX3270 design integrates 24 full-duplex 10-Mbit/s ports and 3 full-duplex 10-/100-Mbit/s ports, as well as an address-lookup engine, all in a single 240-pin package. All ports on the TNETX3270 are designed to support multiple addresses, cut-through or store-and-forward modes of operation, and VLAN. The 10-/100-Mbit/s ports have media-independent interface (MII)-compatible interfaces and can be configured to work as MII uplinks to high-speed switching fabrics. All three of the 10-/100-Mbit/s ports can be logically combined into a single high-performance uplink channel that can be used to provide up to 600-Mbit/s switch-to-switch connections.

The TNETX3270 incorporates an internal content-addressable memory (CAM) capable of supporting 2,048 end stations from a single switch. In addition, the device supports 32 user-configurable VLAN-broadcast domains (IEEE Std 802.1Q), which allows IEEE Std 802.1P priority support interoperability, IEEE Std 802.3X full-duplex flow control, and a collision-based flow-control scheme. The TNETX3270 also integrates an EEPROM interface that allows the device to be initialized and configured without the added expense of a CPU. All of these features on chip greatly reduce the number of external components required to build a switch.

The internal address-lookup engine (IALE) supports up to 2K unicast/multicast and broadcast addresses and up to 32 IEEE Std 802.1Q VLANs. For interoperability, each port can be programmed as an access port or non-access port to recognize VLAN tags and transmit frames with VLAN tags to other systems that support VLAN tagging. The IALE performs destination- and source-address comparisons and forwards unknown source- and destination-address packets to ports specified via programmable masks.

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