Texas Instruments THUNDER TNETX3270 - Manual (Page 2)

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
2
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
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.