Apparatus and method for cascading multiple network switch devices
AssigneeAdvanced Micro Devices, Inc.
InventorsIan Lam, Eric Tsin-Ho Leung
Life of this patent
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Abstract
An arrangement and method of operating a network switch arrangement in a packet switched network connects a plurality of multiport network switches which is in a circular, serial manner so that data is transferable between the network switches only unidirectionally. When it is determined that data is to be transmitted from a first network switch to a port in a second network switch, the data is transmitted over an expansion bus from the first network switch to the second network switch in a continuous stream of data bursts. This extremely fast transmission between the networks switches allows multiple multiport network switches to be cascaded together to effectively form a single network switch with at least twice as many ports.
Claims31
A packet switched network switch arrangement comprising:
- first and second network switches configured to switch packets;
- a data connection between the first and second network switches, the data connection being a unidirectional transmission medium;
- and
- a controller in each of the first and second network switches that controls transmission of data from the first network switch to the second network switch in a continuous stream of data bursts, wherein
- each of the first and second network switches includes an expansion port that comprises:
- the corresponding controller,
- a transmit first in, first out (FIFO) buffer for buffering data to be transmitted to another network switch, and
- a receive FIFO buffer for buffering data received from the other network switch.
A multiport packet switched network switch arrangement comprising:
- a first n-port network switch having an expansion port with a transmit side through which data is transmitted from the first network switch and a receive side through which data is received at the first network switch;
- a second n-port network switch having an expansion port with a transmit side through which data is transmitted from the second network switch and a receive side through which data is received at the second network switch;
- a first unidirectional expansion bus coupled between the expansion port transmit side of the first network switch and the expansion port receive side of the second network switch for transmission of a continuous stream of data bursts;
- a second unidirectional expansion bus coupled between the expansion port transmit side of the second network switch and the expansion port receive side of the first network switch for transmission of a continuous stream of data bursts, wherein
- each network switch has an expansion port controller, a transmit first in (FIFO) buffer for buffering data to be transmitted to another one of the network switches, and
- a receive FIFO buffer for buffering data received from another one of the network switches.
A method of operating an m-port network switch on a packet switched network, the m-port network switch having q network switches, each network switch having n ports, such that q×n=m, the method comprising the steps of:
- connecting the network switches in a circular, serial manner such that data is transferable between the network switches only unidirectionally;
- determining in a first one of the network switches that data is to be transmitted from a selected port of a second one of the network switches;
- retrieving the data from a memory coupled to the first network switch;
- transmitting the data from the first network switch to the second network switch in a continuous stream of data bursts;
- and
- transmitting the data from the selected port of the second network switch, wherein
- each network switch has an expansion port through which data is transmitted and received between the other network switches, the expansion ports including
- a controller,
- a transmit FIFO for buffering data to be transmitted to another one of the network switches, and
- a receive FIFO for buffering data received from another one of the network switches.
Dependencies are inferred from the claim text.