US 5,398,235 AGranted

Cell exchanging apparatus

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsMunenori Tsuzuki, Hideaki Yamanaka, Hirotaka Saito, Hirotoshi Yamada, Kazuyoshi Oshima

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Abstract

A cell exchanging apparatus which distributes cells input through a plurality of input lines to output lines by destination for output. Without stopping the operation of the cell exchanging apparatus, active and standby cell switches of the cell exchanging apparatus can be changed over. The cell exchanging apparatus comprises a first and second cell switches, input selectors for feeding input cells only to either of the first and second cell switches, and output selectors for outputting cells output from either of the first and second cell switches to an external system. When a change-over is instructed by a system change-over signal, the input selectors start to feed input cells into the cell switch in the standby mode. When detecting completion of cell output operation from the active cell switch, the output selectors select a new active cell switch. Upon detection of completion of cell output operation from the former active cell switch, a controller sends an output permission signal to the new active cell switch. Resultantly, the new active cell switch starts to output cells to the output selectors which then output the cells to an external system.

Claims15

Dependent claims

An asynchronous transfer mode cell exchanging apparatus for inputting cells through n input lines, each cell having a data section containing data to be transmitted and a header section containing destination information, and for distributing the cells by destination for outputting to m output lines, wherein n and m are positive integers, said cell exchanging apparatus comprising:

a) first switch means for distributing cells input through said n input lines by destination in response to said destination information and for directing the cells to a first group of m switch output lines, said first switch means including means for outputting idle cells to said first group of switch output lines when there are no cells to be output, said first switch means comprising:
a1) a first group of m output buffers which temporarily store the distributed cells by destination;
and
a2) a first group of m cell monitors, each being provided for each of said first group of m switch output lines, for determining which of a normal cell and an idle cell is output to its corresponding switch output line and outputting a cell presence/absence signal specifying whether a normal cell exists;
b) second switch means for distributing cells input through said n input lines by destination in response to said destination information and for directing the cells to a second group of m switch output lines, said second switch means including means for outputting idle cells to said second group of switch output lines when there are no cells to be output, said second switch means comprising:
b1) a second group of m output buffers which temporarily store the distributed cells by destination;
and
b2) a second group of m cell monitors, each being provided for each of said second group of m switch output lines, for determining which of a normal cell and an idle cell is output to its corresponding switch output line and outputting a cell presence/absence signal specifying whether a normal cell exists;
and
c) m output selectors each being provided for one of said output lines for selecting a switch output line of a corresponding pair of lines of said first group and said second group of m switch output lines in response to a change-over signal, to send cells output through the selected switch output line to the corresponding output line, each of said output selectors including output selector control means for monitoring the cell presence/absence signal output by said cell monitor provided corresponding to said switch output line of the group selected by said output selector to change over said switch output line in response to the change-over signal only if said cell presence/absence signal indicates cell absence.

7 more elements

An asynchronous transfer mode cell exchanging apparatus for inputting cells through n input lines, each cell having a data section containing data to be transmitted and a header section containing destination information and for distributing the cells by destination for outputting to m output lines, wherein n and m are positive integers, said cell exchanging apparatus comprising:

a) input selectors being responsive to a change-over signal for directing cells input through said n input lines to one of a first and a second group of n switch input lines;
b) first switch means for distributing cells input through said first group of n switch input lines by destination in response to said destination information and for directing the cells to a first group of m switch output lines, said first switch means including means for outputting idle cells to said first group of switch output lines when there are no cells to be output, said first switch means comprising:
b1) a first group of m output buffers which temporarily store the distributed cells by destination;
and
b2) a first group of m cell monitors, each being provided for each of said first group of m switch output lines, for determining whether a cell is output to its corresponding switch output line and outputting a cell presence/absence signal specifying whether a cell exists;
c) second switch means for distributing cells input through said second group of n switch input lines by destination in response to said destination information and for directing the cells to a second group of m switch output lines, said second switch means including means for outputting idle cells to said second group of switch output lines when there are no cells to be output, said second switch means comprising:
c1) a second group of m output buffers which temporarily store the distributed cells by destination;
and
c2) a second group of m cell monitors, each being provided for each of said second group of m switch output lines, for determining whether a cell is output to its corresponding switch output line and outputting a cell presence/absence signal specifying whether a cell exists;
d) output selectors for selecting one of said first and second group of m switch output lines in response to a change-over signal to send cells output through the selected group of switch output lines to said output lines, each of said output selectors including:
d1) an output unit selector being provided for each of said m output lines for selecting one switch output line of a pair of switch output lines of said first and second groups and connecting the selected switch output line to the output line corresponding to said output unit selector;
and
d2) output selector control means for monitoring the cell presence/absence signal output by said cell monitor provided corresponding to said switch output line of the group to which said output unit selector is connected to change over said switch output line in response to the change-over signal only if said cell presence/absence signal indicates;
and
e) a controller, responsive to a change-over signal, for granting cell output permission only to a selected one of said first and second switch means, when presence is indicated by at least one output signal of the cell monitors provided for the selected switch means, and for granting cell output permission for the corresponding at least one output line to the other switch means when cell absence is indicated by the cell monitors of the selected switch means.

12 more elements

A packet switching apparatus for inputting a packet through n input lines, each packet having data to be transmitted and destination information, and for distributing the packet according to the destination information to one of m output lines, wherein n and m are positive integers, said packet switching apparatus comprising:

a first switch for distributing packets input through said n input lines to a first group of m switch output lines in response to said destination information, said first switch including means for monitoring whether there are packets in the switch to be output to the switch output lines and for outputting a signal specifying whether there are such packets;
a second switch for distributing packets input through said n input lines to a second group of m switch output lines in response to said destination information, said second switch including means for monitoring whether there are packets in the switch to be output to the switch output lines and for outputting a signal specifying whether there are such packets;
and
output selectors, each being connected to one of said output lines and to a corresponding pair of switch output lines of said first group and said second group, each output selector selecting the switch output line of the first group to output packets to the output line connected thereto and, in response to a change-over signal, monitoring the signal output by the monitor provided for the switch output line of the first group and selecting the switch output line of the second group to output packets to the output line when the monitored signal indicates that no packets are to be output on the switch output line of the first group.

1 more element

a) input selectors being responsive to a change-over signal for directing packets input through said n input lines to one of a first and a second group of n switch input lines;
b) a first switch for distributing packets input through said first group of n switch input lines to a first group of m switch output lines in response to said destination information, said first switch comprising:
b1) means for outputting an idle packet to any of said switch output lines of the first group when there are no packets to be output to the switch output line;
and
b2) a first group of m monitors, each being provided for a corresponding one of said switch output lines of said first group, for detecting whether an idle packet is output to the corresponding switch output line and for outputting a signal specifying whether an idle packet is output;
c) a second switch for distributing packets input through said second group n switch input lines to a second group of m switch output lines in response to said destination information, said second switch comprising:
c1) means for outputting an idle packet to any of the switch output lines of the second group when there are no packets to be output to the switch output line;
and
c2) a second group of m monitors, each being provided for a corresponding one of said switch output lines of said second group, for detecting whether an idle packet is output to the corresponding switch output line and for outputting a signal specifying whether an idle packet is output;
d) output selectors, each being connected to one of said output lines and to a corresponding pair of switch output lines from said first and second group of switch output lines, each of said output selectors selecting the switch output line of the first group to output packets to the output line connected thereto and, in response to the change-over signal, monitoring the signal output by the monitor provided for said switch output line of the first group and selecting said switch output line of the second group to output packets to the output line connected thereto when the signal from the monitor specifies that an idle packet is output on the switch output line of the first group;
and
e) a controller for granting packet output permission to the first switch, and responsive to the change-over signal, for monitoring the signal output by each monitor of the first switch and for granting packet output permission to the second switch when the signal from all monitors of the first switch indicate that idle packets are being output on all switch output lines of the first switch.

9 more elements

In a packet switching system including a first switch having n switch input lines and m switch output lines and a second switch having n switch input lines and m switch output lines corresponding to the switch input and output lines of the first switch, wherein n and m are positive integers wherein the first switch is an active switch for distributing packets received from n input lines corresponding to said switch input lines to m output lines corresponding to said switch output lines and the second switch is a standby switch, a method for making the second switch the active switch and the first switch the standby switch comprising the steps of:

generating a change-over signal indicating that the second switch is to be the active switch;
detecting that no packets are to be output on the switch output lines of the first switch;
selecting the second switch as the active switch in response to a detection that no packets are to be output to the switch output lines of the first switch.

Dependencies are inferred from the claim text.

Facts

Application: 08/020,795Filed 22 Feb 1993 · continuation in part
Priority: JP 3-30047615 Nov 1991
Granted: 14 Mar 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

H04L 12/5601
Packet switching systems: transfer mode dependent, e.g. ATM
H04L 49/106
ATM switching elements: using space switching, e.g. crossbar or matrix
H04L 49/153
Non-blocking multistage, e.g. Clos: aTM switching fabrics having parallel switch planes
H04L 49/405
Constructional details, e.g. power supply, mechanical construction or backplane: physical details, e.g. power supply, mechanical construction or…