Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
143 words
An ATM communication system comprising an ATM switch (1, 25) having a plurality of input ports and a plurality of output ports, each of the input ports being fed from an input port server (2-4) and each of the output ports being arranged to feed an output port server (8), characterised by the input port servers each having a plurality of buffer stores (A, B, Z, 22, 23), one for each of the output ports, to which said output ports data is transmitted through the switch (1, 25), each buffer store (A, B, Z, 22, 23) in the input port servers being arranged to interrogate the output port server (8) with which it communicates before the transmission of data, thereby to determine whether output port server data handling capacity is available, whereby ATM switch operating during periods of peak data traffic is facilitated.
Claim 2
Dependent Claim
102 words
A system as claimed in Claim 1, wherein the interrogation takes the form of a bandwidth request signal from an input port server (2-4) in respect of an associated buffer store (A, B ..........Z, 22, 23), the request signal being directed to an output port server (8) with which that buffer store communicates via the switch (1), and an acknowledgement signal from this output port server (8) in the presence of available capacity, in response to which acknowledgement signal data is thereafter transmitted from the buffer store (A, B ......... Z, 22, 23) to the output port (8) via the switch (1).
Claim 3
Dependent Claim
65 words
A system as claimed in Claim 1 or Claim 2, wherein ATM data traffic is transmitted in frames, wherein each frame comprises a plurality of cells, an end of frame marker being transmitted in the final cell of each frame, the request signal being sent in the first cell of each frame, ie. a cell following a cell which includes an end of frame marker.
Claim 4
Dependent Claim
33 words
A system as claimed in Claim 3, wherein the request cell is arranged to request a bandwidth allotment which is based on mean frame size, ie. the mean data capacity of a frame.
Claim 5
Dependent Claim
30 words
A system as claimed in Claim 1 or Claim 2, wherein the request signal is sent in dependence upon the data stored from time to time in a buffer store.
Claim 6
Dependent Claim
32 words
A system as claimed in Claim 5, wherein each buffer store (22, 23) embodies a plurality of data thresholds (T1, T2, T3), request signals being transmitted in accordance with the threshold reached.
Claim 7
Dependent Claim
45 words
An ATM communication system as claimed in any preceding claim characterised by a queuing arrangement (35) for bandwidth requests received during periods when there is no available bandwidth capacity, the arrangement being such that requests are released in a predetermined order when capacity becomes available.
Claim 8
Dependent Claim
20 words
A system as claimed in Claim 7, wherein the order of release is first to arrive, first to be processed.
Claim 9
Dependent Claim
30 words
A system as claimed in Claim 7, wherein a priority releasing system is provided for queued requests determined in dependence upon the character of data appertaining to each queued request.