EP0785698A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Buffering of multicast cells in switching networks
Assignee: AT&T Inc
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Filing: 1997-01-07
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Granted: —
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Expires: 2017-01-07
Abstract
Abstract Multicasting of an ingress cell received at one of a plurality of input ports is provided through a switch network to one or more of a plurality of output ports. The received ingress cell includes a data payload and a bitmap segment identifying the one or more output ports to which the data payload is to be outputted. The data payload is stored in an available cell buffer; associated with each cell buffer is a reference counter for storing a number equal to the number of ports to which that ingress cell is to be outputted. The bitmap segment is used to identify output ports to which the data payload is to be delivered, and a plurality of linked list queues in the memory, one for each of the output ports, is established. The bitmap segment is interpreted to identify output ports to which the data payload is to be delivered and an entry is made into the associated linked list output queue. The data payload is transmitted to each of the identified output ports, according to a sequence determined by the entries in the corresponding linked list queue.
Inventors
- 👤 Fabio Massimo Chiussi
- 👤 Vijay Pochampalli Kumar
- 👤 Joseph George Kneuer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 23:02
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/30; H04L12/00; H04L12/02; H04L12/16; H04L12/18; H04L12/1886; H04L49/20; H04L49/201; H04L49/203; H04L49/3081; H04Q; H04Q11/00; H04Q11/04; H04Q11/0428; H04Q11/0478; H04L49/15; H04L49/25; H04L49/253; H04L49/254; H04L49/55
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
231 words
Apparatus for multicasting an ingress cell received at one of a plurality of input ports of a switch network to one or more of a plurality of output ports, the apparatus comprising: (a) means for receiving the ingress cell including a data payload and a bitmap segment identifying the one or more output ports to which the data payload is to be outputted, (b) means for storing the data payload in an available cell buffer, (c) a plurality of linked list output queues, at least one for each of the output ports, (d) a reference counter, associated with each cell buffer, for storing a number equal to the number of ports to which that ingress cell is to be outputted, (e) means for interpreting the bitmap segment to identify output ports to which the data payload is to be delivered and for making an entry into one or more linked list output queues, (f) means for transmitting, to each of the identified output ports, one copy of the data payload according to a sequence determined by the entries in the corresponding linked list output queue, and (g) means for deleting, at each of the linked list output queues, an entry therefrom when the payload is outputted to an identified output port and decrementing the reference counter by one, and for making available the cell buffer when the reference counter equals zero.
Claim 2
Dependent Claim
21 words
The apparatus of claim 1 wherein the cell buffer and the linked list output queue are located in the same memory.
Claim 3
Dependent Claim
23 words
The apparatus of claim 1 wherein the linked list output queues of each of the output ports are located in the same memory.
Claim 4
Dependent Claim
27 words
The apparatus of claim 1 wherein a separate memory is dedicated to each output port and wherein entries into the linked list output queues are done concurrently.
Claim 5
Dependent Claim
35 words
The apparatus of claim 1 wherein the bitmap segment is put into a separate queue and the entries are made at a rate that is equal to or faster than an ingress cell receive rate.
Claim 6
Dependent Claim
31 words
The apparatus of claim 1 wherein entries into the linked list output queues occur at a rate equal to the ingress cell receive rate multiplied by the number of output ports.
Claim 7
Dependent Claim
41 words
The apparatus of claim 1 wherein at least one output port includes a plurality of linked list output queues and wherein the processing of each of the singly linked list output queues for said at least one output port is independent.
Claim 8
Dependent Claim
22 words
The apparatus of claim 1 wherein the processing is based on priority as determined by header data included in the ingress cell.
Claim 9
Dependent Claim
32 words
The apparatus of claim 1 further including a separate linked list output queue for a received unicast ingress cell and a separate linked list output queue for a received multicast ingress cell.
Claim 10
Dependent Claim
61 words
The apparatus of claim 1 wherein, when more than one linked list output queues are used for an output port, the more than one linked list output queues are implemented as a single linked list output queue having one or more additional bits indicating from which of the more than one linked list output queues the next cell should be processed.
Claim 11
Dependent Claim
241 words
Switch apparatus for multicasting an ingress cell received at an input port to one or more of a plurality of output ports, the apparatus comprising: input port for receiving the ingress cell including a data payload and a bitmap segment identifying the one or more output ports to which the data payload is to be outputted; processing apparatus for processing the ingress cell by: (a) storing a data payload in an available cell buffer, (b) establishing a plurality of linked list output queues, at least one for each of the output ports, (c) associating with each cell buffer a reference counter for storing a number equal to the number of ports to which that ingress cell is to be outputted, (d) interpreting the bitmap segment to identify output ports to which the data payload is to be delivered, (e) at each of the identified output ports, making an entry into an associated linked list output queue, (f) transmitting, to each of the identified output ports, one copy of the data payload according to a sequence determined by the entries in the corresponding linked list output queue, (g) deleting, at each of the linked list output queues, an entry therefrom when the payload is outputted to an identified output port and decrementing the reference counter by one, and (h) making available the cell buffer when the reference counter equals zero; and output ports for outputting the payload received from the processing apparatus.
Claim 12
Independent Claim
230 words
A method of multicasting an ingress cell received at one of a plurality of input ports of a switch network to one or more of a plurality of output ports, the method comprising the steps of (a) receiving the ingress cell including a data payload and a bitmap segment identifying the one or more output ports to which the data payload is to be outputted, (b) storing the data payload in an available cell buffer, (c) establishing a plurality of linked list output queues, at least one for each of the output ports, (d) associating with each cell buffer a reference counter for storing a number equal to the number of ports to which that ingress cell is to be outputted, (e) interpreting the bitmap segment to identify output ports to which the data payload is to be delivered, (f) at each of the identified output ports, making an entry into the associated linked list output queue, (g) transmitting, to each of the identified output ports, one copy of the data payload according to a sequence determined by the entries in the corresponding linked list output queue, (h) deleting, at each of the linked list output queues, an entry therefrom when the payload is outputted to an identified output port and decrementing the reference counter by one, and (i) making available the cell buffer when the reference counter equals zero.
Claim 13
Dependent Claim
21 words
The apparatus of claim 12 wherein the cell buffer and the linked list output queue are located in the same memory.
Claim 14
Dependent Claim
23 words
The apparatus of claim 12 wherein the linked list output queues of each of the output ports are located in the same memory.
Claim 15
Dependent Claim
27 words
The apparatus of claim 12 wherein a separate memory is dedicated to each output port and wherein entries into the linked list output queues are done concurrently.
Claim 16
Dependent Claim
35 words
The apparatus of claim 12 wherein the bitmap segment is put into a separate queue and the entries are made at a rate that is equal to or faster than an ingress cell receive rate.
Claim 17
Dependent Claim
31 words
The apparatus of claim 12 wherein entries into the linked list output queues occur at a rate equal to the ingress cell receive rate multiplied by the number of output ports.
Claim 18
Dependent Claim
41 words
The apparatus of claim 12 wherein at least one output port includes a plurality of linked list output queues and wherein the processing of each of the singly linked list output queues for said at least one output port is independent.
Claim 19
Dependent Claim
22 words
The apparatus of claim 18 wherein the processing is based on priority as determined by header data included in the ingress cell.
Claim 20
Dependent Claim
32 words
The apparatus of claim 12 further including a separate linked list output queue for a received unicast ingress cell and a separate linked list output queue for a received multicast ingress cell.
References Cited (Backward Citations)
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