Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/20—Support for services
  • H04L49/201—Multicast operation; Broadcast operation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/15—Interconnection of switching modules
  • H04L49/1515—Non-blocking multistage, e.g. Clos
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/25—Routing or path finding in a switch fabric
  • H04L49/253—Routing or path finding in a switch fabric using establishment or release of connections between ports
  • H04L49/254—Centralised controller, i.e. arbitration or scheduling

Definitions

• a three-stage network is operated in strictly nonblocking manner in accordance with the invention includes an input stage having switches and «, inlet links for each of r, switches, an output stage having r 2 switches and n 2 outlet links for each of r 2 switches.
• FIG. IB shows a high-level flowchart of a scheduling method 140, in one embodiment executed by the controller of FIG. 1A.
• a multicast connection request is received in act 141.
• the connection request is fan-out-split if the fan-out of the connection is > s and ⁇ p, (For the network ⁇
• MS( 5 * MIN(n ,n 2 )) are connected to each of the input switches through r, first internal links (for example the links FLl l-FLf ! 1 connected to the middle switch MSI from each of the input switch ISl-ISr , and connected to each of the output switches through r 2 second internal links (for example the links SL1 l-SLr 2 l connected from the middle switch MSI to each of the output switch OSl-OSr 2 ).
• Such a multi-stage switching network is denoted as a V(m, n x ,r x ,n 2 ,r 2 ) network.
• Method 140 of FIG. IB next sets up a connection I 6 from input switch IS2 to output switches OS3, OS6 and OS9 as follows.
• act 142 the scheduling method of FIG. IB finds that, since the fan-out of the connection request I 6 is
• Step 6 marks the already assigned destination switches so that they are not assigned to another fan-out-split connection.
• Step 8 starts a loop to set up each connection or fan-out-split connections of the connection.
• Step 9 checks if the corresponding set 0[i] is not NULL then Step 10 starts a loop and steps through all the middle switches.
• Masson and Jordan (G.M. Masson and B.W. Jordan, "Generalized Multi-stage Connection Networks", Networks, 2: pp. 191-209, 1972 by John Wiley and Sons, Inc.) presented the rearrangeably nonblocking networks and strictly nonblocking networks by following the approach 1, of fanning-out only once in the second stage and arbitrarily fanning out in the first stage.
• U.S. Patent application Serial No. 09/967,815 that is incorporated by reference above
• U.S. Patent application Serial No. 09/967,106 that is incorporated by reference above presented the rearrangeably nonblocking networks and strictly nonblocking networks, respectively, by following the approach 3, of anning-out optimally and arbitrarily in both first and second stages.
• U.S. Patent application, docket No. V-0003 US that is incorporated by reference above presented the strictly nonblocking networks by following the approach 2 of fanning out only once in the first stage and arbitrary fan-out in the second stage.
• V(m,n x ,r x ,n 2 ,r 2 ) strictly nonblocking networks hereinafter "multi-split linear-time V(m,n x ,r x ,n 2 ,r 2 ) strictly nonblocking networks"
• multi-split linear-time V(m,n x ,r x ,n 2 ,r 2 ) strictly nonblocking networks by combining the methods of a) Fan-out only once in the first stage and arbitrary fan-out in the second stage, b) Optimal and arbitrary fan-out in both first and second stages.
• the multi-split linear-time V(m, n x ,r x ,n 2 ,r 2 ) strictly nonblocking networks employ fewer middle stage switches m , but still use linear-time scheduling method for the strictly nonblocking operation.
• the multi-split linear-time V(m, n x ,r x ,n 2 ,r 2 ) strictly nonblocking networks employ more number of middle stage switches m but they are faster in scheduling time.
• V(m,n x ,r x ,n 2 ,r 2 ) are considered.
• Applicant makes a fundamental observation that by arbitrarily splitting the multicast connections in the input switch, when the fan-out of the connection is in a specified range (to be discussed next), the V(m,n,r) network is operable in strictly nonblocking manner for a smaller m than as shown in Table 3. Applicant emphasizes that arbitrary splitting of multicast connections in input switch provides the opportunity to schedule each of the constituent fan-out-spilt connections independent of other and hence scheduling method is linear in time complexity.
• FIG. IC it shows the maximum number of middle switches needed for V(m, n ,r x ,n 2 ,r 2 ) network to be operable in strictly nonblocking manner when a multicast connection is fanned out only once in the input switch, as presented in U.S. Patent application, Docket No. V-0003 that is incorporated by reference above, requires a maximum of
• the V(m, n x ,r x ,n 2 ,r 2 ) network is operable in strictly nonblocking manner when m ⁇ 2.3 x MIN(n x , n 2 ) when r 2 e [12,13] , by arbitrarily fan-out-splitting multicast connections twice and fanning out twice from the input switch when the fan-out of multicast connection is / e [3,4] ; and otherwise by fanning out the connection only once in the input switch.
• V(m, n x ,r x ,n 2 ,r 2 ) network is operable in strictly nonblocking manner when m ⁇ l. ⁇ x MIN(n , n 2 ) when r 2 e [14] , by arbitrarily fan-out-splitting multicast connections twice and fanning out twice from the input switch when the fan-out of multicast connection is / e [3,4] ; and otherwise by fanning out the connection only once in the input switch.
• Table 3 summarizes the results for V(m, n, r) network when r e [9 - 14] , considered so far, to be operable in nonblocking manner according to the current invention.
• Applicant notes that when r 2 e [15] , by arbitrarily fan-out-splitting multicast connections twice and fanning out twice from the input switch when the fan-out of multicast connection is / e [3,4] ; and otherwise by fanning out the connection only once in the input switch with m ⁇ lx MIN(n x , n 2 ) does not make V(m, n x ,r ,n 2 ,r 2 ) operable in
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m,n x ,r x ,n 2 ,r 2 ) is operable in strictly nonblocking manner when
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m, n x ,r x ,n 2 ,r 2 ) is operable in strictly nonblocking manner when m ⁇ 3 MIN(n x ,n 2 ).
• Applicant notes that when r 2 G [49], by arbitrarily fan-out-splitting multicast connections three times and fanning out three times from the input switch when the fan-out of multicast connection is / e [5,18] ; and otherwise by fanning out the connection only once in the input switch with m > 3 MIN(n x , n 2 ) does not make V(m, n x ,r ,n 2 ,r 2 )
• Table 4 summarizes the results for V(m, n, r) network when e [15- 48] , considered so far, to be operable in nonblocking manner according to the current invention.
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m, n x ,r ,n 2 ,r 2 ) is operable in strictly nonblocking manner when m > 4x N( «,, « 2 ).
• the multicast connections with fan-out / e [5,24] are arbitrarily fan-out-split into tour so
• Applicant notes that when r 2 e [100] , by arbitrarily fan-out-splitting multicast connections four times and fanning out four times from the input switch when the fan-out of multicast connection is / e [5,25] ; and otherwise by fanning out the connection only once in the input switch with m ⁇ 4 x MIN(n x , n 2 ) does not make V(m, n x ,r ,n 2 ,r 2 )
• Table 5 summarizes the results for V(m, n, r) network when r e [49 - 99] , considered so far, to be operable in nonblocking manner according to the current invention.
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m, x ,r x ,n 2 ,r 2 ) is operable in strictly nonblocking manner when m ⁇ 5 x MM(n x ,n 2 ) .
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m,n x ,r x ,n 2 ,r 2 )is operable in strictly nonblocking manner when m ⁇ 5 x MLN(n x , n 2 ) .
• Applicant notes that when r 2 e [155] , by arbitrarily fan-out-splitting multicast connections five times and fanning out five times from the input switch when the fan-out of multicast connection is / e [7,31]; and otherwise by fanning out the connection only once in the input switch with m ⁇ 5 MIN(n , n 2 ) does not make V(m, n x ,r x ,n 2 ,r 2 )
• Table 7 summarizes the results for V(m, n, r) network when r e [100 - 154] , considered so far, to be operable in nonblocking manner according to the current invention.
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m, n x ,r ,n 2 ,r 2 ) is operable in strictly nonblocking manner when m ⁇ 6x MIN(n x ,n 2 ) .
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m, n x ,r x ,n 2 ,r 2 ) is operable in strictly nonblocking manner when m ⁇ 6xMIN(n x ,n 2 ) .
• the multicast connection is fanned out only once in the input switch. Then the three-stage network V(m, n x ,r x ,n 2 ,r 2 ) is operable in strictly nonblocking manner when m > 6x ZN(n,, « 2 ) .
• Applicant notes that when r 2 e [225] , by arbitrarily fan-out-splitting multicast connections five times and fanning out five times from the input switch when the fan-out of multicast connection is / e [7,32] ; and otherwise by fanning out the connection only once in the input switch with m ⁇ 6 x MIN(n x , n 2 ) does not make V(m, n ,r x ,n 2 ,r 2 )
• Table 7 summarizes the results for V(m, n, r) network when r e [155 - 224] , considered so far, to be operable in nonblocking manner according to the current invention.
• Each of middle switches MS1-MS4 is a V (4,1,3) three-stage subnetwork.
• the three-stage subnetwork MSI comprises input stage of three, two by four switches MIS1-MIS3 with inlet links FL1-FL6, and an output stage of three, four by two switches MOS1-MOS3 with outlet links SL1-SL6.
• the middle stage of MSI consists of four, three by three switches MMS1-MMS4.
• middle switches MMS1-MMS4 where p is the number of inlet links for each middle input switch MIS1-MIS3 with q being the number of switches in the input stage (equals to 3 in FIG. 5 A) and p is the number of outlet links for each middle output switch MOS1-MOS3 with q being the number of switches in the output stage (equals to 3 in FIG. 5A).
• each connection in any of the recursive three-stage networks each connection can fan out in the first stage switch into only one middle stage subnetwork, and in the middle switches and last stage switches it can fan out any arbitrary number of times as required by the connection request.
• connection Ii fans out in the first stage switch ISl once into middle stage subnetwork MSI.
• middle stage subnetwork MSI it fans out three times into output switches OSl, OS2, and OS3.
• output switches OSl and OS3 it fans out twice. Specifically in output switch OSl into outlet links OL1, OL2, and in output switch OS3 into outlet links OL5, OL6.
• In output switch OS2 it fans out once into outlet link OS4.
• V(m,n x ,r x ,n 2 ,r 2 ) network embodiments described so far, in the current invention are implemented in space-space-space, also known as SSS configuration.
• SSS configuration all the input switches, output switches and middle switches are implemented as separate switches, for example in one embodiment as crossbar switches.
• the three-stage networks V(m,n ,r x ,n 2 ,r 2 ) can also be implemented in a time-space- time, also known as TST configuration.
• TST configuration in the first stage and the last stage all the input switches and all the output switches are implemented as separate switches.
• the middle stage uses s number of switches if m ⁇ s * MIN(n x , n 2 ) where
• the TST configuration implements the switching mechanism, in accordance with the current invention, in MIN(n x ,n 2 ) steps in a circular fashion. So in TST configuration, the middle stage physically implements only s middle switches; and they are shared in time in, MN(n x ,n 2 ) steps, to switch packets or timeslots from input ports to the output ports.
• connections I x and I 6 are fanned out through middle switches MSI and MS2 to the output switches OSl and OS3 respectively, and so connections 7, and 7 6 are fanned out to destination outlet links OL2, OL3 and OL9 respectively, just exactly the same way they are set up in the network of FIG. 6A in all the three stages.
• FIG. 6C implements the switching functionality of middle switches MS3 and MS4, and since in the network of FIG.
• a method of the type described above is modified to set up a multirate multi-stage network as follows.
• a multirate connection can be specified as a type of multicast connection.
• an inlet link transmits to multiple outlet links
• multiple inlet links transmit to a single outlet link when the rate of data transfer of all the paths in use meet the requirements of multirate connection request.
• a multirate connection can be set up (in a method that works backwards from the output stage to the input stage), with fan-in (instead of fan-out) of not more than s in the output stage and arbitrary fan-in in the input stages and middle stages.
• a three-stage multirate network is operated in strictly nonblocking manner with the exact same requirements on the number of middle stage switches as described above for certain embodiments.

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Use Of Switch Circuits For Exchanges And Methods Of Control Of Multiplex Exchanges (AREA)
• Data Exchanges In Wide-Area Networks (AREA)
• Structure Of Telephone Exchanges (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=34312223

Family Applications (1)

Country Status (5)

Families Citing this family (2)

Citations (3)

Family Cites Families (2)

• 2004
  • 2004-09-05 CA CA002537975A patent/CA2537975A1/en not_active Abandoned
  • 2004-09-05 EP EP04783318A patent/EP1665821A4/de not_active Withdrawn
  • 2004-09-05 WO PCT/US2004/029027 patent/WO2005027390A2/en not_active Application Discontinuation
  • 2004-09-05 JP JP2006526222A patent/JP2007504772A/ja active Pending
• 2006
  • 2006-03-05 IL IL174113A patent/IL174113A0/en unknown

Patent Citations (3)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events