JP4293142B2 - Multicast route calculation method and apparatus, program, and storage medium storing multicast route calculation program - Google Patents

Description

  The present invention relates to a multicast path calculation method and apparatus, a program, and a storage medium storing a multicast path calculation program. In particular, in a communication network in which a multicast transfer apparatus and a unicast transmission apparatus are mixed, from a transmission transmission apparatus to a reception transmission apparatus. The present invention relates to a multicast route calculation method and apparatus and a program used for obtaining a route that minimizes the link cost up to and a storage medium storing the multicast route calculation program.

  Conventionally, in a communication network, as shown in FIG. 26, a multicast route is calculated from the topology information 10 collected by the topology information collecting mechanism and the route setting restriction conditions 11 such as a transmission transmission device, a reception transmission device, and a necessary bandwidth. A multicast route calculation device 12 that outputs the calculation result to the route setting mechanism 13 is used.

  Here, the multicast route calculation apparatus using the Dijkstra multicast route calculation method as the prior art will be described with reference to FIG.

  When the topology information including the connection relationship and the link cost as shown in FIG. 27A and the conditions of the transmission transmission device / reception transmission device are input, the link cost from the transmission transmission device to the reception transmission device is minimized. Calculate a multicast route such that

  Next, as shown in FIG. 4B, the cost of the adjacent transmission device (B, I) is calculated from the transmission transmission device A and is set as a candidate device. Next, the one with the lowest link cost from the transmission transmission device is selected from the candidate devices. In this topology, B having a link cost of “2” is selected, and a route from the transmission transmission apparatus A to B is determined. B is removed from the candidate devices, and is a visited device. The transmission apparatus adjacent to the determined transmission apparatus is searched. At that time, the device A immediately before the determined transmission device is not included in the adjacent devices. As shown in FIG. 6C, the link cost from the transmission transmission apparatus via the determined transmission apparatus is calculated for each adjacent transmission apparatus, and is set as a candidate apparatus.

  Similarly, as shown in FIG. 28 (d), I is a visited device, and transmission devices E and H adjacent to I are candidate devices.

  Next, from the candidate devices, the one with the lowest link cost from the transmission transmission device is selected. If there are a plurality of candidate devices, one is selected using other route setting restriction conditions. In this example, G is selected and G is the visited device. Further, when a route adjacent to the transmission device G is selected as a candidate, if the adjacent device is already a candidate device or a visited transmission device, the link cost from the transmission transmission device already calculated, The link cost from the transmission transmission apparatus via the determined transmission apparatus G is compared, and the smaller one is set as a route to the adjacent apparatus. Therefore, in FIG. 28 (e), H is a candidate device from I, but by comparing the link costs from the transmission transmission device (comparison of (e) and (f) in FIG. 28), H is Candidate device from G. F is a candidate device from B because the link cost from the transmission transmission device via G is large.

  Subsequently, as shown in FIG. 28 (f), F is removed from the candidate devices in the route to F as in the previous case, and is set as a visited device. Further, the route to E is determined, E is removed from the candidate devices, and the visited device is set. As shown in FIG. 29 (g), an adjacent device of E is a candidate device D.

  After searching for all devices, the route is determined from the candidate devices in ascending order of link cost from the transmission transmission device.

  As a result, as shown in FIG. 29 (h), a multicast route including all the reception transmission devices input from the transmission transmission device has been found. From the route, as shown in FIG. 29 (i), an unnecessary route that does not reach the receiving transmission device is deleted and output to the route setting mechanism 13.

In this output result, a branch has occurred in B which is a unicast transmission apparatus. In this way, in the prior art, a plurality of candidate devices are determined from the search target device using only the link cost without considering the difference between the multicast transmission device and the unicast transmission device. A route that branches in the transmission device is output (for example, see Non-Patent Document 1).
WIDE 2002 Internet Architecture 6th Lecture Materials http://www.soi.wide.ad.jp/class/20020022/materials_for_student/06/na-06.pdf (10 pages, 11 pages)

  In the technology shown above, a multicast route that minimizes the link cost from the transmitting transmission device to each receiving transmission device is calculated from the input topology information and route setting restriction conditions, and is output to the route setting mechanism. Can do.

  However, in the existing technology, in a communication network in which a multicast transmission device and a unicast transmission device are mixed, route calculation is performed without considering the difference between them, so that even a unicast transmission device that cannot branch may branch. There is a problem that a simple multicast route is output. As a result, the route setting mechanism cannot set the route normally and cannot communicate.

  The present invention has been made in view of the above points. Even in a communication network in which a multicast transmission apparatus and a unicast transmission apparatus are mixed, the link cost from the transmission transmission apparatus to each reception transmission apparatus is reduced, and the unicast transmission apparatus is reduced. An object of the present invention is to provide a multicast route calculation method and apparatus and program capable of outputting a multicast route that does not cause a branch in the cast transmission device, and a storage medium storing the multicast route calculation program.

  FIG. 1 is a diagram for explaining the principle of the present invention.

The present invention relates to a multicast that calculates a multicast path by applying a Dijkstra multicast path calculation method using topology information and path setting constraint conditions of the input communication network in a communication network in which a multicast transmission apparatus and a unicast transmission apparatus are mixed. A route calculation method,
An initial setting step (step 1) for storing information on the transmission source device in the visited device storage means for setting the already searched device as visited.
A multicast determination step (step 2) for determining whether the device to be searched is a multicast transmission device or a unicast transmission device with reference to topology information storage means storing topology information including connection relation and link cost;
In the multicast determination step, when it is determined as a unicast transmission device, a neighboring device is extracted based on the topology information, and based on the neighboring device, candidate device storage means in which a candidate transmission device for search is stored, and already The visited device storage means for storing the searched device as a visited device is referenced, and a device that is a candidate device or a device other than the visited device is stored in the memory among the neighboring devices. If there are a plurality of devices stored in the memory, a priority is given based on a predetermined condition, and the adjacent device having the highest priority is stored in the candidate device storage means as a candidate device, When there is one device stored in the memory, the candidate device is stored in the candidate device storage means, and the route from the candidate device to the transmission transmission device and the link cost are stored in the search route storage means. Paid to unicast device for candidate device determination step (step 3),
When it is determined as a multicast transmission device in the multicast determination step, a neighboring device is extracted by the Dijkstra multicast route calculation method, and the candidate device selected by referring to the candidate device storage unit from the neighboring device is already for the unicast device. If the candidate device is determined in the candidate device determination step, the candidate device is reselected from the neighboring devices of the unicast transmission device, stored in the candidate device storage means, and from the candidate device to the transmission transmission device. A multicast device candidate device determination step (step 4) for storing the route and link cost in the search route storage means;
Search target device determination step (step 5) in which the candidate device having the lowest link cost from the transmission transmission device of each candidate device stored in the candidate device storage means is searched from the candidate device storage means and stored in the visited device storage means. )When,
If the route from the transmission transmission device to all reception transmission devices is found with reference to the search route storage means, the transmission device stored in the search route storage means is read out and output, and has not been found. In this case, a route completion determination step (step 6) is repeated in which the steps after the multicast determination step are repeated.

The present invention (Claim 2) manages the random ratio, increases the random ratio, resets the information of the searched route storage means, the candidate device storage means, and the visited device storage means, Resuming the search as a search target device;
In accordance with the random ratio, further performing a random ratio processing step comprising: notifying the candidate device determining means for unicast device whether or not to follow the condition for giving priority,
In the unicast device candidate device determination step,
In response to the notification from the random ratio processing step, a candidate device is randomly selected from the candidate device storage unit, or one candidate device is selected from the candidate device storage unit according to a condition for giving priority.

  FIG. 2 is a principle configuration diagram of the present invention.

According to the present invention (Claim 3), in a communication network in which a multicast transmission device and a unicast transmission device are mixed, the Dijkstra multicast route calculation method is applied to the multicast using the topology information and route setting constraint conditions of the input communication network. A multicast route calculation device for calculating a route,
Topology information storage means 112 storing topology information including connection relations and link costs;
Constraint storage means 114 for storing route constraint conditions;
Visited device storage means 119 for storing already searched devices as visited devices;
Candidate device storage means 122 for storing candidate devices;
Search route storage means 120 for storing the route to each transmission device and the link cost,
Initial setting means 115 for storing information of the transmission source transmission device in the visiting device storage means 119;
A multicast determination unit 116 that refers to the topology information in the topology information storage unit 112 and determines whether the search target device is a multicast transmission device or a unicast transmission device;
When the multicast determination unit 116 determines that the device is a unicast transmission device, an adjacent device is extracted based on the topology information, and the candidate device storage unit 122 and the visited device storage unit 119 are referred to based on the adjacent device, A device that is a candidate device among neighboring devices or a device other than a visited device is stored in a memory, and when there are a plurality of neighboring devices stored in the memory, a predetermined Priorities are assigned based on conditions, and the neighboring device with the highest priority is stored as a candidate device in the candidate device storage unit 122. If there is one neighboring device stored in the memory, the neighboring device is Unicast device candidate device determining means 1 which stores in the candidate device storage means 122 and stores the path and link cost from the candidate device to the transmission transmission device in the search route storage means 120. And 8,
When it is determined that the multicast transmission device is the multicast transmission device by the multicast determination means 116, the adjacent device is extracted by the Dijkstra multicast route calculation method, and the candidate device selected by referring to the candidate device storage means 122 from the adjacent devices is already unicast. If the candidate device is determined by the device candidate device determining means 118, the candidate device is reselected from the neighboring devices of the unicast transmission device, stored in the candidate device storage means 122, and transmitted from the candidate device. A candidate device determining unit 117 for multicast device for storing the route to the transmission device and the link cost in the searched route storage unit 120;
The link cost from the transmission transmission device of each candidate device stored in the candidate device storage unit 122 is calculated with reference to the topology information, the candidate device with the smallest link cost is extracted from the candidate device storage unit 122, Search target device determining means 123 to be stored in the visited device storage means 119;
If the route to all the receiving transmission devices is found by referring to the searched route storage means 120, the candidate device stored in the searched route storage means 120 is read out and output. A determination unit 116, a unicast device candidate device determination unit 118, a multicast device candidate device determination unit 117, and a route completion determination unit 124 that repeats the processing of the search target device determination unit 123.

Further, the present invention (Claim 4) manages the random ratio, increases the random ratio, resets the information of the searched route storage means, the candidate device storage means, and the visited device storage means, Means for restarting the search as a search target device;
In accordance with the random ratio, further comprising a random ratio processing means comprising: a means for notifying the candidate device determining means for a unicast device whether to comply with a condition for giving priority;
Unicast device candidate device determination means,
In accordance with a notification from the random ratio processing means, a means for randomly selecting a candidate apparatus or selecting one candidate apparatus according to a condition for giving priority is included.

According to the present invention (Claim 5), in a communication network in which a multicast transmission device and a unicast transmission device are mixed, the Dijkstra multicast route calculation method is applied to the multicast using the topology information and route setting constraint conditions of the input communication network. A multicast route calculation program for calculating a route,
Topology information storage means storing topology information including the connection relationship and link cost of each device;
Constraint storage means for storing route constraint conditions;
Visited device storage means for storing already searched devices as visited devices;
Candidate device storage means for storing candidate devices;
Search route storage means for storing the route and link cost to the transmission transmission device of each device,
On a computer with
A program for executing processing for realizing the multicast route calculation method according to claim 1.

According to the present invention (Claim 6), in a communication network in which a multicast transmission apparatus and a unicast transmission apparatus are mixed, the Dijkstra multicast route calculation method is applied to the multicast using the topology information and the route setting constraint conditions of the input communication network. A storage medium storing a multicast route calculation program for calculating a route,
Topology information storage means storing topology information including the connection relationship and link cost of each device;
Constraint storage means for storing route constraint conditions;
Visited device storage means for storing already searched devices as visited devices;
Candidate device storage means for storing candidate devices;
Search route storage means for storing the route and link cost to the transmission transmission device of each device,
On a computer with
A storage medium storing a program for executing processing for realizing the multicast route calculation method according to claim 1.

  As described above, according to the present invention, when a path is sequentially determined from a transmission transmission device to an adjacent transmission device, if the transmission transmission device being searched for is a multicast transmission device, the transmission from the transmission transmission device Branching is performed so that the link cost is minimized. In the case of a unicast transmission apparatus, one candidate apparatus is selected so as to select a desired route, and branching in the multicast transmission apparatus is suppressed.

  In addition, a random ratio is introduced, and even in a route that has no solution, by selecting a random route, the route can be found and applied to more communication networks.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 3 shows the configuration of the multicast route calculation apparatus according to the first embodiment of the present invention.

  The multicast route calculation apparatus shown in the figure includes a topology information input unit 111, a topology information storage unit 112, a route constraint condition input unit 113, a constraint condition setting unit 114, an initial setting unit 115, a multicast determination unit 116, and a multicast device candidate device. Determination unit 117, unicast device candidate device determination unit 118, visited device storage unit 119, search route storage unit 120, route output unit 121, candidate device storage unit 122, search target device determination unit 123, multicast route completion determination unit 124. The topology information storage unit 112, the visited device storage unit 119, the searched route storage unit 120, and the candidate device storage unit 122 are storage media such as a hard disk device.

  The topology information input unit 111 inputs topology information including a connection relation of devices in the communication network and a link cost collected by a topology information collection mechanism (not shown) to the topology information storage unit 112.

  The route constraint condition input unit 113 inputs route setting constraint conditions such as a transmission transmission device, a reception transmission device, and a necessary band to the constraint condition setting unit 114.

  The constraint condition setting unit 114 sets the constraint conditions in the initial setting unit 115 and the multicast route completion determination unit 124.

  The initial setting unit 115 acquires information on the transmission transmission device from the route constraint condition input unit 113, sets it as a visited device in the visited transmission device storage unit 119, and passes it to the multicast determination unit 116.

  The multicast determination unit 116 refers to the topology information in the topology information storage unit 112 and determines whether the input device (search target device) is a multicast transmission device or a unicast transmission device. When it is determined that it is a unicast transmission device, it notifies the unicast device candidate determination unit 118, and when it is determined that it is a multicast transmission device, it notifies the multicast device candidate device determination unit 117.

  Candidate device determination unit 117 for multicast devices and candidate device determination unit 118 for unicast cast devices determine candidate devices by referring to information in visited device storage unit 119, searched route storage unit 120, and candidate device storage unit 122, respectively. Then, the determined candidate device is notified to the visited device storage unit 119, the searched route storage unit 120, and the candidate device management unit 122.

  The visited device storage unit 119 stores the identifier of the search target device determined by the search target device determination unit 123 as visited.

  The search route storage unit 120 stores the route and link cost to the transmission transmission device of each device determined by the multicast device candidate device determination unit 117 or the unicast device candidate device determination unit 118.

  The candidate device storage unit 122 stores the identifier of the candidate device extracted by the multicast device candidate device determination unit 117 or the unicast device candidate device determination unit 118.

  When the multicast determination unit 116 determines that the unicast device candidate device determination unit 118 is a unicast transmission device, the unicast device candidate device determination unit 118 extracts neighboring devices by referring to the topology information, and based on the adjacent device, the candidate device storage unit 122 , Refer to the visited device storage unit 119 based on the neighboring devices, and the devices already visited by the neighboring devices, and extract the devices that have been visited by the neighboring devices. Device is stored in the memory, and priorities are assigned to neighboring devices stored in the memory based on a predetermined condition, and the neighboring device having the highest priority is set as a candidate device, and the identifier of the device is assigned. Store in the candidate device storage unit 122. The predetermined condition will be described later. Further, the search route storage unit 120 stores the route from the transmission transmission device to the candidate device and the link cost.

  When the multicast determination unit 116 determines that the multicast device candidate device determination unit 117 is a multicast transmission device, the multicast device candidate device determination unit 117 extracts neighboring devices by the Dijkstra multicast route calculation method, and searches the candidate device storage unit 122 from the adjacent devices. If the candidate device selected with reference to the path storage unit 120 is already a candidate device determined by the unicast device candidate device determination unit 118, the candidate device is reselected from the neighboring devices of the unicast transmission device. The identifier is stored in the candidate device storage unit 122. Further, the search route storage unit 120 stores the route from the transmission transmission device to the candidate device and the link cost.

  The search target device determination unit 123 examines the link cost from the transmission transmission device of each candidate device stored in the search path storage unit 120, and sets one of the candidate devices having the smallest link cost as the search target device. The device identifier is set in the visited device storage unit 119 and deleted from the candidate device storage unit 122.

  The multicast route completion determination unit 124 refers to the visited storage unit 119 based on the route stored in the searched route storage unit 120 based on the reception transmission device acquired from the constraint condition setting unit 114, and sets all reception transmission devices. It is determined whether or not a route to has been found. When the route is determined, the route output unit 121 is notified. Further, when the route is not found and the search target device is determined by the search target device determination unit 123, information on the device is passed to the multicast determination unit 116.

  The route output unit 121 outputs the route stored in the searched route storage unit 120 when notified from the multicast route completion determination unit 124 that routes to all the receiving transmission devices have been found.

  Next, the operation in the above configuration will be described.

  FIG. 4 is a flowchart of the operation in the first embodiment of the present invention.

  Step 101) The topology information input unit 111 receives topology information and stores it in the topology information storage unit 112.

  Step 102) The route constraint condition input unit 113 sets the route constraint condition in the route condition setting unit 114.

  Step 103) The constraint condition setting unit 114 sets the transmission apparatus to the initial setting unit 115. Specifically, the visited transmission device is set as a visited device in the visited device storage unit 119. In addition, the transmission transmission device is set in the search route storage unit 120 as a search target device.

  Step 104) The multicast determination unit 116 refers to the topology information to determine whether the search target device is a multicast transmission device or a unicast transmission device. In the case of a multicast transmission apparatus, the process proceeds to step 105, and in the case of a unicast transmission apparatus, the process proceeds to step 108.

  Step 105) The multicast device candidate device determination unit 117 extracts neighboring devices from the topology information storage unit 112.

  Step 106) The multicast device candidate device determination unit 117 determines a candidate device from the neighboring devices acquired in Step 105 by the Dijkstra multicast route calculation method, and stores it in the candidate device storage unit 122. Further, the search route storage unit 120 stores the route from the transmission transmission device to the candidate device and the link cost.

  Step 107) If the acquired candidate device is already a candidate device determined by the unicast device candidate device determination unit 118, the process proceeds to step 108, and if not, the process proceeds to step 111.

  Step 108) When it is determined in Step 104 that the search target device is a unicast transmission device, or when the device is already determined by the unicast device candidate device determination unit 118 in Step 107 The candidate device determination unit 118 for unicast device refers to the topology information, extracts neighboring devices of the device, refers to the candidate device storage unit 122 based on the neighboring devices, and already has another one of the neighboring devices. The visited device storage unit 119 is referred to based on the device that is a candidate device from the device and the adjacent device, and the device excluding the device that has been visited by the adjacent device is stored in a memory (not shown). Store.

  Step 109) The candidate device determining unit 118 for the unicast device gives a priority to the adjacent device stored in the memory based on a predetermined condition.

  Step 110) The candidate device determination unit 118 for the unicast device stores the neighboring device having the highest priority in the candidate device storage unit 122 as a candidate device. Further, the route from the transmission transmission device to the candidate device and the link cost are stored in the searched route storage unit 120.

  Step 111) In the search target device determination unit 123, the candidate device is read from the candidate device storage unit 122, and one of the candidate devices having the lowest link cost from the transmission transmission device of each candidate device stored in the search path storage unit 120. The search target device is stored in the visited device storage unit 119 and deleted from the candidate device storage unit 122.

  Step 112) The multicast route completion determination unit 124 refers to the visited storage unit 119 based on the route stored in the searched route storage unit 120 based on the reception transmission device acquired from the constraint condition setting unit 114, It is determined whether a route to the receiving transmission device has been found. When the route is determined, the route output unit 121 is notified. As a result, the route output unit 121 outputs the route stored in the searched route storage unit 120 when notified from the multicast route completion determination unit 124 that the route to all the receiving transmission devices has been found. . Further, when the route is not found and the search target device is determined by the search target device determination unit 123, information on the device is passed to the multicast determination unit 116.

  Next, the processing after step 104 will be described in detail.

  5 to 9 are flowcharts of detailed operations in the first embodiment of the present invention.

  Step 201) The initial setting unit 115 sets the transmission transmission device (s) as a visited device in the visited device storage unit 119 and sets it as a search target transmission device (v). Here, the search target transmission apparatus usually refers to a transmission apparatus whose path has just been determined.

  Step 202) The multicast determination unit 116 determines whether the search target transmission device is a multicast transmission device. If the transmission target device is a multicast transmission device, the multicast determination unit 116 proceeds to Step 203, and if it is a unicast transmission device, proceeds to Step 214. To do.

  Step 203) The multicast device candidate device determination unit 117 sets the transmission device f as a transmission device that is adjacent to the search target transmission device and is not the transmission device immediately preceding the search target transmission device on the determined path. If there is no candidate device, it is not executed.

  Step 204) The multicast device candidate device determination unit 117 calculates a link cost between the transmission device (s) to be transmitted via the search target transmission device (v) and the determined candidate device (f), and sets it as df.

  Step 205) The multicast device candidate device determination unit 117 refers to the visited device storage unit 119 to determine whether the candidate device (f) is a visited device. If it is a visited device, the process proceeds to step 207.

  Step 206) The route and link cost via the search target transmission device (v) from the transmission transmission device (s) to the transmission device (f) are stored in the search route storage unit 120, and the transmission device (f) is set as a candidate device. Control goes to step 213.

  Step 207) It is determined whether the already calculated link cost is higher than df. If it is larger, the process proceeds to Step 208, and if not, the process proceeds to Step 213.

  Step 208) Let p be the transmission apparatus immediately preceding the candidate apparatus (f) in the stored path.

  Step 209) The same processing as step 206 is performed.

  Step 210) The multicast determination unit 116 determines whether p is a multicast transmission apparatus. If the multicast transmission apparatus 116 is a multicast transmission apparatus, the process proceeds to step 213. If not, the process proceeds to step 211.

  Step 211) The candidate device determining unit 118 for the unicast device sets p as the search target transmission device (v).

  Step 212) The processing from step 214 to step 221 is performed, and the routine proceeds to step 213.

  Step 213) Steps 203 to 213 are executed for all f.

  Step 214) The candidate device determination unit 118 for the unicast device sets (f) to a transmission device that is adjacent to the search target transmission device (v) and is not a visited device or a candidate device.

  Step 215) The candidate device determining unit 118 for the unicast device determines whether or not there is a plurality of f. If there are f, the process proceeds to Step 216. If not, the process proceeds to Step 219.

  Step 216) The candidate device determination unit 118 for the unicast device sets one of the transmission devices with the highest priority to f using the following priority condition.

1) A transmission apparatus having one physical link and a receiving transmission apparatus;
2) Transmission equipment with the smallest number of physical links;
3) Multicast transmission device among the above devices;
4) Among the above transmission apparatuses, the transmission apparatus with the lowest link cost from the transmission transmission apparatus (s);
5) Unicast transmission device among the transmission devices of 2);
6) Among the above transmission apparatuses, the transmission apparatus with the lowest link cost from the transmission transmission apparatus (s);
In the above priority condition, when there are a plurality of highest-level transmission devices, the number is limited to one using another route setting restriction condition set by the restriction condition setting unit 114.

  Step 217) The process of Step 204 described above is performed.

  Step 218) The processing of Step 206 described above is performed, and the routine proceeds to Step 222.

  Step 219) In step 215, if there is not a plurality of f, the process moves to step 220 if one f exists, and if not (f is 0), the process moves to step 222.

  Step 220) The process of Step 204 described above is performed.

  Step 221) The processing of Step 206 described above is performed, and the routine proceeds to Step 222.

  Step 222) The search target device determination unit 123 determines whether there is a candidate device in the candidate device storage unit 122. If there is a candidate device, the search target device determination unit 123 proceeds to Step 223, and if not, the process is determined as “no solution”. Force termination.

  Step 223) The search target device determination unit 123 sets i as a candidate device that minimizes the link cost from the transmission transmission device (s). When there are a plurality of conditions, one is selected using the other conditions set from the constraint condition setting unit 114. A route to the i is determined, i is deleted from the candidate device storage unit 122, and i is set in the visited device storage unit 119.

  Step 224) Let i be the search target transmission device (v).

  Step 225) The multicast path completion determination unit 124 refers to the searched path storage unit 120 to determine whether all the receiving transmission devices are included in the determined path. If included, the process proceeds to Step 226. If not included, the process proceeds to step 202.

  Step 226) The route that does not communicate with the reception and transfer device in the searched route storage unit 120 is deleted, and the determined route is output from the route output unit 121.

[Second Embodiment]
FIG. 10 shows the configuration of a multicast route calculation apparatus according to the second embodiment of the present invention. In the figure, the same components as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted. The configuration shown in FIG. 10 is a configuration in which a random ratio processing unit 131 is added to the configuration shown in FIG.

  The random ratio processing unit 131 randomly selects candidate devices from the remaining adjacent devices according to a predetermined ratio (random ratio).

  FIG. 11 is a flowchart of the multicast route calculation method according to the second embodiment of the present invention. In FIG. 11, the same step numbers are assigned to the same operations as those in FIG. 4, and description thereof is omitted.

  In the first embodiment, at the stage of selecting a candidate device, it is determined whether the device to be searched is a unicast transmission device or a multicast transmission device (step 104), and the search target device is a unicast transmission device. In some cases, after removing the neighboring devices that are the candidate devices and visited devices from the neighboring devices (step 108), the random ratio processing unit 131 leaves the remaining neighbors according to a predetermined random ratio. Candidate devices are randomly selected from the devices. When not selecting at random, it selects according to the conditions for giving the determined priority (step 301).

  In step 112, when selecting the search target device with the lowest cost from the candidate devices, the candidate device is stored in the candidate device storage unit 122 even though the multicast route to all the receiving devices has not been found. In the search route storage unit 120, the visited device of the visited device storage unit 119, the candidate device of the candidate device storage unit 122, etc. Information is reset (step 302), and the search is started again from the transmission transmission apparatus (step 104).

  12 and 13 are flowcharts of detailed operations in the second embodiment of the present invention. In FIG. 12 and FIG. 13, only the parts different from the first embodiment are described, the same operations are given the same step numbers, and the description thereof is omitted.

  In step 214, a transmission device that is adjacent to the search target transmission device (v) and is not a visited device or a candidate device is defined as (f). In step 215, it is determined whether or not there are a plurality of fs. If yes, go to Step 401; otherwise, go to Step 219.

  In step 401, the random ratio processing unit 131 determines whether or not to select a random number using a pseudo-random number and a random ratio. When selecting a random number, one is randomly selected using a pseudo-random number. (Step 402), the process proceeds to Step 220. On the other hand, when not selecting at random, it transfers to the process of step 216.

  In step 222, if there is a candidate, the search route in the search route storage unit 120, the candidate device in the candidate device storage unit 122, and the visited device information in the visited device storage unit 119 are reset, and the random ratio is set. And the transmission transmission device (s) is set as the search target transmission device (v) (step 403).

  Embodiments of the present invention will be described below with reference to the drawings.

[First embodiment]
14-16 is a figure for demonstrating the 1st Example of this invention.

  A first embodiment will be described with reference to FIGS.

  In the following, the initial setting unit 115 and the multicast determination unit 116 have received the topology information including the connection relationship and link cost shown in FIG. 14A and the route constraint conditions such as the transmission / transfer device and the reception / transfer device. And

  (1) The initial setting unit 115 sets the transmission transmission device A as a visited device and sets it in the visited device storage unit 119. The multicast determination unit 117 determines whether the transmission transmission device is a multicast transmission device or a unicast transmission device. Judging.

  (2) In this topology, since the transmission transmission device is a multicast transmission device, the multicast device candidate device determination unit 117 calculates the link cost to the adjacent transmission devices B and I with reference to the topology information, The route and the link cost are stored in the search route storage unit 120, and B and I are set as candidate devices and set in the candidate device storage unit 122 (FIG. 14B).

  (3) The search target device determination unit 123 refers to the information on the link cost of the topology information, and selects one candidate device with the lowest link cost from the transmission transmission device from among the candidate devices in the candidate device storage unit 122. The selected device is deleted from the candidate device storage unit 122 and set in the visited storage unit 119. At this time, if there are a plurality of candidate devices having the lowest link cost, one is selected using other route setting restriction conditions. In this topology, B having a link cost of “2” is selected, deleted from the candidate device storage unit 122, a route from the transmission transmission device to B is determined, and the device B is set in the visiting device storage unit 119. .

  (4) The multicast determination unit 116 determines whether the determined transmission device B is a multicast transmission device or a unicast transmission device. In FIG. 14, since transmission apparatus B is a unicast apparatus, unicast apparatus candidate apparatus determination section 118 refers to topology information, candidate apparatus storage section 122, and visited apparatus storage section 119 and is adjacent ( However, when referring to an adjacent transmission device, the previous transmission device in the searched route is not included), candidate devices from other transmission devices and the transmission device is not determined transmission path, In addition, among the transmission devices that have not been visited, one of the transmission devices with the highest priority is set as a candidate device using the priority conditions shown below, and is stored in the candidate device storage unit 122 (FIG. 14C). . Further, the route from the transmission source transmission device to the candidate device and the link cost are stored in the searched route storage unit 120.

1) A transmission apparatus having one physical link and a receiving transmission apparatus;
2) Transmission equipment with the smallest number of physical links;
3) Among the above devices, a multicast transmission device;
4) Among the above transmission apparatuses, the transmission apparatus with the lowest link cost from the transmission transmission apparatus;
5) Unicast transmission device among the transmission devices of 2);
6) Among the above transmission apparatuses, the transmission apparatus with the lowest link cost from the transmission transmission apparatus;
Note that when there are a plurality of highest-level transmission devices in the above priority conditions, the number is limited to one using other route setting restriction conditions. In this topology, there are three transmission devices C, F, and G adjacent to the transmission device B, but there is no transmission device that satisfies the above condition 1), and the transmission device that satisfies the condition 2) is C. Therefore, C is set as a candidate device and set in the candidate storage unit 122.

  (5) The search target device determination unit 123 selects the candidate device with the lowest link cost from the transmission transmission device, and deletes it from the candidate device storage unit 122. Thereby, the route to the route to I is determined, and I is set in the visited device storage unit 119 as a visited device.

  (6) Since I is a unicast device, the search target device determination unit 123 sets H as a candidate device in the candidate device storage unit 122 according to the priorities of 1) to 6) above (FIG. 15D). )).

  (7) The search target device determination unit 123 selects C from candidate devices in the candidate device storage unit 122, deletes it from the candidate device storage unit 122, determines a route to C, and sets C as a visited device. Store in the visited device storage unit 119. The link cost from the transmission transmission device to the transmission device E adjacent to the determined transmission device C is calculated, and E is set as a candidate device in the candidate device storage unit 122 (FIG. 15 (e)).

  (8) The search target device determination unit 123 selects the device H with the lowest link cost from the transmission transmission device from the candidate devices in the candidate device storage unit 119, deletes H from the candidate device storage unit 119, H is set in the visited device storage unit 119 as a visited device. Next, H to G are set as candidate devices in the candidate device storage unit 122 (FIG. 15 (f)).

  (9) G, E, and D are similarly set in the visited device storage unit 119 as visited devices.

  (10) As a result, all the devices have been searched, and a multicast path including all the receiving devices input from the transmitting / transmitting device has been created (FIG. 16 (g)).

  (11) From the routes calculated in this way, the search target device determination unit 123 deletes unnecessary routes that do not reach the receiving transmission device. When the route is completed, the multicast route completion determination unit 124 reads the route from the searched route storage unit 120 and outputs it to the route setting mechanism (FIG. 16 (h)).

[Second Embodiment]
17 to 19 are diagrams for explaining a second embodiment of the present invention.

  In the following, it is assumed that the topology information including the connection relationship and link cost shown in FIG. 17A and the information of the transmission transmission device and the reception transmission device are input.

  (1) The initial setting unit 115 sets the transmission transmission device A as a visited device in the visited device storage unit 119, and the multicast determination unit 116 determines whether the transmission transmission device A is a multicast transmission device or a unicast transmission device. The transmission transmission device A is determined to be a multicast transmission device.

  (2) The multicast device candidate device determination unit 117 calculates the link cost from the adjacent transmission devices B and I of the transmission transmission device A to A. The link cost of B is “2” and the link cost of I is “3”.

  (3) The multicast device candidate device determination unit 117 refers to the visited device storage unit 119, determines whether B and I are visited devices, or refers to the candidate device storage unit 112 for other transmissions. It is determined whether it is a candidate device from the device, and it is determined that it is neither of them.

  (4) The link costs of B and I and the route from the transmission transmission device A are stored in the search route storage unit 120, and B and I are set as candidate devices from A in the candidate device storage unit 122 (FIG. 17B). )).

  (5) The search target device determination unit 123 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (6) The search target device determination unit 123 searches for a candidate device that minimizes the link cost from the transmission transmission device A, and finds B. A route from A to B is determined, B is deleted from the candidate device storage unit 122, and B is set as a visited device in the visited device storage unit 119.

  (7) Let B be the next search target.

  (8) The multicast route completion determination unit 124 determines whether all the reception transmission devices C, D, and G are included in the route determined with reference to the searched route storage unit 120. Since it is not included, the search is continued.

  (9) The multicast determination unit 116 determines whether the transmission device B to be searched is a multicast transmission device or a unicast transmission device, and determines that B is a multicast transmission device.

  (10) The candidate device determining unit 117 for multicast device starts from A of B's adjacent transmission devices C, F, and G (assuming that the adjacent transmission device does not include the previous transmission device in the searched route). Calculate the link cost of. The link cost of C is “7”, the link cost of F is “6”, and the link cost of G is “4”.

  (11) The multicast device candidate device determination unit 117 refers to the searched route storage unit 120 and the candidate device storage unit 122, and C, F, and G are devices that have already determined a route, or other transmission devices. It is determined whether it is a candidate device, and it is determined that it is neither of them.

  (12) The multicast device candidate device determination unit 117 stores the C, F, and G link costs and the route from A in the search route storage unit 120, and sets C, F, and G as candidate devices from B. Set in the storage unit 122.

  (13) The search target device determination unit 123 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (14) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device that minimizes the link cost from the transmission transmission device A, and finds I. A route from A to I is determined, I is deleted from the candidate device storage unit 122, and I is set as a visited device in the visited device storage unit 119.

  (15) The search target device determination unit 123 sets I as the next search target.

  (16) The multicast path completion determination unit 124 determines whether all the receiving transmission apparatuses C, D, and G are included in the determined path. Since it is not included, the search is continued.

  (17) The multicast determination unit 116 determines whether the search target I is a multicast transmission device or a unicast transmission device, and determines that I is a unicast transmission device.

  (18) The unicast device candidate device determination unit 118 refers to the visited device storage unit 119, the searched route management unit 120, and the candidate device storage unit 122, and the adjacent device of I (on the route searched at this time) It searches for a transmission device that is not searched for, has not been searched, has not been searched for, and is not a candidate device, and finds E and H.

  (19) Since there are a plurality of the devices E and H described above, the unicast device candidate device determination unit 118 performs prioritization using the priority condition.

  (20) Since the number of physical links of E is 5 and the number of physical links of H is 2, the minimum link cost, H, is the highest.

  (21) The unicast device candidate device determination unit 118 stores the link cost from the transmission transmission device A of H and the route from A in the search route storage unit 120, and stores H as a candidate device from I as a candidate device. Set to unit 122.

  (22) H is searched and set in the searched device storage unit 120 (FIG. 18D).

  (23) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (24) Search candidate device storage unit 122 for a candidate device with the lowest link cost from transmission transmission device A, and find G. A route from A to G is determined, G is deleted from the candidate device storage unit 122, and G is set as a visited device in the visited device storage unit 119.

  (25) The search target device determination unit 123 sets G as the next search target.

  (26) The multicast route completion determination unit 124 determines whether all the receiving transmission devices C, D, and G are included in the determined route. Since it is not included, the search is continued.

  (27) The multicast determination unit 116 determines whether the search target G is a multicast transmission device or a unicast transmission device, and determines that G is a multicast transmission device.

  (28) The multicast device candidate device determination unit 117 calculates the link cost from A of the G adjacent transmission devices F and H. The link cost of F is 6 and the link cost of H is 5.

  (29) The multicast device candidate device determination unit 117 refers to the searched route storage unit 120 and the candidate device storage unit 122, and F and H are the devices that have already determined the route, or from other transmission devices. It is determined whether it is a candidate device, and it is determined that F and H are candidate devices.

  (30) When the link cost between A and F already calculated and the link cost via G are compared, the link cost via G is not larger than the link cost already calculated, so F is changed from G Not a candidate device. Regarding H, since the already calculated link cost is 6, the link cost via G is 5, and the route via G is smaller, the following processing is performed.

  (31) The search target device determination unit 123 stores the previous transmission device of H on the searched route. In this case, I is stored in the memory.

  (32) The multicast route completion determination unit 124 stores the link cost of H and the route from A in the search route storage unit 120, and sets H as a candidate device from G in the candidate device storage unit 122.

  (33) The multicast determination unit 116 determines whether I previously stored in the memory is a multicast transmission device or a unicast transmission device, and determines that it is a unicast transmission device.

  (34) The candidate device determination unit 118 for unicast device performs the processes (18) to (22) described above, and reselects candidate devices from I (FIG. 18 (e)).

  1) Search for a transmission device that is a neighboring device of I, is not a visited device, and is not a candidate device, and finds E.

  2) Calculate the link cost from A to E via I. The link cost of E is 7.

  3) The link cost from E to A and the route from A are stored in the search route storage unit 120, and E is a candidate device from I.

  (35) The search target device determination unit 123 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (36) A candidate device that minimizes the link cost from A is searched, and H is found. A route from A to H is determined, H is deleted from the candidate device storage unit 122, and H is set in the visited device storage unit 119.

  (37) The search target device determination unit 123 sets H as the next search target.

  (38) The multicast route completion determination unit 124 determines whether all the receiving transmission devices C, D, and G are included in the determined route. Since it is not included, the search is continued.

  (39) The multicast determination unit 116 determines whether the search target H is a multicast transmission device or a unicast transmission device, and determines that H is a unicast transmission device.

  (40) The candidate device determination unit 118 for the unicast transmission device refers to the visited device storage unit 119 and the candidate device storage unit 122, and selects a transmission device that is an adjacent device of H and is not a visited device but a candidate device. Searches but there is none, so the process proceeds to the next process.

  (41) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (42) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device with the lowest link cost from A and finds F. A route from A to F is determined, F is deleted from the candidate device storage unit 122, and F is set as a visited device in the visited device storage unit 119.

  (43) Let F be the next search target.

  (44) The multicast route completion determination unit 124 refers to the searched route storage unit 120 and determines whether all the receiving transmission devices (C, D, G) are included in the determined route. Since it is not included, the search is continued.

  (45) The multicast determination unit 116 determines whether F to be searched is a multicast transmission device or a unicast transmission device, and determines that F is a unicast transmission device.

  (46) The unicast device candidate device determination unit 118 refers to the visited device storage unit 119, the search route storage unit 120, and the candidate device storage unit 122, is an adjacent device of F, and has not been searched. A search is made for a transmission device that is neither a device for which a route has been determined nor a candidate device.

  (47) The search target device determination unit 123 determines whether there is a candidate device and confirms that there is one or more candidate devices.

  (48) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device that minimizes the link cost from the transmission transmission device A, and finds E. At this time, C is also a candidate apparatus having the minimum link cost, but E is selected here. A route from A to E is determined, E is deleted from the candidate device storage unit 122, and E is set as a visited device in the visited device storage unit 119.

  (49) Let E be the next search target.

  (50) The multicast path completion determination unit 124 determines whether all the receiving transmission devices C, D, and G are included in the determined path. Since it is not included, the search is continued.

  (51) The multicast determination unit 11 determines whether E to be searched is a multicast transmission device or a unicast transmission device, and determines that E is a unicast transmission device.

  (52) Unicast device candidate device determination section 118 searches for a transmission device that is an adjacent device of E and has not been searched for, has not been determined, and is not a candidate device, and finds D and J. To do.

  (53) Since there are a plurality of the devices (D, J), the candidate device determining unit 118 for unicast devices performs prioritization using the priority condition.

  (54) Although both D and J are unicast transmission apparatuses, D has the highest number of physical links and is the reception transmission apparatus, so D is the highest.

  (55) The link cost from A of D is calculated, and the link cost and the route from A are stored in the search route storage unit 120. D is set in the candidate device storage unit 122 as a candidate device from E.

  (56) The search target device determination unit 123 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (57) The candidate device having the minimum link cost from A is searched from the candidate device storage unit 122, and C is found. A route from A to C is determined, C is deleted from the candidate device storage unit 122, and C is set as a visited device in the visited device storage unit 119.

  (58) Let C be the next search target.

  (59) The multicast route completion determination unit 124 refers to the searched route storage unit 120 and determines whether all the receiving transmission devices C, D, and G are included in the determined route. Since it is not included, the search is continued.

  (60) The multicast determination unit 116 determines whether C to be searched is a multicast transmission device or a unicast transmission device, and determines that C is a multicast transmission device.

  (61) The multicast device candidate apparatus determination unit 117 calculates the link cost from A of the C adjacent transmission apparatus E. The link cost of E is 9.

  (62) The multicast device candidate device determination unit 117 refers to the searched route storage unit 120 and the candidate device storage unit 122, and E is a device whose route has already been determined or a candidate from another transmission device. And E is determined to be the device that has determined the route.

  (63) When the link cost between A and E already calculated and the link cost via C are compared, the link cost via C is larger than the link cost already calculated. Not a candidate device.

  (64) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (65) Search for a candidate device that minimizes the link cost from A and find D. A route from A to D is determined, and D is deleted from the candidate device storage unit 122. D is set as a visited device in the visited device storage unit 119 (FIG. 19 (h)).

  (66) Let D be the next search target.

  (67) The multicast route completion determination unit 124 determines whether all the reception transmission devices C, D, and G are included in the determined route. Since it is included in all, the search is terminated.

  (68) The route output unit 121 deletes a route that does not communicate with the receiving device (route between BF and GH) from the searched route storage unit 120 and outputs the determined multicast route.

[Third embodiment]
20 to 22 are views for explaining a third embodiment of the present invention.

  In the following, it is assumed that the topology information including the connection relationship and link cost shown in FIG. 20A and the input of the transmission transmission device / reception transmission device are received.

  (1) The initial setting unit 115 sets the transmission transmission device A as a visited device in the visited device storage unit 119, and the multicast determination unit 116 determines whether the transmission transmission device A is a multicast transmission device or a unicast transmission device. And A is determined to be a multicast transmission device.

  (2) The multicast device candidate device determination unit 117 calculates the link cost from A of the adjacent transmission devices B, C, and D of A. The link cost of B is 11, the link cost of C is 1, and the link cost of D is 10.

  (3) The multicast device candidate device determination unit 117 refers to the visited storage unit 119, and C and D are visited devices, or refers to the candidate management storage unit 122, and candidates from other transmission devices. It is determined whether it is a device, and neither is determined.

  (4) The link cost of B, C, D and the route from A are stored in the search route storage unit 120, and B, C, D are set as candidate devices from A (FIG. 20B).

  (5) The search target device determination unit 123 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (6) The search target device determination unit 123 refers to the candidate device storage unit 122 and searches for a candidate device with the minimum link cost from A to find C. A route from A to C is determined, C is deleted from the candidate device storage unit 122, and C is set as a visited device in the visited device storage unit 119.

  (7) Let C be the next search target.

  (8) The multicast route completion determination unit 124 determines whether all the receiving transmission devices (E, F, I) are included in the determined route. Since it is not included, the search is continued.

  (9) The multicast determination unit 116 determines whether C to be searched is a multicast transmission device or a unicast transmission device, and determines that C is a unicast transmission device.

  (10) The candidate device determination unit 118 for the unicast device refers to the candidate device storage unit 122, the visited device storage unit 119, and the searched route storage unit 120, and the adjacent device of C (on the route searched at this time) It searches for a transmission device that is not searched for, is not already searched, has not been searched for, and is not a candidate device, and finds F and G.

  (11) Since there are a plurality of the devices F and G, the unicast device candidate device determination unit 118 performs prioritization using the priority condition.

  (12) Both F and G have the minimum number of physical links of 2, but since F is a multicast transmission device and G is a unicast transmission device, F is the highest and F is selected.

  (13) The link cost of F from A and the route from A are stored in the search route storage unit 120, set as a candidate device from C, and set in the candidate device storage unit 122 (FIG. 20C).

  (14) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (15) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device having a minimum link cost from A and finds D. A route from A to D is determined, and D is deleted from the candidate device storage unit 122. D is set in the visited device storage unit 119 as a visited device.

  (16) Let D be the next search target.

  (17) The multicast route completion determination unit 124 determines whether all the receiving transmission devices E, F, and I are included in the determined route. Since it is not included, the search is continued.

  (18) The multicast determination unit 116 determines whether D to be searched is a multicast transmission device or a unicast transmission device, and determines that D is a multicast transmission device.

  (19) The multicast device candidate device determination unit 117 starts the link cost from A of D adjacent transmission devices E and H (assuming that the adjacent transmission device does not include the previous transmission device in the searched route). Calculate The link cost of E is 60, and the link cost of H is 15.

  (20) The multicast device candidate device determination unit 117 refers to the visited device storage unit 119 and the candidate device storage unit 122 to determine whether E and H are visited devices or candidate devices from other transmission devices. It is judged whether it is neither of them.

  (21) The multicast device candidate device determination unit 117 stores the link costs of E and H and the route from A in the search route storage unit 120, and stores E and H as candidate devices from B in the candidate device storage unit 122. Set.

  (22) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (23) The search target device determination unit 123 searches for a candidate device that minimizes the link cost from A and finds B. A route from A to B is determined, and B is deleted from the candidate device storage unit 122. Also, B is set in the visited device storage unit 119.

  (24) Let B be the next search target.

  (25) The multicast route completion determination unit 124 refers to the searched route determination unit 120 and determines whether all the reception transmission devices E, F, and I are included in the determined route. Since it is not included, the search is continued.

  (26) The multicast determination unit 116 determines whether B to be searched is a multicast transmission device or a unicast transmission device, and determines that B is a multicast transmission device.

  (27) The multicast device candidate device determination unit 117 calculates the link cost from A of the adjacent transmission device F of B. The link cost of F is 14.

  (28) The multicast device candidate device determination unit 117 refers to the visited device storage unit 119 and the candidate device storage unit 122, and F is a visited device or a candidate device from another transmission device. And determine that the device is a candidate device.

  (29) When the multicast device candidate device determination unit 117 compares the already calculated link cost between A and F with the link cost via B, the already calculated link cost becomes the link via B Since it is larger than the cost, the following processing is executed.

  (30) The transmission device immediately before F on the searched route is stored in the memory. In this case, C is stored.

  (31) The search target device determination unit 123 determines the link cost of F via B and the route from A, sets F as a candidate device from B, deletes F from the candidate device storage unit 122, and visits F To the completed device storage unit 119.

  (32) The multicast determination unit 116 determines whether C stored earlier is a multicast transmission device or a unicast transmission device, and determines that it is a unicast transmission device.

  (33) The candidate device determination unit 118 for the unicast device refers to the visited device storage unit 119 and the candidate device storage unit 122, performs the processes from (10) to (14) in the same manner, and selects candidates from C. The device is selected again (FIG. 21 (e)).

  1) Search for a transmission apparatus that is an adjacent apparatus of C, is not a visited apparatus, and is not a candidate apparatus, and finds G.

  2) Since a plurality of the devices (G) are not present and one is present, the process proceeds to the next process.

  3) Calculate the link cost from A to G via C. The link cost of G is 2.

  4) The link cost from A of G and the route from A are stored in the search route storage unit 120 and stored in the candidate device storage unit 122 as a candidate device from C.

  (34) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (35) The search target device determination unit 123 searches for a candidate device with the lowest link cost from A and finds G. A route from A to G is determined, G is deleted from the candidate device storage unit 122, and G is set in the visited device storage unit 119.

  (36) Let G be the next search target.

  (37) The multicast route completion determination unit 124 refers to the searched route storage unit 120 and determines whether all the received transmission devices (E, F, I) are included in the determined route. Since it is not included, the search is continued.

  (38) The multicast determination unit 116 determines whether the search target G is a multicast transmission device or a unicast transmission device, and determines that G is a unicast transmission device.

  (39) The candidate device determination unit 118 for the unicast device refers to the visited device storage unit 119, the searched route storage unit 120, and the candidate device storage unit 122, and is an adjacent device of G and not a visited device. Search for a transmission device that is not a candidate device and find I.

  (40) Since a plurality of devices (I) are not present and one is present, the process proceeds to the next process.

  (41) The unicast device candidate device determination unit 118 calculates the link cost from A to I via G. The link cost of I is 3.

  (42) The link cost from A of I and the route from A are stored in the search route storage unit 120 and set in the candidate device storage unit 122 as a candidate device from G.

  (43) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (44) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device with the lowest link cost from A and finds I. A route from A to I is determined, and I is deleted from the candidate device storage unit 122. I is set in the visited device storage unit 119 as a visited device.

  (45) Let I be the next search target.

  (46) The multicast path completion determination unit 124 determines whether all the receiving transmission devices E, F, and I are included in the determined path. Since it is not included, the search is continued.

  (47) The multicast determination unit 116 determines whether the search target I is a multicast transmission device or a unicast transmission device, and determines that I is a multicast transmission device.

  (48) The multicast device candidate device determination unit 117 calculates the link cost from A of the adjacent transmission device H of I. The link cost of H is 4.

  (49) The multicast device candidate device determination unit 117 refers to the searched route storage unit 120 and the candidate device storage unit 122, and H is a device for which a route has already been determined or a candidate device from another transmission device. To determine whether it is a candidate device.

  (50) Comparing the already calculated link cost between A and H and the link cost via I, the already calculated link cost is larger than the link cost via I. Execute.

  (51) The search target device determination unit 123 stores the previous transmission device of H on the searched route in the memory. In this case, D is stored.

  (52) The link cost of H via I and the route from A are determined, H is deleted from candidate device storage unit 122 as a candidate device from I, and H is set in visited device storage unit 119 (FIG. 21). (G)).

  (53) The multicast determination unit 116 determines whether D stored earlier in (51) is a multicast transmission device or a unicast transmission device, determines that it is a multicast transmission device, and proceeds to the next process.

  (54) The multicast device candidate device determination unit 117 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (55) The search target device determination unit 123 searches for a candidate device that minimizes the link cost from A and finds H. A route from A to H is determined, H is deleted from the candidate device storage unit 122, H is a visited device, and is set in the visited device storage unit 119.

  (56) Let H be the next search target.

  (57) It is determined whether all the receiving transmission devices E, F, and I are included in the determined path. Since it is not included, the search is continued.

  (58) The multicast determination unit 116 determines whether the search target H is a multicast transmission apparatus or a unicast transmission apparatus, and determines that H is a multicast transmission apparatus.

  (59) The multicast device candidate device determination unit 117 calculates the link cost from A of the H adjacent transmission device D. The link cost of D is 9.

  (60) The multicast device candidate device determination unit 117 refers to the searched route storage unit 120 and the candidate device storage unit 122, and D is a device that has already determined a route or a candidate device from another transmission device. It is determined whether or not the device has a determined route.

  (61) When the already calculated link cost between A and D and the link cost via H are compared, the link cost already calculated is larger than the link cost via H, so the next processing is executed. To do.

  (62) The multicast device candidate device determination unit 117 stores the transmission device immediately before D on the searched route in the memory. In this case, A is stored.

  (63) The multicast device candidate device determination unit 117 stores the link cost of D via H and the route from A in the search route storage unit 120, sets D as a candidate device from H, and stores it in the candidate device storage unit 122. This is set (FIG. 21 (h)).

  (64) The multicast determination unit 116 determines whether A stored in the memory in (62) is a multicast transmission device or a unicast transmission device, determines that it is a multicast transmission device, and proceeds to the next process.

  (65) The multicast device candidate device determination unit 117 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (66) The search target device determination unit 123 searches for a candidate device having a minimum link cost from A and finds D. A route from A to D is determined, and D is deleted from the candidate device storage unit 122. Also, D is set in the visited device storage unit 119 as a visited device.

  (67) Let D be the next search target.

  (68) The multicast route completion determination unit 124 determines whether all the reception transmission devices E, F, and I are included in the determined route. Since it is not included, the search is continued.

  (69) The multicast determination unit 116 determines whether D to be searched is a multicast transmission device or a unicast transmission device, and determines that D is a multicast transmission device.

  (70) The candidate device determination unit 118 for the unicast device calculates the link cost from A of the adjacent transmission devices A and E of D. The link cost of A is 19, and the link cost of E is 59.

  (71) With reference to the searched route storage unit 120 and the candidate device storage unit 122, it is determined whether A and E are devices that have already determined a route or candidate devices from other transmission devices. Is a device whose path is determined, and E is a candidate from another transmission device.

  (72) The candidate device determining unit 118 for the unicast device has already been calculated by comparing the link cost between A and A that has already been calculated (link cost is zero) and the link cost via D. Since the link cost is not greater than the link cost via D, A is not a candidate device from D. In addition, when the already calculated link cost between A and E is compared with the link cost via D, the already calculated link cost is larger than the link cost via D. Do.

  (73) The unicast / yst device candidate device determination unit 118 stores the transmission device immediately before E on the searched route in the memory. In this case, D is stored.

  (74) The link cost of E via D and the route from A are stored in the search route storage unit 120, and E is set as a candidate device from H and set in the candidate device storage unit 122 (FIG. 22 (i)).

  (75) The multicast determination unit 116 determines whether D stored in (73) is a multicast transmission device or a unicast transmission device, determines that it is a multicast transmission device, and proceeds to the next process.

  (76) The multicast device candidate device determination unit 117 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (77) The search target device determination unit 123 searches for a candidate device with the lowest link cost from A and finds F. A route from A to F is determined, F is deleted from the candidate device storage unit 122, and F is set in the visited device storage unit 119.

  (78) Let F be the next search target.

  (79) The multicast path completion determination unit 124 determines whether all the receiving transmission devices E, F, and I are included in the determined path. Since it is not included, the search is continued.

  (80) The multicast determination unit 116 determines whether F to be searched is a multicast transmission device or a unicast transmission device, and determines that F is a multicast transmission device.

  (81) The multicast device candidate device determination unit 117 calculates the link cost from A of the F adjacent transmission device I. The link cost of I is 34.

  (82) The multicast device candidate device determination unit 117 refers to the searched route storage unit 120 and the candidate device storage unit 112 and is a device that has already determined a route or a candidate device from another transmission device. I is determined to be the device whose route has been determined.

  (83) When the multicast device candidate device determination unit 117 compares the already calculated link cost between A and I with the link cost via F, the already calculated link cost is determined as the link via D. I is not a candidate device from D because it is not greater than the cost.

  (84) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (85) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device with the lowest link cost from A and finds E. A route from A to E is determined, E is deleted from the candidate device storage unit 122, and E is set in the visited device storage unit 119.

  (86) Let E be the next search target.

  (87) The multicast path completion unit 124 determines whether all the receiving transmission devices E, F, and I are included in the determined path. Since all are included, the search is terminated (FIG. 22 (j)).

  (88) The route output unit 121 deletes the route that does not communicate with the receiving transmission device from the search route storage unit 120 and outputs the determined multicast route (FIG. 22 (k)).

[Fourth embodiment]
23 to 25 are diagrams for explaining a fourth embodiment of the present invention.

  In the following, it is assumed that topology information including the connection relationship and link cost shown in FIG. 23A and the input of the transmission / reception transmission apparatus are received.

  (1) A random ratio 0 is set in the random ratio processing unit 131.

  (2) The initial setting unit 115 sets the transmission transmission device A as a visited device in the visited device storage unit 119. The multicast determination unit 116 determines whether A is a multicast transmission device or a unicast transmission device, and determines that A is a multicast transmission device.

  (3) The multicast device candidate device determination unit 117 calculates the link cost from A of the adjacent transmission devices B and C of A. The link cost of B is 1, and the link cost of C is 1.

  (4) The multicast device candidate device determination unit 117 refers to the visited device storage unit 119 and the candidate device storage unit 122, and B and C are visited devices or candidate devices from other transmission devices. It is judged whether or not it is neither of them.

  (5) The multicast device candidate device determination unit 117 stores the link costs of B and C and the route from A in the search route storage unit 120, and stores B and C as candidate devices from A in the candidate device storage unit 122. Set.

  (6) The search target device determination unit 123 refers to the candidate device storage unit 122 to determine whether there is a candidate device, and confirms that there is one or more candidate devices.

  (7) When the search target device determining unit 123 searches for a candidate device that minimizes the link cost from A, two of B and C are found. In this embodiment, C is selected. A route from A to C is determined, C is deleted from the candidate device storage unit 122, and C is set in the visited device storage unit 119.

  (8) Let C be the next search target.

  (9) The multicast route completion determination unit 124 refers to the searched route storage unit 120 and determines whether all the receiving transmission devices B and G are included in the determined route. Since it is not included, the search is continued.

  (10) The multicast determination unit 116 determines whether C to be searched is a multicast transmission device or a unicast transmission device, and determines that C is a unicast transmission device.

  (11) The unicast cast device candidate device determination unit 117 is an adjacent device of C (not including the previous transmission device on the route searched for at this time), and the visited device storage unit 119, With reference to the candidate device storage unit 122, a transmission device that is neither a visited device nor a candidate device is searched, and D and E are found.

  (12) The random ratio processing unit 131 does not perform random selection because the random ratio is zero.

  (13) Since there are a plurality of the above devices (D, E), the candidate device determination unit 118 for unicast devices performs prioritization using the priority condition.

  (14) Both D and E have two physical links and are multicast transmission apparatuses. In the embodiment of the present invention, D is the highest and D is selected.

  (15) The unicast device candidate device determination unit 118 stores the link cost of D from A and the route from A in the search route storage unit 120, sets it as a candidate device from C, and sets it in the candidate device storage unit 122 (FIG. 23C).

  (16) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (17) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device with the lowest link cost from A and finds B. A route from A to B is determined, B is deleted from the candidate device storage unit 122, and B is set in the visited device storage unit 119.

  (18) Let B be the next search target.

  (19) The multicast path completion determination unit 124 determines whether all the receiving transmission devices (B, G) are included in the determined path. Since it is not included, the search is continued.

  (20) The multicast determination unit 116 determines whether B to be searched is a multicast transmission device or a unicast transmission device, and determines that B is a multicast transmission device.

  (21) The multicast device candidate device determination unit 117 proceeds to the next process because there is no adjacent transmission device B (FIG. 23 (d)).

  (22) The search target device determination unit 123 determines whether there is a candidate device in the candidate device storage unit 122 and confirms that there is one or more candidate devices.

  (23) The search target device determination unit 123 searches the candidate device storage unit 122 for a candidate device with the lowest link cost from A and finds D. A route from A to D is determined, D is deleted from the candidate device storage unit 122, and D is set in the visited device storage unit 119.

  (24) Let D be the next search target.

  (25) The multicast path completion determination unit 124 determines whether all the receiving transmission devices (B, G) are included in the determined path. Since it is not included, the search is continued.

  (26) The multicast determination unit 116 determines whether D to be searched is a multicast transmission device or a unicast transmission device, and determines that D is a multicast transmission device.

  (27) The multicast device candidate device determination unit 117 calculates the link cost from A of the adjacent transmission device F of D. The link cost of F is 3.

  (28) The multicast device candidate device determination unit 117 refers to the searched route storage unit 120 and the candidate device storage unit 122 to determine whether F has already determined a route or candidate devices from other transmission devices. It is judged whether or not it is neither of them.

  (29) The multicast device candidate device determination unit 117 stores the link cost of F and the route from A in the search route storage unit 120, and sets F as a candidate device from F in the candidate device storage unit 122 (FIG. 24 (d)).

  (30) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (31) The search target device determination unit 123 searches for a candidate device having the minimum link cost from A and finds F. The route from A to F is determined, and the candidate device is deleted from the candidate device storage unit 122. F is set in the visited device storage unit 119.

  (32) Let F be the next search target.

  (33) The multicast route completion determination unit 124 determines whether all the receiving transmission devices (B, G) are included in the determined route. Since it is not included, the search is continued.

  (34) The multicast determination unit 116 determines whether F to be searched is a multicast transmission device or a unicast transmission device, and determines that F is a multicast transmission device.

  (35) The multicast device candidate apparatus determination unit 117 proceeds to the next process because there is no F adjacent transmission apparatus (FIG. 24F).

  (36) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is no candidate device.

  (37) The random ratio processing unit 131 increases the random ratio to 0.01, and resets the visited devices in the visited device storage unit 119, the candidate devices in the candidate device storage unit 122, and the link cost of each device.

  (38) The random ratio processing unit 131 sets the transmission transmission device A as a visited device in the visited device storage unit 119 and restarts the search.

  (39) The multicast determination unit 116 determines whether A is a multicast transmission device or a unicast transmission device, and determines that A is a multicast transmission device.

  (40) The multicast device candidate device determination unit 117 calculates the link cost from A of the adjacent transmission devices B and C of A. The link cost of B is 1, and the link cost of C is 1.

  (41) The multicast device candidate device determination unit 117 refers to the visited device storage unit 119 and the candidate device storage unit 122 to determine whether B and C are visited devices or candidate devices from other transmission devices. It is judged whether or not it is neither of them.

  (42) The multicast device candidate device determination unit 117 stores the link costs of B and C and the route from A in the search route management unit 120, and stores B and C as candidate devices from A in the candidate device storage unit 122. It sets (FIG. 24 (g)).

  (43) The search target device determination unit 123 determines whether there is a candidate device in the candidate device storage unit 122 and confirms that there is one or more candidate devices.

  (44) When the search target device determination unit 123 searches for a candidate device that minimizes the link cost from A, two devices B and C are found. In this embodiment, C is selected. A route from A to C is determined, C is deleted from the candidate device storage unit 122, and C is set in the visited device storage unit 119.

  (45) Let C be the next search target.

  (46) The multicast route completion determination unit 124 refers to the searched route storage unit 120 and determines whether all the received transmission devices (B, G) are included in the determined route. Since it is not included, the search is continued.

  (47) The multicast determination unit 116 determines whether C to be searched is a multicast transmission device or a unicast transmission device, and determines that C is a unicast transmission device.

  (48) The candidate device determination unit 118 for the unicast device refers to the visited device storage unit 119 and the candidate device storage unit 122, and the adjacent device of C (the previous transmission device on the route searched for at this time is In this case, a transmission device that has not been visited and is not a candidate device is searched for, and D and E are found.

  (49) The random ratio processing unit 131 uses a random number from 0 to less than 1, and performs random selection when the random ratio is smaller than 0.01. In this embodiment, random selection is performed.

  (50) It is assumed that E is randomly selected from D and E by the random ratio processing unit 131.

  (51) The random ratio processing unit 131 saves the link cost of E from A and the route from A in the search route storage unit 120, sets it as a candidate device from C, and sets E in the candidate device storage unit 122.

  (52) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (53) The search target device determination unit 123 refers to the candidate device storage unit 122, searches for a candidate device with the minimum link cost from A, and finds B. A route from A to B is determined and B is deleted from the candidate device storage unit 122. Also, B is set in the visited device storage unit 119.

  (54) Let B be the next search target.

  (55) The multicast route completion determination unit 124 refers to the searched route storage unit 120 and determines whether all the receiving transmission devices (B, G) are included in the determined route. Since it is not included, the search is continued.

  (56) The multicast determination unit 116 determines whether B to be searched is a multicast transmission device or a unicast transmission device, and determines that B is a multicast transmission device.

  (57) The multicast device candidate apparatus determination unit 117 proceeds to the next process because there is no adjacent transmission apparatus for B (FIG. 25 (i)).

  (58) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (59) The search target device determination unit 123 searches for a candidate device that minimizes the link cost from A and finds E. A route from A to E is determined, E is deleted from the candidate device storage unit 122, and E is set in the visited device storage unit 119.

  (60) Let E be the next search target.

  (61) The multicast path completion determination unit 124 determines whether all the receiving transmission devices (B, G) are included in the determined path. Since it is not included, the search is continued.

  (62) The multicast determination unit 116 determines whether E to be searched is a multicast transmission device or a unicast transmission device, and determines that E is a multicast transmission device.

  (63) The multicast device candidate device determination unit 117 calculates the link cost from A of the adjacent transmission device G of E. The link cost of G is 3.

  (64) With reference to the visited device storage unit 119 and the candidate device storage unit 122, it is determined whether G is a visited device or a candidate device from another transmission device, and it is determined that it is neither of them.

  (65) The multicast device candidate device determination unit 117 stores the link cost of G and the route from A in the search route storage unit 120, and sets G as a candidate device from E in the candidate device storage unit 122 (FIG. 25 (j)).

  (66) The search target device determination unit 123 refers to the candidate device storage unit 122, determines whether there is a candidate device, and confirms that there is one or more candidate devices.

  (67) The search target device determination unit 123 searches for a candidate device with the lowest link cost from A and finds G. A route from A to G is determined, G is deleted from the candidate device storage unit 122, and G is set in the visited device storage unit 119.

  (68) Let G be the next search target.

  (69) The multicast route completion determination unit 124 refers to the searched route storage unit 120 and determines whether all the receiving transmission devices (B, G) are included in the determined route. Therefore, the search is terminated (FIG. 25 (k)).

  (70) The route output unit 121 acquires the determined multicast route from the searched route storage unit 120 and outputs it.

  The flowcharts shown in FIG. 4 to FIG. 9 and FIG. 11 to FIG. 13 can be constructed as a program, installed in a computer used as a multicast route calculation device, executed, or distributed via a network. Is possible.

  In addition, the constructed program can be stored in a portable storage medium such as a hard disk, a flexible disk, or a CD-ROM, and can be installed in a computer or distributed.

  The present invention is not limited to the above-described embodiments and examples, and various modifications and applications can be made within the scope of the claims.

  The present invention is applicable to a technique for setting a multicast route for a communication network in which a multicast transmission apparatus and a unicast transmission apparatus are mixed, such as the MPLS technique.

It is a figure for demonstrating the principle of this invention. It is a principle block diagram of this invention. It is a block diagram of the multicast route calculation apparatus in the 1st Embodiment of this invention. It is a flowchart of the multicast route calculation method in the 1st Embodiment of this invention. It is a flowchart (the 1) of the detailed operation | movement in the 1st Embodiment of this invention. It is a flowchart (the 2) of the detailed operation | movement in the 1st Embodiment of this invention. It is a flowchart (the 3) of the detailed operation | movement in the 1st Embodiment of this invention. It is a flowchart (the 4) of the detailed operation | movement in the 1st Embodiment of this invention. It is a flowchart (the 5) of the detailed operation | movement in the 1st Embodiment of this invention. It is a block diagram of the multicast route calculation apparatus in the 2nd Embodiment of this invention. It is a flowchart of the multicast route calculation method in the 2nd Embodiment of this invention. It is a flowchart of the detailed operation | movement in the 2nd Embodiment of this invention. It is a flowchart of the detailed operation | movement in the 2nd Embodiment of this invention. It is FIG. (1) for demonstrating the 1st Example of this invention. It is FIG. (2) for demonstrating the 1st Example of this invention. It is FIG. (3) for demonstrating the 1st Example of this invention. It is FIG. (1) for demonstrating the 2nd Example of this invention. It is FIG. (2) for demonstrating the 2nd Example of this invention. It is FIG. (3) for demonstrating the 2nd Example of this invention. It is FIG. (1) for demonstrating the 3rd Example of this invention. It is FIG. (2) for demonstrating the 3rd Example of this invention. It is FIG. (3) for demonstrating the 3rd Example of this invention. It is FIG. (1) for demonstrating the 4th Example of this invention. It is FIG. (2) for demonstrating the 4th Example of this invention. It is FIG. (3) for demonstrating the 4th Example of this invention. It is a figure for demonstrating the conventional multicast route calculation apparatus. It is FIG. (1) for demonstrating a prior art. It is FIG. (2) for demonstrating a prior art. It is FIG. (3) for demonstrating a prior art.

Explanation of symbols

111 Topology Information Input Unit 112 Topology Information Storage Unit, Topology Information Storage Unit 113 Path Restriction Condition Input Unit 114 Restriction Condition Storage Unit, Restriction Condition Setting Unit 115 Initial Setting Unit, Initial Setting Unit 116 Multicast Determination Unit, Multicast Determination Unit 117 Multicast Device Candidate apparatus determining means, multicast apparatus candidate apparatus determining section 118 Unicast apparatus candidate apparatus determining means, unicast apparatus candidate apparatus determining section 119 Visited apparatus storage means, visited apparatus storage section 120 Search path storage means, search Route storage unit 121 Route output unit 122 Candidate device storage unit, candidate device storage unit 123 Search target device determination unit, search target device determination unit 124 Route completion determination unit, multicast route completion determination unit 131 Random ratio processing unit

Claims (6)

A multicast route calculation method that calculates a multicast route by applying the Dijkstra multicast route calculation method using the topology information and route setting constraint conditions of the input communication network in a communication network in which multicast transmission devices and unicast transmission devices are mixed. There,
An initial setting step of storing information on the transmission source device in a visited device storage means for setting as visited for a device that has already been searched;
A multicast determination step for determining whether the device to be searched is a multicast transmission device or a unicast transmission device with reference to topology information storage means storing topology information including connection relation and link cost;
In the multicast determination step, when it is determined as a unicast transmission device, a neighboring device is extracted based on the topology information, and a candidate device storage means in which a candidate transmission device for search is stored based on the neighboring device; The visited device storage means for storing the already searched device as the visited device is referred to, and the device that is a candidate device or the device other than the visited device is stored in the memory. In the case where there are a plurality of devices stored in the memory, priority is given based on a predetermined condition, and the adjacent device having the highest priority is set as a candidate device in the candidate device storage means. When there is one device stored and stored in the memory, the candidate device is stored in the candidate device storage means, and the route from the transmission transmission device to the candidate device and the link cost are searched. A candidate device determination step for unicast device to be stored in the storage means,
If it is determined that the multicast transmission device is the multicast transmission device in the multicast determination step, the adjacent device is extracted by the Dijkstra multicast route calculation method, and the candidate device selected by referring to the candidate device storage unit from the adjacent device is already the If the candidate device is determined by the candidate device determination step for unicast device, the candidate device is reselected from the neighboring devices of the unicast transmission device, stored in the candidate device storage means, and the transmission transmission device A candidate device determination step for multicast device that stores the route from the candidate device to the candidate device and the link cost in the searched route storage means;
A search target device determination step of searching the candidate device storage means for a candidate device having a minimum link cost from the transmission transmission device of each candidate device stored in the candidate device storage means, and storing the searched candidate device in the visited storage means;
When the route from the transmission transmission device to all reception transmission devices is found with reference to the searched route storage means, the transmission device stored in the search route storage means is read out and output, and found. If not, a route completion determination step that repeats the steps after the multicast determination step is performed. Manage the random ratio, increase the random ratio, reset the information of the search path storage means, the candidate device storage means, and the visited device storage means, and resume the search with the transmission transmission device as the search target device And steps to
In accordance with the random ratio, further performing a random ratio processing step comprising: notifying the candidate device determining means for unicast device whether to comply with a condition for giving priority,
In the candidate device determination step for the unicast device,
The step of selecting one candidate device from the candidate device storage means according to a condition for randomly selecting a candidate device or giving the priority according to a notification from the random ratio processing step. 2. The multicast route calculation method according to 1. A multicast route calculation device that calculates a multicast route by applying the Dijkstra multicast route calculation method using topology information and route setting constraint conditions of the input communication network in a communication network in which multicast transmission devices and unicast transmission devices are mixed. There,
Topology information storage means storing topology information including the connection relationship and link cost of each device;
Constraint storage means for storing route constraint conditions;
Visited device storage means for storing already searched devices as visited devices;
Candidate device storage means for storing candidate devices;
Search route storage means for storing the route and link cost to the transmission transmission device of each device,
Initial setting means for storing information on the transmission source device in the visited device storage means;
Multicast determination means for referring to the topology information in the topology information storage means and determining whether the search target device is a multicast transmission device or a unicast transmission device;
When it is determined as a unicast transmission device by the multicast determination means, the neighboring device is extracted based on the topology information, and the candidate device storage means and the visited device storage means are referred to based on the adjacent device, When a device that is a candidate device from the neighboring devices or a device other than a visited device is stored in a memory, and there are a plurality of the neighboring devices stored in the memory, A priority is given based on a predetermined condition, the neighboring device having the highest priority is stored in the candidate device storage means as a candidate device, and if there is one neighboring device stored in the memory, the neighboring device Unicast device candidate device determining means for storing a device in the candidate device storage means, and storing a route from the candidate device to the transmission transmission device and a link cost in the search route storage means;
When the multicast determination unit determines that the device is a multicast transmission device, an adjacent device is extracted by the Dijkstra multicast route calculation method, and the candidate device selected by referring to the candidate device storage unit from the adjacent device is already If the candidate device is determined by the unicast device candidate device determining means, the candidate device is reselected from the adjacent devices of the unicast transmission device, stored in the candidate device storage means, and the candidate device. A candidate device determining unit for multicast device for storing the route from the transmission device to the transmission device and the link cost in the search route storage unit
Search target device determination for extracting a candidate device having the lowest link cost from the transmission transmission device of each candidate device stored in the candidate device storage means from the candidate device storage means and storing it in the visited device storage means Means,
If the route to all the receiving transmission devices is found with reference to the searched route storage means, the candidate device stored in the searched route storage means is read and output, and if not found, A multicast route calculation device comprising: a multicast determination unit; a candidate device determination unit for the unicast device; a candidate device determination unit for the multicast device; a route completion determination unit that repeats the processing of the search target device determination unit. . Manage the random ratio, increase the random ratio, reset the information of the search route storage means, the candidate device storage means, and the visited device storage means, and resume the search with the transmission transmission device as the search target device Means,
In accordance with the random ratio, further comprising a means for notifying the candidate device determining means for unicast device whether to comply with a condition for giving priority, or a random ratio processing means comprising:
The unicast device candidate device determining means includes:
The multicast route calculation according to claim 3, further comprising means for selecting a candidate device at random according to a notification from the random ratio processing unit or selecting one candidate device according to a condition for assigning the priority. apparatus. A multicast route calculation program that calculates the multicast route by applying the Dijkstra multicast route calculation method using the topology information and route setting constraint conditions of the input communication network in a communication network where multicast transmission devices and unicast transmission devices coexist. There,
Topology information storage means storing topology information including the connection relationship and link cost of each device;
Constraint storage means for storing route constraint conditions;
Visited device storage means for storing already searched devices as visited devices;
Candidate device storage means for storing candidate devices;
Search route storage means for storing the route and link cost to the transmission transmission device of each device,
On a computer with
A multicast route calculation program for executing a process for realizing the multicast route calculation method according to claim 1 or 2. A multicast route calculation program for calculating a multicast route by applying a Dijkstra multicast route calculation method using topology information and route setting constraint conditions of the input communication network in a communication network in which multicast transmission devices and unicast transmission devices are mixed A stored storage medium,
Topology information storage means storing topology information including the connection relationship and link cost of each device;
Constraint storage means for storing route constraint conditions;
Visited device storage means for storing already searched devices as visited devices;
Candidate device storage means for storing candidate devices;
Search route storage means for storing the route and link cost to the transmission transmission device of each device,
On a computer with
A storage medium storing a multicast route calculation program, wherein a program for executing a process for realizing the multicast route calculation method according to claim 1 or 2 is stored.

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