Method and Apparatus for Configuring and Managing a Robust Overlay Multicast Tree

• US 20080222277A1
• Filed: 11/04/2005
• Published: 09/11/2008
• Est. Priority Date: 11/06/2004
• Status: Abandoned Application

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Park, Ju Young, Kang, Shin Gak, Kim, Eun Sook, Jeong, Ok Jo, Kwon, Ei Yeon
• Application Number:
  US11/577,381
• Publication Number:
  US 20080222277A1
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 41/0823 characterised by the purposes of a change of settings, e.g. optimising configuration for enhancing reliability for optimising operational conditions of wireless networks H04W24/02
• CPC Class Codes: H04L 67/55 Push-based network services
• CPC Class Codes: H04L 67/61 taking into account QoS or priority requirements

Abstract

Provided is a method and apparatus for configuring and managing an overlay multicast data delivery tree in a transmission network having a SM (session manager) and at least one MA (multicast agent). The method includes the steps of at the MA intending to joining a session, obtaining an active neighbor MA list from the SM; detecting information on QoS information of each neighbor MA in the active neighbor MA list, selecting a MA having the most optimized QoS as a parent MA based on the QoS information of each Neighbor MA in the active neighbor MA list, joining an overlay multicast data communication session through the selected parent MA, periodically receiving HB (heart beat) information having information on a path from a root to the MA and determining whether to perform a parent-switching based on me HB information and parent-switching from the current parent MA to a MA having a better QoS when it is determined to perform the parent-switching

Claims

1. A method for configuring and managing an overlay multicast data delivery tree in a transmission network including a session manager (SM) and at least one multicast agent (MA), the method comprising the steps of:

at the MA intending to joining a session,

(a) obtaining an active neighbor MA list from the SM;

(b) detecting information on QoS information of each neighbor MA in the active neighbor MA list;

(c) selecting a MA having the most optimized QoS as a parent MA based on the QoS information of each neighbor MA in the active neighbor MA list;

(d) joining an overlay multicast data communication session through the selected parent MA;

(e) periodically receiving HB(heart beat) information having information on a path from a root to the MA, and determining whether to perform a parent-switching based on the HB information; and

(f) parent-switching from the current parent MA to a MA having a better QoS when it is determined to perform the parent-switching.

2. The method according to claim 1, wherein said step (a) comprises the sub-steps of:

(a1) transmitting a subscription request message to the SM by the MA intending to joining an overlay multicast data transmission session; and

(a2) receiving a subscription answer message containing the active neighbor MA list from the SM.

3. The method according to claim 1, wherein the MA stores root path information on a path from the root to the MA in its belonging overlay multicast data delivery tree:

parent MA and child MA information in the tree;

a probed neighbor MA list storing at least one probed MA; and

a non-probed neighbor MA list storing at least one non-probed MA.

4. The method according to claim 3, wherein said step (b) comprises the sub-steps of:

(b1) storing the active neighbor MA list in its non-probed neighbor MA list;

(b2) selecting a to-be-probed MA from its non-probed neighbor MA list;

(b3) transmitting a probe request message containing its neighbor MA list, to the to-be-probed MA;

(b4) receiving a probe answer message containing neighbor MA list of the to-be-probed MA, from the to-be-probed MA;

(b5) adding the to-be-probed MA information to its probed neighbor MA list; and

(b6) adding MA information, which is included in the neighbor MA list of the to-be-probed MA, but not included in its probed neighbor MA list, to its non-probed MA list.

5. The method according to claim 3, wherein said step (b) is periodically performed.

6. The method according to claim 1, wherein in said step (c), the MA having the most optimized QoS information is decided depending on a specific service requirement.

7. The method according to claim 1, wherein said step (d) comprises the sub-steps of:

(d1) transmitting a data relay request message to the parent MA;

(d2) receiving a data relay answer message having data relay permission or rejection, from the parent MA; and

(d3) determining the data relay permission or rejection based on the data relay answer message,

wherein when the data relay answer message represents the data relay rejection, a MA having next better QoS is selected as the parent MA and the sub-steps of (d1) to (d3) are repeated.

8. The method according to claim 1, wherein said step (e) comprises the sub-steps of:

(e1) calculating possible QoS information using the HB information;

(e2) comparing the possible QoS information with QoS information of the current parent MA, and determining whether the possible QoS is better than that of the current parent MA and is over a predetermined threshold;

(e3) when it is determined that the possible QoS is better than that of the current parent MA and is over the predetermined threshold, deciding that the parent-switching is needed; and

(e4) otherwise, deciding that the parent-switching is not needed.

9. The method according to claim 1, wherein said step (f) comprises the sub-steps of:

(f1) selecting a MA having the most optimized QoS as a parent MA, among the neighbor MAs;

(f2) transmitting a data relay request message to the parent MA;

(f3) receiving a data relay answer message having data relay permission or rejection, from the parent MA;

(f4) determining the data relay permission or rejection, based on the data relay answer message; and

(f5) when the data relay answer message represents the data relay rejection, selecting a MA having next optimized QoS, and repeating the sub-steps of (f2) to (f5).

10. The method according to claim 1, further comprising the steps of, at the MA, transmitting a relay request message to the parent MA, at regular intervals, and receiving a relay answer message from the parent MA.

11. The method according to claim 1, further comprising the step of determining that a loop error occurs in the session, when the MA redundantly exists or a child MA of the MA exists in the path from the root to the MA, which is included in the periodically received HB information.

12. The method according to claim 11, further comprising the step of perform the parent-switching, when the loop error occurs.

19. A computer readable recording media recording a computer program for performing a method for configuring and managing an overlay multicast data delivery tree according to any one of claims 1 to 18.

1-1. A method for configuring and managing an overlay multicast data delivery tree in a transmission network including a session manager (SM) and at least one multicast agent (MA), the method comprising the steps of:

at the MA intending to joining a session,

(a) obtaining an active neighbor MA list from the SM;

(b) detecting information on QoS information of each neighbor MA in the active neighbor MA list;

(c) selecting a MA having the most optimized QoS as a parent MA based on the QoS information of each neighbor MA in the active neighbor MA list;

(d) joining an overlay multicast data communication session through the selected parent MA;

(e) periodically receiving HB(heart beat) information having information on a path from a root to the MA, and determining whether to perform a parent-switching based on the HB information; and

(f) parent-switching from the current parent MA to a MA having a better QoS when it is determined to perform the parent-switching.

2-2. The method according to claim 1, wherein said step (a) comprises the sub-steps of:

(a1) transmitting a subscription request message to the SM by the MA intending to joining an overlay multicast data transmission session; and

(a2) receiving a subscription answer message containing the active neighbor MA list from the SM.

3-3. The method according to claim 1, wherein the MA stores root path information on a path from the root to the MA in its belonging overlay multicast data delivery tree:

parent MA and child MA information in the tree;

a probed neighbor MA list storing at least one probed MA; and

a non-probe;

neighbor MA list storing at least one non-probed MA.

4-4. The method according to claim 3, wherein said step (b) comprises the sub-steps of:

(b1) storing the active neighbor MA list in its non-probed neighbor MA list;

(b2) selecting a to-be-probed MA from its non-probed neighbor MA list;

(b3) transmitting a probe request message containing its neighbor MA list, to the to-be-probed MA;

(b4) receiving a probe answer message containing neighbor MA list of the to-be-probed MA, from the to-be-probed MA;

(b5) adding the to-be-probed MA information to its probed neighbor MA list; and

(b6) adding MA information, which is included in the neighbor MA list of the to-be-probed MA, but not included in its probed neighbor MA list, to its non-probed MA list.

5-5. The method according to claim 3, wherein said step (b) is periodically performed.

6-6. The method according to claim 1, wherein in said step (c), the MA having the most optimized QoS information is decided depending on a specific service requirement.

7-7. The method according to claim 1, wherein said step (d) comprises the sub-steps of:

(d1) transmitting a data relay request message to the parent MA;

(d2) receiving a data relay answer message having data relay permission or rejection, from the parent MA; and

(d3) determining the data relay permission or rejection based on the data relay answer message,

wherein when the data relay answer message represents the data relay rejection, a MA having next better QoS is selected as the parent MA and the sub-steps of (d1) to (d3) are repeated.

8-8. The method according to claim 1, wherein said step (e) comprises the sub-steps of:

(e1) calculating possible QoS information using the HB information;

(e2) comparing the possible QoS information with QoS information of the current parent MA, and determining whether the possible QoS is better than that of the current parent MA and is over a predetermined threshold;

(e3) when it is determined that the possible QoS is better than that of the current parent MA and is over the predetermined threshold, deciding that the parent-switching is needed; and

(e4) otherwise, deciding that the parent-switching is not needed.

9-9. The method according to claim 1, wherein said step (f) comprises the sub-steps of:

(f1) selecting a MA having the most optimized QoS as a parent MA, among the neighbor MAs;

(f2) transmitting a data relay request message to the parent MA;

(f3) receiving a data relay answer message having data relay permission or rejection, from the parent MA;

(f4) determining the data relay permission or rejection, based on the data relay answer message; and

(f5) when the data relay answer message represents the data relay rejection, selecting a MA having next optimized QoS, and repeating the sub-steps of (f2) to (f5).

10-10. The method according to claim 1, further comprising the steps of, at the MA, transmitting a relay request message to the parent MA, at regular intervals, and receiving a relay answer message from the parent MA.

11-11. The method according to claim 1, further comprising the step of determining that a loop error occurs in the session, when the MA redundantly exists or a child MA of the MA exists in the path from the root to the MA, which is included in the periodically received HB information.

12-12. The method according to claim 11, further comprising the step of perform the parent-switching, when the loop error occurs.

13-13. The method according to claim 1, further comprising the step of determining that a network-partitioning error occurs, when the periodically received HB information is not received within a predetermined time.

13-18. The method according to claim 15, further comprising the steps of:

at the SM,

periodically updating the active MA list at first periods; and

periodically updating the ready MA list at second periods.

14-14. The method according to claim 13, further comprising the steps of when the network partitioning error occurs,

i) checking whether a child MA is alive or not:

ii) when it is checked that the child MAs is not alive, determining that disconnection occurs in the network; and

iii) when it is checked that the child MA is alive,

checking if a next upper parent MA is alive or not,

when the next upper parent MA is alive, perform the parent-switching to the next upper parent MA, and

when the next upper parent MA is not alive, determining that the session is terminated, transmitting a leave request message to the child MA, and leaving the session.

15-15. A method for configuring and managing an overlay multicast data delivery tree in a transmission network having a session manager (SM) and at least one multicast agent (MA), the method comprising the steps of:

at the SM,

storing a list of active MAs having joined a session managed by the SM and being currently in a normal operation, and a list of ready MAs not yet confirmed whether to normally operate in the session;

receiving a subscription request message from a MA intending to joining the session;

determining whether to permit subscription of the MA, in response to the received subscription request message;

when it is determined that session subscription is permitted, extracting a portion of the active MA list, and transmitting a subscription answer message having the extracted portion of the active MA list to the MA;

when it is determined that the session subscription is rejected, transmitting a subscription answer message having a rejection reason to the MA; and

adding the MA information to the ready MA list.

16-16. The method according to claim 15, further comprising the step of, a1 the SM, checking session status in response to a user request.

17-17. The method according to claim 16, wherein the step of checking the session status comprises the sub-steps of:

at the SM,

receiving from the user a message of asking the status of a specific MA;

transmitting a status report request message to the specific MA;

receiving a report answer message from the specific MA; and

forwarding the received report answer message to the user.

19-19. A computer readable recording media recording a computer program for performing a method for configuring and managing an overlay multicast data delivery tree according to any one of claims 1 to 18.

20. A multicast agent apparatus comprising:

means for obtaining an active neighbor MA list from a SM;

means for detecting QoS information of each neighbor MA in the active neighbor MA list;

means for selecting a MA having the most optimized QoS as a parent MA based on the QoS information of each the neighbor MA, and joining an overlay multicast data communication session through the selected parent MA;

means for periodically receiving HB information having information on a path from a root to the MA, and determining whether to perform a parent switching based on the received HB information; and

means for parent-switching from the current parent MA to a MA having a better QoS when it is determined to perform the parent-switching.

20-20. A multicast agent apparatus comprising:

means for obtaining an active neighbor MA list from a SM;

means for detecting QoS information of each neighbor MA in the active neighbor MA list;

means for selecting a MA having the most optimized QoS as a parent MA based on the QoS information of each the neighbor MA, and joining an overlay multicast data communication session through the selected parent MA;

means for periodically receiving HB information having information on a path from a root to the MA, and determining whether to perform a parent switching based on the received HB information; and

means for parent-switching from the current parent MA to a MA having a better QoS when it is determined to perform the parent-switching.

21. A session manager apparatus comprising:

means for storing a list of active MAs having joined a session managed by itself and being currently in a normal operation, and a list of ready MAs not yet confirmed whether normally operating in the session, and periodically updating the lists;

means for receiving a subscription request message from a MA intending to joining the session, and determining whether permitting subscription of the MA in response to the subscription request message;

means for extracting a portion of the active MA list and transmitting to the MA a subscription answer message having the extracted portion of the active MA list, when it is determined to permit session subscription, and transmitting to the MA a subscription answer message having a rejection reason, when it is determined to reject the session subscription; and

means for adding the MA information to the ready MA list.

21-21. A session manager apparatus comprising:

means for storing a list of active MAs having joined a session managed by itself and being currently in a normal operation, and a list of ready MAs not yet confirmed whether normally operating in the session, and periodically updating the lists;

means for receiving a subscription request message from a MA intending to joining the session, and determining whether permitting subscription of the MA in response to the subscription request message;

means for extracting a portion of the active MA list and transmitting to the MA a subscription answer message having the extracted portion of the active MA list, when it is determined to permit session subscription, and transmitting to the MA a subscription answer message having a rejection reason, when it is determined to reject the session subscription; and

means for adding the MA information to the ready MA list.