Enhanced DVMRP for destination-based forwarding of multicast data

• US 20050083933A1
• Filed: 12/31/2003
• Published: 04/21/2005
• Est. Priority Date: 08/25/2003
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Fine, Mark, Garff, Jeremy, Marinan, Kelly
• Granted Patent: US 7,522,596 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/033 by updating distance vector protocols
• CPC Class Codes: H04L 45/124 using a combination of metrics
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06

Abstract

An enhanced DVMRP method for regulating multicast traffic in a destination-based forwarding router is disclosed. As a plurality of neighbor multicast routers are detected and route reports exchanged, the enhanced DVMRP router transmits one or more restricted route reports, each of the restricted route reports omitting the routes associated with one or more of its branch interfaces. With the exception of the neighbor router detected on a given interface, a route report omits reference to other branch interfaces to prevent branch-to-branch routing of multicast streams that may cause a destination-based forwarding router in a multi-access network to transmit duplicate packets to a group member. The enhanced DVMRP method also employs flash updates indicating that some branch interfaces are inaccessible in order to prevent multicast routing through newly-detected neighbor multicast routers.

Claims

1. An enhanced Distance Vector Multicast Routing Protocol (DVMRP) method for regulating one or more multicast streams in a first destination-based forwarding router, comprising the steps of:

(a) transmitting a DVMRP route report to a first branch interface detected; and

(b) for each new branch interface detected;

(i) transmitting, to each branch interface previously detected, a flash update for preventing one or more neighbor multicast routers from expressing dependency on the first destination-based forwarding router; and

(ii) transmitting, to the new branch interface, a restricted route report for preventing one or more neighbor multicast routers from expressing dependency on the first destination-based forwarding router.

2. The enhanced DVMRP method in claim 1, wherein the DVMRP route report comprises routes accessible through one or more interfaces of the first destination-based forwarding router enabled with the enhanced DVMRP method.

3. The enhanced DVMRP method in claim 1, wherein the restricted route report omits reference to routes accessible through each branch interface previously detected.

4. The enhanced DVMRP method in claim 3, wherein the restricted route report consists of routes accessible through the one or more leaf interfaces of the first destination-based forwarding router.

5. The enhanced DVMRP method in claim 1, wherein the flash update comprises an unreachable metric for the new branch interface.

6. The enhanced DVMRP method in claim 5, wherein the unreachable metric is a cost metric having a value of 32.

7. An enhanced DVMRP method for regulating multicast streams in a destination-based forwarding router, comprising the steps of:

(a) detecting a plurality of branch interfaces, wherein each branch interface is operably coupled to one or more neighbor multicast routers; and

(b) transmitting one or more restricted route reports to at least one of the plurality of branch interfaces, wherein at least one of the one or more restricted route reports omits one or more branch interfaces; and

wherein at least one of the one or more neighbor multicast routers are prevented from expressing dependency on branch interfaces of the destination-based forwarding router.

8. The enhanced DVMRP method in claim 7, wherein the method further includes the step of transmitting, to at least one of the plurality of branch interfaces, a flash update for preventing at least one of the one or more neighbor multicast routers from expressing dependency on branch interfaces of the destination-based forwarding router.

9. An enhanced DVMRP router for regulating one or more multicast streams in a first destination-based forwarding router, enhanced DVMRP router for:

(a) transmitting, to a first branch interface detected, a DVMRP route report comprising routes accessible through one or more enhanced-DVMRP interfaces of the first destination-based forwarding router; and

(b) for each new branch interface detected;

(i) transmitting, to each branch interface previously detected, a flash update comprising an unreachable metric for the new branch interface; and

(ii) transmitting, to the new branch interface, a restricted route report omitting reference to routes accessible through each branch interface previously detected.

10. The enhanced DVMRP method in claim 9, wherein the flash update comprises an unreachable metric for the new branch interface.

11. A computer-readable medium containing instructions for regulating one or more multicast streams in a first destination-based forwarding router, the instructions comprising the steps of:

(a) transmitting a DVMRP route report to a first branch interface detected; and

(b) for each new branch interface detected;

(i) transmitting, to each branch interface previously detected, a flash update for preventing one or more neighbor multicast routers from expressing dependency on the first destination-based forwarding router; and

(ii) transmitting, to the new branch interface, a restricted route report for preventing one or more neighbor multicast routers from expressing dependency on the first destination-based forwarding router.

12. The instructions in claim 11, wherein the DVMRP route report comprises routes accessible through one or more interfaces of the first destination-based forwarding router enabled with the enhanced DVMRP method.

13. The instructions in claim 11, wherein the restricted route report omits reference to routes accessible through each branch interface previously detected.

14. The instructions in claim 13, wherein the restricted route report consists of routes accessible through the one or more leaf interfaces of the first destination-based forwarding router.

15. The instructions in claim 11, wherein the flash update comprises an unreachable metric for the new branch interface.