REDUCING ACCESS NETWORK CONGESTION CAUSED BY OVERSUBSCRIPTION OF MULTICAST GROUPS
First Claim
1. A method at a multicast router for reducing congestion in an access network caused by oversubscription of multicast groups, wherein the multicast router is coupled with a multicast enabled layer 2 device that is coupled with a source of multicast data traffic for the multicast groups and maintains multicast membership state of the multicast groups, the method comprising the steps of:
- receiving a first multicast membership report message that indicates that a multicast host of a subscriber has joined a first multicast group, wherein the multicast host is one of a set of one or more multicast hosts of the subscriber, and wherein one or more of the set of multicast hosts are a member of a set of one or more second multicast groups;
calculating an amount of bandwidth currently being attributed as being used by the subscriber based on at least an amount of bandwidth that is required for the first multicast group and the set of second multicast groups; and
responsive to determining that the amount of bandwidth currently being attributed as being used by the subscriber exceeds its allowed bandwidth limit due to the multicast host joining the first multicast group, switching from periodically transmitting multicast membership general query messages to the set of multicast hosts to transmitting one or more multicast membership group-specific query messages to those of the set of multicast hosts that are a member of the set of second multicast groups that do not request membership reception state of the first multicast group to impede the multicast host from refreshing its membership to the first multicast group to cause the multicast membership state of the multicast host for the first multicast group in the multicast enabled layer 2 device to expire and the multicast data traffic for the first multicast group from being transmitted to the multicast host;
whereby congestion is reduced in the access network by impeding the multicast host of the subscriber from refreshing its membership state to the first multicast group that caused the subscriber to exceed its allowed bandwidth limit.
1 Assignment
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Accused Products
Abstract
A multicast router is coupled with a multicast enabled layer 2 device that is coupled with a source of multicast data traffic for multicast groups. Responsive to determining that the amount of bandwidth currently being attributed as being used by the subscriber exceeds its allowed bandwidth limit due to oversubscription of multicast groups, the multicast router switches from periodically transmitting multicast membership general query messages to the multicast hosts of the subscriber, to transmitting one or more multicast membership group-specific query messages to one or more multicast hosts of the subscriber for a subset of the subscribed multicast groups to impede the subscribed multicast groups that are not part of the subset from being refreshed to cause the multicast data traffic for those multicast groups from being transmitted on the access network to the multicast hosts of the subscriber.
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Citations
19 Claims
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1. A method at a multicast router for reducing congestion in an access network caused by oversubscription of multicast groups, wherein the multicast router is coupled with a multicast enabled layer 2 device that is coupled with a source of multicast data traffic for the multicast groups and maintains multicast membership state of the multicast groups, the method comprising the steps of:
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receiving a first multicast membership report message that indicates that a multicast host of a subscriber has joined a first multicast group, wherein the multicast host is one of a set of one or more multicast hosts of the subscriber, and wherein one or more of the set of multicast hosts are a member of a set of one or more second multicast groups; calculating an amount of bandwidth currently being attributed as being used by the subscriber based on at least an amount of bandwidth that is required for the first multicast group and the set of second multicast groups; and responsive to determining that the amount of bandwidth currently being attributed as being used by the subscriber exceeds its allowed bandwidth limit due to the multicast host joining the first multicast group, switching from periodically transmitting multicast membership general query messages to the set of multicast hosts to transmitting one or more multicast membership group-specific query messages to those of the set of multicast hosts that are a member of the set of second multicast groups that do not request membership reception state of the first multicast group to impede the multicast host from refreshing its membership to the first multicast group to cause the multicast membership state of the multicast host for the first multicast group in the multicast enabled layer 2 device to expire and the multicast data traffic for the first multicast group from being transmitted to the multicast host; whereby congestion is reduced in the access network by impeding the multicast host of the subscriber from refreshing its membership state to the first multicast group that caused the subscriber to exceed its allowed bandwidth limit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A multicast router to reduce congestion in an access network caused by oversubscription of multicast groups, the multicast router comprising:
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a control card having a multicast module configured to perform the following; receive multicast membership report messages originated from a set of one or more multicast hosts of a plurality of subscribers, wherein each multicast membership report message indicates multicast group membership status of one of the set of multicast hosts of one of the subscribers for one or more multicast groups, wherein multicast data traffic for the one or more multicast groups is not forwarded through the multicast router, track bandwidth usage attributed to the plurality of subscribers based at least in part on the received multicast membership report messages, and for each subscriber whose bandwidth usage exceeds their allowed bandwidth limit due to oversubscription to a plurality of multicast groups, switching from periodically transmitting multicast membership general query messages to the set of multicast hosts of that subscriber to periodically transmitting one or more multicast membership group-specific query messages to one or more of the set of multicast hosts for a subset of one or more of the plurality of multicast groups to impede those multicast hosts from refreshing their membership to other multicast groups not included in the subset of the plurality of multicast groups; whereby congestion is reduced in the access network through impeding the multicast hosts of the subscribers from maintaining their multicast group oversubscription. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A system to reduce congestion in an access network, comprising:
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a multicast source of multicast data traffic for a plurality of multicast groups; a multicast enabled layer 2 device that is coupled with the multicast source, a multicast router, and an access network element, wherein the multicast enabled layer 2 device is configured to; maintain multicast membership state to the plurality of multicast groups for a plurality of multicast hosts of a plurality of subscribers that are coupled with the access network element, and forward multicast membership report messages originated from the multicast hosts to the multicast source and the multicast router; and the multicast router including a multicast module configured to perform the following; receive the multicast membership report messages, wherein each multicast membership report message indicates a multicast group membership status of one of the multicast hosts of the subscribers for one or more of the multicast groups, track bandwidth usage attributed to the plurality of subscribers based at least in part on the received multicast membership report messages, and for each subscriber whose bandwidth usage exceeds their allowed bandwidth limit due to oversubscription of multicast groups, switching from periodically transmitting multicast membership general query messages to the multicast hosts of that subscriber to periodically transmitting one or more multicast membership group-specific query messages to one or more of the multicast hosts of the subscriber for a subset of the subscribed multicast groups to impede the multicast hosts of the subscriber from refreshing their membership to other multicast groups not included in the subset of the subscribed multicast groups to reduce the bandwidth usage attributed to that subscriber; whereby congestion is reduced in the access network element through impeding the multicast hosts of the subscribers from maintaining their multicast group oversubscription. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification