Multiplex communications – Network configuration determination – Using a particular learning algorithm or technique
Reexamination Certificate
1999-10-22
2003-04-29
Vincent, David (Department: 2666)
Multiplex communications
Network configuration determination
Using a particular learning algorithm or technique
C370S390000, C370S400000, C370S408000
Reexamination Certificate
active
06556544
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This is the first application filed for the present invention.
MICROFICHE APPENDIX
Not Applicable.
TECHNICAL FIELD
The present invention relates to multicast services, and in particular to a method and system for provisioning network resources for dynamic multicast groups.
BACKGROUND OF THE INVENTION
The recent evolution of communication networks (e.g. the Internet) has been accompanied by increasing demand by users for delivery of multi-cast services over such networks. Multicast services include, for example, news or entertainment content, which is transported over the networks from a single source to a plurality of sinks. In this context, a source may be a server at the network edge acting as a source of the content; or an edge node serving as a gateway between affiliated sub-networks, through which the content (which originates elsewhere) is supplied to the sub-network. Similarly, a sink node may be an end-user's communication device (e.g. a personal computer [PC] connected to the network via a modem); or an edge node which serves as a gateway between affiliated sub-networks, and through which the content (having been transported across the sub-network from the source) is supplied to an adjacent sub-network.
In order to enable multicast transport of content, a network provider (NP) must provision the network with both physical and service resources having sufficient band-width capacity and buffers. Physical resources are provisioned by installation of the physical plant used to construct the network fabric. Since changes in the physical resources necessarily involves the installation of new hardware, such changes are generally expensive, and consequently infrequent. Network providers typically utilize various known methods for predicting future bandwidth capacity requirements, and attempt to deploy physical plant having sufficient excess capacity to satisfy anticipated growth in demand for forecast service offerings. However, at least during any specific multicast session, the total available resources (i.e. link band-width and buffers) are fixed, and these may be logically allocated (typically allocation of bandwidth capacity and buffers) to multiple communications sessions (or data transport paths) up to a practical limit of the band-width and buffer capacity of the resource.
The logical allocation of resources for any communication session is normally conducted during set-up of a data transport path across the network. Various methods are known for service resource allocation, such as, for example, resource reservation protocol (RSVP) and constrained routing-label distributed protocol (CR-LDP). In each case, an end-to-end path across the network between source and sink nodes is first negotiated, and then transport resources along the path are allocated in accordance with a service requested for the communication session. In a situation where the allocation of resources to satisfy the service requested exhausts (or exceeds) the practical capacity of any element (e.g. a node or link) in the path (given pre-existing resource allocations for other communications sessions already utilizing that element), then the path must be abandoned, and the process of path setup and provisioning restarted.
Known service resource allocation methods are well suited to unicast, and predetermined point-to-predetermined point (i.e. 1-to-1, in which both source and sink nodes are predetermined and static) connections across the network. In such cases, it is a simple matter to set up a path and allocate resources during set-up of the connection. These methods can also be used effectively for multicast groups in which source and sink nodes are predetermined and static (i.e. 1-to-Many, in which all nodes are predetermined and static) because resource requirements can be accurately predicted prior to setting up the multicast tree. However, in cases where a multicast group is dynamic (i.e. in which any edge node of the network may serve as a sink node, and/or new sink nodes may join or leave the group during a multicast session), the network must be logically provisioned to provide for “1-to-Any” distribution, and it is therefore very difficult to predict provisioning requirements a priori.
In order to service a dynamic multicast group, the network provider must hypothesize probable delivery paths for the multicast traffic, and estimate the service resources required in the network. Because the egress nodes in a multicast group can be dynamic, this can result in:
multicast traffic not being delivered at a service level agreed to if parts of the network utilized by a multicast group lack adequate service resources; or
under-utilization of network resources if the network provider over-estimates the bandwidth capacity required for multicast traffic in a portion of the network.
In addition, individual egress nodes in a multicast group may experience very different service levels, depending on whether their respective distribution paths “hit” or “miss” adequately provisioned portions of the network. If on the other hand the network service provider chooses to distribute resources in potential paths from any ingress node to all possible egress nodes, then the multicast traffic may be delivered consistently below a service level contracted for in a SLS.
Accordingly, there remains a need for a method and apparatus that enable network resources to be allocated to a dynamic multicast group, such that multicast traffic associated with the group can be delivered at a service level required by a SLS associated with the multicast.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and system for provisioning a distribution path of a dynamic multicast group, such that multicast traffic can be delivered through the distribution path at a service level required by an SLS associated with the dynamic multicast group.
A further object of the present invention is to provide a method and system for provisioning a distribution path of a dynamic multicast group, in which multicast traffic can be delivered to each member of the dynamic multicast group at the same service level.
Accordingly, an aspect of the present invention provides a method of provisioning a distribution path of a multicast tree between an ingress node and an egress node in a dynamic multicast group in a differentiated services (DS) network, the method comprising the steps of: receiving information respecting a predetermined service level specification (SLS) for the dynamic multicast group; and provisioning the distribution path from the egress node back to the ingress node, on the basis of the received information respecting the SLS.
Another aspect of the present invention provides a edge node for receiving a multicast traffic of a dynamic multicast group transmitted over a differentiated services (DS) network from an ingress node, the edge node comprising a multicast traffic engineering (MCTE) entity adapted for: receiving information respecting a predetermined service level specification (SLS) of the dynamic multicast group; and provisioning a distribution path from the edge node back to the ingress node, on the basis of the received information respecting the SLS.
A further aspect of the present invention provides a system for provisioning a distribution path of a dynamic multicast group over a differentiated services (DS) network. The system comprises an ingress node adapted to serve as a source of data traffic of the dynamic multicast group; and an egress node adapted to serve as a sink of the data traffic of the dynamic multicast group. The egress node comprising a multicast traffic engineering (MCTE) entity adapted for: receiving information respecting a predetermined service level specification (SLS) of the dynamic multicast group; and provisioning a distribution path from the egress node back to the ingress node, on the basis of the received information respecting the SLS.
In an embodiment of the invention, information respecting the SLS includes resource r
(Ogilvy Renault)
Daniels Kent
Duong Frank
Nortel Networks Limited
Vincent David
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