Multiplex communications – Network configuration determination
Reexamination Certificate
1999-12-03
2004-05-25
Olms, Douglas (Department: 2661)
Multiplex communications
Network configuration determination
C370S255000, C370S229000, C370S235000
Reexamination Certificate
active
06741572
ABSTRACT:
FIELD OF THE INVENTION
The invention is directed to communication networks and in particular to architectures for a high performance data networks.
BACKGROUND OF THE INVENTION
Known routed data networks comprise a plurality of data routers interconnected by an incomplete mesh of transmission links. Traffic routed between geographically distant nodes on the routed network generally transits multiple routers at tandem nodes between source and destination nodes. As the network grows in geographic size and capacity, the number of nodes increases, and a larger percentage of the data routed by the network transits routers at multiple tandem nodes.
Unfortunately, routers are not well suited to the tandem routing functions they perform at tandem nodes. Because routers route data packets on a packet-by-packet basis, they must perform a great deal of processing to route a high bit rate data stream. Consequently, they require considerable processing power and contribute heavily to the cost of a routed data network, and their processing of each packet contributes to unpredictable end-to-end transmission delay across the network, which is problematic for some services.
Some of the problems of routed networks can reduced by providing transport layer switches at some nodes of the network. The transport layer switches are configured to provide high capacity end-to-end transmission paths between distant nodes that exchange enough traffic to justify the allocation of the high capacity paths, thereby diverting such traffic from tandem routers. Because the transport layer switches process traffic on a coarse granularity channel-by-channel basis rather than on a fine granularity packet-by-packet basis, they perform less processing on a high bit rate data stream than a tandem router. Consequently, they require less processing power and can contribute less cost and less unpredictable end-to-end delay than tandem routers on high capacity routes between distant nodes.
With transport layer switches performing tandem switching functions, network operators can define end-to-end transmission paths that logically connect the nodes in a full mesh, even though the nodes of the network are physically connected in an incomplete mesh or in interconnected rings.
The capacity required for each end-to-end transmission path is determined by network operators based on router traffic loads. The network operators change the capacity allocated to the end-to-end transmission paths based on traffic measurements and service requests using a centralized network management system that is connected to the transport layer switches. Today, this is a relatively slow process requiring human interaction, a change in capacity typically taking hours to days and, in some cases, months to implement.
Because the time needed to implement changes in capacity for end-to- end transmission paths is measured in hours to months, transmission capacity must be provided well ahead of need to avoid blocking due to inadequate capacity. Otherwise traffic in excess of the allocated capacity will be blocked, resulting in lost revenue and dissatisfied network users, or overflow traffic will be forced onto routers at tandem nodes, reducing the capacity of such routers which is available to local traffic.
Providing excess transmission capacity ahead of need increases the cost of the network. Failing to provide sufficient excess capacity to accommodate growth and fluctuations in traffic patterns can result in lost revenue. Consequently, network and service providers would welcome a network architecture that enables them to tailor the capacity of their data networks more responsively to the traffic demands of their network users.
SUMMARY OF THE INVENTION
This invention provides a novel architecture for a new generation of data networks. The novel architecture delivers more usable traffic throughput through a given level of transmission infrastructure when traffic patterns are unpredictable or rapidly fluctuating by dynamically and quickly allocating transmission capacity where it is needed.
In this specification, the term Agile Bandwidth Usage Device (ABUD) refers to any ABUD having time-varying transmission capacity requirements and being capable of providing signals indicative of transmission capacity needs.
ABUDs may use any form of switching or multiplexing, and may signal time-varying transmission capacity needs either directly by means of transmission capacity requests or indirectly by means of traffic data, such as traffic port occupancy statistics. Routers, Data Switches (for example ATM switches) and servers can all be ABUDs, for example.
One aspect of the invention provides a communications network comprising a plurality of interconnected nodes. Each of a plurality of the nodes comprises at least one ABUD, a switch connected to the ABUD for configuring transmission channels connected to other nodes, and a configuration controller connected to the ABUD and to the switch for controlling configuration of the transmission channels. The configuration controller receives signals from the ABUD indicative of transmission capacity needs of the ABUD, processes the received signals to determine that reconfiguration of the transmission channels is favoured and determines a favoured reconfiguration of the transmission channels. The configuration controller also communicates with configuration controllers at other nodes to determine paths between nodes for reconfiguration of the transmission channels, and communicates with the switch, configuration controllers at other nodes and the ABUD to implement reconfiguration of the transmission channels.
Networks as defined above automate interactions between ABUDs, such as routers, requiring allocated transmission channels and transmission channels provided to meet those requirements rapidly, without human intervention.
The ABUDs may be routers, data switches, servers or Time Division Multiplex (TDM) systems, or other ABUDs that require allocated transmission capacity.
The configuration controllers may receive signals comprising traffic data from the ABUD, and may process the received traffic data to determine that allocation of a transmission channel to a particular route is favoured. The configuration controllers may comprise a storage device for storing policy rules. The configuration controllers may be operable to download policy rules from a central management system and to apply the policy rules in processing the received traffic data to determine that allocation of a transmission channel to a particular route is favoured. In this case, the rapid reconfiguration capabilities of distributed automated transmission channel reallocation are combined with the ability to set network policy governing transmission channel allocation centrally.
Alternatively, the configuration controllers may receive signals comprising transmission channel allocation messages from the ABUD, and process the received transmission channel allocation request messages to determine that allocation of a transmission channel to a particular route is favoured.
Consequently, transmission channels are reconfigured automatically without human interaction in response to traffic patterns sensed at ABUDs.
The configuration controllers may determine a possible path for the transmission channel to be allocated. The configuration controllers may comprise a storage device for storing a map of network connectivity, and the configuration controller at the particular node may consult the map of network connectivity to determine the possible path for the transmission channel to be allocated.
The configuration controllers send transmission channel allocation request messages to configuration controllers at other nodes on the possible path and receive reply messages from the configuration controllers at other nodes on the possible path. The reply messages may indicate whether the transmission channel can be allocated at the other nodes. In response to reply messages indicating that the transmission channel can be allocated at all other nodes on the possible p
Graves Alan F.
Hobbs Christopher W. L.
Junkin C. W.
Nortel Networks Limited
Olms Douglas
Wilson Robert W.
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