摘要:
The present invention sets forth a methodology for providing improved downlink backhaul services from a radio network controller (RNC) to a plurality of base stations via a backhaul network that provides Ethernet services. The Ethernet services are provided by a group of provider edge (PE) switches and regular label switch routers (referred to as P switches). Base stations within the network are assigned into clusters, each of the clusters having a cluster ID. The RNC transmits packets to a given switch or switches out on the network based on a cluster ID included within the transmitted packet. The communications traffic is then multicast from at least one last hop switch in the network to candidate base stations on the basis of the cluster ID and an active set within the cluster. Advantageously, the clusters act as subgroups for more easily directing the transmission of the backhaul multicast traffic. Significant advantages are realized through use of the present invention, including the ability to allow faster and smoother handoffs, as well as backhaul bandwidth savings since intelligence regarding cell switching is extended out at a point farther along the network than was previously enabled.
摘要:
The present invention provides systems and methods for providing distributed, adaptive IP filtering techniques used in detecting and blocking IP packets involved in DDOS attacks through the use of Bloom Filters and leaky-bucket concepts to identify “attack” flows. In an exemplary embodiment of the present invention, a device tracks certain criteria of all IP packets traveling from IP sources outside a security perimeter to network devices within the security perimeter. The present invention examines the criteria and places them in different classifications in a uniformly random manner, estimates the amount of criteria normally received and then determines when a group of stored classifications is too excessive to be considered normal for a given period of time. After the device determines the criteria that excessive IP packets have in common, the device then determines rules to identify the packets that meet such criteria and filters or blocks so identified packets.
摘要:
In a network including a centralized controller and a plurality of routers forming a security perimeter, a method for selectively discarding packets during a distributed denial-of-service (DDoS) attack over the network. The method includes aggregating victim destination prefix lists and attack statistics associated with incoming packets received from the plurality of routers to confirm a DDoS attack victim, and aggregating packet attribute distribution frequencies for incoming victim related packets received from the plurality of security perimeter routers. Common scorebooks are generated from the aggregated packet attribute distribution frequencies and nominal traffic profiles, and local cumulative distribution function (CDF) of the local scores derived from the plurality of security perimeter routers are aggregated. A common discarding threshold is derived from the CDF and sent to each of the plurality of security perimeter routers, where the discarding threshold defines a condition in which an incoming packet may be discarded at the security perimeter.
摘要:
A network element maintains failure information for a packet-based network and usage information for a backup path. Upon receipt of a new demand, with an associated bandwidth, d, the network element determines if the backup path can be shared as a function of the failure information and the usage information associated with the backup path.
摘要:
An engineered or manufactured elongate wooden I-beam of the type having continuous upper and lower flange sections and a central web section therebetween is provided with a rectangular opening in the web along the span of the beam. A rectangular and open reinforcing frame constructed from at least four wooden pieces is securely positioned in the opening and is exteriorly dimensioned so that the height of the frame corresponds to the distance between the opposed interfaces of the upper and lower flange sections and the width of the frame is no less than the distance between the spaced apart web sections. This reinforced opening facilitates the passage of ductwork or the like laterally therethrough. Employing apertured I-beams of the foregoing description also facilitates a structural beam and bridging assembly where an elongate wooden bridging element can be employed by extending through and being interconnected to the frames of adjacent pairs of apertured joists.
摘要:
An improved flow control method for ABR service in an ATM network. In particular, a dual local/global ingress flow control method for ABR service in a distributed ingress queueing switch including a plurality of ingress buffer-pools, at least one shared buffer-pool and a plurality of egress buffer-pools. Utilization of the egress port of each shared buffer-pool is periodically measured and together with the current state of the global-ingress control forms the basis for toggling global-ingress control in an active/inactive state. Queue-length based flow control algorithms such as DMRCA are applied to each resource management cell for the egress subport queue and ingress flow queue through which the resource management cell passes to determine the egress and local-ingress congestion marking values, respectively, for the resource management cell. In addition, global-ingress congestion is detected by applying a queue-length based flow control algorithm to the summation of the ingress flow queues contributing to the shared buffer-pool egress port through which the resource management cell passed. If global-ingress control is active then the resource management cell is marked based on the merged egress, global-ingress, local-ingress congestion marking values and the congestion marking values originally carried by the resource management cell. Otherwise the resource management cell is marked based on the merged egress, local-ingress congestion marking values and the congestion marking values originally carried by the resource management cell.
摘要:
We formulate the network-wide traffic measurement/analysis problem as a series of set-cardinality-determination (SCD) problems. By leveraging recent advances in probabilistic distinct sample counting techniques, the set-cardinalities, and thus, the network-wide traffic measurements of interest can be computed in a distributed manner via the exchange of extremely light-weight traffic digests (TD's) amongst the network nodes, i.e. the routers. A TD for N packets only requires O(loglog N) bits of memory storage. The computation of such O(loglog N)-sized TD is also amenable for efficient hardware implementation at wire-speed of 10 Gbps and beyond. Given the small size of the TD's, it is possible to distribute nodal TD's to all routers within a domain by piggybacking them as opaque data objects inside existing control messages, such as OSPF link-state packets (LSPs) or I-BGP control messages. Once the required TD's are received, a router can estimate the traffic measurements of interest for each of its local link by solving a series of set-cardinality-determination problems. The traffic measurements of interest are typically in form of per-link, per-traffic-aggregate packet counts (or flow counts) where an aggregate is defined by the group of packets sharing the same originating and/or destination nodes (or links) and/or some intermediate nodes (or links). The local measurement results are then distributed within the domain so that each router can construct a network-wide view of routes/flow patterns of different traffic commodities where a commodity is defined as a group of packets sharing the same origination and/or termination nodes or links. After the initial network-wide traffic measurements are received, each router can further reduce the associated measurement/estimation errors by locally conducting a minimum square error (MSE) optimization based on network-wide commodity-flow conservation constraints.
摘要:
A network-wide traffic measurement/analysis problem is formulated as a series of set-cardinality-determination (SCD) problems, using probabilistic distinct sample counting techniques to compute network-wide traffic measurements of interest in a distributed manner via the exchange of light-weight traffic digests (TD's) amongst network nodes/routers. A TD for N packets uses only requires O(loglog N) bits of memory storage, making it possible to distribute nodal TD's to all routers within a domain by piggybacking them as opaque data objects inside existing control messages, such as OSPF link-state packets (LSPs) or I-BGP control messages. A router receiving the TD's can estimate the traffic measurements of interest for each of its local links by solving a series of set-cardinality-determination problems. The traffic measurements of interest are typically per-link, per-traffic-aggregate packet (or flow) counts, where an aggregate is defined by the group of packets sharing the same originating and/or destination nodes (or links) and/or some intermediate nodes (or links).
摘要:
In one embodiment, a method for estimating the number of tags in a set of tags in a system of tags and readers. The method includes, during each of a plurality of time intervals: (i) transmitting a command requesting that each tag that receives the command determine whether to transmit a reply; and (ii) receiving, in one or more timeslots of a frame corresponding to the time interval, replies from one or more tags. The method further includes providing an estimate of the number of tags in the set of one or more tags based on (i) timeslots in each of the plurality of time intervals that are zero timeslots, i.e., timeslots having no received reply, and (ii) the total number of timeslots in each frame.
摘要:
Methods and apparatus are provided for designing IP networks with substantially improved performance as compared to existing IP networks such as, for example, those networks designed under best-effort criteria. Particularly, the invention includes methods and apparatus for: computing worst-case and optimistic link capacity requirements; optimizing network topology; and determining router placement within a network.