1602 results about "Label switching" patented technology

A Provider Network Controller (PNC) addresses the challenges in building services across Next Generation Network (NGN) architectures and creates an abstraction layer as a bridge, or glue, between the network transport and applications running over it. The PNC is a multi-layer, multi-vendor dynamic control plane that implements service activation and Layer 0-2 management tools for multiple transport technologies including Carrier Ethernet, Provider Backbone Transport (PBT), Multi-protocol Label Switching (MPLS), Transport MPLS (T-MPLS), optical and integrated networking platforms. Decoupling transport controls and services from the network equipment simplifies service creation and provides options for carriers to choose best-in-class equipment that leverages the PNC to enable rapid creation and management of transports and services. The PNC provides Service-Oriented Architecture (SOA) interfaces to abstract transport objects expressly designed to support both wholesale and retail services, and supports service offerings with varied bandwidth and Quality of Service (QoS) requirements, thus achieving enterprise Ethernet economics.

In an MPLS network, multicast, broadcast and address learning belonging to the layer 2 functions are realized. An ingress router comprises a frame receiving unit, a determining unit, a first frame transmitting unit, a physical address table for multicast, a label switching unit, a tunnel label table, a VCID giving unit, a L2 header creating unit and a second frame transmitting unit. The load on the network is suppressed, the band is efficiently used, and wasteful frame duplication and frame forwarding between edge routers are avoided.

An optical signaling header technique applicable to optical networks wherein packet routing information is embedded in the same channel or wavelength as the data payload so that both the header and data payload propagate through network elements with the same path and the associated delays. The technique effects survivability and security of the optical networks by encompassing conventional electronic security with an optical security layer by generating replicated versions of the input data payload at the input node, and the transmission of each of the replicated versions over a corresponding one of the plurality of links. Moreover, each of the links is composed of multiple wavelengths to propagate optical signals or optical packets, and each of the replicated versions of the data payload may be propagated over a selected one of the wavelengths in each corresponding one of the plurality of links.

A method for avoiding loops from forming when setting up label switched paths is provided. The method uses a Label Splicing Message is followed by an Acknowledgment message to determine if loops are formed in the process of joining a new node or subtree to a multicast MPLS tree. By verifying that the path towards the root of the MPLS tree is loop-free during the construction of the tree, this method complements the loop detection mechanism provided by the label switched protocol (LDP).

A system and method for transmitting information between a source host and a destination host. A source host generates a message and forwards the message via a label switched path to the destination host so that when a central routing module receives the message, the message includes a label. A central routing module establishes a local master mapping table including a plurality of physical addresses, and each of the plurality of physical addresses is associated with a unique identifier such as a label. When a switch egress module receives the message with the label, the switch egress module determines a physical address associated with the label, maps the physical address to the message, and forwards the message to the destination host associated with the label.

When a node has to restart its control component, or a (e.g., label-switched path signaling) part of its control component, if that node can preserve its forwarding information across the restart, the effects of such restarts on label switched path(s) the include the restarting node are minimized. A node's ability to preserve forwarding information across a control component (part) restart is advertised. In the event of a restart, stale forwarding information can be used for an limited time before. The restarting node can use its forwarding information, as well as received label-path advertisements, to determine which of its labels should be associated with the path, for advertisement to its peers.

A technique efficiently load balances traffic engineering (TE) label switched paths (LSPs) from a head-end node to a tail-end node of a computer network. The novel load balancing technique identifies (e.g., at the head-end node or a path computation element, PCE) a set of paths with equal costs from the head-end node to the tail-end node, where each path of the set is composed of one or more associated links. “Link values” such as, e.g., the number of unconstrained TE-LSPs on the link, the amount of available bandwidth on the link, or the percent of total available bandwidth already in use on the link, are applied to each link of each path. The most restrictive link values (link availability) of each path of the set, such as, e.g., the link with the lowest amount of available bandwidth, etc., are then compared. Upon comparing the link availability, the novel technique load balances established and / or new TE-LSPs from the head-end node to the tail-end node over the set of paths accordingly.

A technique dynamically protects against failure of a head-end node of one or more primary Traffic Engineering Label Switched Paths (TE-LSPs) in a computer network. According to the novel technique, a neighboring upstream node (“protecting node”) of the head-end node learns of the primary TE-LSPs (and their respective state control blocks) extending from the head-end node to one or more address prefixes. The protecting node establishes a repair TE-LSP for each of the primary TE-LSPs to a corresponding downstream neighboring node of the head-end node (a “next-next-hop”). In response to detecting a failure of the head-end node, the protecting node locally reroutes traffic destined for the address prefixes to an appropriate repair TE-LSP. Due to the failure of the head-end node, the protecting node then refreshes the states of the primary TE-LSPs using replicated state control blocks accordingly, until the repair TE-LSPs are no longer needed.

A method of providing at least one restoration path for a primary routing path in a network. The method includes receiving a customer connection request to route information. Costs are assigned for the primary routing path, and the primary routing path is computed based upon the primary routing path costs. A backtracking distance over the primary routing path is determined, and costs for at least one restoration path are assigned. The at least one restoration path may then be computed based upon the at least one restoration path costs.

A method and apparatus for ordering, synchronizing and scheduling work in a multi-core network services processor is provided. Each piece of work is identified by a tag that indicates how the work is to be synchronized and ordered. Throughput is increased by processing work having different tags in parallel on different processor cores. Packet processing can be broken up into different phases, each phase having a different tag dependent on ordering and synchronization constraints for the phase. A tag switch operation initiated by a core switches a tag dependent on the phase. A dedicated tag switch bus minimizes latency for the tag switch operation.

A system and method for providing rapid rerouting of real-time transport protocol (RTP) multi-media flows is disclosed. Generally, a first endpoint is connected to a second endpoint, wherein the first endpoint comprises a transceiver, software stored within the first endpoint defining functions to be performed by the first endpoint, and a processor configured by the software. The processor is configured to perform the steps of, performing flow processing on a data packet received at a first endpoint, from a second endpoint, removing a multi-protocol label switching (MPLS) tag from the data packet, translating a source address and destination address of the data packet, and determining a forwarding destination if more than one destination address of the data packet is provided.

Source routed multicast LSP is described herein. In one embodiment, when a first node receives a first packet having a label stack including a plurality of labels compatible with MPLS (multi-protocol label switching), in response to a first label on a top of the label stack, the first packet is duplicated into a second packet. In addition, at least two labels are popped from the top of the label stack of the second packet forming a third packet. Thereafter, the first and third packets are processed based on a label on the top of the label stack of the first and third packets respectively. Other methods and apparatuses are also described.

Methods and apparatus for rerouting network traffic are described herein. In one embodiment, an example of process includes maintaining as a part of a routing table of a network element information regarding one or more backup links leading to a node using label switched protocols (LSPs), the node being adjacent to the network element, and in response to a failure of a primary link coupling the network element to the node, the network element rerouting network traffic to the node via the one or more backup paths without having to notifying and waiting for a response from a headend node that originates the network traffic. Other methods and apparatuses are also described.

A system, device, and method for establishing and removing a label switched path in a communication network uses a packet-driven mechanism rather than using an explicit signaling protocol to exchange label switching information from an upstream label switching device to a downstream label switching device. In order to establish a label switched path from the upstream label switching device to the downstream label switching device, the upstream label switching device allocates a new label for the label switched path, sets up the label switched path by adding the new label to its forwarding table, and forwards a labeled packet including the new label and an indicator indicating that the packet is labeled. Upon receiving the labeled packet from the upstream label switching device, the downstream label switching device sets up the label switched path by adding the new label to its forwarding table, and forwards the packet based upon network layer addressing information in the packet. In order to remove the label switched path, the upstream label switching device forwards unlabeled packets to the downstream label switching device, and both devices remove the label from its respective forwarding table.

A system for servicing streaming media requests. The system includes stream director nodes and intelligent stream engine nodes, such as permanent storage devices with network interfaces. The stream director node receives a streaming media request and enqueues the request until all resources on a path from the stream engine node having the media object being requested to the user / client system have been reserved. Once reserved, the enqueued request is then serviced by requesting the stream object from the stream engine node, which then transfers the requested stream object between the stream engine node and the user / client system over the prepared path without involving the stream director node. Upon completion, the prepared path is torn down. In one embodiment the prepared path is a Label Switched Path. A provision is made for balancing the load among the stream engine nodes by duplicating stream objects on other stream engine nodes.

Methods and apparatus for implementing bi-directional logical signal interfaces (LSIs) in communications systems which use uni-directional label switched paths (LSPs), e.g., MPLS networks, are described. To implement an LSI, two uni-directional LSPs between the same end points, e.g., routers, and extending in opposite directions, are associated together. The association of LSPs may be done by setting LSI configuration information in the routers at both ends of an LSI. Each router at the end of an LSI serves as an egress router for one of the LSPs associated with the LSI and an ingress router for the other LSP associated with the LSI. To enable an egress router to determine which, if any, LSI a packet or message corresponds to, a real as opposed to a null label is used when sending packets over an LSI LSP to an LSI LSP egress router.

A method, system, and computer program product are presented to optimize OSI Level 2 switch forwarding of frames comprising IP addresses, 802.1 QinQ VLAN identifiers, multi-protocol label switching labels, and any other usable information meaningful to derive an L2 forwarding result on frames. In one embodiment, a 16-bit key is included as a prefix to a 48-bit OSI Level 2 address entry, thereby allowing the inclusion of a 32-bit OSI Level 3 address in the lookup table (e.g., a complete IP version 4 address). Implementations of such a solution are presented to resolve address aliasing issues experienced with multicast group destination addresses, including single source multicast. Solutions to optimizing forwarding of frames in an IEEE 802.1 QinQ environment are also presented. A result of these implementations can be reduction of the amount of unnecessary network traffic generated by a network switch incorporating such an OSI Level 2 address lookup table.

A novel fast and scalable protection mechanism for protecting hierarchical multicast service in ring based networks. The mechanism of the present invention is especially suitable for use in Multi-Protocol Label Switching (MPLS) ring based networks such as Metro Ethernet Networks (MENs). The mechanism provides fast protection for MPLS based point-to-multipoint (P2MP) Label Switched Paths (LSPs) in a scalable manner. Each multicast connection on each ring in the network is split into two sub-LSPs: a primary P2MP sub-LSP originating on a primary node and a secondary P2MP sub-LSP originating on a secondary node traveling opposite to the primary path. For each node to be protected, a point-to-point protection tunnel is provisioned from that node to a secondary node that forwards the packets to the secondary path on all child rings connected to that parent ring through the protected node and that are provisioned to receive the specific multicast connection. In the event of a failure, all the multicast traffic on that ring is directed through the protection tunnel to the secondary node. Upon exiting the protection tunnel, the packets are forwarded to the secondary LSP on the child rings for which this node is the secondary node and also continue along the primary LSP on the parent ring and along all child rings for which this node is the primary node.

An admission controller and its method of operation for controlling admission of data flows into an aggregate data flow are described. Admitted data flows are aggregated into an aggregate data flow for transmission by a router, for example, over a data network. The aggregate data flow typically follows a pre-established path through the network; for example a multi-protocol label switched (MPLS) path. The path has minimum and maximum bandwidth limits assigned to it. The admission controller controls admission of new data flows into the aggregate data flow by granting or denying new session requests for the new data flows. Congestion notifications received from the network and bandwidth limits of the path are considered in determining whether to grant or deny a new session request. In this way, the admission controller provides elastic sharing of network bandwidth among data flows without exacerbating network congestion and while remaining within the path's bandwidth limits. The data flows may include transaction oriented traffic.

A technique protects against failure of a tail-end node of a Traffic Engineering (TE) Label Switched Path (LSP) in a computer network. According to the protection technique, a node along the TE-LSP that is immediately upstream to the protected tail-end node and that is configured to protect the tail-end node (i.e., the “point of local repair” or PLR) learns reachable address prefixes (i.e., “protected prefixes”) of next-hop routers from the tail-end node (i.e., “next-next-hops,” NNHOPs to the protected prefixes from the PLR). The PLR creates a backup tunnel to each NNHOP that excludes the tail-end node, and associates each backup tunnel with one or more protected prefixes accordingly. When the tail-end node fails, Fast Reroute is triggered, and the protected prefix traffic (from the TE-LSP) is rerouted by the PLR onto an appropriate backup tunnel to a corresponding NNHOP. Notably, the PLR performs a penultimate hop popping (PHP) operation prior to forwarding the traffic along the backup tunnel(s).

An apparatus and method for emulating a shared or source distribution tree within an MPLS network. In one embodiment of the method, a router receives a multicast data packet. The router transmits the multicast data packet to a first router via a first point-to-point label switched path (LSP). The router replicates the multicast data packet to produce a replicated multicast data packet. Then the router transmits the replicated multicast data packet to a second router via a second point-to-point LSP. The first point-to-point LSP is distinct from the second point-to-point LSP.

A method of creating virtual private networks within a packet network having a mesh topology. A flexible virtual private network is established based upon a topology calculated at each member node. The network is set up using label switched paths between adjacent member nodes according to the topology. The topology may be a ring or a tree. A virtual ring is created as a closed-loop sequence of label switched paths established between a set of member nodes. The closed-loop sequence of label switched paths is established by the member nodes as each member node connects to its neighbours on the virtual ring. The virtual ring may expand by adding member nodes and may contract by removing member nodes. A member node's position on the virtual ring may be established using a sortable value.

A label switching routing protocol for establishing a datapath as a sequence of locally unique labels in an optical communications network, is provided. A wavelength on an optical cross-connect is considered as a label, or one portion of a label. Timeslots may be assigned to designated wavelengths so as to form the second portion of a composite label. An optical / time cross-connect (OTXC) capable of wavelength conversion from an input to an output interface creates the datapath based on wavelength to wavelength substitution, under the control of a multi-protocol label switching (MPLS) protocol.

A method and apparatus for network monitoring using a proxy are disclosed. In one embodiment, a method generally comprises receiving at a proxy, path information for a label switched path (LSP) from a forwarding device located in the LSP, generating a connectivity verification message based on the path information, adding a proxy label to the connectivity verification message, and transmitting the connectivity verification message to the forwarding device. The proxy label is configured to inject the connectivity verification message into a forwarding plane at the forwarding device and the connectivity verification message is configured for transmittal from the forwarding device over the LSP to a destination node to verify a forwarding path associated with the path information received from the forwarding device.

A scalable packet forwarding approach to speed up unicast and multicast routing-table lookups in the Internet which we refer to as "Cluster-based Aggregation Switching Technique" or "CAST". CAST integrates the use of two mechanisms: (i) organizing table entries into clusters and (ii) using cluster-label swapping so that packets can refer to specific clusters within which the routing-table lookup should take place. The motivation for introducing CAST is the escalating rate of improvement of Internet bandwidth available at backbone routers, which continues to exceed the maximum rate of packet processing power of high-speed routers. Simulations show that the hybrid approach used in CAST to expedite routing table lookups is more attractive for unicast routing than all prior approaches in terms of its lookup power and total memory size. Furthermore, CAST applies equally well to multicast routing, while many prior schemes do not.

A method performed by a network device may include assembling a multiprotocol label switching (MPLS) echo request, the echo request including an instruction for a transit node to forward the echo request via a bypass path associated with the transit node, and an instruction for an egress node to send an echo reply indicating that the echo request was received on the bypass path. The method may also include sending the MPLS echo request over a functioning label switched path (LSP).