Abstract: In one embodiment, a node determines a ratio of traffic that is to be marked at an output. The node also determines if an input feeding the output has less traffic marked than is to be marked at the output, and marks unmarked traffic of that particular input corresponding to a ratio substantially equal to the difference between what is needed at the output and what is marked at the input. Also, in one embodiment, a node may determine a fair share of an output for unconstrained inputs (e.g., a preemption threshold divided among the inputs, taking into consideration inputs that use less than their fair share), and mark traffic accordingly.

Abstract: A hierarchical multi-rate multi-precedence policer is disclosed. The policer discards packets based on assigned precedence levels. When traffic exceeds an available service rate, the policer drops packets of lower precedence levels to make room for packets of higher precedence levels. In certain implementations, the policer also guarantees bandwidth to each level, thus preventing complete loss of lower precedence traffic when there is a large amount of higher precedence traffic.

Abstract: A method and system for call admission and preemption in a network having an ingress node and an egress node defining an ingress/egress node pair, and one or more core nodes located in a path between the ingress node and the egress node and configured to mark packets exceeding an admission threshold. The method includes calculating a sustainable preemption rate based on a rate of traffic received at the egress node from the ingress node that passed through the one or more core nodes without being marked, and a ratio between a preemption threshold and the admission threshold. If a traffic load to the egress node is greater than the sustainable preemption rate, at least some traffic is dropped so that the traffic load does not exceed the sustainable preemption rate for the ingress/egress node pair.

Abstract: In one embodiment, for each port of an access node in an access-based computer network, one access server of a plurality of access servers is configured as a preferred access server for that port. Upon receiving a session initiation message at a particular port, the access node forwards the session initiation message to one or more of the access servers based on the configured preferred access server for the particular port.

Abstract: In one embodiment, a head-end node determines a path for un-reroutable tunnels, and establishes a tunnel having zero bandwidth indicating the corresponding bandwidth desired for the tunnel. Intermediate nodes send feedback regarding a bandwidth scaling factor for the path, and the head-end node resizes each tunnel accordingly.

Abstract: Methods and systems for preemption in a network having a core device with at least one egress interface are disclosed. In one embodiment, the method includes performing flow-based hash utilizing a plurality of hash-buckets each set to a first state or a second state and computing a load based on a rate measurement that excludes flows which hash into hash-buckets having a state set to the second state. The computed load is compared to a preemption threshold and if the computed load exceeds the preemption threshold, the state of at least one of the hash-buckets is changed from the first state to the second state. An action, such as dropping all packets or marking all packets, is performed on flows hashing in a hash-bucket in the second state.

Abstract: In one embodiment, head-end nodes receive a list of tunnels to be rerouted from a particular link of an intermediate node. If a head-end node is unable to reroute a tunnel for which it is the head-end node using conventional distributed routing, each head-end node executes the same algorithm to compute paths for all tunnels in the list (e.g., potentially applying bandwidth scaling).

Abstract: IPv6 traffic may be carried through an MPLS IPv4 network without the use of IPv6-over-IPv4 tunneling. This provides great savings in overhead, signaling, and state information storage and also allows for routing through the MPLS IPv4 network to adjust in response to changes in network state. In one embodiment, an edge node of an MPLS IPv4 network resolves a destination IPv6 network of a received IPv6 packet to an MPLS label switched path. The resolution exploits received inter-domain routing information. This information identifies the IPv4 address of an egress node that is usable as a gateway to the destination network. Within the inter-domain routing information, the IPv4 address may be encoded in IPv6 format.

Abstract: Devices, softwares and methods can establish an IP connection with each other through a network. Dynamic connection attributes of the called device are inferred locally by the calling device. These may include any one or more of type of codec, bandwidth, port number, and so on. A rule may be used for inference, expecting that the called device uses the same rule. Setup takes place without the calling device receiving this information explicitly by signaling. Plus setup may take place even though expected handshake signals might not be transmitted at all, due to differences in implementation, or even a difference in protocols.

Abstract: A method and apparatus for demoting network traffic are disclosed. In one embodiment, a method includes transmitting traffic associated with a session over a first path, and maintaining state information identifying the first path as a forwarding path for the session. Traffic associated with the session is rerouted from the first path to a second path following a network failure and the rerouted traffic is marked so that at least a portion of the rerouted traffic can be dropped at any point in the network if rerouting causes network congestion.

Abstract: In one embodiment, an intermediate node computes paths for a set of tunnels that do not include a particular link (e.g., and possibly a scaled-down bandwidth for each tunnel), considering all of the tunnels of the set. The intermediate node informs head-end nodes of the tunnels of the computed paths (e.g., and scaled bandwidth) and/or a time to reroute the tunnels.

Abstract: In one embodiment, a head-end node determines a path for un-reroutable tunnels, and establishes a tunnel having zero bandwidth indicating the corresponding bandwidth desired for the tunnel. Intermediate nodes send feedback regarding a bandwidth scaling factor for the path, and the head-end node resizes each tunnel accordingly.

Abstract: In one embodiment, head-end nodes receive a list of tunnels to be rerouted from a particular link of an intermediate node. If a head-end node is unable to reroute a tunnel for which it is the head-end node using conventional distributed routing, each head-end node executes the same algorithm to compute paths for all tunnels in the list (e.g., potentially applying bandwidth scaling).

Abstract: In one embodiment, a node determines a ratio of traffic that is to be marked at an output. The node also determines if an input feeding the output has less traffic marked than is to be marked at the output, and marks unmarked traffic of that particular input corresponding to a ratio substantially equal to the difference between what is needed at the output and what is marked at the input. Also, in one embodiment, a node may determine a fair share of an output for unconstrained inputs (e.g., a preemption threshold divided among the inputs, taking into consideration inputs that use less than their fair share), and mark traffic accordingly.

Abstract: Methods and systems for preemption in a network having a core device with at least one egress interface are disclosed. In one embodiment, the method includes performing flow-based hash utilizing a plurality of hash-buckets each set to a first state or a second state and computing a load based on a rate measurement that excludes flows which hash into hash-buckets having a state set to the second state. The computed load is compared to a preemption threshold and if the computed load exceeds the preemption threshold, the state of at least one of the hash-buckets is changed from the first state to the second state. An action, such as dropping all packets or marking all packets, is performed on flows hashing in a hash-bucket in the second state.

Abstract: In one embodiment, a node (e.g., a router) performs reservations for data flows, each on a corresponding selected (reserved) path having adequate reservation availability. Also, the node forwards data from data flows, each over a corresponding selected (forwarded) path having adequate load availability, wherein forwarded paths are decoupled from reserved paths for the data flows.

Abstract: A method and system for call admission and preemption in a network having an ingress node and an egress node defining an ingress/egress node pair, and one or more core nodes located in a path between the ingress node and the egress node and configured to mark packets exceeding an admission threshold. The method includes calculating a sustainable preemption rate based on a rate of traffic received at the egress node from the ingress node that passed through the one or more core nodes without being marked, and a ratio between a preemption threshold and the admission threshold. If a traffic load to the egress node is greater than the sustainable preemption rate, at least some traffic is dropped so that the traffic load does not exceed the sustainable preemption rate for the ingress/egress node pair.

Abstract: IPv6 traffic may be carried through an MPLS IPv4 network without the use of IPv6-over-IPv4 tunneling. This provides great savings in overhead, signaling, and state information storage and also allows for routing through the MPLS IPv4 network to adjust in response to changes in network state. In one embodiment, an edge node of an MPLS IPv4 network resolves a destination IPv6 network of a received IPv6 packet to an MPLS label switched path. The resolution exploits received inter-domain routing information. This information identifies the IPv4 address of an egress node that is usable as a gateway to the destination network. Within the inter-domain routing information, the IPv4 address may be encoded in IPv6 format.

Abstract: IPv6 traffic may be carried through an MPLS IPv4 network without the use of IPv6-over-IPv4 tunneling. An IPv6 packet is sent through the MPLS IPv4 network through a label switched path (LSP). The IPv6 packet is encapsulated with a label stack associated with the LSP. A second level label is used in the label stack (in addition to the label associated with the LSP). This second level label provides important benefits.

Abstract: Each network node having at least one destination-oriented link toward a directed acyclic graph (DAG) destination can receive a corresponding set of path performance metrics via the destination-oriented link. The set of path performance metrics, initiated by the DAG destination outputting initial link metrics on each of its source-connecting links, identifies aggregate link metrics for a corresponding path to the DAG destination via the corresponding destination-oriented link. The network node outputs a corresponding updated set of path performance metrics on each of its source-connecting links based on the received set of path performance metrics and the corresponding link metric for the corresponding source-connecting link. Hence, each network node in the DAG can assess the performance of each connected path to the DAG destination, and forward a data packet via a selected destination-oriented link based on the corresponding path performance metrics and forwarding policies for the forwarded data packet.