Atrica Israel Ltd.

Atrica Ireland Limited

Yaron Raz

Lior Shabtay

Yoav Kluger

Ofir Friedman

Golan Schzukin

Amir Lahat

Gila Klein

Pavel Hardak

Uri Avimor

Yoram Shamir

Leonid Shmulevich

Zacky Pickholz

Alex Arnon

Doron Vider

A centralized clock distribution mechanism for synchronous TDM communications traffic transported over asynchronous networks such as Ethernet networks. The centralized clocking mechanism of the present invention distributes a high accuracy central clock source to a plurality of CES modules over an Ethernet network. Clock synchronization information based on a high quality clock reference source is distributed to circuit emulation service (CES) modules in the network. CES modules receive the clock synchronization information and use it to reconstruct a local clock. A plurality of clock distributors provide clock redundancy whereby each CES module selects the best clock source to use in reconstructing the local clock.

Centralized clock synchronization for time division multiplexed traffic transported over Ethernet networks

An apparatus for and method of enforcing precedence of committed traffic over excess traffic that overcomes the difficulty in supporting committed over excess traffic and has particular application to distributed queuing systems. Queue control messages are generated and transmitted to other line cards to guarantee that committed traffic is not dropped when sent from multiple sources such as line interface cards to a single destination. When the level of a queue exceeds a threshold and flow control is received for the corresponding destination, the queue starts dropping excess traffic and messages indicating the queue status are sent to all other lines cards. When a line card receives a queue control message that another line card started dropping excess traffic to a specific destination, it also starts dropping excess traffic to that destination as well.

Apparatus for and method of support for committed over excess traffic in a distributed queuing system

A subport forwarding and provisioning mechanism whereby a plurality of subports implemented using slower speed processors are used to perform the packet processing for a higher speed packet stream. Outbound packets are assigned a subport based on their MPLS labels. Once assigned, the packets are forwarded to a particular subport. The output of all the subports is aggregated and combined into a single high speed packet stream and transmitted over the link. Inbound packets are received by the high speed PHY and forwarded to one of a plurality of subports. The subport chosen is the one having the same subport index as the one through which the packet was sent out over at the transmitting node. Conventional layer 2 switches can also be used whereby reserved source MAC addresses are assigned to subports. The switch forwards the inbound packets to one of the subports in accordance with the packet's source MAC address. The invention also comprises a mechanism for provisioning protection tunnels and a method for allocating subport bandwidth to subports.

Link multiplexing mechanism utilizing path oriented forwarding

A protection mechanism capable of providing both local and end-to-end connection protection for dual homed access/aggregation devices or customer-edge devices in a network. The protection mechanism provides end-to-end and fast local protection for off the shelf access devices that do not have any built in per-connection protection capabilities. The access device is connected via two separate physical uplinks to two edge switches of the network. For each connection to be protected, a main path is provisioned from one edge switch and an alternative path is provisioned from the other edge switch. The edge switches are adapted to comprise means for switching traffic from the main path to the alternative path in the event a failure along the main path is detected. Failures both in the stack portion, the core portion and in the access device uplinks are protected against.

Connection protection mechanism for dual homed access, aggregation and customer edge devices

An end-to-end monitoring mechanism whereby edge nodes are notified that a particular path flows through a local protection tunnel along the way. The notification mechanism utilizes OAM packets which include a link protection indication that are transmitted on the Ethernet service layer. The link protection indication may be represented by one or more flags to indicate that local protection is in place along the path. The mechanism enables fast local protection to be used with slower end-to-end protection by informing the latter when local protection is activated. In an implementation in which local-protection does not preserve the CIR of the protected traffic, the invention provides minimal interruption of Committed Information Rate (CIR) connections by minimizing the time traffic is diverted through local protection tunnels. Notification of the edge node that local protection is in use occurs very quickly, thus allowing the edge node to rapidly switch to a backup path.

End-to-end notification of local protection using OAM protocol

A fast protection mechanism capable of maintaining end-to-end and fast local protection on the order of sub 50 ms for both VLAN only based connections and for connections that are based partially on VLAN technology and partially on MPLS technology. The present invention is suitable for use edge switches configured in a stack or ring topology. The NMS provisions both the main and alternative VLANs in each edge switch in the stack portions of the network. When a link failure occurs, the edge switches on either end of the failed link immediately switch all protected traffic going through that link to the alternative VLAN. The packets are then returned on the links over which they were received. Hello messages are used to signal the remote end that a link failure has occurred and that protected traffic must be switched to the main or alternative VLAN in accordance with the VLAN the Hello message was received on.

Fast connection protection in a virtual local area network based stack environment

A path reroute mechanism for use in communication networks comprising multiple searches for a routing path to restore traffic following a failure that could not be protected by a previously established protection route (i.e. protection tunnel, bypass, etc.) or for routing or rerouting of traffic paths for optimization or any other purpose. Each node advertises TLVs that include bandwidth allocation information used to derive the actual amount of bandwidth available for protection purposes, protected paths and unprotected paths or a portion of this information such as in the case where unprotected paths are not supported. Searches are performed on larger and larger portions of the available bandwidth until a route for the path is found.

Growing community of inventors

Ramot Meir, Israel

Yaron Raz