Alcatel Lucent

Alcatel

Laurence Rose

Vincent Magret

Jessy Victor Rouyer

Guillaume Ivaldi

Nalinakshan Kunnath

David Elie-Dit-Cosaque

Girish Chiruvolu

Ljubisa Tancevski

Jagjeet Bhatia

Roberto Henrique Jacob Da Silva

L Michele Goodwin

Jean-Francois Cartier

Roberto Henrique J Da Silva

Manish Gupta

Jessy Rouyer

Jessy V Rouyer

An apparatus and method for controlling bridge protocol data unit bursts is disclosed. The invention in the preferred embodiment is a switching device with a port enabled with a link management protocol and a burst control state machine. The burst control state machine is adapted to receive BPDUs and, under certain conditions, delay responding with its own BPDU falsely advertising itself as the new root bridge. The delay is preferably long enough to enable another bridge to identity the true root bridge. The delay, e.g., a burst control delay, is preferably equal to or less than a Hello time timer value generally defined to be 2 seconds in a Rapid Spanning Tree Protocol standard, for example.

Spanning tree protocol with burst avoidance

A node (bridge, switch, router) and method are described herein that implement a loop prevention mechanism for Ethernet ring protection. In one embodiment, the loop prevention mechanism can enhance the current draft of the standard ITU-T G.8032 Ethernet Ring Protection Switching.

Loop prevention mechanism for ethernet ring protection

A system and method of operating a set of stack elements that are stackable and connected to form a ring. In one embodiment, the stack Media Access Control (MAC) address is stored in each stack element of the ring; and responsive to an assessment that communication with a primary stack element is lost, a determination is made whether to replace the first MAC address with a second MAC address or to retain the first MAC address in each stack element remaining of the set of stack elements.

System and method for avoiding duplication of MAC addresses in a stack

A manner of providing for re-convergence in a dual homing network following the failure of one of the dual homing links. When such a failure is detected, the port roles are recomputed using an xSTP protocol. Prior to the completion of the computation, the operEdge variable is set to true, typically resulting in a more rapid re-convergence that may achieve sub 50 ms performance. When the computation is complete, the operEdge variable is reset to 'false. The xSTP protocol may be, for example, RSTP or MSTP. The invention may be implemented in a CE device attached to a VPLS core or other network, and may be used in a LAG environment.

Method for reconvergence after failure in a dual-homing network environment

Customer virtual local area networks (C-VLANs) connecting multiple LAN segments are set up through a provider network (). Provider edge bridges (PEs) are coupled to customer edge bridges (CEs) to provide a transparent link between LAN segments. To determine whether a backdoor link is used in the C-VLAN topology, PEs monitor MAC address from a predetermined time after a TCN is received to determine if there are contradictory addresses or new addresses relative to the existing MAC address tables (or forwarding databases) that are indicative of a backdoor link. If so, an unlearning message is sent to bridges in the provider domain. In another embodiment, CEs set a snoop bit to indicate which TCNs must be snooped.

Method and apparatus for updating provider domain due to customer TCNs

A Layer 2 device configured for providing at least one of bridging and switching functionality in a local area network comprising computer readable instructions for providing GVRP functionality and computer-readable instructions for limiting the number of dynamic VLANs that the GVRP functionality creates on a Layer 2 device of a local area network and on all ports of a data plane card of the Layer 2 device.

Method and network element configured for limiting the number virtual local area networks creatable by GVRP

In a method for enabling facilitation of re-convergence, designation information for a first port of each one of a plurality of bridges in a multi-bridge ring is received and designation information for a second port of each one of a plurality of bridges in a multi-bridge ring is received. The first port of each one of a plurality of bridges is a first direction Ring Rapid Spanning Tree Protocol (RRSTP) port and the second port of each one of a plurality of bridges is a second direction RRSTP port. The first direction around the ring (e.g., a forward direction) is opposite the second direction around said ring (e.g., a backward direction). A first reserved RRSTP MAC address is associated with the first direction port of each one of the bridges and a second reserved MAC address is associated with the second direction port of each one of the bridges.

Ring rapid spanning tree protocol

In an embodiment, a method is disclosed for operating a network having a group of bridges connected together to form a ring, each bridge having two ports assigned to the ring to form a group of ring ports. The claimed embodiment includes forwarding information through the ring according to one or more spanning tree instances, each instance designating one of the group of ring ports as a respective alternate port that is in a state of discarding. Responsive to learning of a failure by a bridge within the ring, a determination is made, for each spanning tree instance, whether the bridge contains a respective alternate port and if the bridge contains a respective alternate port, changing the state of the respective alternate port to forwarding.

Ring rapid multiple spanning tree protocol system and method

A bridge (e.g., IEEE 802.1 bridge) and a method are described herein which ensure the proper propagation of a 'cut' within a bridged network (e.g., Ethernet-based bridged network). In one embodiment, the bridge has a port role transitions (PRT) state machine which uses a first condition represented as (proposed && !agree) to transit to an X_PROPOSED state and a second condition represented as (! proposed && allSynced && !agree) &#x2225; (proposed && agree) to transit to an X_AGREED state (where X represents 'ROOT', &#x201c;ALTERNATE&#x201d; and &#x201c;MASTER&#x201d;). The first condition and the second condition are both defined such that the X_PROPOSED state is always entered before the X_AGREED state which ensures the proper propagation of a &#x201c;cut&#x201d; within the bridged network.

Deterministic operation of rapid spanning tree protocols for proper propagation of a 'cut'

A protocol for discovering a silent device, such as a printer, attached to a mobile port of a switching node. A command is transmitted to the switching node for associating an IP address for the silent device to a particular virtual local area network (VLAN). Entry of the command causes the switching node to start searching for the silent device on the mobile ports. As part of the searching process, an ARP request with the IP address provided in the command is sent to each mobile port of the switching node. When the silent device responds with its MAC address in an ARP reply message, the MAC address is learned in a layer 2 table used for making forwarding decisions of data units received by the switching node. Furthermore, the port where the silent device was discovered, that is, the port receiving the ARP reply message, is associated with the VLAN of the silent device.

Printer discovery protocol system and method

The present invention features embodiments of alleviating the impact to a system of stack switches, as well as to neighboring nodes communicating with such a system, when a primary master switch to secondary master switch failover occurs. The features of the present invention, generally enables a system of stack switches to retain, for a fixed or indefinite period of time, its stack address even when multiple primary master to secondary master failovers occur. This way recalculation of certain protocols&#x2014;e.g., spanning trees and link aggregations&#x2014;and updating of certain tables&#x2014;e.g., address resolution protocol (ARP) and routing tables&#x2014;are minimized.

Retention of a stack address during primary master failover

A method for providing Topology Change functionality in a Local Area Network (LAN) comprises a plurality of operations. An operation is performed for determining that a Multiple Spanning Tree Instance (MSTI) Master port on a Bridge of a LAN has transitioned to Forwarding state from a corresponding Common Internal Spanning Tree Instance (CSTI) Root port state and an operation is performed for transitioning a Port Transmit state machine of the Bridge from an Idle state to a Transmit state for enabling issuance of a Topology Change (TC) BPDU message from the MSTI Master port. The operation of transitioning the Port Transmit state machine is performed in response to performing the operation of determining that the Multiple Spanning Tree Instance (MSTI) Master port has transitioned to Forwarding state.

Facilitating topology change functionality when regional root information changes

A method is described herein for configuring a computer network managed by the IEEE Std 802.1s&#x2122;-2002 MSTP standard or any other equivalent standard such as IEEE Std 802.1Q&#x2122;-2003 in a fully- or semi-automatic manner such that: (1) if at all possible and in the case of a failure in the MSTP-based computer network affecting a Multiple Spanning Tree Instance (MSTI), MSTP reestablishes connectivity in that MSTI by preferably activating links whose activation ensures that the connectivity within a Virtual Local Area Network (VLAN) mapped onto and associated with that MSTI is not lost; and (2) a VLAN is mapped onto a MSTI whose active topology covers the topology of this VLAN, this being ensured by setting up that MSTI depending on the desired VLAN topology.

Method for obtaining the best connectivity achievable within virtual local area networks

In a method for enabling facilitation of re-convergence, designation information for a first port of each one of a plurality of bridges in a multi-bridge ring is received and designation information for a second port of each one of a plurality of bridges in a multi-bridge ring is received. The first port of each one of a plurality of bridges is a first direction Ring Rapid Spanning Tree Protocol (RRSTP) port and the second port of each one of a plurality of bridges is a second direction RRSTP port. The first direction around the ring (e.g., a forward direction) is opposite the second direction around said ring (e.g., a backward direction). A first reserved MAC address is associated with the first direction port of each one of the bridges and a second reserved MAC address is associated with the second direction port of each one of the bridges.

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Oak Park, CA, United States of America

Laurence Rose