Method of resolving split virtual LANs utilizing a network management system

• US 6,269,076 B1
• Filed: 05/28/1998
• Issued: 07/31/2001
• Est. Priority Date: 05/28/1998
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Barkai, Sharon, Shamir, Yoram, Shani, Sarit
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): LOGSDON, JOSEPH B
• Application Number:
  US09/086,104
• Time in Patent Office: 1,160 Days
• Field of Search: 370/94.1, 370/60.1, 370/207, 370/255, 370/396, 370/85.2, 370/85.13, 370/404, 370/216, 370/217, 370/218, 370/219, 370/220, 370/221, 370/222, 370/223, 370/225, 370/242, 370/244, 370/245, 370/248, 370/250, 370/251, 709/218
• US Class Current: 370/217
• CPC Class Codes: H04L 41/0213 Standardised network management protocols, e.g. simple network management protocol [SNMP]
• CPC Class Codes: H04L 41/0654 using network fault recovery ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437
• CPC Class Codes: H04L 41/0816 the condition being an adaptation, e.g. in response to network events
• CPC Class Codes: H04L 41/082 the condition being updates or upgrades of network functionality
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 41/40 using virtualisation of network functions or resources, e.g. SDN or NFV entities
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/10 Routing in connection-oriented networks, e.g. X.25 or ATM
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/247 using M:N active or standby paths
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

A method for creating and resolving split VLANs in ATM networks. The method utilizes a Network Management System (NMS) and a standard management protocol such as SNMP. The method monitors the network by continuously polling all the devices in the network. Status related information collected by the NMS is used to construct a physical and logical topology of the network. In response to the detection of one or more physical splits in the network, the NMS creates one or more corresponding logical splits in the network by splitting one or more VLANs. In the case of two split portions, the split VLAN can be created if a redundant LES and second LECS are located on the side of the split which does not include the primary LES. The second LECS is configured to use the address of the redundant LES in replying to requests to join an ELAN from the disconnected LECs. The repair of the physical split is detected by the NMS and, in response, the NMS modifies the databases of all the LECS in the ELAN so that the same primary LES address is returned to any LEC requesting to join an ELAN. LECs previously attached to the redundant LES are disconnected and subsequently attached to the primary LES.

Claims

1. A method of creating and subsequently re-uniting a split Virtual Local Area Network (VLAN) in the event of a physical break in an Emulated Local Area Network (ELAN) consisting of a plurality of network devices, said ELAN including a primary LAN Emulation Configuration Server (LEC), a primary LAN Emulation Server (LES) and one or more LAN Emulation Clients (LECs), said method comprising the steps of:

detecting the occurrence of a physical split in said ELAN;

configuring a second LECS to reply to LEC initialization requests with the address of a secondary LES, thus creating a split VLAN, wherein said secondary LECS and said primary LES operate on one side of said split and said secondary LES and secondary LES operate on an opposite side of said split;

detecting the repair of said physical split in said ELAN;

configuring said secondary LECS to reply to LEC initialization requests with the address of said primary secondary LES;

terminating connections between said secondary LES and any LECs connected thereto; and

resetting all LECs whose connections to said secondary LES were terminated so as to cause the establishment of connections between said primary LES and LECs whose connections to said secondary LES were terminated, thus re-uniting said split VLAN.

2. The method according to claim 1, wherein said step of detecting the occurrence of and said step of detecting the repair of a physical split comprise the step of collecting status related information by polling using a Network Management System (NMS) and one or more standard Management Information Base (MIBs) configured in said plurality of network devices.

3. The method according to claim 2, wherein said step of collecting status related information utilizes out of band Ethernet based communications between said NMS and said one or more standard MIBs.

4. The method according to claim 2, wherein said step of collecting status related information utilizes in band LAN Emulation based communications between said NMS and said one or more standard MIBs.

5. A method of creating and subsequently re-uniting a plurality of split Virtual Local Area Networks (VLANs) in the event of a plurality of physical breaks in an Emulated Local Area Network (ELAN) consisting of a plurality of network devices, said ELAN including a primary LAN Emulation Configuration Server (LEC), a primary LAN Emulation Server (LES) and one or more LAN Emulation Clients (LECs), said method comprising the steps of:

detecting the occurrence of a plurality of physical splits in said ELAN, said plurality of physical splits partitioning said ELAN into a primary portion and a plurality of secondary portions;

configuring a secondary LECS in each secondary portion of said ELAN to reply to LEC initialization requests with the address of a secondary LES in each secondary portion of said ELAN, thus creating a plurality of split VLANs wherein said primary LECS and said primary LES operate in said primary portion of said ELAN and the secondary LECSs and the secondary LESs operate in said plurality of secondary portions of said ELAN;

detecting the repair of said plurality of physical splits in said ELAN;

configuring the secondary LECSs to reply to LEC initialization requests with the address of said primary LES;

terminating connections between the secondary LESs and any LECs connected thereto; and

resetting all LECs whose connections to the secondary LESs were terminated so as to cause the establishment of connections between said primary LES and LECs whose connections to the secondary LESs were terminated, thus removing said plurality of split VLANs and re-uniting said ELAN.

6. A Network Management System (NMS) for creating and subsequently re-uniting a split Virtual Local Area Network (VLAN) in the event of a physical break in an Emulated Local Area Network (ELAN) consisting of a plurality of network devices, said ELAN including a primary LAN Emulation Configuration Server (LEC), a primary LAN Emulation Server (LES) and one or more LAN Emulation Clients (LECs), comprising:

first detecting means for detecting the occurrence of a physical split in said ELAN;

first configuration means for configuring a secondary LECS to reply to LEC initialization requests with the address of a secondary LES, thus creating a split VLAN, wherein said primary LECS and said primary LES operate on one side of said split and said secondary LECS and secondary LES operate on an opposite side of said split;

second detecting means for detecting the repair of said physical split in said ELAN;

second configuration means for configuring said secondary LECS to reply to LEC initialization requests with the address of said primary LES;

means for terminating connections between said secondary LES and any LECs connected thereto; and

means for resetting all LECs whose connections to said secondary LES were terminated so as to cause the establishment of connections between said primary LES and LECs whose connections to said secondary LES were terminated, thus re-uniting said split VLAN.

7. The system according to claim 6, wherein said first detecting means and said second detecting means comprise means for collecting status related information by polling using one or more standard Management Information Base (MIBs) configured in said plurality of network devices.

8. The system according to claim 7, wherein said means for collecting status related information utilizes out of band Ethernet based communications between said NMS and said one or more standard MIBs.

9. The system according to claim 7, wherein said means for collecting status related information utilizes in band LAN Emulation based communications between said NMS and said one or more standard MIBs.

10. The system according to claim 7, wherein said first configuration means comprises means for synchronizing a database located in said secondary LECS to reply to LEC initialization requests with the address of said secondary LES.

11. The system according to claim 7, wherein said second configuration means comprises means for synchronizing a database located in said secondary LECS to reply to LEC initialization requests with the address of said primary LES.