Communication apparatus and method of hand over of an assigned group address from one communication apparatus to another

• US 6,598,071 B1
• Filed: 07/26/1999
• Issued: 07/22/2003
• Est. Priority Date: 07/27/1998
• Status: Expired due to Term

• Current Assignee: Alaxala Networks Corporation (Fortinet Inc.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Hayashi, Kenji, Atarashi, Yoshifumi, Ikeda, Naoya
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): NGUYEN, THU HA T
• Application Number:
  US09/360,688
• Time in Patent Office: 1,457 Days
• Field of Search: 709/203, 709/220, 709/226, 709/240, 709/201, 709/227, 709/231, 709/200, 709/105, 709/219, 709/245, 709/224, 709/223, 370/465, 370/256, 712/27
• US Class Current: 709/203
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources

Abstract

Unique addresses are provided to identify and communicate with each of a plurality of servers and a client connected on a network. A group address which differs from the unique address is assigned to any of the plurality of servers. The client specifies that group address when receiving service from the server. The traffic status of the communication path between server and client is monitored and if factors such as communication speed and response time have exceeded a preset threshold, the group address is dynamically passed to another server.

Thereby a communications system is able to dynamically switch servers, the source for generating traffic, on the network without rerouting of paths on which traffic is concentrated and requiring no change settings or addition of control functions by the client and further able to effectively use portions of the network having low usage rates.

Claims

1. A server that is assigned a group address and is accessed from a client by using said group address, comprising;

a detecting means for detecting traffic status between said client and said server,

a selecting means for selecting an appropriate server for said client to access based on traffic status detected by said detecting means,

a means for handing over said group address from said server to said selected appropriate server,

wherein said selected appropriate server stores said group address and invalidates said group address, and

said means for handing over said group address sends a packet for directing said selected appropriate server to validate said stored group address.

2. A server according to claim 1, wherein

said means for handing over said group address sends a switching command packet containing said group address to said selected appropriate server.

3. A method of handing over a group address that is assigned to a communication apparatus to another communication apparatus , said communication apparatus being accessed from a client by using said group address, comprising the steps of;

detecting traffic status between said client and said communication apparatus,

selecting another communication apparatus for said client to access based on detected traffic status,

handing over said group address from said communication apparatus to said selected another communication apparatus,

wherein said selected another communication apparatus stores said group address and invalidates said group address, and

said handing over step includes a step of sending a packet for directing said selected another communication apparatus to validate said group address.

4. A method according to claim 3, wherein

said handing over step includes a step of sending a switching command packet containing said group address to said selected another communication apparatus.

5. A communication method according to claim 3, further comprising;

providing a relay equipment installed between the client and server, said relay equipment performs conversion between the group address and the unique address of the server, thereby communication is performed utilizing the unique address of the server between said server and said relay equipment and the group address of said server between said client and said relay equipment.

6. A method according to claim 3, wherein

said detecting step includes a step of sending a return packet to said client for measuring a response time between said client and said communication apparatus.

7. A method according to claim 3, wherein

said detecting step comprising the steps of;

providing a traffic measuring apparatus on a communication path between said client and said communication apparatus,

monitoring traffic on the communication path to measure traffic.

8. A method according to claim 3, wherein

said detecting step includes a step of receiving a message from a network which is sent when a communication packet has been discarded due to congestion on the network.