Distributed cache for state transfer operations

• US 8,458,340 B2
• Filed: 10/03/2011
• Issued: 06/04/2013
• Est. Priority Date: 02/13/2001
• Status: Expired due to Term

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Aventail LLC
• Inventors: Erickson, Rodger D.
• Primary Examiner(s): Lim, Krisna
• Application Number:
  US13/252,170
• Publication Number:
  US 20120084384A1
• Time in Patent Office: 610 Days
• Field of Search: 709223-227
• US Class Current: 709/227
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/148 Migration or transfer of sessions
• CPC Class Codes: H04L 67/288 Distributed intermediate devices, i.e. intermediate devices for interaction with other intermediate devices on the same level
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A network arrangement that employs a cache having copies distributed among a plurality of different locations. The cache stores state information for a session with any of the server devices so that it is accessible to at least one other server device. Using this arrangement, when a client device switches from a connection with a first server device to a connection with a second server device, the second server device can retrieve state information from the cache corresponding to the session between the client device and the first server device. The second server device can then use the retrieved state information to accept a session with the client device.

Claims

1. A system for maintaining session based communications with a client computer, the system comprising:

a first server that communicates with a client computer, wherein the first server includes a copy of a cache memory storing at least a portion of state information for a session corresponding to a session between the first server and the client computer; and

a second server including a copy of the cache memory stored at the first server, wherein the client computer establishes a new session with the second server when a connection with the first server terminates, and wherein the second server requests an additional portion of state information from a third server when the additional portion of state information is not immediately present at the second server upon establishment of the connection with the client computer and the additional portion of state information is required to properly conduct the session.

2. The system of claim 1, wherein the second server sequentially requests the additional portions of state information from the third server until the required additional state information is received in reply.

3. The system of claim 1, wherein the first server further includes:

a proxy application stored in memory and executable by the first server to establish a secure communication with the client computer;

a distributed cache application programming interface executable to retrieve information from the cache memory and pass the information to a distributed cache application; and

a distributed cache application stored in memory and executable to store information in the cache memory.

4. The system of claim 3, further comprising a communicator application stored in memory and executable to allow communication between the distributed cache application and the second server.

5. The system of claim 1, wherein the state information is credential information.

6. The system of claim 5, wherein the credential information includes Secure Sockets Layer (SSL) session identifiers.

7. The system of claim 6, wherein the credential information includes authentication information.

8. The system of claim 1, wherein the state information includes Transmission Control/Internet Protocol (TCP/IP) header information.