System to limit access when calculating network data checksums

• US 7,096,415 B1
• Filed: 10/17/2003
• Issued: 08/22/2006
• Est. Priority Date: 04/28/2000
• Status: Expired due to Fees

• Current Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Bots, Henk J.
• Primary Examiner(s): Baker, Stephen M.
• Application Number:
  US10/688,205
• Time in Patent Office: 1,040 Days
• Field of Search: 714/805, 714/807
• US Class Current: 714/807
• CPC Class Codes: H03M 13/096 Checksums

Abstract

The invention provides a method and process for transmitting data without using additional CPU cycles and memory accesses to calculate checksums. The transmitting device obtains data from internal or external data source and stores data in memory. Data is then divided into zones and checksums are calculated for each zone. Checksums are recorded on a checksum array. A data pointer containing an address for data stored in memory, a description of the data and address for the checksum array is transferred through data transfer protocol to network and transmission layers. Network and transmission layers are then able to access and send data without having to either copy data through data transfer protocol to network and transfer layers or read all of the data to calculate the checksums. This method and process uses fewer CPU cycles and memory accesses to transmit data and is, therefore, more efficient than the prior art.

Claims

1. A method, including:

identifying data to be transferred;

dividing said data into zones;

calculating zone checksum values for said zones;

calculating chunk checksum values responsive to plural of said zone checksum values;

transferring one or more pointers to said data from a source to a destination; and

transferring a pointer to said zone checksum values from said source to said destination.

2. A method as in claim 1, wherein said steps of transferring are to or from a Network Interface Card (NIC).

3. A method as in claim 1, wherein one or more of said chunks include one or more partial zones.

4. A method as in claim 3, further including calculating partial zone checksum values for said partial zones.

5. A method as in claim 4, wherein calculating a chunk checksum value for any of said chunks that include one or more partial zones is responsive to one or more of said partial zone checksum values.

6. Apparatus including a memory including:

data to be transferred, said data divided into zones;

zone checksum values calculated for said zones;

chunk checksum values responsive to plural of said zone checksum values;

a transferable pointer to said data; and

a transferable pointer to said zone checksum values.

7. Apparatus as in claim 6, wherein said memory is in communication with a Network Interface Card (NIC) to or from which said data can be transferred.

8. Apparatus as in claim 6, wherein one or more of said chunks include one or more partial zones.

9. Apparatus as in claim 8, wherein said memory further includes partial zone checksum values calculated for said partial zones.

10. Apparatus as in claim 9, wherein a chunk checksum value calculated for any of said chunks that include one or more partial zones is responsive to one or more of said partial zone checksum values.