Method and apparatus for testing packet data integrity using data check field
US6424632B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1999 |
| Grant date | Jul 23, 2002 |
| Priority date | — |
| Expiry date | Jan 27, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2012/565
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A single check field can be generated and appended to packets prior to a switching or other operation to support post-operation verification that protected fields were not altered during the operation and that the post-operation packet sequence matches the pre-operation packet sequence. The check field requires the use of nominally-synchronized packet counters at the check field generating system and at the verification system. The check field is generated by performing a CRC calculation on the protected fields of the packet. The CRC result is combined with the current packet count to obtain the final check field, which is appended to the packet. At the verification system, a CRC calculation is performed on the protected fields of the packet, included the appended final check field. This provides an interim check result which is compared to the current packet count at the verification system. A non-null compare result is indicative of an error condition. The type of error condition can be established by comparing verification results for successive packets.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.