Security Parameters Index: Difference between revisions

Revision as of 22:05, 24 June 2008

Revision as of 10:46, 22 August 2008

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The SPI (as per RFC 2401) is an essential part of an [[IPSec]] SA ([[Security Association]]) because it enables the receiving system to select the SA under which a received packet will be processed. An SPI has only local significance, since is defined by the creator of the SA; an SPI is generally viewed as an opaque bit string. However, the creator of an SA may interpret the bits in an SPI to facilitate local processing.

This works like Port numbers in TCP and UDP connections. What it means is that there could be different SA’sSAs used so as to provide security to one connection. Which meansAn SA could therefore act as a set of rules.