SPI meaning in Networking ?

Answer:

What is Security Parameter Index mean?

The Security Parameter Index (SPI) is an identification tag added to the header while using IPsec for tunneling the IP traffic. This tag helps the kernel discern between two traffic streams where different encryption rules and algorithms may be in use.

The SPI (as per RFC 2401) is a required part of an IPsec Security Association (SA) 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 it 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 SAs used to provide security to one connection. An SA could therefore act as a set of rules.

Carried in Encapsulating Security Payload (ESP) header or Authentication Header (AH), its length is 32 bits.

reference

Full Form	Category
Student Press Initiative	Academic & Science
Soy Protein Isolate	Academic & Science
Self-Paced Instruction	Academic & Science
Stanford Pascal Imaging	Academic & Science
Store Payment Interface	Accounts and Finance
Springfield (il)	Airport Code
Spitfire Resources Ltd	Business
Scottish Power, PLC	Business
Sales Per Item	Business
Selected Period Investment	Business
Staal Private Investigation	Business
Simulations Publications, Inc.	Business
Silverstein Properties, Inc.	Business
Singapore Paranormal Investigators	Business
Structure Probe, Inc.	Business
Special Projects International	Business
Solar Power Inc	Business
Security Personnel Inc	Business
Schaumburg Polk Inc	Business
Swiss Performance Index	Business
Single Process Initiative	Business
Skim Pembiayaan Ikhtiar loan scheme	Business
Strategy Productivity Insight	Business
Summary of Proposed Investment	Business
Slagging Pyrolysis Incinerator	Chemistry
Samaritan's Purse International	Community
Software in the Public Interest	Community
spots per inch	Computer and Networking
Standard Programmatic Interface	Computer and Networking
Synchronous Parallel Interface	Computer Hardware
Scsi (small Computer System Interface) Parallel Interface	Computer Hardware
SaaS PaaS and IaaS	Computing
Service Programming Interface	Computing
Synchronous Peripheral Interface	Computing
Software Process and Infrastructure	Computing
Sub Port Identifier	Computing
Smart Plug-In	Computing
Saas Paas Iaas	Computing
System Peripheral Interface	Computing
Software Pirates Inc.	Computing
Synchronization Programming Interface	Computing
Serial Peripheral Interconnect	Computing
Sensitive Personal Information	Computing
SCSI-3 (Small Computer System Interface) Parallel Interface	Computing
Security Parameters Index	Computing
Suse Plug-In	Computing
Scsi Parallel Interface	Computing
System Parameters Information	Computing
Software Process Impediment	Computing
Safeguarding Proprietary Information	Computing
Single Point Imaging	Computing
Single Point Interchange	Computing
Security Policy Index	Computing
Shopping	Cryptocurrency
Solder Paste Inspection	Electronics
Split Port Induction	Electronics
Single Point Injection	General
Senior Photographers International	General
Split Port Injection	General
Safety Performance Indicator	General
Society of the Plastics Industry	General
Smartphone Integration	General
Suzuki Philippines Inc.	General
Service Performance Insight	General
Sierra Pacific Industries	General
Swiss Precision Instruments	General
Sales Performance International	General
Specialty Products Insulation	General
Smart Passive Income	General
State Personal Income	General
Solar Power International	General
Scholastic Phonics Inventory	General
Smart Plant Instrumentation	General
Smart Policing Initiative	General
Synthetic Personality Inventory	General
Social Progress Imperative	General
Standardized Precipitation Index	General
Strategies for Policing Innovation	General
Sonography Principles and Instrumentation	General
Serial Parallel Interface	General
Sustainable Preservation Initiative	General
Sow Productivity Index	General
Sectoral Performance Indicators	General
Self Publishing Insight	General
Sector Partnerships Initiative	General
Stitch Per Inch	General
Service Performance Improvement	General
SPecial Investigative	Governmental
Strategy Planning and Implementation	Governmental
Special Private Intelligence	Governmental
Special Public Interest	Governmental
Stored Product Insects	Governmental
Social Progress Index	Governmental
Summer Peacebuilding Institute	Governmental
Southern Police Institute	Governmental
Serial Peripheral Interface	Information Technology
Stateful Packet Inspection	Information Technology
Societ Psicoanalitica Italiana	International
Societe de Proteines Industielles	International
Springfield Illinois Airport. Springfield, Illinois. USA Abraham Lincoln Capital Airport.	International
Superintendent of Public Instruction	Jobs
S Polynomial Information	Maths
Semantics, Proof, and Implementation	Maths
Samples Per Inch	Measurement Unit
Scottsdale Prevention Institute	Medical
Strategic Planning Initiative	Military and Defence
Standard Performance Indicator	Military and Defence
Special Packaging Instruction	Military and Defence
Special Inspection	Military and Defence
Schedule Performance Index	Military and Defence
Software Process Improvement	Military and Defence
Special Investigative (usaf)	Military and Defence
Sensor Point of Interest	Military and Defence
Subsequent Protocol Identifier	Networking
Scsi-3 Parallel Interface	Networking
Security Parameter Index	Networking
Statefull Packet Inspection	Networking
Session Parameter Index	Networking
Capital Airport, Springfield, Illinois USA	Regional
South Padre Island, Texas	Regional
Software Patent Institute	Softwares
Standard Practice Instruction	Space Science
Surface Position Indicator	Space Science
Soccer Power Index	Sports
Service Provider Interface	Telecommunication