| Abbreviation | Definition |
|---|---|
| SIF | Solid Interchange Format |
| SIGCOMM | Special Interest Group on data COMMunications (ACM) |
| SIGNA | Simplified Internet Gigabit Networking Architecture |
| SIGNT | Signals Intelligence |
| SIMM | Single In-line Memory Module |
| SIMP | Secure Instant Messaging Protocol |
| SIMPLE | SIP for Instant Messaging and Presence Leveraging Extensions |
| SIMS | Solaris Internet Mail Server |
| SIN | Static Ip Notification |
| SIN | Study Information Network |
| SINA | Secure Inter Networking Architecture |
| SINA | Sensor Information and Networking Architecture |
| SINE | Secure Inbound Network Environment |
| SIP | Session Initialization Protocol |
| SIP | SMDS Interface Protocol |
| SIP | System Interface Procedure |
| SIPN | Secure IP Network |
| SIPP | Simple Internet Protocol Plus |
| SIPS | Session Initiation Protocol - Secure |
| SIT | Simple Interface Tunnel |