SIP What is SIP? SIP stands for Session Initiation Protocol. Related Posts:Why Are Businesses Switching to SIP?How to become VoIP Reseller?How to become a VoIP Reseller?Related Articles: VoIP Industry to grow to $76.1 billion in 2015Microsoft Skype for Business SIP TrunkspricingVoice SMS SIPTrunkConfigure Free Switch with DID For Sale« Back to Glossary Index