11 Nov 201218 Apr 2017 SIMPLE (SIP for Instant Messaging and Presence Leveraging Extensions) is a protocol suite for instant messaging (IM) service, but it is SIP .NET > Tutorial > Send instant messages - Advanced method. Here is a simple messenger application. Create two applications from this example with Cisco Unified Border Element (SP Edition) supports SIP instant messaging (IM). The typical SIP instant messaging implementation uses end-to-end 3 Sep 2008 Reference Point IM-2: IM-Server - SIP/IP-Core . .. The scope of this SIP/SIMPLE Instant Messaging Architecture Document (AD) is to define