diff -r 72ab3344e053 -r 6e4ad8540edd data/dictionary.xml
--- a/data/dictionary.xml	Mon Aug 19 21:13:01 2013 +0200
+++ b/data/dictionary.xml	Mon Aug 19 21:23:59 2013 +0200
@@ -1297,12 +1297,25 @@
 	</concept>
 	<concept>
 		<term abbreviation="SIP" completeForm="session initiation protocol" language="en"/>
-		<explanation language="en"><text></text></explanation>
+		<explanation language="en">
+			<text>
+				an open signalling protocol for initiation of VoIP calls (audio, video or possibly other media sessions);
+				uses UDP and has similar format of headers to HTTP;
+				can also be transported over TCP (for TLS encryption) or SCTP;
+				for the media payload is typically used RTP protocol
+			</text>
+		</explanation>
 		<tag>protocol</tag>
 	</concept>
 	<concept>
 		<term abbreviation="RTP" completeForm="real-time transport protocol" language="en"/>
-		<explanation language="en"><text></text></explanation>
+		<explanation language="en">
+			<text>
+				a standardized packet format for delivering audio and video over IP;
+				can transfer audio or video streams for telephony or television streams;
+				is used heavily in VoIP in combination with SIP
+			</text>
+		</explanation>
 		<tag>protocol</tag>
 	</concept>
 	<concept>