diff --git a/IGP.md b/IGP.md
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--- a/IGP.md
+++ b/IGP.md
@@ -31,7 +31,7 @@
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 # InteractiveGraphProtocol
 
-InteractiveGraphProtocol(IGP) defines a set of graph interaction interfaces via HTTP protocol.
+InteractiveGraphProtocol(IGP) defines a set of graph interaction interfaces over HTTP protocol.
 
 An IGP request is a HTTP POST request, which contains a `command` parameter in query string and a JSON parameter in request body, like: