Readme is more easy to understand.

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-# stellar-c: c adapter for stellar
+# Stellar-C: c adapter for stellar
+## Concepts
+The Stellar-C is a transition solution from Sapp to Stellar for fast DPI plugin development. The Stellar-C is built on the concepts of sessions and messages. A session is defined as a sequence of packets that share the same traffic attributes, such as TCP or UDP sessions. 
+* Each session has a message queue, which facilitates the exchange of messages among plugins. The message delivery is in the session scope. In Stellar-C, plugins are decoupled through the publish-subscribe mechanism.
+* EXdata (Extra Data) is attached to a session for plugin context management.
 
-## Architecture
+## Components
+The Stellar-C consists of the following components:
+* Sapp adaptor converts a Sapp stream to a Stellar session, and calls Stellar plugins to process the session.
+* Firewall is a Sapp plugins that interact with TCP/UDP and L7 decoders. It inherits all TSG firewall functions and publish messages to Stellar plugins.
+* Stellar plugins are DPI plugins that process the session, such as AppSketch, Session Flagging, Session Recorder.
+* Common libraries are shared libraries that are used by Stellar plugins, such as utable, logger.
+* Test framework generates sessions and messages from different data source for testing Stellar plugins. Possible data sources include pcap file, Kafka message queue, and fuzzing data.
 
 ![stellar-c-high-level-design](./docs/images/firewall-stellar-c.jpg)