Clarify what SCIONLab is (and is not) (#202)

* Clarify what SCIONLab is (and is not)

index.md

@@ -10,6 +10,9 @@ layout: default
 This website provides step-by-step instructions on how to run a SCION autonomous system (AS) in [SCIONLab](https://www.scionlab.org).
 It also provides a list of interesting projects that are using the SCION infrastructure for communication.
 
+**Note**: SCIONLab is a *testbed* network for SCION with *limited performance* intended for *development and experimentation*. If you want to 
+connect to the normal public SCION network, please refer to the [official website](https://scion.org) or the [developer documentation](https://docs.scion.org). 
+
 
 ## Table of contents
 {: .no_toc .text-delta }