protocol info update for L4proxy

Author: jaesoni

articles/application-gateway/application-gateway-components.md

@@ -48,14 +48,14 @@ A port is where a listener listens for the client request. You can configure por
 
 ### Protocols
 
-Application Gateway supports four protocols: HTTP, HTTPS, HTTP/2, and WebSocket:
+Application Gateway supports web protocols HTTP, HTTPS, HTTP/2, and WebSocket with its Layer 7 proxy. The TLS and TCP protocols are supported with its Layer 4 proxy ([Preview](tcp-tls-proxy-overview.md)) and can be configured on the same resource. 
 >[!NOTE]
 >HTTP/2 protocol support is available to clients connecting to application gateway listeners only. The communication to backend server pools is always over HTTP/1.1. By default, HTTP/2 support is disabled. You can choose to enable it.
 
-- Specify between the HTTP and HTTPS protocols in the listener configuration.
+- Choose between the HTTP, HTTPS, TLS or TCP protocols in the listener configuration.
 - Support for [WebSockets and HTTP/2 protocols](features.md#websocket-and-http2-traffic) is provided natively, and [WebSocket support](application-gateway-websocket.md) is enabled by default. There's no user-configurable setting to selectively enable or disable WebSocket support. Use WebSockets with both HTTP and HTTPS listeners.
 
-Use an HTTPS listener for TLS termination. An HTTPS listener offloads the encryption and decryption work to your application gateway, so your web servers aren't burdened by the overhead.
+Use an HTTPS or TLS listener for TLS termination. An HTTPS/TLS listener offloads the encryption and decryption work to your application gateway, so your servers aren't burdened by the computation overhead.
 
 ### Custom error pages