Change organization of the HTTP section of Architecture overview

docs/intro/arch_overview/arch_overview.rst

@@ -8,11 +8,9 @@ Architecture overview
   threading_model
   listeners
   network_filters
-  http_connection_management
-  http_protocols
   http_filters
+  http_connection_management
   http_routing
-  http_access_logs
   grpc
   cluster_manager
   service_discovery

docs/intro/arch_overview/http_connection_management.rst

@@ -13,3 +13,36 @@ also handles functionality common to all HTTP connections and requests such as :
 <arch_overview_http_routing>` management, and :ref:`statistics <config_http_conn_man_stats>`.
 
 HTTP connection manager :ref:`configuration <config_http_conn_man>`.
+
+.. _arch_overview_http_protocols:
+
+HTTP protocols
+--------------
+
+Envoy’s HTTP connection manager has native support for both HTTP/1.1 and HTTP/2. It does not support
+SPDY. Envoy’s HTTP support was designed to first and foremost be an HTTP/2 multiplexing proxy.
+Internally, HTTP/2 terminology is used to describe system components. For example, an HTTP request
+and response take place on a *stream*. A codec API is used to translate from different wire
+protocols into a protocol agnostic form for streams, requests, responses, etc. In the case of
+HTTP/1.1, the codec translates the serial/pipelining capabilities of the protocol into something
+that looks like HTTP/2 to higher layers. This means that the majority of the code does not need to
+understand whether a stream originated on an HTTP/1.1 or HTTP/2 connection.
+
+.. _arch_overview_http_access_logs:
+
+HTTP access logging
+-------------------
+
+The HTTP connection manager supports extensible access
+logging with the following features:
+
+* Any number of access logs per connection manager.
+* Asynchronous IO flushing architecture. Access logging will never block the main network processing
+  threads.
+* Customizable access log formats using predefined fields as well as arbitrary HTTP request and
+  response headers.
+* Customizable access log filters that allow different types of requests and responses to be written
+  to different access logs.
+
+HTTP access log :ref:`configuration <config_http_conn_man_access_log>`.
+