diff --git a/envoy/api/v3alpha/cds.proto b/envoy/api/v3alpha/cds.proto
index adae481c..ab7fa9dd 100644
--- a/envoy/api/v3alpha/cds.proto
+++ b/envoy/api/v3alpha/cds.proto
@@ -586,8 +586,8 @@ message Cluster {
   //   verification.
   auth.UpstreamTlsContext tls_context = 11;
 
-  // Additional options when handling HTTP requests. These options will be applicable to both
-  // HTTP1 and HTTP2 requests.
+  // Additional options when handling HTTP requests upstream. These options will be applicable to
+  // both HTTP1 and HTTP2 requests.
   core.HttpProtocolOptions common_http_protocol_options = 29;
 
   // Additional options when handling HTTP1 requests.
diff --git a/envoy/api/v3alpha/core/protocol.proto b/envoy/api/v3alpha/core/protocol.proto
index e9761292..95890ed1 100644
--- a/envoy/api/v3alpha/core/protocol.proto
+++ b/envoy/api/v3alpha/core/protocol.proto
@@ -18,11 +18,19 @@ message TcpProtocolOptions {
 }
 
 message HttpProtocolOptions {
-  // The idle timeout for upstream connection pool connections. The idle timeout is defined as the
+  // The idle timeout for connections. The idle timeout is defined as the
   // period in which there are no active requests. If not set, there is no idle timeout. When the
-  // idle timeout is reached the connection will be closed. Note that request based timeouts mean
-  // that HTTP/2 PINGs will not keep the connection alive.
+  // idle timeout is reached the connection will be closed. If the connection is an HTTP/2
+  // downstream connection a drain sequence will occur prior to closing the connection, see
+  // :ref:`drain_timeout
+  // <envoy_api_field_config.filter.network.http_connection_manager.v3alpha.HttpConnectionManager.drain_timeout>`.
+  // Note that request based timeouts mean that HTTP/2 PINGs will not keep the connection alive.
   google.protobuf.Duration idle_timeout = 1;
+
+  // The maximum number of headers. If unconfigured, the default
+  // maximum number of request headers allowed is 100. Requests that exceed this limit will receive
+  // a 431 response for HTTP/1.x and cause a stream reset for HTTP/2.
+  google.protobuf.UInt32Value max_headers_count = 2 [(validate.rules).uint32 = {gte: 1}];
 }
 
 message Http1ProtocolOptions {
diff --git a/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto b/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto
index 8efeba2d..6f4132e9 100644
--- a/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto
+++ b/envoy/config/filter/network/http_connection_manager/v2/http_connection_manager.proto
@@ -241,7 +241,7 @@ message HttpConnectionManager {
 
   // Additional settings for HTTP requests handled by the connection manager. These will be
   // applicable to both HTTP1 and HTTP2 requests.
-  envoy.api.v2.core.HttpProtocolOptions common_http_protocol_options = 35;
+  api.v2.core.HttpProtocolOptions common_http_protocol_options = 35;
 
   // Additional HTTP/1 settings that are passed to the HTTP/1 codec.
   api.v2.core.Http1ProtocolOptions http_protocol_options = 8;
diff --git a/envoy/config/filter/network/http_connection_manager/v3alpha/http_connection_manager.proto b/envoy/config/filter/network/http_connection_manager/v3alpha/http_connection_manager.proto
index 26ab41dd..546b1e74 100644
--- a/envoy/config/filter/network/http_connection_manager/v3alpha/http_connection_manager.proto
+++ b/envoy/config/filter/network/http_connection_manager/v3alpha/http_connection_manager.proto
@@ -23,7 +23,7 @@ import "validate/validate.proto";
 // [#protodoc-title: HTTP connection manager]
 // HTTP connection manager :ref:`configuration overview <config_http_conn_man>`.
 
-// [#comment:next free field: 35]
+// [#comment:next free field: 36]
 message HttpConnectionManager {
   enum CodecType {
     // For every new connection, the connection manager will determine which
@@ -194,7 +194,9 @@ message HttpConnectionManager {
     google.protobuf.BoolValue enabled = 3;
   }
 
-  reserved 27;
+  reserved 27, 11;
+
+  reserved "idle_timeout";
 
   // Supplies the type of codec that the connection manager should use.
   CodecType codec_type = 1 [(validate.rules).enum = {defined_only: true}];
@@ -234,6 +236,10 @@ message HttpConnectionManager {
   // <envoy_api_msg_config.trace.v3alpha.Tracing>`.
   Tracing tracing = 7;
 
+  // Additional settings for HTTP requests handled by the connection manager. These will be
+  // applicable to both HTTP1 and HTTP2 requests.
+  api.v3alpha.core.HttpProtocolOptions common_http_protocol_options = 35;
+
   // Additional HTTP/1 settings that are passed to the HTTP/1 codec.
   api.v3alpha.core.Http1ProtocolOptions http_protocol_options = 8;
 
@@ -258,15 +264,6 @@ message HttpConnectionManager {
   google.protobuf.UInt32Value max_request_headers_kb = 29
       [(validate.rules).uint32 = {lte: 96 gt: 0}];
 
-  // The idle timeout for connections managed by the connection manager. The
-  // idle timeout is defined as the period in which there are no active
-  // requests. If not set, there is no idle timeout. When the idle timeout is
-  // reached the connection will be closed. If the connection is an HTTP/2
-  // connection a drain sequence will occur prior to closing the connection. See
-  // :ref:`drain_timeout
-  // <envoy_api_field_config.filter.network.http_connection_manager.v3alpha.HttpConnectionManager.drain_timeout>`.
-  google.protobuf.Duration idle_timeout = 11;
-
   // The stream idle timeout for connections managed by the connection manager.
   // If not specified, this defaults to 5 minutes. The default value was selected
   // so as not to interfere with any smaller configured timeouts that may have