new file mode 100644
--- /dev/null
+++ b/src/http/ngx_http_upstream_round_robin.h
@@ -0,0 +1,77 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ */
+
+
+#ifndef _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_
+#define _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+
+typedef struct {
+    struct sockaddr                *sockaddr;
+    socklen_t                       socklen;
+    ngx_str_t                       name;
+
+    ngx_uint_t                      current_weight;
+    ngx_uint_t                      weight;
+
+    ngx_uint_t                      fails;
+    time_t                          accessed;
+
+    ngx_uint_t                      max_fails;
+    time_t                          fail_timeout;
+
+    ngx_uint_t                      down;          /* unsigned  down:1; */
+
+#if (NGX_SSL)
+    ngx_ssl_session_t              *ssl_session;
+#endif
+} ngx_http_upstream_rr_peer_t;
+
+
+typedef struct {
+    ngx_uint_t                      current;
+
+    ngx_uint_t                      number;
+    ngx_uint_t                      last_cached;
+
+ /* ngx_mutex_t                    *mutex; */
+    ngx_connection_t              **cached;
+
+    ngx_str_t                      *name;
+
+    ngx_http_upstream_rr_peer_t     peer[1];
+} ngx_http_upstream_rr_peers_t;
+
+
+typedef struct {
+    ngx_http_upstream_rr_peers_t   *peers;
+    ngx_uint_t                      current;
+    uintptr_t                      *tried; 
+    uintptr_t                       data;
+} ngx_http_upstream_rr_peer_data_t;
+
+
+ngx_int_t ngx_http_upstream_init_round_robin(ngx_conf_t *cf,
+    ngx_http_upstream_srv_conf_t *us);
+ngx_int_t ngx_http_upstream_init_round_robin_peer(ngx_http_request_t *r,
+    ngx_http_upstream_srv_conf_t *us);
+ngx_int_t ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc,
+    void *data);
+void ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc,
+    void *data, ngx_uint_t state);
+
+#if (NGX_HTTP_SSL)
+void ngx_http_upstream_save_round_robin_peer(ngx_peer_connection_t *pc,
+    void *data);
+#endif
+
+
+
+#endif /* _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ */