diff -u -r ../apache_1.3.20/src/include/http_protocol.h ./src/include/http_protocol.h
--- ../apache_1.3.20/src/include/http_protocol.h	Mon Jan 15 12:04:35 2001
+++ ./src/include/http_protocol.h	Mon Jun 11 17:12:57 2001
@@ -88,6 +88,10 @@
 
 API_EXPORT(void) ap_send_http_header(request_rec *l);
 
+/* Maybe set Scavenger service. */
+
+API_EXPORT(void) ap_maybe_start_scavenging(request_rec *r);
+
 /* Send the response to special method requests */
 
 API_EXPORT(int) ap_send_http_trace(request_rec *r);
diff -u -r ../apache_1.3.20/src/include/httpd.h ./src/include/httpd.h
--- ../apache_1.3.20/src/include/httpd.h	Tue May 15 11:58:46 2001
+++ ./src/include/httpd.h	Mon Jun 11 15:34:36 2001
@@ -321,6 +321,16 @@
 #endif
 
 /*
+ * QBSS (QBone Scavenger Service) TOS value.
+ * It's officially DSCP 001000, which corresponds to TOS 0x20 for
+ * marking purposes.
+ * See http://qbone.internet2.edu/qbss/ for more QBSS info.
+ */
+#ifndef TOS_SCAVENGER
+#define TOS_SCAVENGER 0x20
+#endif
+
+/*
  * Special Apache error codes. These are basically used
  *  in http_main.c so we can keep track of various errors.
  *
@@ -958,6 +968,10 @@
     int keep_alive_max;		/* Maximum requests per connection */
     int keep_alive;		/* Use persistent connections? */
     int send_buffer_size;	/* size of TCP send buffer (in bytes) */
+    int start_scavenging_from_size;
+				/* For files this large or larger, turn on
+				   Scavenger service (DSCP 001000).  Set
+				   to 0 to disable. */
 
     char *path;			/* Pathname for ServerPath */
     int pathlen;		/* Length of path */
diff -u -r ../apache_1.3.20/src/main/http_config.c ./src/main/http_config.c
--- ../apache_1.3.20/src/main/http_config.c	Tue Jan 23 21:11:09 2001
+++ ./src/main/http_config.c	Mon Jun 11 17:07:47 2001
@@ -1482,6 +1482,10 @@
 	if (virt->send_buffer_size == 0)
 	    virt->send_buffer_size = main_server->send_buffer_size;
 
+	if (virt->start_scavenging_from_size == 0)
+	    virt->start_scavenging_from_size =
+		main_server->start_scavenging_from_size;
+
 	/* XXX: this is really something that should be dealt with by a
 	 * post-config api phase */
 	ap_core_reorder_directories(p, virt);
diff -u -r ../apache_1.3.20/src/main/http_core.c ./src/main/http_core.c
--- ../apache_1.3.20/src/main/http_core.c	Fri Mar  9 05:10:25 2001
+++ ./src/main/http_core.c	Mon Jun 11 16:55:32 2001
@@ -2021,6 +2021,22 @@
     return NULL;
 }
 
+static const char *
+set_start_scavenging_from_size(cmd_parms *cmd, void *dummy, char *arg)
+{
+    int s = atoi(arg);
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;             
+    }
+
+    if (s < 0) {
+        return "StartScavengingFromSize must be non-negative (0 to disable)";
+    }
+    cmd->server->start_scavenging_from_size = s;
+    return NULL;
+}
+
 static const char *set_user(cmd_parms *cmd, void *dummy, char *arg)
 {
 #ifdef WIN32
@@ -3148,6 +3164,8 @@
   "A port number or a numeric IP address and a port number"},
 { "SendBufferSize", set_send_buffer_size, NULL, RSRC_CONF, TAKE1,
   "Send buffer size in bytes"},
+{ "StartScavengingFromSize", set_start_scavenging_from_size, NULL, RSRC_CONF,
+  TAKE1, "File size starting from which Scavenger service will be used"},
 { "AddModule", add_module_command, NULL, RSRC_CONF, ITERATE,
   "The name of a module" },
 { "ClearModuleList", clear_module_list_command, NULL, RSRC_CONF, NO_ARGS, 
@@ -3636,6 +3654,8 @@
 	rangestatus = ap_set_byterange(r);
 
 	ap_send_http_header(r);
+	/* It makes sense to set scavenger only after the headers are sent. */
+	ap_maybe_start_scavenging(r);
 	
 	if (!r->header_only) {
 	    if (!rangestatus) {
@@ -3682,6 +3702,7 @@
 
 	rangestatus = ap_set_byterange(r);
 	ap_send_http_header(r);
+	ap_maybe_start_scavenging(r);
 	
 	if (!r->header_only) {
 	    if (!rangestatus) {
diff -u -r ../apache_1.3.20/src/main/http_protocol.c ./src/main/http_protocol.c
--- ../apache_1.3.20/src/main/http_protocol.c	Fri Mar  9 05:10:26 2001
+++ ./src/main/http_protocol.c	Mon Jun 11 18:05:12 2001
@@ -1809,6 +1809,18 @@
 #endif /*CHARSET_EBCDIC*/
 }
 
+/* Possibly turn on QBSS marking on the client connection. */
+API_EXPORT(void) ap_maybe_start_scavenging(request_rec *r)
+{
+    int qbss = TOS_SCAVENGER;
+    if (r->server->start_scavenging_from_size
+	&& r->server->start_scavenging_from_size < r->finfo.st_size) {
+	/* If it fails, we just go on as if nothing has happened. */
+	setsockopt(r->connection->client->fd, IPPROTO_IP, IP_TOS,
+		   (char*) &qbss, sizeof qbss);
+    }
+}
+
 /* finalize_request_protocol is called at completion of sending the
  * response.  It's sole purpose is to send the terminating protocol
  * information for any wrappers around the response message body