Index: xen-3.3.0-testing/tools/examples/xend-config.sxp
===================================================================
--- xen-3.3.0-testing.orig/tools/examples/xend-config.sxp
+++ xen-3.3.0-testing/tools/examples/xend-config.sxp
@@ -141,7 +141,8 @@
 #
 # (network-script 'network-bridge netdev=eth1')
 #
-# The bridge is named xenbr0, by default.  To rename the bridge, use
+# The bridge is named to match the outgoing interface, by default.  For example,
+# eth1 is on xenbr1.  To rename the bridge, use
 #
 # (network-script 'network-bridge bridge=<name>')
 #
Index: xen-3.3.0-testing/tools/ioemu-remote/vl.c
===================================================================
--- xen-3.3.0-testing.orig/tools/ioemu-remote/vl.c
+++ xen-3.3.0-testing/tools/ioemu-remote/vl.c
@@ -134,8 +134,8 @@ int inet_aton(const char *cp, struct in_
 #include "exec-all.h"
 
 #ifndef DEFAULT_NETWORK_SCRIPT
-#define DEFAULT_NETWORK_SCRIPT "/etc/qemu-ifup"
-#define DEFAULT_NETWORK_DOWN_SCRIPT "/etc/qemu-ifdown"
+#define DEFAULT_NETWORK_SCRIPT "/etc/xen/qemu-ifup"
+#define DEFAULT_NETWORK_DOWN_SCRIPT "/etc/xen/qemu-ifdown"
 #endif
 #ifdef __sun__
 #define SMBD_COMMAND "/usr/sfw/sbin/smbd"
@@ -4997,10 +4997,10 @@ static int net_client_init(const char *s
                 pstrcpy(down_script, sizeof(down_script), DEFAULT_NETWORK_DOWN_SCRIPT);
             }
             if (get_param_value(script_arg, sizeof(script_arg), "scriptarg", p) == 0 &&
-                get_param_value(script_arg, sizeof(script_arg), "bridge", p) == 0) { /* deprecated; for xend compatibility */
-                pstrcpy(script_arg, sizeof(script_arg), "");
-            }
-            ret = net_tap_init(vlan, ifname, setup_script, down_script, script_arg);
+                get_param_value(script_arg, sizeof(script_arg), "bridge", p) == 0) /* deprecated; for xend compatibility */
+                ret = net_tap_init(vlan, ifname, setup_script, NULL, NULL);
+            else
+                ret = net_tap_init(vlan, ifname, setup_script, down_script, script_arg);
         }
     } else
 #endif
Index: xen-3.3.0-testing/tools/python/xen/xend/image.py
===================================================================
--- xen-3.3.0-testing.orig/tools/python/xen/xend/image.py
+++ xen-3.3.0-testing/tools/python/xen/xend/image.py
@@ -764,14 +764,16 @@ class HVMImageHandler(ImageHandler):
             mac = devinfo.get('mac')
             if mac is None:
                 raise VmError("MAC address not specified or generated.")
-            bridge = devinfo.get('bridge', 'xenbr0')
+            bridge = devinfo.get('bridge', None)
             model = devinfo.get('model', 'rtl8139')
             ret.append("-net")
             ret.append("nic,vlan=%d,macaddr=%s,model=%s" %
                        (nics, mac, model))
             ret.append("-net")
-            ret.append("tap,vlan=%d,ifname=tap%d.%d,bridge=%s" %
-                       (nics, self.vm.getDomid(), nics-1, bridge))
+            net = "tap,vlan=%d,ifname=tap%d.%d" % (nics, self.vm.getDomid(), nics-1)
+            if bridge:
+                net += ",bridge=%s" % bridge
+            ret.append(net)
 
         if nics == 0:
             ret.append("-net")
Index: xen-3.3.0-testing/tools/ioemu-remote/i386-dm/qemu-ifup
===================================================================
--- xen-3.3.0-testing.orig/tools/ioemu-remote/i386-dm/qemu-ifup
+++ xen-3.3.0-testing/tools/ioemu-remote/i386-dm/qemu-ifup
@@ -1,11 +1,11 @@
 #!/bin/sh
 
-#. /etc/rc.d/init.d/functions
-#ulimit -c unlimited
-
-echo 'config qemu network with xen bridge for ' $*
-
 bridge=$2
+if [ -z "$bridge" ]; then
+    brnum=$(ip route list | awk '/^default / { print $NF }' | sed 's/^[^0-9]*//')
+    brnum=${brnum:-0}
+    bridge=xenbr${brnum}
+fi
 
 #
 # Old style bridge setup with netloop, used to have a bridge name