vlan problem in Essex Release

+I have problem with vlan . The compute node doesn't get metadata from metadata_server.
different switch result in different performance:

test A: 2 compute nodes + normal switch = get metadata ok.
test B: 2 compute nodes + some switch (just like cisco 3750, cisco 2950) = metadata get failed.

failed error like this:

cloud-setup: failed to read iid from metadata. tried 30
WARN: /etc/rc3.d/S45-cloud-setup failed
Starting dropbear sshd: generating rsa key... generating dsa key... OK
===== cloud-final: system completely up in 40.61 seconds ====
wget: can't connect to remote host (169.254.169.254): Network is unreachable
wget: can't connect to remote host (169.254.169.254): Network is unreachable
wget: can't connect to remote host (169.254.169.254): Network is unreachable

+there are 2 compute node (172.16.200.1, 172.16.200.2), 1 vlan(172.16.0.0/24),
and dnsmasq from nova-network is ok:

nobody 1508 0.0 0.0 27708 1000 ? S 14:22 0:00 dnsmasq --strict-order --bind-interfaces --pid-file=/var/run/libvirt/network/default.pid --conf-file= --except-interface lo --listen-address 192.168.122.1 --dhcp-range 192.168.122.2,192.168.122.254 --dhcp-lease-max=253 --dhcp-no-override
nobody 2416 0.0 0.0 29140 1148 ? S 14:22 0:00 dnsmasq --strict-order --bind-interfaces --conf-file= --domain=novalocal --pid-file=/var/lib/nova/networks/nova-br100.pid --listen-address=172.16.0.1 --except-interface=lo --dhcp-range=172.16.0.3,static,120s --dhcp-lease-max=256 --dhcp-hostsfile=/var/lib/nova/networks/nova-br100.conf --dhcp-script=/opt/nova/bin/nova-dhcpbridge --leasefile-ro
root 2417 0.0 0.0 29140 492 ? S 14:22 0:00 dnsmasq --strict-order --bind-interfaces --conf-file= --domain=novalocal --pid-file=/var/lib/nova/networks/nova-br100.pid --listen-address=172.16.0.1 --except-interface=lo --dhcp-range=172.16.0.3,static,120s --dhcp-lease-max=256 --dhcp-hostsfile=/var/lib/nova/networks/nova-br100.conf --dhcp-script=/opt/nova/bin/nova-dhcpbridge --leasefile-ro

+I run nova from source script, which version is 2012.1(Essex Release)

+ the network between instance and compute node is unreachable in Test B, although `curl 169.254.169.254` run well in compute node.

thx a lot for any reply!

compute node nova.conf:

[DEFAULT]
verbose=True
auth_strategy=keystone
allow_resize_to_same_host=True
state_path=/var/lib/nova
lock_path=/var/lock/nova
compute_scheduler_driver=nova.scheduler.filter_scheduler.FilterScheduler
dhcpbridge_flagfile=/etc/nova/nova.conf
fixed_range=172.16.0.0/16
s3_host=172.16.200.1
s3_port=3333
connection_type=libvirt
network_manager=nova.network.manager.VlanManager
osapi_compute_extension=nova.api.openstack.compute.contrib.standard_extensions
my_ip=172.16.200.1
vlan_interface=eth0
sql_connection=mysql://root:root@172.16.200.1/nova?charset=utf8
libvirt_type=kvm
instance_name_template=instance-%08x
logdir=/var/log/nova
libvirt_use_virtio_for_bridges=true
resume_guests_state_on_host_boot=true
reclaim_instance_interval=0
novncproxy_base_url=http://192.168.176.200:6080/vnc_auto.html
xvpvncproxy_base_url=http://192.168.176.200:6081/console
vncserver_listen=127.0.0.1
vncserver_proxyclient_address=127.0.0.1
api_paste_config=/etc/nova/api-paste.ini
image_service=nova.image.glance.GlanceImageService
ec2_dmz_host=172.16.200.1
rabbit_host=172.16.200.1
rabbit_password=rabbit
glance_api_servers=172.16.200.1:9292
force_dhcp_release=True
instances_path=/var/lib/nova/instances

compute interface :

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:1e:67:09:ab:dc brd ff:ff:ff:ff:ff:ff
    inet 172.16.200.2/16 brd 172.16.255.255 scope global eth0
    inet6 fe80::21e:67ff:fe09:abdc/64 scope link
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 100
    link/ether 00:1e:67:09:ab:dd brd ff:ff:ff:ff:ff:ff
    inet 192.168.176.200/24 brd 192.168.176.255 scope global eth1
    inet6 fe80::21e:67ff:fe09:abdd/64 scope link tentative
       valid_lft forever preferred_lft forever
4: eth2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether 00:15:1a:6e:0b:08 brd ff:ff:ff:ff:ff:ff
5: eth3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
    link/ether 00:15:1a:6e:0b:09 brd ff:ff:ff:ff:ff:ff
6: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
    link/ether de:ce:f9:c2:5a:e4 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
8: vlan100@eth0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP
    link/ether 00:1e:67:09:ab:dc brd ff:ff:ff:ff:ff:ff
    inet6 fe80::21e:67ff:fe09:abdc/64 scope link
       valid_lft forever preferred_lft forever
9: br100: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
    link/ether 00:1e:67:09:ab:dc brd ff:ff:ff:ff:ff:ff
    inet6 fe80::2095:25ff:fe39:ee6e/64 scope link
       valid_lft forever preferred_lft forever
10: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500
    link/ether fe:16:3e:32:1b:6d brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc16:3eff:fe32:1b6d/64 scope link
       valid_lft forever preferred_lft forever