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[Windows] Packet is dropped over the tunnel when the tunnel peer MAC is not found in ARP cache #253

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wenyingd opened this issue Apr 28, 2022 · 1 comment
Open

[Windows] Packet is dropped over the tunnel when the tunnel peer MAC is not found in ARP cache #253

wenyingd opened this issue Apr 28, 2022 · 1 comment

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@wenyingd
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wenyingd commented Apr 28, 2022 •
edited

On Windows platform, we run containers/VMs on host, and use OVS tunnel to support the container/VMs connections inter two Nodes. We use "ping" command to test the connectivity between the containers/VMs accross the Windows hosts. Then we find several packets are lost. After some capturing the packets, we find that the first packet which expected to be transferred over the tunnel is actually dropped, if the tunnel peer' MAC is not existing on the Windows host's ARP cache.

With tests, we got some output like this,

Pinging 192.168.2.5 with 32 bytes of data:
Request timed out.
Reply from 192.168.2.5: bytes=32 time<1ms TTL=128

Ping statistics for 192.168.2.5:
    Packets: Sent = 2, Received = 1, Lost = 1 (50% loss),

To reproduce it, the steps include,

  1. create tunnel port on OVS on each Windows host (there should be 2 Windows hosts at least in the setup)
  2. run one container per Windows host
  3. clear ARP cache on each Windows host
  4. login to the one container, and ping peer container
@wenyingd wenyingd changed the title [Windows] Packet is dropped over the tunnel when not found dst MAC in ARP cache [Windows] Packet is dropped over the tunnel when the tunnel peer MAC is not found in ARP cache Apr 28, 2022
@wenyingd wenyingd mentioned this issue Apr 28, 2022
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ovsrobot pushed a commit to ovsrobot/ovs that referenced this issue Aug 22, 2022
@ovsrobot
datapath-windows: Fix first tunnel packet drop before MAC learned.
337d025 
when traffic is sent through tunnel, it will drop untile MAC is learned.

I tested with installingw ovsext driver, normally after driver installed and
all is setup, the first ping packet will drop, with this patch, the first
ping packet is OK.

Reported-at:openvswitch/ovs-issues#253
Signed-off-by: Frank Guo <frankg@vmware.com>
Signed-off-by: 0-day Robot <robot@bytheb.org>
@aserdean aserdean reopened this Apr 20, 2023
@xfliu2665
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xfliu2665 commented Jun 28, 2023 •
edited

AFAIK， this issue also exists in linux. do you have any idea to solve it now?

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@wenyingd @aserdean @xfliu2665