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network-programmingwindows-cearpwindows-embedded-compact

WEC7 not sending gratuitous ARP messages

I am looking at the startup behavior of the network of our WEC7 platform. What I see is that a PC that is connected to my WEC7 box takes two minutes to reconnect after a reset of the target.

On my PC I am continuously pinging the target (ping -t), and I am getting replies before I reset.

What I see on the network is the following:

  1. On reset the network interface goes down, and comes back up.
  2. The PC is checking its IP address using ARP and also sending gratuitous ARP request after the check is finished.
  3. The PC tries to find the IP address of the WEC7 image using ARP requests, but does not succeed as WEC7 is not yet ready.
  4. When the WEC7 image is started it checks its IP address by sending out ARP requests.
  5. After a timeout of 1 to 2 minutes the PC sends an ARP request to WEC7 and now it gets the reply. The ping now starts to work again. (When I clear the ARP cache of the PC the timeout is shorter).

What I would expect is a gratuitous ARP message after step 4 (i.e. ARP message with both sender and target IP address filled with own IP address, which are used by other devices to update the ARP cache).

I did try to implement this using SendARP, but this returned directly with its own MAC address, without sending an ARP message.

Is there a way to have WEC7 send out a gratuitous ARP message after it got its MAC address?

Regards,

Johan Borkhuis

Solution

  • The above issue has been fixed by Microsoft in the June 2014 update. The issue was recorded as KB2964369: Windows Embedded Compact 7-based device does not send Gratuitous ARP after restart.