In the DESIGN course, there is a question about how to bridge different network segments in different sites on to the same layer 2 network. One of the obvious solutions is using GRE tunnel between routers.

But here, I am not going to discuss how to configure GRE tunnel, as there are many documents on it. What I am going to discuss is, if you cannot change the router configuration (say if the router is not managed by you), then can you directly bridge 2 or even more Windows PC to the same layer 2 network? The solution is using the UBridge tool.

Long time ago, I have discussed how to use the Ethernet over UDP feature of UBridge. By using the new release, right now you can use the VXLAN encapsulation. Moreover, you can use the head end replication to bridge more than 2 PCs.

For example, if you have 3 different PCs on 3 sites and have IP address 10.10.1.10, 10.10.2.10 and 10.10.3.10 respectively, and want to bridge them all over subnet 10.20.1.0/24.

Then you can click here to download the UBridge tool, install the Winpcap. Create a loopback interface (or use other existing interface other than the one for the VTEP IP) in each PC. Configure the loopback interface of the 3 PCs to have IP address 10.20.1.1, 10.20.1.2 and 10.20.1.3 respectively.

Now, in PC1, execute:

C:\> ubdg 5000#V:E@10.10.1.10:10.10.2.10+10.10.3.10 5000#W:E

Select the loopback interface as prompted.

Similarly, under PC2:

C:\> ubdg 5000#V:E@10.10.2.10:10.10.1.10+10.10.3.10 5000#W:E

Similarly, under PC3:

C:\> ubdg 5000#V:E@10.10.3.10:10.10.1.10+10.10.2.10 5000#W:E

You should be able to ping among the loopback interfaces of all the PCs.

Some other design choose, such as it you don’t want to use the full mesh configuration, you can actually use the hub-and-spoke design by using the relay mode, you can further encrypt the traffic. Please refer to my other VXLAN blog entries.