Re: 答复: Mesh Network Configure Questions.

[T Gillett]

Hi Edwin

The Mesh Gateway mode is typically used when you have a mesh network with more than one gateway. The traffic from a node will be directed towards a particular gateway node based on what batman-adv calculates as the best possible path, taking into account the number of mesh hops required, the quality of the links and the bandwidth offered by the gateway nodes.

There is documentation on this here:

       http://www.open-mesh.org/projects/batman-adv/wiki/Gateways

The mechanism uses DHCP requests from the node to direct the traffic, on the assumption that connected devices will need to get an IP address from an upstream DHCP server connected to the gateway nodes.

Once a device gets its IP address from the upstream DHCP server, its Default Route (aka LAN Gateway) address will also be typically set to point to that upstream device, so requests for upstream network services will be routed accordingly.

If a gateway node fails, then devices using that node will have no service until such time as their DHCP lease expires, at which time a new route will be set up based on the new DHCP request.

That is the best explanation I can offer, but others on the list may care to add further information.

Regards

Terry

On Thu, Apr 16, 2015 at 4:08 PM, edwin <ed...@dragino.com> wrote:

Hello, Terry,

 

I tried to understand how the MESH Mode works. in what case do we set the Mesh Mode to Gateway and Client? Any document for this point?

 

Also, in a simple mesh network with a single gateway, there is no real point in setting up the Mesh Gateway and Client modes. 

These settings are really only useful if you are running a more complex mesh with multiple gateways. 

It is probably better (and simpler) just to leave the Mesh Gateway setting to "Off" on all nodes.

 

Having them set will not in itself cause a problem, but it is just one more setting that has to be correct on every node. 

This setting activates the batman-adv DHCP request intercept handling, which is the mechanism used to route data requests to the appropriate gateway on the mesh. For a simple mesh this is unnecessary, and it is one more setting that has to be correct on every node to avoid issues.

For example, if one node is not set to Client mode, then DHCP requests from devices connected to that node will not be handled correctly, which can lead to lots of debugging effort trying to work out what is wrong.

 

Best Regards
Edwin Chen