dhcrelay over wireless mesh

Simon Hobson dhcp1 at thehobsons.co.uk
Wed Jul 11 13:42:38 UTC 2012

Randall C Grimshaw wrote:
>The mesh network should not be introducing any routing, so putting a 
>relay on each of the nodes is going to introduce a magnifying effect 
>that will eventually contribute to a DOS. You only need one relay 
>per layer-2 network and that is usually done on the router with the 
>layer-3 interface.

What I know about mesh networks could be written on the back of a 
stamp, without using exceedingly small text ...

But I think they are not a layer 2 network in the sense that we are 
used to dealing with it. For that to work in the massively 
interconnected mesh, it would involve some very inefficient packet 
routing by the time redundant links had been disabled. In fact I 
doubt that something like STP would even reach stability on many 
I think they tend to do some sort of hybrid where the network "sort 
of" looks like a layer 2 network to devices, but is in fact more like 
a layer 3 network in terms of how it routes packets.

So I assume they probably filter broadcast traffic in some way, hence 
running relay agents.

Another thought is that perhaps once the request goes through more 
than one node, a second agent picks it up and incorrectly mangles it 
- meaning that the reply doesn't go back to the correct node.

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
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