[CUWiN] assigning numbers to a community wireless mesh

Stephane Alnet stephane at shimaore.net
Mon Dec 6 11:54:35 CST 2004

Hi Dave,

Before I say anything more, let me say I think you've a great idea. 
I'll just highlight two points.

> So there's no harm using
> link-local addresses for the routing protocol packets.  There's also
> no harm using link-local nexthops (the OSPFv3 RFC recommends it, IIRC).

The only drawback I see is that it makes troubleshooting a little bit 
more difficult because it breaks traceroute(1). But I'd agree that the 
simplification in management of IP addresses is probably worth the 

> The address
> on the ethernet, however, had better be unique.  I think we should use
> the ethernet's address to identify the router.

That's fine too, for the explicit purpose of selecting a routing ID.

Where I have a problem is that with this scheme you don't have any 
_management_ address for the routers. The Ethernet address does not 
qualify because if the interface goes down (for example because the 
switch/hub/PC connected to it is shut down for any reason), then you 
have no way to communicate with the device (can't talk to a down 
interface), even though you can route to it.
You may want to think about using a loopback interface (or 
sub-interface, depending on the capabilities of the OS) and assign it a 
unique address (you only need one per device, no subnets, and they 
don't have to aggregate nicely since HSLS is supposed to take care of 
routing them). That's a pretty common setup. (IOS for example will use 
a loopback interface's IP as the OSPF ID if one is configured, for that 
explicit purpose.)


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