[c-nsp] Something like MTR, but forced path

Peter Hicks peter.hicks at poggs.co.uk
Tue Dec 18 16:17:29 EST 2007


Tuc at T-B-O-H.NET wrote:

> Problem we have is a small wireless network is basically flat, not
> networked. There are 10 pieces of equipment between 2 machines. However,
> they are both on the same subnet, so it just looks like it only needs to 
> hop once. Instead, it goes from the router, to a client antenna (IP'd),
> to an Access Point (IP'd), to a switch (IP'd), to a backhaul (IP'd), to
> another backhaul(IP'd)... You get the jist. I basically want to force the
> system to believe my path, not what routed networking tells it.

traceroute shows a layer 3 path.  Your client antenna, access point etc. are 
bridging - a layer 2 activity.

If you want to 'force' extra hops, you need to have each device decrement the 
TTL of forwarded IP datagrams and correctly send ICMP unreachables.

There is some Layer 2 traceroute functionality built in to Cisco kit, useful to 
trace paths through a network that may change due to Spanning Tree - but I have 
to ask, what are you trying to achieve here?


Peter

-- 
Peter Hicks | e: my.name at poggs.co.uk | g: 0xE7C839F4 | w: www.poggs.com

   A: Because it destroys the flow of the conversation
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