Use of mtr

sahil · 06-29-2011, 10:09 PM

i am using mtr as a network diagnostic tool and i have a basic doubt that whether the intermediate switches or router ping the next switch/router on behalf of the original machine and report it back the route and corresponding response and packet loss to it or it itself identifies the route and pings the individual machines and get the response time and packet loss.

Thanks for your patience and time
Sahil

acid_kewpie · 06-30-2011, 02:33 AM

Are you just asking how traceroute works? The ttl is increased with each packet. So it gets as far as it can gefore the ttl expires. When it expires the router or switch it expired at responds back to you telling you it expired and of course uses its own IP there, identifying the route.

sahil · 06-30-2011, 10:25 PM

what i want to know is whether the host machine actually pings all the intermediate router/switches or the successive router/switch pings the next hop and report the time delay back to the initial host. Another part is whether it first computes the route and then pings the intermediate hops and then the result is obtained by the host.
Thanks for your patience and reply
Sahil

acid_kewpie · 07-01-2011, 03:06 AM

I already explained that. I'd really suggest referring to standard documentation for queries like this. I bet there's a good wikipedia page for traceroute.

A route is not calculated. it is just the next hop that any machine is aware about (save for heavy duty dynamic routing protocols which are not relevant here. your client system fundamentally never has a clue how a packet gets where is it going if it's not on the local network.

sahil · 10-25-2011, 12:15 AM

Thanks