[Olsr-dev] Seeking comments: OLSR+ETX v/s DSR+ETX

Sven-Ola Tuecke (spam-protected)
Wed Dec 19 13:05:23 CET 2007

Hey again,

two more points, while we are at the "basics track"...

For ETT we need a round trip time to calculate. To measure/evaluate the RTT 
difference between large and small packets. So basically, you will send out 
a packet and listen for the answer, checking the time. Why not combine this 
with a firewall/forward check"? Example: The package is unicast. And has the 
IP addr of the sending node as destination and the dest-MAC addr of the 
receiving node. If it does not come back, the node is misconfigured, a 
lazybone, [...] and should be ignored. Requires some low-level hacks to send 
out such a packet...

For gateways to other routing domains (aka "Internet Gateway"), you do not 
receive ETT / LQ measurements from the link neighbour. Because the other 
side does not run a compatible routing daemon. There should be a way to 
configure such a value manually or evaluate it out-of-protocol (e.g. by 
switching measurements to ICMP echo requests).

Hope it's not too unreflected and understandable...
// Sven-Ola

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