On sab, mar 26, 2011 at 04:31:42 +0100, Marek Lindner wrote:
In these days I was wondering whether the TTL
field in the OGM packet is
really useful or not...Due to hop_penalty an OGM will be discarded as
soon as the TQ will reach 0 (which is a sort of TTL mechanism itself).
At this point why is the TTL field needed?
uhm.., you probably are right. As long as there is a hop penalty it also
functions as a TTL. Keep in mind that it is possible to set the hop penalty to
zero. With the current default hop penalty of 10 the maximum number of hops is
limited to 25.
I think it is wrong: TQ is not decremented by hop_penalty each time, but it is
multiplied by (TQ_MAX-hop_penalty/TQ_MAX), then the number of hops is
bigger than what you said. With hop_penalty = 10 we can probably reach
~135 hops (raw calculus 255*(TQ_MAX-hop_penalty/TQ_MAX)^135) =~ 0)
Someone could probably say that a node far at
least TTL hops will never
be reached by a unicast packet, then it is meaningless to let it know
about me. But then it could be possible to recalibrate the TTL such that
it has to be equal to the maximum length in number of hops of the longest
path the OGM can traverse.
Not quite sure what you are proposing. A TTL of TQ_MAX / hop penalty ?
Looking at the calculus above, I'm proposing to use TTL = ~135
..each of us alone is worth nothing..
Ernesto "Che" Guevara