Here it is a little addition to the document:
http://netsukuku.freaknet.org/doc/main_doc/qspn.pdf (section 11.2)
----
\subsection{Disjoint routes}
The routing table of each node should be differentiated, i.e. it should not
contain redundant routes.
For example, consider these $S \rightarrow D$ routes:
\begin{align}
& SBCFG_1G_2G_3G_4G_5G_6G_7 \dots G_{19} D \\
& SRTEG_1G_2G_3G_4G_5G_6G_7 \dots G_{19} D \\
& SZXMNO_1O_2O_3O_4O_5D \\
& SQPVY_1Y_2Y_3Y_4D
\end{align}
The first two are almost identical, indeed they differ only in the first three
hops. The last two are, instead, totally different from all the others.\\
Since the first two routes are redundant, the node $S$ should keep in memory
only
one of them, saving up space for the others non-redundant routes.
\newline
Keeping redundant routes in the routing table isn't optimal, because if one of
the
routes fails, then there's a high probability that all the other redundant
routes will fail too. Moreover when implementing the multipath routing to load
balance the traffic there won't be any significative improvements.
\newline
The Q2 itself should avoid to spread redundant routes. In order to achieve
this result, we refine the efficiency value associated to a route. Suppose we
want to affect the efficiency value $R_e$ assigned to the route $R$:
\begin{enumerate}
\item let $0\le s(R,S)\le 1$ be the similarity level of the route $R$
with $S$.
\item for each memorised route $S$ we compute $s(R,S)$ and if we find
a route $S$ such that $s(R,S) > 0.5$ we go to step 3.
\item we set \[R_e = R_e\frac{1-s(R,S)}{k}\] where $k$ is an appropriate
coefficient.
\end{enumerate}
As explained in section \ref{sec:routes_limit} the efficiency of a route is
used as a parameter to evaluate its interest, therefore the more a route is
similar to a memorised route the more its efficiency will decrease. Hence it
will be considered less interesting.\\
Note that this is a generalization of concept of interesting route defined in
section \ref{sec:routes_limit}, in fact, when $R$ and $S$ are equal,
$s(R,S)=1$ and the $R_e$ value will be equal to $0$.
--
:wq!
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