diff --git a/en/chap02.tex b/en/chap02.tex index 7c3dd8b..03f53f3 100644 --- a/en/chap02.tex +++ b/en/chap02.tex @@ -29,7 +29,7 @@ exchanged messages. First, each network elects a \emph{designated router} (or DR) which coordinates exchange of the messages in that network segment. Second, the system can be partitioned into \emph{areas}. That way, the frequent LSAs are only flooded throughout a limited set of networks; the \emph{area -border routers} send accumulated LSAs into other areas.\footnote{These +border routers} (ABRs) send accumulated LSAs into other areas.\footnote{These inter-area LSAs are called \uv{Summary LSAs}, but there is no requirement that the routing information is actually aggregated.} These LSAs do not describe the topology of the originating area. @@ -48,6 +48,14 @@ originating from or destinated to that network. For representing routes outside of the area and the whole system, OSPF recognises \emph{extra-area} and \emph{external} networks respectively. It is also possible for a router to be adjacent to an extra-area router through a point-to-point link. +Figure.~\ref{fig:nettypes} shows the same classification visually. + +\begin{figure}[h] + \centering + \includegraphics[width=12cm]{../img/types-of-networks.pdf} + \caption{Types of networks as seen from the cyan area.} + \label{fig:nettypes} +\end{figure} Once the router has complete information about the topology of an area, it constructs a graph representation of the network and calculates the shortest path diff --git a/img/types-of-networks.pdf b/img/types-of-networks.pdf new file mode 100644 index 0000000..8554963 Binary files /dev/null and b/img/types-of-networks.pdf differ diff --git a/img/types-of-networks.svg b/img/types-of-networks.svg new file mode 100644 index 0000000..65ab35e --- /dev/null +++ b/img/types-of-networks.svg @@ -0,0 +1,549 @@ + + + +backbone areaNetwork systemptp linkstubextra-areatransitexternalvirtual linkexternalABRABRextra-arearouter