+As we are dealing with routes between AS, it means that those we'll have some definition at AS_Big level. Let consider AS_1 contains 1 host, 1 link and one router and AS_2 3 hosts, 4 links and one router. There will be a central router, and a cross-like topology. At the end of the crosses arms, you'll find the 3 hosts and the router that will act as a gateway. We have to define routes inside those two AS. Let say that AS_1 contains full routes, and AS_2 contains some Floyd routing (as we don't want to bother with defining all routes). As we're using some shortest path algorithms to route into AS_2, we'll then have to define some <b>route</b> to gives some topological information to SimGrid. Here is a file doing it all :
+
+\verbatim
+<AS id="AS_Big" routing="Dijsktra">
+ <AS id="AS_1" routing="Full">
+ <host id="AS_1_host1" power="1000000000"/>
+ <link id="AS_1_link" bandwidth="1250000000" latency="5E-4"/>
+ <router id="AS_1_gateway"/>
+ <route src="AS_1_host1" dst="AS_1_gateway">
+ <link_ctn id="AS_1_link"/>
+ </route>
+ </AS>
+ <AS id="AS_2" routing="Floyd">
+ <host id="AS_2_host1" power="1000000000"/>
+ <host id="AS_2_host2" power="1000000000"/>
+ <host id="AS_2_host3" power="1000000000"/>
+ <link id="AS_2_link1" bandwidth="1250000000" latency="5E-4"/>
+ <link id="AS_2_link2" bandwidth="1250000000" latency="5E-4"/>
+ <link id="AS_2_link3" bandwidth="1250000000" latency="5E-4"/>
+ <link id="AS_2_link4" bandwidth="1250000000" latency="5E-4"/>
+ <router id="central_router"/>
+ <router id="AS_2_gateway"/>
+ <!-- routes providing topological information -->
+ <route src="central_router" dst="AS_2_host1"><link_ctn id="AS_2_link1"/></route>
+ <route src="central_router" dst="AS_2_host2"><link_ctn id="AS_2_link2"/></route>
+ <route src="central_router" dst="AS_2_host3"><link_ctn id="AS_2_link3"/></route>
+ <route src="central_router" dst="AS_2_gateway"><link_ctn id="AS_2_link4"/></route>
+ </AS>
+ <link id="backbone" bandwidth="1250000000" latency="5E-4"/>
+
+ <ASroute src="AS_1" dst="AS_2"
+ gw_src="AS_1_gateway"
+ gw_dst="AS_2_gateway">
+ <link_ctn id="backbone"/>
+ </ASroute>
+</AS>
+\endverbatim