Information Technology Reference
In-Depth Information
List the network/subnet mask entries that will be the routing table for each router. Remember that not
all routers will have full knowledge of the individual subnets.
R1 routing table:
Network/subnet masks in R1's routing table:
10.10.0.0/16, 10.20.0.0/16, 10.30.0.0/16, 10.40.0.0/16, 172.16.1.0/24, 172.16.2.0/24, 172.16.3.0/24,
192.168.1.64/26, and 192.168.1.128/26
Network/subnet masks in R2's routing table:
10.10.0.0/16, 10.20.0.0/16, 10.30.0.0/16, 10.40.0.0/16, 172.16.0.0/16, and 192.168.1.0/24
Network/subnet masks in R3's routing table:
10.0.0.0/8, 172.16.0.0/16, 192.168.1.64/26 and 192.168.128/26
Network/subnet masks in R4's routing table:
10.0.0.0/8, 172.16.1.0/24, 172.16.2.0/24, 172.16.3.0/24, and 192.168.1.0/24
Network/subnet masks in R5's routing table:
10.10.0.0/16, 10.20.0.0/16, 10.30.0.0/16, 10.40.0.0/16, 172.16.1.0/24, 172.16.2.0/24, 172.16.3.0/24,
and 192.168.1.0/24
Are there any other problems with this configuration?
Yes. R4 will have a suboptimal entry because it will load-balance between R1 and R5 when routing to
the 10.0.0.0/8 classful network. This is suboptimal for the LAN attached to R5, which is best reached
by always sending traffic directly to R5. In addition, when sending packets to the R2 LAN, R4 will
load-balance between R1 and R5. This is also suboptimal because the best route is through R1.
Although there is no Packet Tracer Activity file for you to use, you can test your answers to the pre-
ceding questions by building and configuring the topology shown in Figure 5-8 from scratch.
Default Routes and RIPv1
Default routes are used by routers to represent all routes that are not specifically in the routing table.
In the following sections, you will configure the topology to use default routing.
Default Routing Exercise
Figure 5-9 shows the modified topology to include static and default routing. R3 is the service
provider with access to the Internet, as signified by the cloud. R3 and R2 do not exchange RIP
updates. Instead, R2 uses a default route to reach the R3 LAN and all other destinations that are not
listed in its routing table. R3 uses a summary static route to reach the subnets of 192.168.1.0/24.
