Information Technology Reference
In-Depth Information
Task 5: Verify Connectivity
All PCs and routers should have end-to-end connectivity. Pinging from any source to any destination
should be successful. You can also click
Check Results
and then click the
Connectivity Tests
tab to
see whether all the connectivity tests are successful.
Task 6: Save the Packet Tracer File
Save your Packet Tracer file as LSG02-0501-end.pka.
Automatic Summarization
Fewer number of routes in a routing table means that the routing table process can more quickly
locate the route needed to forward the packet. Summarizing several routes into a single route is known
as route summarization or route aggregation. Some routing protocols, such as RIP, automatically sum-
marize routes on certain routers. The following sections reinforce your knowledge of automatic sum-
marization and describe how RIP performs this automatic summarization.
Automatic Summarization Concepts
Boundary Routers and Automatic Summarization
RIP is a classful routing protocol that automatically summarizes classful networks across major net-
work boundaries. In the topology shown earlier in Figure 5-4, which router or routers are boundary
routers? Why?
R2 is a boundary router because it has interfaces in two different major classful networks: 192.168.1.0
and 172.16.0.0.
Boundary routers summarize RIP subnets from one major network to the other but advertise subnet
addresses within the boundary.
What networks/subnets does R2 send to R3?
192.168.1.0
What networks/subnets does R2 send to R1?
192.168.1.96, 172.16.0.0, 172.17.0.0
If you are not sure, use
debug ip rip
on your LSG02-0501-end.pka file.
Rules for Processing RIPv1 Updates
In regard to RIP's classful operation, what two rules govern RIPv1 updates:
If a routing update and the interface on which it is received belong to the same major network,
the subnet mask of the interface is applied to the network in the routing update.
■
If a routing update and the interface on which it is received belong to different major networks,
the classful subnet mask of the network is applied to the network in the routing update.
■
