configuration. Lab Activity Lab Exercise:
Converting RIP v1 to RIP v2 In this lab, the students will
configure RIP v1 on the routers and then convert to RIP v2.
Lab Activity e-Lab Activity: Converting RIP v1 to RIP
v2 In this lab, the student will configure RIP v1 and then
convert to RIP v2.
Content 1.2 RIP Version
2 1.2.5 Verifying RIP v2 The show ip
protocols and show ip route commands display
information about routing protocols and the routing table. This
section describes how to use show commands to verify the
RIP configuration. The show ip protocols command
displays values about routing protocols and routing protocol
timer information associated with the router. In the example,
the router is configured with RIP and sends updated routing
table information every 30 seconds. This interval is
configurable. If a router running RIP does not receive an
update from another router for 180 seconds or more, the first
router marks the routes served by the non-updating router as
being invalid. In Figure , the holddown timer is set to 180
seconds. Therefore, an update to a route that was down and is
now up could stay in the holddown state until the full 180
seconds have passed. If there is still no update after 240
seconds the router removes the routing table entries. In the
figure, it has been 18 seconds since Router A received an
update from Router B. The router is injecting routes for the
networks listed following the Routing for Networks line. The
router is receiving routes from the neighboring RIP routers
listed following the Routing Information Sources line. The
distance default of 120 refers to the administrative distance
for a RIP route. The show ip interface brief command can
also be used to list a summary of the information and status of
an interface. The show ip route command displays the
contents of the IP routing table. The routing table contains
entries for all known networks and subnetworks, and contains a
code that indicates how that information was learned. The
output of key fields from this command and their function is
explained in the table. Examine the output to see if the
routing table is populated with routing information. If entries
are missing, routing information is not being exchanged. Use
the show running-config or show ip protocols
privileged EXEC commands on the router to check for a possible
misconfigured routing protocol. Lab Activity Lab
Exercise: Verifying RIP v2 Configuration In this lab, the
students will configure RIP v1 and v2 on routers and use
show commands to verify RIP v2 operation.
Content
1.2 RIP Version 2 1.2.6
Troubleshooting RIP v2 This section explains the use of the
debug ip rip command.Use the debug ip rip
command to display RIP routing updates as they are sent and
received. The no debug all or undebug all
commands will turn off all debugging. The example shows that
the router being debugged has received updates from one router
at source address 10.1.1.2. The router at source address
10.1.1.2 sent information about two destinations in the routing
table update. The router being debugged also sent updates, in
both cases to broadcast address 255.255.255.255 as the
destination. The number in parentheses is the source address
encapsulated into the IP header. Other outputs sometimes seen
from the debug ip rip command includes entries such as
the following: RIP: broadcasting general request on
Ethernet0
RIP: broadcasting general request on Ethernet1
These outputs appear at startup or when an event occurs such as
an interface transition or a user manually clears the routing
table. An entry, such as the following, is most likely caused
by a malformed packet from the transmitter: RIP: bad version
128 from 160.89.80.43 Examples of debug ip rip outputs
and meanings are shown in Figure . Lab Activity Lab
Exercise: Troubleshooting RIP v2 using Debug In this
lab, the students will use debug commands to verify
proper RIP operation and analyze data transmitted between
routers. Lab Activity e-Lab Activity: RIP v2 using
Debug In this lab, the students will enable routing on the
router, save the configuration, and ping interfaces on
routers.
Content 1.2 RIP Version 2
1.2.7 Default routes By default, routers learn
paths to destinations three different ways: - Static
routes – The system administrator manually defines the
static routes as the next hop to a destination. Static routes
are useful for security and traffic reduction, as no other
route is known.
- Default routes – The system
administrator also manually defines default routes as the path
to take when there is no known route to the destination.
Default routes keep routing tables shorter. When an entry for a
destination network does not exist in a routing table, the
packet is sent to the default network.
- Dynamic
routes – Dynamic routing means that the router learns of
paths to destinations by receiving periodic updates from other
routers.
In Figure , the default route is indicated
by the following command: Router(config)#ip route 172.16.1.0
255.255.255.0 172.16.2.1 The ip default-network
command establishes a default route in networks using dynamic
routing protocols: Router(config)#ip default-network
192.168.20.0 Generally after the routing table has been set
to handle all the networks that must be configured, it is often
useful to ensure that all other packets go to a specific
location. One example is a router that connects to the
Internet. This is called the default route for the router. All
the packets that are not defined in the routing table will go
to the nominated interface of the default router. The ip
default-network command is usually configured on the
routers that connect to a router with a static default route.
In Figure , Hong Kong 2 and Hong Kong 3 would use Hong Kong 4
as the default gateway. Hong Kong 4 would use interface
192.168.19.2 as its default gateway. Hong Kong 1 would route
packets to the Internet for all internal hosts. To allow Hong
Kong 1 to route these packets it is necessary to configure a
default route as: HongKong1(config)#ip route 0.0.0.0 0.0.0.0
192.168.20.1 The zeros represent any destination network
with any mask. Default routes are referred to as quad zero
routes. In the diagram, the only way Hong Kong 1 can go to the
Internet is through the interface 192.168.20.1.
Content
Summary An understanding of the following key points
should have been achieved: - VLSM and the reasons for
its use
- Subnetting networks of different sizes using
VLSM
- Route aggregation and summarization as they
relate to VLSM
- Router configuration using VLSM
- Key features of RIP v1 and RIP v2
- Important
differences between RIP v1 and RIP v2
- Configuration of
RIP v2
- Verifying and troubleshooting RIP v2
operation
- Configuring default routes using the ip
route and ip default-network commands