Routing Protocols
RIP version 1
Objectives
Describe the functions, characteristics, and operation of the RIPv1 protocol.
Configure a device for using RIPv1.
Verify proper RIPv1 operation.
Configure, verify, and troubleshoot default routes propagated in a routed network implementing RIPv1.
Use recommended techniques to solve problems related to RIPv1
RIP Characteristics
-A classful, Distance Vector (DV) routing protocol
-Metric = hop count
-Routes with a hop count > 15 are unreachable
-Updates are broadcast every 30 seconds
RIP Operation
–RIP uses 2 message types:
Request message
-This is sent out on startup by each RIP enabled interface
-Requests all RIP enabled neighbors to send routing table
Response message
-Message sent to requesting router containing routing table
IP addresses initially divided into classes
-Class A
-Class B
-Class C
RIP is a classful routing protocol
-Does not send subnet masks in routing updates
Administrative Distance
–RIP’s default administrative distance is 120
A typical topology suitable for use by RIPv1 includes:
-Three router set up
-No PCs attached to LANs
-Use of 5 different IP
subnets
Router RIP Command
–To enable RIP enter:
-Router rip at the global configuration prompt
-Prompt will look like R1(config-router)#
Specifying Networks
–Use the network command to:
-Enable RIP on all interfaces that belong to this network
-Advertise this network in RIP updates sent to other
routers every 30 seconds
Show ip Route
To verify and troubleshoot routing
-Use the following commands:
-show ip route
-show ip protocols
-debug ip rip
Verification and Troubleshooting
show ipprotocols command
-Displays routing protocol configured
on router
Debug ip rip command
-Used to display RIP routing updates
as they are happening
Verification and Troubleshooting
Passive interface command
-Used to prevent a router from sending updates through an interface
-Example:
Router(config-router)#passive-interface interface-type interface-number
Passive interfaces
Default Route and RIPv1
Modified Topology: Scenario C
Default routes
Packets that are not defined specifically in a routing
table will go to the specified interface for the default route
Example: Customer routers use default routes to
connect to an ISP router.
Command used to configure a default route is
ip route 0.0.0.0 0.0.0.0 s0/0/1
Propagating the Default Route in RIPv1
Default-information originate command
-This command is used to specify that the router is to originate
default information, by propagating the static default route in
RIP update.
Summary
RIP characteristics include:
Classful, distance vector routing protocol
Metric is Hop Count
Updates every 30 seconds