RIP version 1 : RIP version 1 Routing Protocols and Concepts – Chapter 5
Objectives : Objectives Describe the functions, characteristics, and operation of the RIPv1 protocol.
Configure a device for using RIPv1.
Verify proper RIPv1 operation.
Describe how RIPv1 performs automatic summarization.
Configure, verify, and troubleshoot default routes propagated in a routed network implementing RIPv1.
Use recommended techniques to solve problems related to RIPv1
RIPv1 : 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
Full routing table sent with every update
RIPv1 RIP Message Format : RIPv1 RIP Message Format RIP header - divided into 3 fields
-Command field
-Version field
-Must be zero
Route Entry - composed of 3 fields
-Address family identifier
-IP address
-Metric
RIP Operation : 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
Rip messages are encapsulated in a UDP segment with source and destination ports of 520
Classful Routing : Classful Routing IP addresses initially divided into classes
-Class A
-Class B
-Class C
RIPv1 is a classful routing protocol
-Does not send subnet masks in routing updates
RIPv1 : RIPv1 Administrative Distance
RIP’s default administrative distance is 120
Basic RIPv1 Configuration : Basic RIPv1 Configuration A typical practice topology suitable for use by RIPv1 includes:
- Three router set up
- No PCs attached to LANs
- Use of 5 different IP subnets
Basic RIPv1 Configuration : Basic RIPv1 Configuration Router RIP Command
To enable RIP enter:
-Router rip at the global configuration prompt
-Prompt will look like R1(config-router)#
Specifying Networks Using RIP : Specifying Networks Using RIP 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
Note: interface will not broadcast updates unless associated network is advertised
Verification and Troubleshooting : Verification and Troubleshooting To verify and troubleshoot routing
-Use the following
commands:
-show ip route
-show ip protocols
-debug ip rip
Verification and Troubleshooting : Verification and Troubleshooting show ip protocols command
-Displays routing protocol(s) configured on router
Verification and Troubleshooting : Verification and Troubleshooting Debug ip rip command
-Used to display RIP routing updates as they are happening
Passive Interface Command : Passive Interface Command Used to prevent a router from sending updates through an interface *
Reduces traffic on a segment
May be used to address security issues (sniffers)
Example:
Router(config-router)#passive-interface FA 0/0
* Interface will still receive updates
Automatic Summarization (Modified Topology) : Automatic Summarization (Modified Topology) The original scenario has been modified:
Three classful networks are used:
172.30.0.0/16
192.168.4.0/24
192.168.5.0/24
The 172.30.0.0/16 network is subnetted into three subnets:
172.30.1.0/24
172.30.2.0/24
172.30.3.0/24
The following devices are part of the 172.30.0.0/16 classful network address:
All interfaces on R1
S0/0/0 and Fa0/0 on R2
Automatic Summarization : Automatic Summarization Boundary Routers
RIP automatically summarizes classful networks
Boundary routers summarize RIP subnets from one major network to another.
Automatic Summarization - Good : Automatic Summarization - Good Advantages of automatic summarization:
-The size of routing updates is reduced
-Single routes are used to represent multiple routes which results in faster lookup in the routing table.
Automatic Summarization - Bad : Automatic Summarization - Bad Disadvantage of Automatic Summarization:
-Does not support discontiguous networks
Will RIP Work with Subnetting? : Will RIP Work with Subnetting? Answer: Maybe!!
2 rules govern RIPv1 updates:
-If a routing update and the interface it’s received on belong to the same CLASS network then:
The subnet mask of the interface is applied to the network in the routing update
-If a routing update and the interface it’s received on belong to a different CLASS network then:
The classful subnet mask of the network is applied to the network in the routing update.
Default Route and RIPv1 : Default Route and RIPv1 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
Default Route and RIPv1 : Default Route and RIPv1 Propagating the Default Route in RIPv1
Default-information originate command
-This command is used to specify that the router is to originate (send) default information by propagating the static default route in RIP updates
Removing RIP from Configuration : Removing RIP from Configuration Configuration Details
-To remove the RIP routing process use the following command
No router rip
-To check the configuration use the following command
Show run
Summary: Commands used by RIP : Summary: Commands used by RIP
Chapter 5 Labs : Chapter 5 Labs 5.6.1 Basic RIP Configuration
5.6.3 Troubleshooting RIP
Slide 25 :