Chapter_7_RIPv2

RIPv2
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Routing Protocols and Concepts – Chapter 7
Objectives
Encounter and describe the limitations of RIPv1’s limitations.
Apply the basic Routing Information Protocol Version 2 (RIPv2) configuration commands and evaluate RIPv2 classless routing updates.
Analyze router output to see RIPv2 support for VLSM and CIDR.
Identify RIPv2 verification commands and common RIPv2 issues.
Configure, verify, and troubleshoot RIPv2 in “hands-on” labs.
Introduction
Chapter focus
Difference between RIPv1 & RIPv2
RIPv1
A classful distance vector routing protocol
Does not support discontiguous subnets
Does not support VLSM
Does not send subnet mask in routing update
Routing updates are broadcast
RIPv2
A classless distance vector routing protocol that is an enhancement of RIPv1’s features
Next hop address is included in updates
Routing updates are multicast
The use of authentication is an option
Introduction
Similarities between RIPv1 & RIPv2
Use of timers to prevent routing loops
Use of split horizon or split horizon with poison reverse
Use of triggered updates
Maximum hop count of 15
RIPv1 Limitations
Lab Topology
Scenario:
3 router set up
Topology is discontiguous
There exists a static summary route
Static route information can be injected into routing table updates using redistribution
Routers 1 & 3 contain VLSM networks
RIPv1 Limitations
Scenario Continued
VLSM
Recall this is sub netting the subnet
Private IP addresses are on LAN links
Public IP addresses are used on WAN links
Loopback interfaces
These are virtual interfaces that can be pinged and added to routing table
RIPv1 Limitations
Null Interfaces
This is a virtual interface that does not need to be created or configured
Traffic sent to a null interface is discarded
Null interfaces do not send or receive traffic
Static routes and null interfaces
Null interfaces will serve as the exit interface for static route
Example of configuring a static supernet route with a null interface
R2(config)#ip route 192.168.0.0 255.255.0.0 Null0
RIPv1 Limitations
Route redistribution
Redistribution command is way to disseminate a static route from one router to another via a routing protocol
Example
R2(config-router)#redistribute static
RIPv1 Limitations
Verifying and Testing Connectivity
Use the following commands:
show ip interfaces brief
ping
traceroute
RIPv1 Limitations
RIPv1 – a classful routing protocol
Subnet mask are not sent in updates
Summarizes networks at major network boundaries
If network is discontiguous and RIPv1 configured convergence will not be reached
RIPv1 Limitations
Examining the routing tables
To examine the contents of routing updates use the debug ip rip command
If RIPv1 is configured then Subnet masks will not be included with the network address
RIPv1 Limitations
RIPv1 does not support VLSM
Reason: RIPv1 does not send subnet mask in routing updates
RIPv1 does summarize routes to the Classful boundary
Or uses the Subnet mask of the outgoing interface to determine which subnets to advertise
RIPv1 Limitations
No CIDR Support
In the diagram R2 will not include the static route in its update
Reason: Classful routing protocols do not support CIDR routes that are summarized with a smaller mask than the classful subnet mask
Configuring RIPv2
Comparing RIPv1 & RIPv2 Message Formats
RIPv2 Message format is similar to RIPv1 but has 2 extensions
1st extension is the subnet mask field
2nd extension is the addition of next hop address
Configuring RIPv2
Enabling and Verifying RIPv2
Configuring RIP on a Cisco router
By default it is running RIPv1
Configuring RIPv2
Configuring RIPv2 on a Cisco router
Requires using the version 2 command
RIPv2 ignores RIPv1 updates
To verify RIPv2 is configured use the
show ip protocols command
Configuring RIPv2
Auto-Summary & RIPv2
RIPv2 will automatically summarize routes at major network boundaries and can also summarize routes with a subnet mask that is smaller than the classful subnet mask
Disabling Auto-Summary in RIPv2
To disable automatic summarization issue the no auto-summary command
Configuring RIPv2
Configuring RIPv2
Verifying RIPv2 Updates
When using RIPv2 with automatic summarization turned off
Each subnet and mask has its own specific entry, along with the exit interface and next-hop address to reach that subnet
To verify information being sent by RIPv2 use the
debug ip rip command
VLSM & CIDR
RIPv2 and VLSM
Networks using a VLSM IP addressing scheme
Use classless routing protocols (i.e. RIPv2) to disseminate network addresses and their subnet masks
VLSM & CIDR
CIDR uses Supernetting
Supernetting is a bunch of contiguous classful networks that is addressed as a single network
VLSM & CIDR
To verify that supernets are being sent and received use the following commands
Show ip route
Debug ip rip
Verifying & Troubleshooting RIPv2
Basic Troubleshooting steps
Check the status of all links
Check cabling
Check IP address & subnet mask configuration
Remove any unneeded configuration commands
Commands used to verify proper operation of RIPv2
Show ip interfaces brief
Show ip protocols
Debug ip rip
Show ip route
Verifying & Troubleshooting RIPv2
Common RIPv2 Issues
When trouble shooting RIPv2 examine the following issues:
Version
Check to make sure you are using version 2
Network statements
Network statements may be incorrectly typed or missing
Automatic summarization
If summarized routes are not needed then disable automatic summarization
Verifying & Troubleshooting RIPv2
Reasons why it’s good to authenticate routing information
Prevent the possibility of accepting invalid routing updates
Contents of routing updates are encrypted
Types of routing protocols that can use authentication
RIPv2
EIGRP
OSPF
IS-IS
BGP
Summary