SEMESTER 2 Chapter 7
RIPv2
V 4.0
7.0.1.1 / Why has RIP lost favor as opposed to other protocols? / EIGRP, OSPF, and IS-IS offer more features and are more scalableWhen is RIP a desirable protocol? / its sheer simplicity and widespread use in multiple operating systems makes it an ideal candidate for smaller, homogeneous networks where multi-vendor support is necessary - especially within UNIX environments
What are the enhanced features of RIPv2? / Next-hop addresses included in the routing updates
Use of multicast addresses in sending updates
Authentication option available
What do both versions of RIP share in features and limitations? / Use of holddown and other timers to help prevent routing loops.
Use of split horizon or split horizon with poison reverse to also help prevent routing loops.
Use of triggered updates when there is a change in the topology for faster convergence.
Maximum hop count limit of 15 hops, with the hop count of 16 signifying an unreachable network.
7.1.1.3 / What type of address must be used when a packet is sent outside your private network? / Public ip address
What subnet mask is used when only two ip addresses are needed? / /30 or 255.255.255.252
7.1.1.4 / What is a loopback interface? / a software-only interface that is used to emulate a physical interface
What is a loopback address used for in the lab setting? / creating additional networks without having to add more physical interfaces on the router.
7.1.2.1 / What is the command to establish a supernet route? / R2(config)#ip route 192.168.0.0 255.255.0.0 Null0
What does a supernet route do to the routing table? / It makes it smaller
What are the two characteristics of a null interface? / It is always up but does not forward or receive traffic
What happens to traffic sent to a null interface? / It is discarded
What command will send a route to other routers in the network? / R2(config-router)#redistribute static
7.1.2.2 / What is the first command to check network connectivity? / show ip interface brief
What should the result of the above command show? / Up and up
What is the second command to use to check connectivity? / Ping
7.1.3.1 / What is not included in a RIPv1 message? / Subnet mask
7.1.3.3 / What happens is RIP has two routes to the same network? / There are inconsistent results for pings
Why doesn’t R2 include the route to 172.30.0.0/24 to either routers? / Split horizon rule
7.1.4 / What are the two methods RIPv1 uses to determine the subnet mask for an ip address? / summarizes the subnets to the classful boundary or uses the subnet mask of the outgoing interface to determine which subnets to advertise
7.1.5.1 / Why is the route 192.168.0.0 /16 not included in the routing updates from R2? / It’s subnet mask is less than the classful subnet mask
What subnet mask would allow this route to be included in the routing updates? / /24 or 255.255.255.0
7.2.1.1 / What type of packet is a RIPv2 encapsulated in? / UDP
What port number does it use? / 520
How many routes can be included? / 25
What are the two extensions added to RIPv2? / Subnet mask and NextHop address
7.2.1.2 / What does a router running RIPv1 do with a RIPv2 update? / Ignores the RIPv2 fields
What command is used to modify the version of RIP being used to version 2? / Router(config-router)#version 2
What command can be used to revert back to version 1? / Router(config-router)#version 1
Or Router(config-router)#no version
7.2.2.1 / What is the new route included in the routing table? / the 192.168.0.0/16 supernet
Why is the only route in the table 172.30.0.0/16 used? / Autosummarization is turned on
7.2.3.1 / What is the command to turn off autosummarization? / no auto-summary
What is different in the show ip protocols display? / "automatic network summarization is not in effect"
7.2.4.1 / What has been added to the routing tables? / Each subnet and mask has its own specific entry, along with the exit interface and next-hop address to reach that subnet.
What happens when a route is incremented? / 1 is added to the hop count before the route is sent to the next router
What type of address is being used for routing updates? / Multicast
What is the advantage of using the above type of address? / Uses less bandwidth
7.3.1 / How does RIPv2 determine the subnet mask for a route? / It is included in the routing update
7.3.2 / What is one of the goals of CIDR? / to provide a mechanism for the aggregation of routing information
What is a supernet? / a block of contiguous classful networks that is addressed as a single network
What is a characteristic of a supernet’s subnet mask? / It is smaller than the classful subnet mask
7.4.1 / Where should you start when troubleshooting? List them. / The basics:
1. Make sure all of the links (interfaces) are up and operational.
2. Check the cabling.
3. Check to make sure you have the correct IP address and subnet mask on each interface.
4. Remove any unnecessary configuration commands that are no longer necessary or have been replaced by other commands.
What will the show ip route command verify? / Network convergance
What will the show ip interface brief command verify? / The status of all interfaces
What will the show ip protocols command verify? / that RIP is enabled, the version of RIP, the status of automatic summarization, and the networks that were included in the network statements
What will the debug ip rip command verify? / Routing updates
What will the ping command verify? / end-to-end connectivity
What will the show running-config command verify? / All commands currently configured
7.4.2 / What is considered a good place to begin when troubleshooting RIPv2? / Verify that all routers are using RIPv2
What 2 things does the network command do? / It enables the routing protocol to send and receive updates on any local interfaces that belong to that network.
It includes that network in its routing updates to its neighboring routers.
What is the final command listed to check for? / autosummarization
7.4.3.1 / What is a security concern for routing updates? / accepting invalid routing updates
What are the three methods of receiving an invalid update listed? / Malicious attacker, misconfigured router, and a host running a routing protocol
What is listed as a good practice when configuring a routing protocol? / Authenticate routing information
* You need to be able to make a detail comparison between RIPv1 and RIPv2.
* Which are the similarity in RIP version 1 and 2?
* What are the limitation that will apply to both RIPv1 and RIPv2?
* Which RIP updates using 255.255.255.255?
* Which RIP version will not run VLSM? Why?
* Which RIP version will run VLSM? Why?
* What is address 224.0.0.9?
* RIP V1 sends which version of update and receives which version of update?
* RIP V2 sends which version of update and receives which version of update?
* What is the purpose of the command “default-information originated”?
* How do you configure a RIPv1 router to run RIPv2?
* How do you configure a RIPv2 router to run RIPv1?
- Both V1 and V2 will auto summarized the network.
- You can only turn-off auto summary of the network on V2, but not V1.
* What are the RFC 1918 addresses?
* Make sure you still remember the purpose of “network” command for “router rip”.
* You have learned that RIPv2 will include the subnet mask in the routing update. You have configured the network routers to run RIPv2. Now,
1) What is the reasonthe networks192.30.1.0/24 and 192.30.2.0/24 and all other 172.30.X.0 are not showing up in the routing table in R2?
2) What do you have to do so the router R2 will learn all the networks for 172.30.X.0 /24 networks?
3) Now you know the source and the solution to the problem, you will see the similar problem in the chapter exam, but expect they will show you the different network and different diagram.
* The objective of this chapter is setup all your routers to run RIPv2. One of many things that you are expected to know is how to read the “debug ip RIP” output between 2 routers and when one of them is using RIPv1 and the other is RIPv2. You need to be able to read the output and figure out which router is running RIPv1 and which router is running RIPv2 and them make them to all running the RIPv2.
* Another way of looking at the “debug ip rip” output is looking for the “send update to ______”. If the update is sending to 255.255.255.255, you know it is RIPv1. If the update is sending to 224.0.0.9, you know it is RIPv2.
* Example of “debug ip rip” for version 1. * Example of “debug ip rip” for version 2
* Now you know how to use to output from “debig ip rip” to figure out the version of the RIP. You also know RIPv1 does not support VLSM and RIPv2 supports the VLSM. When you see the figuration like the one below, you should know the reason why R3 only sends some of the route update to R4, but not sending all the route updates to R4.
* When the RIP network is not working and you are trying to use the “show ip protocol” command to figure out the problems. Here are the things that you will be looking for:
* Send RIP version? Make sure they are sending the correct version.
* Receive RIP version? Make sure they are receiving the correct version.
* Auto Network Summarization? Make sure you know whether network should be summarized or not
* Routing for networks? Make sure all the DIRRECTLY CONNECTEDnetworks are listed here.
* Passive interface? Make only the right interface is setup for passive interface.
If configurations are not setup correctly in the output (in the exam), fix them.
* One of the many topics that you learned in this chapter is “redistribute static” command. This command take the static route that you configured on the router and converted into the RIP route and also treat it as RIP route and pass it to other routers. Also, all routersmust be configured with RIP v2. See the example shown below:
* Make sure you still know your subnetting and how to read the “show ip route” output. For example:
209.165.200.0 /30 is subnetted, 2 subnets
209.165.200.232 [120/1] via ……….. Addresses used [232, 233, 234, 235]
209.165.200.228 is directly connected serial 0/0/0Addresses used [228, 229, 230, 231]
It means the address from 228 till 231 are used by your serial 00/0 and 232 till 235 are used by other router. You cannot use these range of addresses to create another interface. For example, the following are not allowed, because address is already used by other interfaces.
R1(config)# interface loopback 0
R1(config-if)# ip address 209.165.200.230 255.255.255.252
* Make sure you know the purpose of “loopback” interface.